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Scientific Writing, HRP 214 Weekly Quiz. Scientific Writing, HRP 214 Weekly Quiz. A. It was a secret among friends. B. It was a secret between friends. Scientific Writing, HRP 214 Weekly Quiz. A. It was a secret among friends. B. It was a secret between friends.

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scientific writing hrp 214 weekly quiz2
Scientific Writing, HRP 214Weekly Quiz

A. It was a secret among friends.

B. It was a secret between friends.

scientific writing hrp 214 weekly quiz3
Scientific Writing, HRP 214Weekly Quiz

A. It was a secret among friends.

B. It was a secret between friends.

scientific writing hrp 214 weekly quiz4
Scientific Writing, HRP 214Weekly Quiz

A. The close friendship that existed between them was quickly dissolved.

B. The close friendship that existed among them was quickly dissolved.

scientific writing hrp 214 weekly quiz5
Scientific Writing, HRP 214Weekly Quiz

A. The close friendship that existed between them was quickly dissolved.

B. The close friendship that existed among them was quickly dissolved.

scientific writing hrp 214 weekly quiz6
Scientific Writing, HRP 214Weekly Quiz

A. She eluded to the fight that occurred earlier.

B. She alluded to the the fight that occurred earlier.

scientific writing hrp 214 weekly quiz7
Scientific Writing, HRP 214Weekly Quiz

A. She eluded to the fight that occurred earlier.

B. She alluded to the the fight that occurred earlier.

scientific writing hrp 214 weekly quiz8
Scientific Writing, HRP 214Weekly Quiz

A. She eluded the fight.

B. She alluded the fight.

scientific writing hrp 214 weekly quiz9
Scientific Writing, HRP 214Weekly Quiz

A. She eluded the fight.

B. She alluded the fight.

scientific writing hrp 214 weekly quiz10
Scientific Writing, HRP 214Weekly Quiz

A. She lies out in the sun.

B. She lays out in the sun.

scientific writing hrp 214 weekly quiz11
Scientific Writing, HRP 214Weekly Quiz

A. She lies out in the sun.

B. She lays out in the sun.

scientific writing hrp 214 weekly quiz12
Scientific Writing, HRP 214Weekly Quiz

A. She is lying out in the sun.

B. She is laying out in the sun.

scientific writing hrp 214 weekly quiz13
Scientific Writing, HRP 214Weekly Quiz

A. She is lying out in the sun.

B. She is laying out in the sun.

scientific writing hrp 214 weekly quiz14
Scientific Writing, HRP 214Weekly Quiz

A. She laid out in the sun yesterday.

B. She lay out in the sun yesterday.

scientific writing hrp 214 weekly quiz15
Scientific Writing, HRP 214Weekly Quiz

A. She laid out in the sun yesterday.

B. She lay out in the sun yesterday.

scientific writing hrp 214 weekly quiz16
Scientific Writing, HRP 214Weekly Quiz

A. She had laid out in the sun too much as a kid.

B. She had lain out in the sun too much as a kid.

scientific writing hrp 214 weekly quiz17
Scientific Writing, HRP 214Weekly Quiz

A. She had laid out in the sun too much as a kid.

B. She had lain out in the sun too much as a kid.

scientific writing hrp 214 weekly quiz18
Scientific Writing, HRP 214Weekly Quiz

A. She lies the book on the table.

B. She lays the book on the table.

scientific writing hrp 214 weekly quiz19
Scientific Writing, HRP 214Weekly Quiz

A. She lies the book on the table.

B. She lays the book on the table.

scientific writing hrp 214 weekly quiz20
Scientific Writing, HRP 214Weekly Quiz

A. She is lying the book on the table.

B. She is laying the book on the table.

scientific writing hrp 214 weekly quiz21
Scientific Writing, HRP 214Weekly Quiz

A. She is lying the book on the table.

B. She is laying the book on the table.

scientific writing hrp 214 weekly quiz22
Scientific Writing, HRP 214Weekly Quiz

A. She laid the book on the table this morning.

B. She lay the book on the table this morning.

scientific writing hrp 214 weekly quiz23
Scientific Writing, HRP 214Weekly Quiz

A. She laid the book on the table this morning.

B. She lay the book on the table this morning.

scientific writing hrp 214 weekly quiz24
Scientific Writing, HRP 214Weekly Quiz

A. She had lain the book on the table.

B. She had laid the book on the table.

scientific writing hrp 214 weekly quiz25
Scientific Writing, HRP 214Weekly Quiz

A. She had lain the book on the table.

B. She had laid the book on the table.

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Scientific Writing, HRP 214Weekly Quiz

A. Now I lay down to sleep.

B. Now I lie down to sleep.

scientific writing hrp 214 weekly quiz27
Scientific Writing, HRP 214Weekly Quiz

A. Now I lay down to sleep.

B. Now I lie down to sleep.

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Scientific Writing, HRP 214Weekly Quiz

A. Now I lay me down to sleep.

B. Now I lie me down to sleep.

scientific writing hrp 214 weekly quiz29
Scientific Writing, HRP 214Weekly Quiz

A. Now I lay me down to sleep.

B. Now I lie me down to sleep.

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Scientific Writing, HRP 214Weekly Quiz

A. She commented on the clearly defined mutant traits.

B. She commented on the clearly-defined mutant traits.

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Scientific Writing, HRP 214Weekly Quiz

A. She commented on the clearly defined mutant traits.

B. She commented on the clearly-defined mutant traits.

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Scientific Writing, HRP 214Weekly Quiz

A. I am disinterested in your results.

B. I am uninterested in your results.

scientific writing hrp 214 weekly quiz33
Scientific Writing, HRP 214Weekly Quiz

A. I am disinterested in your results.

B. I am uninterested in your results.

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Scientific Writing, HRP 214Weekly Quiz

A. We think you should look into an alternative career path, i.e. get a new job.

B. We think you should look into an alternative career path, e.g. get a new job.

scientific writing hrp 214 weekly quiz35
Scientific Writing, HRP 214Weekly Quiz

A. We think you should look into an alternative career path, i.e. get a new job.

B. We think you should look into an alternative career path, e.g. get a new job.

scientific writing hrp 214 weekly quiz36
Scientific Writing, HRP 214Weekly Quiz

A. They prefer mixed drinks, e.g. gin and tonic or martinis.

B. They prefer mixed drinks, i.e. gin and tonic or martinis.

scientific writing hrp 214 weekly quiz37
Scientific Writing, HRP 214Weekly Quiz

A. They prefer mixed drinks, e.g. gin and tonic or martinis.

B. They prefer mixed drinks, i.e. gin and tonic or martinis.

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Scientific Writing, HRP 214Weekly Quiz
  • She served as a disinterested party in the dispute.
  • She served as an uninterested party in the dispute.
scientific writing hrp 214 weekly quiz39
Scientific Writing, HRP 214Weekly Quiz
  • She served as a disinterested party in the dispute.
  • She served as an uninterested party in the dispute.
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Scientific Writing, HRP 214Weekly Quiz

A. You should eat more sweets, e.g. chocolate.

B. You should eat more sweets, i.e. chocolate.

scientific writing hrp 214 weekly quiz41
Scientific Writing, HRP 214Weekly Quiz

A. You should eat more sweets, e.g. chocolate.

B. You should eat more sweets, i.e. chocolate.

scientific writing hrp 214 weekly quiz42
Scientific Writing, HRP 214Weekly Quiz

A. Runners who develop overuse running-related injuries have lower intakes of several key nutrients compared to non-injured runners.

B. Runners who develop overuse running-related injuries have lower intakes of several key nutrients compared with non-injured runners.

scientific writing hrp 214 weekly quiz43
Scientific Writing, HRP 214Weekly Quiz

A. Runners who develop overuse running-related injuries have lower intakes of several key nutrients compared to non-injured runners.

B. Runners who develop overuse running-related injuries have lower intakes of several key nutrients compared with non-injured runners.

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Scientific Writing, HRP 214Weekly Quiz

A. Over half the runners sustained an injury during the year.

B. More than half the runners sustained an injury during the year.

scientific writing hrp 214 weekly quiz45
Scientific Writing, HRP 214Weekly Quiz

A. Over half the runners sustained an injury during the year.

B. More than half the runners sustained an injury during the year.

scientific writing hrp 214
Scientific Writing, HRP 214

Lecture 7:

The Abstract, Introduction, and Discussion

scientific writing hrp 214 abstracts
Scientific Writing, HRP 214Abstracts

Abstracts (ab=out, trahere=pull; “to pull out”)

  • Overview of the main story
  • Gives highlights from each section of the paper
  • Limited length (100-300 words, typically)
  • Stands on its own
  • Used, with title, for electronic search engines
  • Most often, the only part people read
scientific writing hrp 214 abstracts48
Scientific Writing, HRP 214Abstracts

Gives:

  • Background
  • Question asked
    • “We asked whether,” “We hypothesized that,”…etc.
  • Experiment(s) done
    • Material studied (molecule, cell line, tissue, organ) or the animal or human population studied
    • The experimental approach or study design and the independent and dependent variables
  • Results found
    • Key results found
    • Minimal raw data (prefer summaries)
  • The answer to the question asked
  • Implication, speculation, or recommendation
scientific writing hrp 214 abstracts49
Scientific Writing, HRP 214Abstracts

Abstracts may be structured (with subheadings) or free-form.

scientific writing hrp 214 abstracts50
Scientific Writing, HRP 214Abstracts

Structured example: (The Lancet, 2006 Feb 11;367(9509):475-81.)

Development of adenoviral-vector-based pandemic influenza vaccine against antigenically distinct human H5N1 strains in mice.

Hoelscher MA, Garg S, Bangari DS, Belser JA, Lu X, Stephenson I, Bright RA, Katz JM, Mittal SK, Sambhara S.

scientific writing hrp 214 abstracts51

Question

asked

Background

Experiments done

Scientific Writing, HRP 214Abstracts

INTRODUCTION: Avian H5N1 influenza viruses currently circulating in southeast Asia could potentially cause the next pandemic. However, currently licensed human vaccines are subtype-specific and do not protect against these H5N1 viruses. We aimed to develop an influenza vaccine and assessed its immunogenicity and efficacy to confer protection in BALB/c mice.

METHODS: We developed an egg-independent strategy to combat the avian influenza virus, because the virus is highly lethal to chickens and the maintenance of a constant supply of embryonated eggs would be difficult in a pandemic. We used a replication-incompetent, human adenoviral-vector-based, haemagglutinin subtype 5 influenza vaccine (HAd-H5HA), which induces both humoral and cell-mediated immune responses against avian H5N1 influenza viruses isolated from people.

scientific writing hrp 214 abstracts52

Results found

Answer to the question asked

Wider implication

Scientific Writing, HRP 214Abstracts

FINDINGS: Immunisation of mice with HAd-H5HA provided effective protection from H5N1 disease, death, and primary viral replication (p<0.0001) against antigenically distinct strains of H5N1 influenza viruses. Unlike the recombinant H5HA vaccine, which is based on a traditional subunit vaccine approach, HAd-H5HA vaccine induced a three-fold to eight-fold increase in HA-518-epitope-specific interferon-gamma-secreting CD8 T cells (p=0.01).

INTERPRETATION: Our findings highlight the potential of an Ad-vector-based delivery system, which is both egg-independent and adjuvant-independent and offers stockpiling options for the development of a pandemic influenza vaccine.

scientific writing hrp 214 abstracts53
Scientific Writing, HRP 214Abstracts

Structured example 2:

N Engl J Med. 2006 Feb 16;354(7):684-96.

Calcium plus vitamin D supplementation and the risk of colorectal cancer.

Wactawski-Wende J, Kotchen JM, Anderson GL, Assaf AR, Brunner RL, O'Sullivan MJ, Margolis KL, Ockene JK, Phillips L, Pottern L, Prentice RL, Robbins J, Rohan TE, Sarto GE, Sharma S, Stefanick ML, Van Horn L, Wallace RB, Whitlock E, Bassford T, Beresford SA, Black HR, Bonds DE, Brzyski RG, Caan B, Chlebowski RT, Cochrane B, Garland C, Gass M, Hays J, Heiss G, Hendrix SL, Howard BV, Hsia J, Hubbell FA, Jackson RD, Johnson KC, Judd H, Kooperberg CL, Kuller LH, LaCroix AZ, Lane DS, Langer RD, Lasser NL, Lewis CE, Limacher MC, Manson JE; Women's Health Initiative Investigators.

scientific writing hrp 214 abstracts54

Literature gap.

Background

Study Design

Scientific Writing, HRP 214Abstracts

ABSTRACT

BACKGROUND: Higher intake of calcium and vitamin D has been associated with a reduced risk of colorectal cancer in epidemiologic studies and polyp recurrence in polyp-prevention trials. However, randomized-trial evidence that calcium with vitamin D supplementation is beneficial in the primary prevention of colorectal cancer is lacking.

METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 36,282 postmenopausal women from 40 Women's Health Initiative centers: 18,176 women received 500 mg of elemental calcium as calcium carbonate with 200 IU of vitamin D3 twice daily (1000 mg of elemental calcium and 400 IU of vitamin D3) and 18,106 received a matching placebo for an average of 7.0 years. The incidence of pathologically confirmed colorectal cancer was the designated secondary outcome. Baseline levels of serum 25-hydroxyvitamin D were assessed in a nested case-control study.

scientific writing hrp 214 abstracts55

Results found

Answer to the question asked

The caveats.

Scientific Writing, HRP 214Abstracts

RESULTS: The incidence of invasive colorectal cancer did not differ significantly between women assigned to calcium plus vitamin D supplementation and those assigned to placebo (168 and 154 cases; hazard ratio, 1.08; 95 percent confidence interval, 0.86 to 1.34; P=0.51), and the tumor characteristics were similar in the two groups. The frequency of colorectal-cancer screening and abdominal symptoms was similar in the two groups. There were no significant treatment interactions with baseline characteristics.

CONCLUSIONS: Daily supplementation of calcium with vitamin D for seven years had no effect on the incidence of colorectal cancer among postmenopausal women. The long latency associated with the development of colorectal cancer, along with the seven-year duration of the trial, may have contributed to this null finding. Ongoing follow-up will assess the longer-term effect of this intervention.

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Scientific Writing, HRP 214Abstracts

Even more subheadings…

Effect of Rimonabant, a Cannabinoid-1 Receptor Blocker, on Weight and Cardiometabolic Risk Factors in Overweight or Obese Patients RIO-North America: A Randomized Controlled Trial

F. Xavier Pi-Sunyer, MD; Louis J. Aronne, MD; Hassan M. Heshmati, MD; Jeanne Devin, MS; Julio Rosenstock, MD; for the RIO-North America Study Group

JAMA.2006;295:761-775.

scientific writing hrp 214 abstracts57
Scientific Writing, HRP 214Abstracts

Context: Rimonabant, a selective cannabinoid-1 receptorblocker, may reduce body weight and improve cardiometabolicrisk factors in patients who are overweight or obese.

Objective: To compare the efficacy and safety of rimonabantwith placebo each in conjunction with diet and exercise forsustained changes in weight and cardiometabolic risk factorsover 2 years.

Design, Setting, and Participants: Randomized, double-blind,placebo-controlled trial of 3045 obese (body mass index 30)or overweight (body mass index >27 and treated or untreatedhypertension or dyslipidemia) adult patients at 64 US and 8Canadian clinical research centers from August 2001 to April2004.

Intervention: After a 4-week single-blind placebo plusdiet (600 kcal/d deficit) run-in period, patients were randomizedto receive placebo, 5 mg/d of rimonabant, or 20 mg/d of rimonabantfor 1 year. Rimonabant-treated patients were rerandomized toreceive placebo or continued to receive the same rimonabantdose while the placebo group continued to receive placebo duringyear 2.

scientific writing hrp 214 abstracts58
Scientific Writing, HRP 214Abstracts

Results: At year 1, the completion rate was 309 (51%) patientsin the placebo group, 620 (51%) patients in the 5 mg of rimonabantgroup, and 673 (55%) patients in the 20 mg of rimonabant group.Compared with the placebo group, the 20 mg of rimonabant groupproduced greater mean (SEM) reductions in weight (–6.3[0.2] kg vs –1.6 [0.2] kg; P<.001), waist circumference(–6.1 [0.2] cm vs –2.5 [0.3] cm; P<.001), andlevel of triglycerides (percentage change, –5.3 [1.2]vs 7.9 [2.0]; P<.001) and a greater increase in level ofhigh-density lipoprotein cholesterol (percentage change, 12.6[0.5] vs 5.4 [0.7]; P<.001). Patients who were switched fromthe 20 mg of rimonabant group to the placebo group during year2 experienced weight regain while those who continued to receive20 mg of rimonabant maintained their weight loss and favorablechanges in cardiometabolic risk factors. Use of different imputationmethods to account for the high rate of dropouts in all 3 groupsyielded similar results. Rimonabant was generally well tolerated;the most common drug-related adverse event was nausea (11.2%for the 20 mg of rimonabant group vs 5.8% for the placebo group).

scientific writing hrp 214 abstracts59
Scientific Writing, HRP 214Abstracts

Conclusions: In this multicenter trial, treatment with20 mg/d of rimonabant plus diet for 2 years promoted modestbut sustained reductions in weight and waist circumference andfavorable changes in cardiometabolic risk factors. However,the trial was limited by a high drop-out rate and longer-termeffects of the drug require further study.

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Scientific Writing, HRP 214Abstracts

Science. 2006 Feb 17;311(5763):1020-2. Causal reasoning in rats. Blaisdell AP, Sawa K, Leising KJ, Waldmann MR.

Empirical research with nonhuman primates appears to support the view that causal reasoning is a key cognitive faculty that divides humans from animals. The claim is that animals approximate causal learning using associative processes. The present results cast doubt on that conclusion. Rats made causal inferences in a basic task that taps into core features of causal reasoning without requiring complex physical knowledge. They derived predictions of the outcomes of interventions after passive observational learning of different kinds of causal models. These competencies cannot be explained by current associative theories but are consistent with causal Bayes net theories.

scientific writing hrp 214 introduction and background62
Scientific Writing, HRP 214Introduction and Background

The Literature Search

  • Utilize online databases, such as MEDLINE, PubMed, and Ovid.
  • Have a search strategy.
  • Have an organizational system!
scientific writing hrp 214 introduction and background63
Scientific Writing, HRP 214Introduction and Background

The Literature Review

  • Summarize the current state of knowledge in the area of investigation.
  • You may have to return to the literature once your results are in hand.
  • Assume your reader is knowledgeable about the field.
  • Do not provide an exhaustive historical review.
  • Avoid nonessential details.
  • Summarize previous results and conclusions, but do not give the methods that generated these findings unless they are relevant to your research question (i.e., your experiment addresses a specific methodologic limitation of previous experiments)
  • Refer the reader to general surveys or reviews of the topic if available.
  • Cite references that reflect the key work that led to your research question.
  • Limit the number of references.
scientific writing hrp 21464
Scientific Writing, HRP 214

In writing the literature review, summarize rather than listing every possible reference and example.

scientific writing hrp 214 introduction and background65

Critical literature review

Scientific Writing, HRP 214Introduction and Background

Introduction and Background

1. What’s known

2. What’s unknown

  • limitations and gaps in previous studies

3. Your burning question

4. Your experimental approach

5. Why your experimental approach is new and different and important

  • From: Essentials of Writing Biomedical Research Papers by Mimi Zeiger
scientific writing hrp 214 introduction
Scientific Writing, HRP 214Introduction

Tell a story:

  • Write it in plain English, not tech-speak.
  • Take the reader step by step from what is known to what is unknown. End with your specific question.

(KnownUnknownQuestion)

  • Emphasize what is new and important about your work.
  • Do not state the answer to the research question.
  • Do not include results or implications.
introduction
Introduction
  • Overweight, Obesity, and Mortality from Cancer in a Prospectively Studied Cohort of U.S. AdultsEugenia E. Calle, Ph.D., Carmen Rodriguez, M.D., M.P.H., Kimberly Walker-Thurmond, B.A., and Michael J. Thun, M.D.
slide68

What’s known

What’s unknown

What’s known

What’s unknown

“This study will

answer the

question with

better methods.”

Gaps/limitations of

previous studies

The relations between excess body weight and mortality, notonly from all causes but also from cardiovascular disease, arewell established.1,2,3,4,5,6 Although we have known for sometime that excess weight is also an important factor in deathfrom cancer,7 our knowledge of the magnitude of the relation,both for all cancers and for cancers at individual sites, andthe public health effect of excess weight in terms of totalmortality from cancer is limited.Previous studies have consistently shown associations betweenadiposity and increased risk of cancers of the endometrium,kidney, gallbladder (in women), breast (in postmenopausal women),and colon (particularly in men).8,9,10,11,12 Adenocarcinomaof the esophagus has been linked to obesity.11,13,14 Data oncancers of the pancreas, prostate, liver, cervix, and ovaryand on hematopoietic cancers are scarce or inconsistent.7,8,9,10,11,15,16,17The lack of consistency may be attributable to the limited numberof studies (especially those with prospective cohorts), thelimited range and variable categorization of overweight andobesity among studies, bias introduced by reverse causalitywith respect to smoking-related cancers, and possibly real differencesbetween the effects of overweight and obesity on the incidenceof cancer and on the rates of death from some cancers.18,19

We conducted a prospective investigation in a large cohort ofU.S. men and women to determine the relations between body-massindex (the weight in kilograms divided by the square of theheight in meters) and the risk of death from cancer at specificsites. This cohort has been used previously to examine the associationof body-mass index and death from any cause.5

scientific writing hrp 21469

Gaps in

previous

research

The lit.

review

What’s unknown/the research question

What’s known

This study

Scientific Writing, HRP 214

Introduction

Exogenous estrogens prevent or substantially retard the decrease in bone mineral density (BMD) that accompanies menopause [1]. However, it is unclear whether exogenous estrogens, administered as oral contraceptives (OCs), can modify premenopausal BMD. Several studies suggest that exposure to OCs during the premenopausal years has a favorable effect on BMD [2-10], whereas other studies show no effect [11-18].

Past studies of the relationship between OC use and BMD have several limitations. Studies have focused primarily on crude measures of OC use, such as current, past and never. These categories combine diverse types of OC use and may reduce the power to detect an effect. Many studies also failed to take into account lifestyle characteristics of study participants. Finally, few studies have considered an effect of OCs on BMD in women of races other than white.

The aim of this study was to evaluate the associations of OCs with spine, hip and whole body BMD in black and white premenopausal women. Our primary hypothesis was that there would be an association between cumulative exposure to estrogen from OCs and BMD.

scientific writing hrp 21470
Scientific Writing, HRP 214

Neurohumoral Features of Myocardial Stunning Due to Sudden Emotional StressIlan S. Wittstein, M.D., David R. Thiemann, M.D., Joao A.C. Lima, M.D., Kenneth L. Baughman, M.D., Steven P. Schulman, M.D., Gary Gerstenblith, M.D., Katherine C. Wu, M.D., Jeffrey J. Rade, M.D., Trinity J. Bivalacqua, M.D., Ph.D., and Hunter C. Champion, M.D., Ph.D. T

New Engl J Med Volume 352:539-548; Feb 10, 2005.

scientific writing hrp 21471

Background/relevance

The lit.

review

This study

What’s unknown

Scientific Writing, HRP 214

The potentially lethal consequences of emotional stress aredeeply rooted in folk wisdom, as reflected by phrases such as"scared to death" and "a broken heart." In the past decade,cardiac contractile abnormalities and heart failure have beenreported after acute emotional stress,1,2,3,4,5,6 but the mechanismremains unknown. We evaluated 19 patients with "stress cardiomyopathy,"a syndrome of profound myocardial stunning precipitated by acuteemotional stress, in an effort to identify the clinical featuresthat distinguish this syndrome from acute myocardial infarctionand the cause of transient stress-induced myocardial dysfunction.

introduction systematic review
Introduction: systematic review

Effectiveness of speed cameras in preventing road traffic collisions and related casualties: systematic review

Paul Pilkington, lecturer in public health1, Sanjay Kinra, lecturer in epidemiology and public health medicine21 University of the West of England, Faculty of Health and Social Care, Bristol BS16 1DD, 2 Department of Social Medicine, University of Bristol, Bristol .

BMJ Feb. 10, 2005

slide73

Statement of problem. What’s known.

What’s unknown/controversial.

Limitations of previous research.

What we did to answer this question better.

Road traffic collisions are an important cause of death anddisability worldwide. Every year around the world 1.2 millionpeople are killed and up to 50 million are injured or disabledas a result of road traffic collisions.1 Morbidity from roadtraffic collisions is expected to increase in future years,and it is estimated that road traffic collisions will move fromninth to third place in the global burden of disease ranking,as measured in disability adjusted life years.23

Measures to reduce traffic speed are considered essential toreducing casualties on the road.145 Speed cameras are increasinglyused to help to reduce traffic speeds in the belief that thiswill reduce road traffic collisions and casualties, and an expansionin the use of speed cameras is under way in many countries,most notably the United Kingdom.6 The use of speed cameras iscontroversial, however. Vociferous opponents, including somemotoring associated organisations, oppose their use, and camerasare often criticised in the media.7-9 The lack of readily availableevidence of the effectiveness of cameras has made it difficultfor road safety and health professionals to engage in an informeddebate about the effectiveness of speed cameras.

A previous small non-systematic review of six studies founda 17% reduction in collisions after introduction of speed cameras.10Non-systematic reviews can, however, be limited by bias. Weaimed, therefore, to systematically assess the evidence forthe effectiveness of speed cameras in reducing road trafficcollisions and related casualties.

introduction cohort study
Introduction: cohort study

Adherence to Mediterranean diet and risk of developing diabetes: prospective cohort study

M Á Martínez-González, professor of epidemiology and chair,1 C de la Fuente-Arrillaga, research assistant,1 J M Nunez-Cordoba, research fellow,1,2 F J Basterra-Gortari, research fellow,1,3 J J Beunza, assistant professor,1 Z Vazquez, research assistant,1 S Benito, research assistant,1 A Tortosa, research fellow,1 and M Bes-Rastrollo, assistant professor1

BMJ June 14, 2008

slide75
Diabetes mellitus is an increasingly important global public health problem that threatens to reach pandemic levels by 2030.12 As some randomised trials have consistently shown, increased physical activity and weight loss are efficient approaches for the control and prevention of type 2 diabetes.34 Diet has also long been believed to be an important risk factor for diabetes. Many studies have shown that the Mediterranean food pattern has a role in prevention of cardiovascular disease.56789 The similarity of some risk factors and some empirical and mechanistic evidence suggest that the Mediterranean diet can also protect against diabetes. The major protective characteristics include a high intake of fibre, a high intake of vegetable fat, a low intake of trans fatty acids, and a moderate intake of alcohol.41011 Moreover, a particular feature of the diet is the abundant use of virgin olive oil for cooking, frying, spreading on bread, or dressing salads.12 This leads to a high ratio of monounsaturated fatty acids to saturated fatty acids. This ratio can be used to score adherence to a Mediterranean diet8 as the traditional diet. Despite having a relatively high total fat content, this food pattern is rich in monounsaturated fatty acids (from olive oil) and poor in saturated fatty acids. Diets rich in monounsaturated fatty acids improve lipid profiles and glycaemic control in people with diabetes, suggesting that a high intake improves insulin sensitivity.13141516 Together these associations suggest the hypothesis that following an overall pattern of Mediterranean diet can protect against diabetes. In addition to having a long tradition of use without evidence of harm, a Mediterranean diet is highly palatable, and people are likely to comply with it.17

Background on the Mediterranean diet.

What is known about Mediterranean diet and diabetes.

slide76

What’s unknown/gaps in literature.

What we did to answer this question better.

  • Few prospective studies have evaluated the specific role of the Mediterranean diet on the risk of developing diabetes in initially healthy Mediterranean populations. A prospective follow-up study recently reported an inverse association between adherence to the diet and the incidence of diabetes.18 All members of that study, however, had survived a previous myocardial infarction and the tool to assess dietary habits had inherent limitations because it included only a short list of items, and the authors did not attempt to measure the entire diet.
  • We evaluated the association between adherence to a Mediterranean diet and the incidence of diabetes using a full validated food frequency questionnaire to measure the entire diet.
scientific writing hrp 214 introduction and background77

Critical literature review

Scientific Writing, HRP 214Introduction and Background

Introduction and Background

1. What’s known

2. What’s unknown

  • limitations and gaps in previous studies

3. Your burning question

4. Your experimental approach

5. Why your experimental approach is new and different and important

  • From: Essentials of Writing Biomedical Research Papers by Mimi Zeiger
scientific writing hrp 214 introduction78
Scientific Writing, HRP 214Introduction

Tell a story:

  • Write it in plain English, not tech-speak.
  • Take the reader step by step from what is known to what is unknown. End with your specific question.

(KnownUnknownQuestion)

  • Emphasize what is new and important about your work.
  • Do not state the answer to the research question.
  • Do not include results or implications.
scientific writing hrp 214 the discussion
Scientific Writing, HRP 214THE DISCUSSION

The Discussion is the section that…

  • Gives you the most freedom
  • Gives you the most chance to put good writing on display
  • Is the most challenging to write
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Scientific Writing, HRP 214The Discussion

Follow your rules for good writing!

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Scientific Writing, HRP 214The Discussion

The purpose of the discussion:

  • Answer the question posed in the Introduction
  • Support your conclusion with details (yours, others)
  • Defend your conclusion (acknowledge limits)
  • Highlight the broader implications of the work

i.e., What do my results mean and why should anyone care?

framework of the discussion

QUESTION TO ADDRESS

CONTENT

What’s the central finding?

Restate the finding.

Place in the context of other work.

Clearly state what’s new.

Could it be wrong?

Identify and deal with threats to validity. Consider alternative explanations for your findings given the study design (for clinical or epidemiologic studies):

BEFORE/AFTER

OBSERVATIONAL

RANDOMIZED TRIAL

Temporal trend

Regression to the mean

Selection bias

Loss to follow-up

Low response rate

Recall bias

Unmeasured confounding

Inadequate blinding

Ascertainment bias

Loss to follow-up

What does it mean?

Put your work in perspective. Assess its generalizability, and speculate about its implications.

Suggest mechanisms. 

Specify what you think should happen next.

Framework of the Discussion

Table 2, Adapted From: Welch HG. Preparing Manuscripts for Submission to Medical Journals: The Paper Trail. Effective Clinical Practice. 1999; 2: 131-137.

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Scientific Writing, HRP 214The Discussion

The introduction moves from general to specific.

The discussion moves from specific to general.

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Scientific Writing, HRP 214The Discussion

Elements of the typical discussion section…

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Key finding (answer to the question(s) asked in Intro.)
    • Supporting explanation, details (lines of evidence)
    • Possible mechanisms or pathways
    • Is this finding novel?
  • Key secondary findings
  • Context
    • Compare your results with other people’s results
    • Compare your results with existing paradigms
    • Explain unexpected or surprising findings
  • Strengths and limitations
  • What’s next
    • Recommended confirmatory studies (“needs to be confirmed”)
    • Unanswered questions
    • Future directions
  • The “so what?”: implicate, speculate, recommend
    • Clinical implications of basic science findings
  • Strong conclusion (kicker!)
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EXAMPLE:Samaha FF, Iqbal N, Seshadri P, et al. A low-carbohydrate as compared with a low-fat diet in severe obesity. N Engl J Med 2003;348:2074-2081.

INTRODUCTION

The differences in health benefits between a carbohydrate-restricteddiet and a calorie- and fat-restricted diet are of considerablepublic interest. However, there is concern that a carbohydrate-restricteddiet will adversely affect serum lipid concentrations.1 Previousstudies demonstrating that healthy volunteers following a low-carbohydratediet can lose weight have involved few subjects, and few useda comparison group that followed consensus guidelines for weightloss.2,3 The reported effects of a carbohydrate-restricted dieton risk factors for atherosclerosis have varied.2,3,4We performeda study designed to test the hypothesis that severely obesesubjects with a high prevalence of diabetes or the metabolicsyndrome [a]would have a greater weight loss, [b]without detrimentaleffects on risk factors for atherosclerosis, while on a carbohydrate-restricted(low-carbohydrate) diet than on a calorie- and fat-restricted(low-fat) diet.

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Scientific Writing, HRP 214The Discussion

1. We found that severely obese subjects with a high prevalenceof diabetes and the metabolic syndrome lost more weight in asix-month period on a carbohydrate-restricted diet than on afat- and calorie-restricted diet. [answer to a] The greater weight loss inthe low-carbohydrate group suggests a greater reduction in overallcaloric intake, rather than a direct effect of macronutrientcomposition. [mechanisms] However, the explanation for this difference isnot clear. Subjects in this group may have experienced greatersatiety on a diet with liberal proportions of protein and fat.However, other potential explanations include the simplicityof the diet and improved compliance related to the novelty ofthe diet.[possible mechanisms/unanswered questions]

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Scientific Writing, HRP 214The Discussion

2. Subjects in the low-carbohydrate group had greater decreasesin triglyceride levels than did subjects in the low-fat group;nondiabetic subjects on the low-carbohydrate diet had greaterincreases in insulin sensitivity, and subjects with diabeteson this diet had a greater improvement in glycemic control.No adverse effects on other serum lipid levels were observed.[answer to b]Most studies suggest that lowering triglyceride levels has anoverall cardiovascular benefit.14,15,16 Insulin resistance promotessuch atherosclerotic processes as inflammation,17 decreasedsize of low-density lipoprotein particles,18 and endothelialdysfunction.19 Impaired glycemic control in subjects with otherfeatures of the metabolic syndrome markedly increases the riskof coronary artery disease.20 As expected, we found that theamount of weight lost had a significant effect on the degreeof improvement in these metabolic factors. [comparison to previous studies and paradigms]However, even afteradjustment for the differences in weight loss between the groups,assignment to the low-carbohydrate diet predicted greater improvementsin triglyceride levels and insulin sensitivity. [unexpected]Subjects wholost more than 5 percent of their base-line weight on a carbohydrate-restricteddiet had greater decreases in triglyceride levels than thosewho lost a similar amount of weight while following a calorie-and fat-restricted diet.[supporting details]

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Scientific Writing, HRP 214The Discussion

3. There was a consistent trend across weight-loss strata towarda greater increase in insulin sensitivity in the low-carbohydrategroup, although these changes were small and were not significantwithin each stratum. [supporting details: dose/response] Although greater weight loss could notentirely account for the greater decrease in triglyceride levelsand increase in insulin sensitivity in the low-carbohydrategroup, we cannot definitively conclude that carbohydrate restrictionalone accounted for this independent effect. [mechanisms] Other uncontrolledvariables, such as the types of carbohydrates selected (e.g.,the proportion of complex carbohydrates or the ratio of carbohydrateto fiber), or other unknown variables may have contributed tothis effect. In addition, more precise measurements of insulinsensitivity than we used would be needed to confirm this effectof a carbohydrate-restricted diet.[limitations/future studies]

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Scientific Writing, HRP 214The Discussion

4. Many of our subjects were taking lipid-lowering medicationsand hypoglycemic agents. Although enrolling these subjects introducedconfounding variables, it allowed the inclusion of subjectswith the obesity-related medical disorders typically encounteredin clinical practice. Analyses from which these subjects wereexcluded still revealed greater improvements in insulin sensitivityand triglyceride levels on a carbohydrate-restricted diet thanon a fat- and calorie-restricted diet. [limitations and how they were addressed]

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Scientific Writing, HRP 214The Discussion

5. Our study included a high proportion of black subjects, a grouppreviously underrepresented in lifestyle-modification studies.[strength] As compared with the white subjects, the black subjects hada smaller overall weight loss. Future studies should explorewhether greater weight loss in this population can be achievedby more effective incorporation of culturally sensitive dietarycounseling. [future directions]

6. The high dropout rate in our study occurred very early and affectedour findings. The very early dropout of these subjects may indicatethat attrition most closely reflected base-line motivation tolose weight, rather than a response to the dietary interventionitself. [limitation]

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Scientific Writing, HRP 214The Discussion

7. Taken together, our findings demonstrate that severely obesesubjects with a high prevalence of diabetes and the metabolicsyndrome lost more weight during six months on a carbohydrate-restricteddiet than on a calorie- and fat-restricted diet. The carbohydrate-restricteddiet led to greater improvements in insulin sensitivity thatwere independent of weight loss and a greater reduction in triglyceridelevels in subjects who lost more than 5 percent of their base-lineweight. [conclusion; restate answers to a and b] These findings must be interpreted with caution, however,since the magnitude of the overall weight loss relative to oursubjects' severe obesity was small, and it is unclear whetherthese benefits of a carbohydrate-restricted diet extend beyondsix months. Furthermore, the high dropout rate and the smalloverall weight loss demonstrate that dietary adherence was relativelylow in both diet groups. [big picture]This study proves a principle and doesnot provide clinical guidance; given the known benefits of fatrestriction, future studies evaluating long-term cardiovascularoutcomes are needed before a carbohydrate-restricted diet canbe endorsed. [take-home message]

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Scientific Writing, HRP 214The Discussion

Things to avoid in the discussion:

  • Do not simply repeat what is in the Results
  • Do not try to explain every minor flaw
  • Do not attempt to explain away every unexpected result
  • Do not exaggerate or make extravagant claims
  • Don’t hedge
what not to do
What NOT to do!

Don’t start your discussion like this!!

Discussion

  • This meta-analysis is subject to a number of limitations. Theestimates of risk for melanoma subsequent to using sunlamps/sunbedsare based on published data in a series of 10 articles overa period of 20 years. A pooled analysis of original observationstaken in the 10 studies would have provided a more powerfulapproach …
scientific writing hrp 214 the discussion verb tense
Scientific Writing, HRP 214The Discussion: verb tense

Verb Tenses (active!):

Past, when referring to study details, results, analyses, and background research:

  • We found that
  • They lost more weight than
  • Subjects may have experienced
  • Miller et al. found

Present, when talking about what the data suggest …

The greater weight loss suggests

The explanation for this difference isnot clear.

Potential explanations include

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EXAMPLE 2:Low-Fat Dietary Pattern and Risk of Colorectal Cancer The Women's Health Initiative Randomized Controlled Dietary Modification Trial. JAMA. 2006;295:643-654.

INTRODUCTION

The Women's Health Initiative (WHI) Dietary Modification Trial is a randomized controlled trial designed in 1991-1992 to test whether a low-fat eating pattern with increased fruits, vegetables, and grains reduces the risk of breast cancer, colorectal cancer, or, secondarily, coronary heart disease in postmenopausal women. At that time, international comparisons suggested that countries with 50% lower fat intake than the US population had approximately one third the risk of colorectal cancer.1-2 Migration studies supported this hypothesis. Women migrating from countries with low fat consumption to countries with high fat consumption experienced the higher colorectal cancer rates of their new country.3-4 Fairly consistent evidence existed for an effect of dietary fat, vegetables and fruits, and grains on colorectal cancer risk from within-country observational studies,2, 5-8 although the protective effect of lower fat intake was no longer clear after adjusting for energy intake.2, 9The WHI Dietary Modification Trial is the first randomized trial to directly address the health effects of a low-fat eating pattern in predominantly healthy postmenopausal women from diverse racial/ethnic, geographic, and socioeconomic backgrounds. This article reports the principal results for colorectal cancer. [the question]

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Scientific Writing, HRP 214The Discussion

1. An intervention aimed toward a low-fat eating pattern did notreduce colorectal cancer risk in postmenopausal women. [answer to the question asked] Despitea significant change in fat intake and increases in vegetable,fruit, and grain consumption, the intervention hazard ratiois in the direction of an increased risk. [supporting evidence from this trial] There were no substantialdifferences in tumor characteristics or in rates of bowel screeningbetween groups. [supporting evidence] Although self-reported incidence of colorectalpolyps or adenomas was lower in the intervention group, no evidenceof a trend toward lower colorectal cancer risk with time inthe intervention group was observed over the mean 8.1-year studyperiod.

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Scientific Writing, HRP 214The Discussion

2. These findings are consistent with the findings from the PolypPrevention Trial,31 a secondary prevention trial of polyp recurrence,which had a similar goal for fat, fruit, and vegetable intakebut also included a goal of 18 g/1000 kcal of dietary fiber.32The Polyp Prevention Trial observed no effect on polyp recurrencein the 2079 participants followed up for 4 years.32A smalltrial in Toronto, Ontario, of high fiber and low fat showedno effect on recurrence of neoplastic polyps, but, within anintensive counseling subgroup, concentrations of fecal bileacids appeared to be reduced.33 A small factorial trial in Australiaof a low-fat intervention, -carotene supplementation, or wheatbran supplementation found no reduction in recurrence ratesof adenomas but suggested that the combination of low fat andwheat bran reduced the transition from smaller to larger adenomas.34[supporting evidence: other TRIALS]

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Scientific Writing, HRP 214The Discussion

3. Since the WHI Dietary Modification Trial was designed, the hypothesizedrelationship between dietary fat and risk of colorectal cancerhas been questioned.35 More recently, higher red meat consumptionhas been associated with increased colorectal cancer risk,23, 36-39 particularly in the distal colon.23 The putative mechanismmay be related to heme, the iron carrier of red meat, ratherthan to its fat content.23 In the WHI, the dietary interventionreduced red meat consumption (Table 2), with no apparent overallbenefit on colorectal cancer risk but, perhaps, some shift inrisk in distal vs proximal colon cancers.

[consistency with the latest paradigm]

[mechanisms: is red meat more important than fat?]

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Scientific Writing, HRP 214The Discussion

4. Mixed support exists for an influence of vegetables and fruitson colorectal cancer risk.37, 40-42 Some of the antioxidantsthey contain have not proved efficacious in reducing colorectaladenomas or preventing incident colorectal cancer in randomizedtrials.43-45 Regular consumption of alcohol has been associatedwith elevated risk of colorectal cancer in some prospectivestudies, particularly among persons with low folate status.46This pattern was not found in the comparison group of this study.Observations in East Africa by Burkitt47 led to the hypothesisthat very high fiber reduces colorectal cancer risk. This hasmixed support from observational studies48-50 and polyp andadenoma recurrence trials.31, 33-34,51-52 A European trial foundan adverse effect of soluble fiber on colorectal adenoma recurrence,51while an Arizona trial found no effect of wheat bran supplementon colorectal adenoma recurrence.52 Our study is consistentwith lack of association in that women in the intervention groupmodestly increased their fiber (Table 2) with no apparent benefitover 8.1 years of follow-up.

[existing paradigms: does fiber matter?]

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Scientific Writing, HRP 214The Discussion

5. The observed interactions between the intervention and baselineaspirin use, and between intervention and use of combined hormonetherapy, are consistent with synergistic effects of a low-fatdietary pattern and these potentially protective agents. However,given the large number of interactions tested, these findingscould also have occurred by chance.

[Could the null finding be wrong? Maybe low-fat diet matters for some groups]

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Scientific Writing, HRP 214The Discussion

6. FromNational Health and Nutrition Examination Survey (NHANES) data,in 1977, women reported consuming 40.5% of their energy fromfat, while in 1987, the average was only 35.9%,54 and in 2000,the average was 33% (NHANES 1999-2000). Organizations includingthe National Cancer Institute, American Cancer Society, andInstitute for Cancer Prevention have recommended both lowerfat intake and increased vegetable and fruit use.55-56

7. One explanation for a lack of intervention effect on colorectalcancer could be that the intervention did not achieve a largeenough difference between the intervention and comparison groups.Although the changes achieved were substantial, and likely aslarge as could be achieved in a trial of free-living individuals,they fell short of the original design assumptions based onthe Women's Health Trial studies.27 Using food frequency data,the WHI intervention on average achieved only about 70% of thedesigned reduction in fat. If design assumptions are revisedto take into account this departure from goal, the predictedHR would have been 0.86, an effect size excluded by these results.The power to detect this effect size under the observed comparisongroup incidence rate and the achieved adherence is approximately40%.[Could the null finding be wrong? Alternative explanations to no association]

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Scientific Writing, HRP 214The Discussion

8. Whether greater adherence, intervention of longer duration,or initiation of change at an earlier age would influence colorectalcancer risk remain unanswered questions. The self-reported firstoccurrence of polyps or adenomas was lower in dietary interventionwomen, suggesting that longer follow-up (currently planned)may reveal delayed benefit in favor of the intervention. Yetno time trends regarding colorectal cancer risk over 8 yearsof follow-up have been seen. To the extent that the WHI DietaryModification Trial intervention addressed the recommendationsfrom national organizations, the current results suggest thatchanging dietary patterns to meet these recommendations in midto late life will have limited or no benefit in preventing colorectalcancers in postmenopausal women.[Defending their results]

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Scientific Writing, HRP 214The Discussion

9. The strengths of this study are its randomized design, long-termfollow-up, large numbers of participants, diversity of race/ethnicityand socioeconomic status, and high retention rate. The limitationsof this study include not attaining intervention goals as designedfor reducing fat intake or achieving large separation from thecomparison group in increased fruit, vegetable, or grain intake.Thus the potential intervention effect of the WHI low-fat dietarypattern may be underestimated. Furthermore, there was no study-specifiedcolonoscopy, nor was there systematic screening for adenomatouspolyps; hence, the incidence of both colorectal cancer and polypsor adenomas would be underestimated.[Strengths and limitations]

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Scientific Writing, HRP 214The Discussion

10. In conclusion, there is no evidence that a low-fat dietary patternintervention reduces colorectal cancer risk over an averageof 8.1 years of follow-up. [Restatement of findings] Evidence from this study, along withthat from polyp prevention trials, strongly suggests that loweringdietary fat intake and increasing fruit, vegetable, and fiberintake in mid to late life cannot be expected to reduce therisk of colorectal cancer in this length of time.[Take-home message]

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EXAMPLE:Adherence to Mediterranean diet and risk of developing diabetes: prospective cohort studyBMJ June 2008

END OF INTRODUCTION:

We evaluated the association between adherence to a Mediterranean diet and the incidence of diabetes using a full validated food frequency questionnaire to measure the entire diet.

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Scientific Writing, HRP 214The Discussion

1. This large prospective study shows that a traditional Mediterranean food pattern is associated with a significant reduction in the risk of developing type 2 diabetes. [answer to question asked]

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Scientific Writing, HRP 214The Discussion

2. Interestingly, among participants with the highest adherence to the diet, there was a high prevalence of important risk factors for diabetes, such as older age, higher BMI, family history of diabetes, and personal history of hypertension and a higher proportion of ex-smokers. Therefore, we would have expected a higher incidence of diabetes among these participants. These higher risk participants with better adherence to the diet, however, had a lower risk of diabetes, suggesting that the diet might have a substantial potential for prevention. [ “bonus” finding/additional evidence]This finding is consistent with our previous report of an inverse association between a Mediterranean diet and the metabolic syndrome.24[fits with previous research]The metabolic syndrome is closely associated with a generalised metabolic disorder of insulin resistance, which is one of the underlying causes of type 2 diabetes. Therefore a high biological plausibility exists to support the causality of our findings. [biological mechanisms]In addition, a previous cohort study of survivors of myocardial infarction also reported that a higher adherence to a Mediterranean diet was associated with a reduction in the risk of type 2 diabetes,18[fits previous research]despite use of a relatively inaccurate tool for the dietary assessment. The inverse graded dose-response pattern and the significant inverse trend that we observed also support a causal relation. [dose-response evidence]

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Scientific Writing, HRP 214The Discussion
  • 3. Diet and disease
  • Experimental evidence suggesting that a diet similar to the Mediterranean diet and rich in plant based foods might protect against diabetes can also be found in the Indian diabetes prevention programme. That trial promoted a plant based diet (together with increases in physical activity) and found a significant reduction in the incidence of diabetes,28 although there are clear differences between the Mediterranean and Indian food patterns. There is an analogy between coronary heart disease and diabetes because patients with type 2 diabetes and no coronary heart disease have a risk of coronary heart disease similar to patients without diabetes but with prior coronary heart disease.29 There is evidence that a Mediterranean diet protects against coronary heart disease, and the analogy between coronary heart disease and diabetes suggests that this diet might also prevent diabetes. It has been shown to provide protection against coronary mortality893031 and the incidence of non-fatal myocardial infarction.32 In addition, both cohort studies333435 and randomised trials36 have found that adherence to a Mediterranean diet protects against mortality in patients who already have established coronary heart disease. [more supporting background evidence]
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Scientific Writing, HRP 214The Discussion
  • 4.The potential mechanisms explaining the protective effect of a Mediterranean diet on diabetes have been reviewed elsewhere.37383940 Two trials have shown that virgin olive oil protects against insulin resistance and the metabolic syndrome.67 Indexes of insulin resistance were significantly improved among participants allocated to a Mediterranean diet rich in virgin olive oil. Olive oil is rich in monounsaturated fatty acids, and a diet rich in monounsaturated fatty acids is beneficial among those with diabetes and might lead to improved insulin sensitivity and better lipid profiles than diets rich in carbohydrate.131539 People allocated to a Mediterranean diet secrete more glucagon-like peptide-1,16 a finding also seen in animals.14 The non-fat minor components of virgin olive oil also exert a beneficial effect on pro-inflammatory cytokines.404142
  • Apart from olive oil, adherence to an overall Mediterranean-type food pattern is related to lower plasma concentrations of inflammatory markers and markers of endothelial dysfunction.4344 These biomarkers are predictive of the future occurrence of type 2 diabetes.4546 In addition, a large cross sectional study nested in the nurses’ health study found that increased adherence to a Mediterranean diet was associated with higher levels of adiponectin,47 and higher levels of adiponectin are associated with a reduced risk of diabetes.

[supporting evidence in the literature/biological mechanisms]

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Scientific Writing, HRP 214The Discussion
  • Limitations
  • The number of new cases of diabetes was small, despite the follow-up of several thousand people for over four years. This small number of incident cases is a major drawback and can compromise the statistical power of our study. Nevertheless, our participants had high absolute levels of consumption of the typical food items of the Mediterranean diet, even among those participants classified as poorly compliant (score <3). For example, among those in the lowest category of adherence to the diet, the estimated mean daily absolute consumption (g/day) of olive oil (12), vegetables (308), fruits (176), cereals (77), and legumes (17) can be considered as healthy for the standards of nutritional epidemiological studies. This high consumption of plant based foods in our cohort could be because our participants were from a Mediterranean country and were highly educated and health conscious. The small number of new cases observed in this study should therefore not be surprising. If the Mediterranean diet is actually protecting against diabetes, we would expecta low incidence in a young cohort (mean age is 37.8 years) with these characteristics. The low number of observed cases precluded assessment of the specific role of single dietary factors because we would have needed
  • …..
  • A potential limitation, inherent to every observational design, is the possibility of residual confounding by unmeasured or unrecorded factors. Our major confounders, however, were sex and age. Additional adjustment for other factors made only negligible changes in the estimates, suggesting that residual confounding is unlikely.in the nurses’ health study found that increased adherence to a Mediterranean diet was associated with higher levels of adiponectin,47 and higher levels of adiponectin are associated with a reduced risk of diabetes.

[Limitations—5 paragraphs!!]

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Scientific Writing, HRP 214The Discussion
  • Conclusion
  • Our prospective cohort study suggests that substantial protection against diabetes can be obtained with the traditional Mediterranean diet, rich in olive oil, vegetables, fruits, nuts, cereals, legumes, and fish but relatively low in meat and dairy products. The limited number of cases of diabetes and the possibility of under-reporting, however, requires that further larger cohorts and trials are needed to confirm our findings.

[Restatement of the findings—take home message]

scientific writing hrp 214 discussion
Scientific Writing, HRP 214Discussion

The Discussion:

  • The answer to the key question asked
  • What’s new
  • The context
    • How your results fit into, contradict, or add to what’s known or believed
  • Strengths and limits of the study
  • The “so what?”: implicate, speculate, recommend
  • Overall conclusion
  • Powerful finish
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Scientific Writing, HRP 214

1. Peremptory v. preemptive

Peremptory = cannot be denied

Preemptive = action is one taken before an adversary can act

He issued a peremptory order.

He ordered a preemptive war in Iraq.

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Scientific Writing, HRP 214

2. Subject v. patient

A subject is a volunteer.

A patient is under treatment by a doctor.

The subjects in our study took a quiz about love.

The patients in our study were being treated for their stomach conditions.

Alternatives to “subject”: participants, volunteers, men, women, postmenopausal women, runners, smokers, etc.

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Scientific Writing, HRP 214

3. Strata v. stratum

“Strata” is plural.

“Stratum” is singular.

We analyzed the data, adjusting for the different age strata.

I was only interested in the association in the stratum of elderly subjects.

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Scientific Writing, HRP 214

4. Averse v. adverse

Averse means “opposed” and usually describes a person’s attitude.

Adverse means “hostile, unfavorable, opposed” but usually applies to situations, conditions, or events—not people.

The bad weather has an adverse effect on my car.

I would not be averse to trying that new restaurant.

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Scientific Writing, HRP 214

5. Historic v. historical

Historic means notable in history.

--indicates that it in some way changed the course of human events

Historical means relating to history or past events.

--not necessarily historic

The signing of the Declaration of Independence was a historic moment in American history.

Professor Smith gave a historical lecture on the evolution of toothpicks.

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Scientific Writing, HRP 214

6. Regardless vs. irregardless

Regardless: without regard for

Irregardless: informal blend of regardless and irrespective; would actually mean “with regard to” (double negative)

Use regardless!!

I go walking every day regardless of season or weather.

The allowance is paid regardless of age or income.

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Scientific Writing, HRP 214

7. Ultimate and Penultimate

Ultimate: last (from Latin, ultimare=“come to an end”)

Penultimate: second to last (paene=“almost”; ultimas=“last”)

The ultimate aim was to force his resignation.

The character was arrested in the penultimate chapter, setting up the central tension of the final chapter.

scientific writing hrp 214 homework for next time
Scientific Writing, HRP 214Homework for next time…

Assignments for Next Week

  • Read:
    • Chapter 2 in Successful Science Writing

(3-units):

Write intro/background using what you learned in this week’s lecture

Work on Letter to the Editor (due in two weeks, along with Discussion section)