Above a BMI of 20 kg/m2, morbidity for a number of health conditions increases as BMI increases. Higher morbidity in association with overweight and obesity has been observed for hypertension (2-6, 76-80), dyslipidemia, type 2 diabetes (7, 8, 10, 81, 82, 84-89), coronary heart disease (CHD) (11, 42, 86, 88, 90), stroke (11-13), gallbladder disease, osteoarthritis (16-18, 91-95), sleep apnea and respiratory problems (21, 96-98), and some types of cancer (endometrial, breast, prostate, and colon) (107-115). Obesity is also associated with complications of pregnancy, menstrual irregularities, hirsutism, stress incontinence, and psychological disorders (depression) (112, 116-128).
The nature of obesity-related health risks is similar in all populations, although the specific level of risk associated with a given level of overweight or obesity may vary with race/ethnicity, and also with age, gender, and societal conditions. For example, the absolute risk of morbidity in chronic conditions such as CHD is highest in the aged population, while the relative risk of having CHD in obese versus nonobese individuals is highest in the middle adult years (129-131). A high prevalence of diabetes mellitus in association with obesity is observed consistently across races/ethnicities, while the relative prevalence of hypertension and CHD in obese versus nonobese populations varies between groups.
The health risks of overweight and obesity are briefly described in the next sections.