Loading in 2 Seconds...
Loading in 2 Seconds...
Obesity Paul R. Earl Facultad de Ciencias Biológicas Universidad Autónoma de Nuevo León San Nicolás de los Garza, NL, 66540 Mexico.
The backgroundOverweight and obesity in about 3-4 decades have reached worldwide epidemic proportions from China to Argentina. In 1976, 15 % of Americans were obese. This rate doubled by 2006. It is impossible to explain this epidemic by a) urbanization and b) an escape from hunger as the Industrial revolution of perhaps 1850 is far earlier. Taking an escalator instead of the stairs is part of today's story. Obesity can be controlled by rationing food, especially energy-dense foods like french fries..
The milestone discovery of the hormone leptin by Jeff Friedman and colleagues in 1994 is one key to understanding obesity. Also, leptin connects with insulin. In 1988 another giant step was taken by Gerald Reavens who diagnosed metabolic syndrome (Diabetes 37: 1595-607). It is caused by being overweight, physical inactivity and by genetic factors. We do not yet have a crystal clear view of our energy metabolism, although we are close.
Leptin, the product of the ob (obese) gene, is a singlechain 16 kiloDalton protein consisting of 146 amino acid residues. It is produced mainly in the adipose tissue. It controls appetite, fat metabolism and body weight regulation via signals to the hypothalamus.In humans, leptin levels correlate with body mass index (BMI) and percentage body fat, and are elevated even in obese individuals. Leptin has a dual action, decreasing appetite and increasing energy consumption.
If the body's energy system begins to store FAT, disease is a likely consequence.An increase in mortality is associated with overweight and obesity. Individuals who are obese have a 50-100 % increased risk of premature death from all causes compared to normal weight individuals. Life insurance companies will charge fat people more and smokers more. An estimated 300,000 deaths a year may be attributable to obesity in the US. Most of the cost associated with obesity is due to a/ type 2 diabetes, b/ coronary heart disease and c/ hypertension.
The worldwide malnutritional extremes of rural hunger with stunting and urban obesity need to be much better understood through nutritional education, demography and ecology. Policies to reverse environmental degradation and reduce population pressure seem essential. More overpopulation can soon swallow the world's grain production whether or not policymakers continue to be deluded by "sustainable development."Calorie intake is much of the story and physical INACTIVITY via desk jobs is also much of it. “If a larger percentage of population became physically active, the public health burden associated with obesity would be greatly reduced."Gregory J. Welk, Iowa State University, Ames, and Steven N. Blair, The Cooper Institute, Dallas.
Body mass index (BMI)BMI is a measure of weight in relation to height. BMI is calculated as weight in pounds divided by the square of the height in inches, multiplied by 703. BMI is more usually calculated as weight in kilograms divided by the square of the height in meters. This is (W/H*H).BMI is significantly correlated with total body fat content for most people, but can overestimate body fat in persons who are very muscular. It can underestimate body fat in persons who have lost muscle mass, such as many of the elderly.
The simple measurement of the waist will always be popular: 2.54 cm = 1 inch.Health riskMen – waist sizeWomen- waist sizeHealthy < 94 cm < 80 cmIncreased health 94-101cm 80 to 88cmrisk (37-40 inches) (32-35 inches)Highest health More than 101cm More than 88cmrisk (>40 inches) (>35 inches)By order (sequence), BMI has the following equation given in the graph.
The worldwide epidemic of obesityThe table gives you a rough idea of how obesity is distributed in the world. There is no attempt to treat the BMI for each nation separately. The sitting height measurement should be added in to find leg length (LL). Shorter races have larger BMIs. LL/H is a useful index.The striking feature in the table is the extremely low obesity rate in Japan, which is combined with an extremely high longevity. Such gains in the length and quality of life should not be destroyed by the new threat: obesity.
Two priority testsWhen a person is obviously overweight, they should obtain test results from 1/ the glucose tolerance test and 2/ the cholesterol level test.Glucose tolerance testAfter an overnight fast, a sample of blood is taken. Then 75 g of glucose dissolved in 250-350 ml of water is drunk. Two hours later another blood sample is taken. The levels of glucose in the 2 samples are then measured. Account is taken of the fact that the concentration of glucose measured in plasma is 10 % higher than in whole blood.Diabetes is present when the fasting blood sample is over 6.7 mmol/l or the level in plasma is over 7.8 mmol/l, or the second sample has 10 mmol/l and 11.1 mmol/l.
The cholesterol testCholesterolol is a fat (lipid) in your blood. High-density lipoprotein (HDL) ("good" cholesterol) helps protect your heart, but low-density lipoprotein (LDL) ("bad" cholesterol) can clog the arteries of your heart. Triglycerides are another type of fat in the blood. As high level cholesterol is associated with hardening of the arteries, heart disease and a higher risk of death from hear attacks. Cholesterol testing is a routine part of preventive medicine.
Excercise1/ Causes a very modest weight loss, 2/ Decreases abdominal fat, 3/ Increases cardiorespiratory fitness and4/ Helps to maintain weight loss.Build physical activity into regular routines and playtime for all children and their families. Ensure that adults get at least 30 minutes of moderate physical activity on most days of the week. Children and adolescents should aim for 1-2 hours in school games, often after classes at 3 PM.Do the primary and secondary schools have enough space devoted to competitive games? The probable answer is: No.
How many meters can you walk in 6 minutes? Were you short of breath? Were your muscles fatigued? What was your pulse? Blood pressure? 140/80 ? Oxygen saturation percent? 97 % ? What do you weight? Distance times weight is equal to work done.Can the 6-minute walk test predict your longevity ? How old are you now ?Ensure daily, quality physical education in all school grades. Such education can develop the knowledge, attitudes, skills, behaviors and confidence needed to be physically active for life. This instruction often is handled rather poorly.
Obesity is associated with an increased risk of: Premature death Type 2 diabetes Heart disease Stroke Hypertension Gallbladder disease Osteoarthritis (degeneration of cartilage and bone in joints) Sleep apnea (breath stopping in sleep!) Asthma Breathing problems, perhaps from smoking
PrevalenceThe prevalence ranges from 6.7 % at ages 20–29 to 43.5 % for ages 60–69 and 42.0 % for those aged 70 and older. The age-adjusted prevalence is 24.0 % for men and for women at 23.4 %.Mexican Americans have the highest age-adjusted prevalence of obesity at 31.9 %). The lowest prevalence is among whites (23.8 %), Blacks (21.6 %) and other ethnicities at 20.3 %. However, LL is unfortunately not usually considered in prevalence. Races like some Mexicans have shorter legs therefore higher BMIs. When YOU DO NOT HAVE the sitting height, the racial meaning of BMI is hidden. You do not have a BMI scale for each race.
Height, weight and morbidityAn inheritable optimal metabolic rate is associated with the lowest mortality risk (M), greatest height (H) and a desirable body weight (W). Deviations from this rate are reflected in high BMI, overweight and higher mortality. Negative deviations occur with shorter H. The population optimal metabolic rate may differ among genotypes. Those with higher rates are the ones who can translate more energy intake into growth in H. They are able to reach greater final adult H with a lower BMI than genotypes with a lower optimal rate.
Insulin resistanceLack of energy, low metabolism and some obesity can be the first symptoms of insulin resistance. In order to use sugar, the body releases the insulin required by cells to convert it into energy. Since our modern diet can be so heavily comprised of carbohydrates and sugar, cells can start to be insensitive to your own insulin due to this chronic abundance. Do the salivary glands and other glands produce anti-insulin ? When your cells start to resist your own insulin and therefore, your body has to produce more insulin to get the same job done. Left untreated over time, your over-production of insulin will reach chronic levels.
Metabolic syndromeThis syndrome known as metabolic syndrome can be defined as a cluster of abnormalities, including obesity, hypertension, dyslipidemia and type 2 diabetes, that are associated with insulin resistance and compensatory hyperinsulinemia. However, a cause-and-effect relationship between insulin resistance, these diseases and the mechanisms through which insulin resistance influences their development has yet to be proven sufficiently.
More vital informationOverweight, obesity and their associated health problems have substantial economic consequences. Direct health care costs refer to preventive, diagnostic and treatment services like home care. Indirect costs refer to lost wages, etc.Morbidity from obesity may be as great as those from poverty, smoking or problem drinkings. Overweight and obesity are associated with an increased risk of cancer such as endometrial, colon and postmenopausal breast cancer.
Racial and ethnic disparities in overweight may also occur in children and adolescents. Mexican American boys tended to have a higher prevalence of overweight than non-Hispanic black and non-Hispanic white boys. Black girls tended to have a higher prevalence of overweight compared to non-Hispanic white and Mexican American girls.In addition to racial, ethnic and gender disparities, the prevalence of overweight and obesity also varies by age. Among both men and women, the prevalence of overweight and obesity increases with advancing age until the sixth decade, after which it starts to decline.
AdultsThe age-adjusted prevalence of overweight (BMI of 25.0 or higher) increased from 55.9 % in NHANES III (US Nacional Health and Nutrition Estimate Studies 3) (1988–94) to 65.1 % in NHANES (1999–2002). The prevalence of obesity (BMI of 30.0 or higher) also increased during this period from 22.9 % to 30.4 %. Extreme obesity (BMI of 40.0 or higher) increased from 2.9 to 4.9 % (JAMA 2004; 291: 2847–2850).Since 1991 the prevalence of those who are obese increased 75 %. Among states in 2001, Mississippi had the highest rate of obesity and Colorado had the lowest.In participants ages 18–24, studied from 1990–2000, obesity increased among every ethnic group, especially in Black women. Almost 20 % of Black women were obese by ages 18–24, increasing to over 35 % by ages 25–44.
Heart Disease and Stroke StatisticsAmerican Heart Association — 2005 Update. The Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (ATP III, NHLBI) defines the metabolic syndrome as 3 or more of the following abnormalities: Waist circumference greater than 102 cm (40 inches) in men and 88 cm (35 inches) in women. Serum triglyceride level of 150 mg/dL or higher. High-density lipoprotein (HDL) cholesterol level less than 40 mg/dL in men and less than 50 mg/dL in women. Blood pressure of 130/85 mm Hg or higher. Fasting glucose level of 110 mg/dL or higher.
Prevalence of Metabolic Syndrome Among AdolescentsThe prevalence of metabolic syndrome (Mets) among 12–19 year old U.S. adolescents was estimated in an analysis of NHANES III data, by applying a modification of the ATP III definition for adults. MetS during adolescence was defined as 3 or more of the following abnormalities: Serum triglyceride level of 110 mg/dL or higher. High-density lipoprotein (HDL) cholesterol level of 40 mg/dL or lower. Elevated fasting glucose of 110 mg/dL or higher. Blood pressure at or above the 90th percentile for age, sex and height. Waist circumference at or above the 90th percentile for age and sex.
Prevalence of Metabolic Syndrome Among AdultsThe prevalence ranges from 6.7 % at ages 20–29 to 43.5 % for ages 60–69 and 42.0 % for those aged 70 and older. The age-adjusted prevalence is similar for men at 24.0 and for women at 23.4 %.Mexican Americans have the highest age-adjusted prevalence of MetS at 31.9 %). The lowest prevalence is among whites (23.8 %), African Americans (21.6 %) and it is “other” race or ethnicity at 20.3 %. Among Blacks, women had about a 57 % higher prevalence of Mets than men had. Among Mexican Americans, women had a 26 % higher prevalence than men had.
We need much more health applications-Teach nutrition in the primary schools.- Increase playgrounds.- Increase research on behavioral and environmental causes of overweight and obesity. - Increase research and evaluation on prevention and treatment interventions for overweight and obesity, and develop and advertize the bestguidelines.- Increase research on disparities in the prevalence of overweight and obesity among racial and ethnic, gender, socioeconomic and age groups, and use this research to identify effective and culturally appropriate interventions.
We need much more health applications- Develop and use noninvasive sensors for the Basal Metabolic Rate (BMR).- Create more opportunities for physical activity at worksites. Encourage all employers to make facilities and opportunities available for physical activity for all employees.- Make community facilities more available and accessible for physical activity for all people, including the elderly.- Promote more healthful food choices, including at least 5 servings of fruits and vegetables each day, and reasonable portion sizes at home, in schools and at worksites.