Drinking and Smoking and Colorectal Cancer
Download
1 / 23

Drinking and Smoking and Colorectal Cancer - PowerPoint PPT Presentation


  • 202 Views
  • Updated On :

Drinking and Smoking and Colorectal Cancer - A Population-Based Case-Control Study among NL Residents, 1999-2003. PhD student: Jinhui Zhao Supervisor: Peizhong Peter Wang Committee: Roy West and Sharon Buehler The Annual Colorectal Meeting, June 16-17, 2008, St John’s, NL. Background.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Drinking and Smoking and Colorectal Cancer' - Gideon


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Slide1 l.jpg

Drinking and Smoking and Colorectal Cancer - A Population-Based Case-Control Study among NL Residents, 1999-2003

PhD student: Jinhui Zhao

Supervisor: Peizhong Peter Wang

Committee: Roy West and Sharon Buehler

The Annual Colorectal Meeting, June 16-17, 2008, St John’s, NL


Background l.jpg
Background

  • Studies on the effects of drinking and smoking on colorectal cancer (CRC) have been inconclusive

  • One study on smoking and CRC conducted in Montreal did not provide evidence (1995)

  • One study on drinking and CRC in Montreal men showed OR=2.3 (95% CI:1.4-3.7) of distal colon cancer and OR=1.6 (95% CI: 1.0-2.6) for daily drinkers vs non-drinkers (2002)

  • Drinking beer showed stronger effect on proximal, distal and rectum cancer than wine and spirits

ACM, June 16-17, 2008, St. John's NL


Research questions l.jpg
Research questions

  • Incidence rate is high in eastern provinces

  • Age-standardized rate is highest (83/100,000) in NL males and second highest (51) in NL females

  • Highest rate of heavy drinkers is 3 territories, NL and NS

  • Smoking rate in BC, AB, NL and NS exceeded the national average

ACM, June 16-17, 2008, St. John's NL


Research questions4 l.jpg
Research questions

  • Drinking and smoking are potential risk factors of CRC?

  • Subtypes risk of CRC may vary

  • Effects may vary based on types of beverages and tobaccos (differential brands of beverages and tobaccos

  • CRC cluster may exist, but has not been taken into account in studies and statistical analyses

ACM, June 16-17, 2008, St. John's NL


Objective of study l.jpg
Objective of study

  • To investigate effects of drinking and smoking on CRC and its subsites

  • To investigate effects of drinking beer, wine and spirits on CRC and its subsites

  • To investigate effects of smoking cigarette, cigar and pipe on CRC and its subsites

  • Evaluate validity of reliability of self-reported lifetime drinking and smoking

  • Investigate non-participation bias of CRC cases

ACM, June 16-17, 2008, St. John's NL


Research methods designs l.jpg
Research methods-designs

  • Case-control study for effect of drinking and smoking on CRC

  • Comparison of characteristics of CRC participants with non-participants

  • Annul ethanol litres and annual cigarettes and cigarette packs per control compared to 1996 and 2001 alcohol and tobacco sale data by Statistics Canada for validity

  • Cronbach’s alpha for internal reliability

ACM, June 16-17, 2008, St. John's NL


Research methods analyses l.jpg
Research methods-analyses

  • Binary multilevel logistic model for all CRC cases to controls

  • Multinomial multilevel logistic model for colon, rectum cancer cases to controls

  • Multinomial multilevel logistic model for survival, died cases to controls

  • Multinomial multilevel logistic model for CRC at stage I-II, III-IV to controls

ACM, June 16-17, 2008, St. John's NL


What do we find non response bias l.jpg
What do we find?-non-response bias

  • 59.94% eligible CRC cases and 44.76% eligible controls participated in the study

  • Cases aged 20-54 tended to over-represent

  • Cases aged 65 years old and over tended to under-represent in the participating sample.

  • Participating rate tended to decrease with an increase in TNM stages

  • The most serious cases tended to under-represent in the participating sample

  • The deceased tended to be included in the study

ACM, June 16-17, 2008, St. John's NL


What do we find reliable self report l.jpg
What do we find?-reliable self-report

  • Self-reported substance uses are reliable:

  • Reliability of self-reported drinking:

  • Internal reliability of all constructed alcohol-items is high, with

  • Cronbach α = 0.9144 (70+ is acceptable)

  • Reliability of self-reported smoking

  • Internal reliability of all constructed tobacco-items is high, with

  • Cronbach α = 0.8966 (70+ is acceptable)

ACM, June 16-17, 2008, St. John's NL


What do we find valid self report l.jpg
What do we find?-valid self-report

  • What did CRC cases and controls drink?

ACM, June 16-17, 2008, St. John's NL


What do we find valid self report11 l.jpg
What do we find?- valid self-report

  • What did a Canadian drink?

ACM, June 16-17, 2008, St. John's NL


What do we find valid self report12 l.jpg
What do we find?-valid self-report

  • How much did a CRC case and control drank per year?

ACM, June 16-17, 2008, St. John's NL


What do we find valid self report13 l.jpg
What do we find?-valid self-report

  • How much did a Canadian drink?

ACM, June 16-17, 2008, St. John's NL


What do we find valid self report14 l.jpg
What do we find?-valid self-report

  • What and how much did a CRC case and control smoke?

ACM, June 16-17, 2008, St. John's NL


What do we find valid self report15 l.jpg
What do we find?-valid self-report

  • How much did a Canadian smoke?

ACM, June 16-17, 2008, St. John's NL


What do we find effects of drinking l.jpg
What do we find?-effects of drinking

  • Drinking shows weak protective effect on CRC risk

  • 42% lower risk of CRC for drinking 1-19 years vs never drinker (OR: 0.58, 95% CI: 0.37-0.91)

  • 43% lower risk of CRC for drinking beer 1-19 yrs vs no (OR: 0.57, 95% CI: 0.36-0.92)

  • 1-2 drinks of beer decreased by 33% CRC risk compared to no (OR: 0.67, 95% CI: 0.47-0.96)

  • 42% lower risk of CRC for drinking liquor 1-19 years vs no (OR: 0.53, 95% CI: 0.35-0.80)

ACM, June 16-17, 2008, St. John's NL


What do we find beer liquor l.jpg
What do we find?-beer & liquor

  • Drinking shows weak protective effect on risk of rectum cancer but not colon cancer

  • Drinking shows weak protective effect on risk of died CRC, but not survival CRC

  • Drinking shows weak protective effect on risk of CRC at stage III-IV, but not CRC at stage I-II

ACM, June 16-17, 2008, St. John's NL


What do we find effects of smoking l.jpg
What do we find?-effects of smoking

  • Cigarette smoking increased CRC risk (OR & 95% CI)

ACM, June 16-17, 2008, St. John's NL


What do we find effects of smoking19 l.jpg
What do we find?- effects of smoking

  • CRC risk increased with smoking cigarette years, number of cigarettes per day, cigarette pack years, and years since cigarette commencing

  • CRC risk decreased with years of abstention from smoking cigarettes

  • CRC risk associated with age of initiation of smoking greater than 16 years old

ACM, June 16-17, 2008, St. John's NL


What do we find effects of smoking20 l.jpg
What do we find?-effects of smoking

  • Smoking increased CRC risk of males, but females

  • Smoking increased CRC risk of drinkers, but not non-drinkers

  • Smoking shows stronger effect on rectum than colon cancer

  • Smoking shows stronger effect on died CRC than survival CRC

  • Smoking shows stronger effect on CRC at stage III-IV than CRC at stage I-II

ACM, June 16-17, 2008, St. John's NL


In summary l.jpg
In summary

  • Non-participation bias: low participation rate among eligible cases & controls might bias the estimates to be generalized to wide population, but it seems unlikely that the bias would be substantial enough to account for the main results

  • Validity and reliability of self-reported drinking and smoking: accurate and reliable

ACM, June 16-17, 2008, St. John's NL


In summary22 l.jpg
In summary

  • Drinking shows weak protective effect on CRC.

  • Smoking cigarettes significantly increased CRC risk

  • CRC risk increased with smoking cigarette years, smoking pack years, daily number of cigarettes, years since cigarettes smoking commencing

  • Smoking increased CRC risk among males and drinkers

  • Smoking tended to be stronger effect on rectum cancer than colon, died CRC than survival, and CRC at stage III-IV than I-II

ACM, June 16-17, 2008, St. John's NL


What shall we do next l.jpg
What shall we do next?

  • Regarding the study:

  • Further studies to evaluate the effects of drinking on CRC among Canadians

  • Expand studies of smoking and CRC in other provinces

  • Regarding our study:

  • Complete my thesis

  • Complete 3-4 papers for publication

  • Complete one report and submit to NL government and other provinces to share our results

  • Incorporate alcohol & tobacco sale data into multilevel analysis which will help us to explain effects of alcohol & tobacco use on CRC in Canada

ACM, June 16-17, 2008, St. John's NL


ad