U.S. Obesity Trends
During the past 20 years there has been a dramatic increase in obesity in the United States.
Currently, more than 64% of US adults are either overweight or obese, according to results from the 1999-2000 National Health and Nutrition Examination Survey (NHANES). This figure represents a 14% increase in the prevalence rate from NHANES III (1988-94) and a 36% increase from NHANES II (1976 -80). (Prevalence is the percentage of the population that falls into the designated category.)
The greatest increase took place in the obese group (Body Mass Index > 30), where the prevalence doubled from NHANES II (1976-80). Roughly 59 million American adults are in this group, which is at the greatest health risk. (Please note that NHANES data are based on weights and heights as actually measured by trained health professionals using standardized measuring equipment.)
The maps below graphically depict this trend over a 16-year span. It is important to note that these figures are based on telephone interviews where weight and height are self-reported. Self reported data tend to underestimate weight and over-report height. Therefore, the prevalence rates are actually under-estimates compared to the NHANES data which originate from actual measurements.
to view the entire presentation go to: http://www.cdc.gov/nccdphp/dnpa/obesity/trend/maps/index.htm
Obesity is associated with significantly increased risk of diabetes mellitus, hypertension, dyslipidemia, certain forms of cancer, sleep apnea, and osteoarthritis. In addition, the increasing prevalence of obesity and its associated complications places a tremendous burden on healthcare utilization and costs. This epidemic of obesity mandates prompt attention from the heath care and preventive health services in order to minimize the rise in the incidence of new case of diabetes, heart disease and other obesity-related complications.
Relationship of BMI to mortality risk
The risks of many medical complications increase with increasing body mass index. These medical complications lead to premature mortality in obese persons. In a prospective study of more than 1 million adults in the United States (457,785 men and 588,369 women), Calle et al studied the relation between body mass index and the risk of death from all causes, cancer, and cardiovascular disease (2). In people who had never smoked, the lowest point of the mortality curve occurred at a body mass index of 23.5 to 24.9 in men and 22.0 to 23.4 in women. Above those points, the relative risk of death increased linearly with increased body mass indices in both men and women.
Relationship of overweight and obesity to hypertension
Blood pressure is clearly strongly correlated with BMI. In the INTERSALT study (3), the relationship between body mass index (BMI) and blood pressure was studied in over 10,000 men and women, between 20 and 59 years of age, sampled from 52 centers around the world. BMI was significantly associated with systolic and diastolic blood pressure, independent of age, alcohol intake, smoking habit, and sodium and potassium excretion. The precise prevalence of obesity-related hypertension associated with obesity varies with age, race, and sex of the population studied and with the criteria used for the definition of hypertension and obesity.(4) Roughly 30% of cases of hypertension may be attributable to obesity, and in men under 45 years of age, the figure may be as high as 60%.(5) In the Framingham Offspring Study, 78% of cases of hypertension in men and 64% in women were attributable to obesity.(6)
Prospective studies have shown that obesity increases the risk of developing hypertension.(6)(7) Moreover, weight gain in adulthood is in itself an important risk factor for the development of hypertension.(6)(8) In the long-term Nurses Health Study (8), BMIs at 18 years of age and at midlife were positively associated with the occurrence of hypertension. Weight gain after 18 years of age significantly increased the risk for hypertension. Compared with women who gained less than 2 kg (4.4 pounds), women who gained 5.0 to 9.9 kg (11-22 pounds) were 74% more likely to have hypertension, and those who gained more than 25 kg (55 pounds) were more than 5 times more likely to have hypertension. (7) Excess weight and even modest adult weight gain substantially increase risk for hypertension: each 1-kg increase in weight after age 18 was associated with a 5% increase in risk for hypertension.
Relationship of overweight and obesity to type 2 diabetes
It is likely that the 25% increase in the prevalence of diabetes in the last 20 years in the United States (9) is due to the marked increase in the prevalence of obesity. Body mass index, abdominal fat distribution, and weight gain are important risk factors for type 2 diabetes mellitus. Data from NHANES III indicated that two-thirds of adult men and women in the United States diagnosed with type 2 diabetes have a BMI of 27 kg/m² or greater.(10) Moreover, the risk of diabetes increased with BMI; diabetes prevalence was 2%, 8% and 13% in those with BMI 25-29.9kg/m² (overweight), 30-34.9 kg/m² (class 1 obesity), and >35 kg/m² (class 2 and 3 obesity), respectively.(9) Data from the Nurses Health Study demonstrated that the risk of diabetes begins to increase in "normal" weight women when BMI exceeds 22 kg/m².(11)(12) Weight gain during adulthood also increases the risk of diabetes, even at relatively low levels of BMI in initially normal weight individuals.(12)(13) Compared with women who kept their weight within 5 kg (11 pounds) of their initial weight over a 14-year period, women who gained only 5 to 8 kg (11-17.6 pounds) were nearly twice as likely to develop diabetes over that period, even after adjusting for initial BMI. Those who gained 11 to 20 kg (about 24 to 44 pounds) were more than 5 times as likely to develop diabetes. (12)
- US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics, Division of Data Services, Hyattsville, MD
- Calle, EE, et al. (1999) Body mass index and mortality in a prospective cohort of US adults, N. Eng. J Med, 341, 1097-1105
- Dyer, AR, et al, (1990) Body mass index versus height and weight in relation to blood pressure. Finding for the 10,079 persons in the INTERSALT Study, Am J Epidemiol. 131, 589-596
- Aronne, LJ, Segal, KR (2002) Adiposity and fat distribution outcome measures: assessment and clinical implications, Obes Res 10: 14S-21S
- MacMahon, SW, et al. (1984) Obesity, alcohol consumption and blood pressure in Australian men and women. The National Foundation of Australia Risk Factor Prevalence Study, J. Hyperten 2, 85-91
- Garrison, RJ, et al (1987) Incidence and precursors of hypertension in young adults: The Framingham Offspring Study, Prev Med 16, 235-25
- Huang, Z et al (1998) Body weight, weight change, and risk for hypertension in women, Ann Intern Med 128, 81-88
- Brown, CD et al, (2000) Body mass index and the prevalence of hypertension and dyslipidemia, Obes Res. 8, 605-619
- Harris, MI, et al (1998) Prevalence of diabetes, impaired fasting glucose, and impaired glucose tolerance in US adults. The Third National Health and Nutrition Examination Survey, 19988-1994 Diabetes Care, 21, 518-524
- National Task Force on the Prevention and Treatment of Obesity (2000), Overweight, obesity, and health risk, Arch Intern Med 160, 898-904
- Colditz, GA et al, (1990) Weight as a risk factor for clinical diabetes in women AM J Epedemiol. 132, 501-513
- Colditz, GA, et al, (1995) Weight gain as a risk factor for clinical diabetes mellitus in women Ann Intern Med, 122, 481-486
- Chan JM, et al, (1994) Obesity, fat distribution and weight gain as risk factors for clinical diabetes in men, Diabetes Care 17, 961-969
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