Information concerning bowel habits was gathered from a representative sample of 14,407 United States adults in the first National Health and Nutrition Examination Survey in 1971-1975 and approximately 10 years later among the same individuals. The prevalence of self-reported constipation, diarrhea, infrequent defecation (three or fewer bowel movements per week), and frequent defecation (two or more bowel movements per day) increased with aging. Women were more likely than men (P less than 0.05) to report constipation (20.8% compared to 8.0%) and infrequent defecation (9.1% compared to 3.2%). Blacks were more likely than whites to report infrequent defecation (P less than 0.05). Older respondents reporting constipation were more likely to use laxatives or stool softeners than younger respondents reporting constipation, but they were also less likely to have infrequent defecation. To evaluate factors predictive of impaired bowel function, case definitions were created using information concerning complaint of constipation, laxative use, frequency of defecation, and stool consistency. Female gender, black race, fewer years of education, low physical activity, and symptoms of depression were independent risk factors for impaired bowel function. This study provides national estimates of bowel complaints and their natural history and examines possible risk factors for constipation.

The 1982-1984 Hispanic Health and Nutrition Examination Survey used ultrasonography to investigate risk factors for gallstone disease (gallstones or cholecystectomy). Mexican American, Cuban American, and Puerto Rican men (n = 968) and women (n = 1,325) aged 20-74 years were selected from household samples in nine states. Among men, the risk of gallstone disease increased with age, education, and subscapular skinfold thickness. Among women, the risk of gallstone disease increased with age, body mass index, four skinfold measures, diabetes, impaired glucose tolerance, and oral contraceptive usage, but not with parity. Women currently using oral contraceptives were also found to be at increased risk of current gallstones. Menopause was a risk factor for gallstone disease and cholecystectomy. Alcohol consumption was negatively related to the risk of gallstone disease. In men, the cholesterol/high density lipoprotein cholesterol ratio was positively related to gallstone disease and, in women, this ratio was negatively related. This interaction between the effect of sex and the cholesterol/high density lipoprotein cholesterol ratio on gallstone disease was highly significant (p = 0.002). Mexican Americans were at increased risk of gallstone disease even when other risk factors were controlled in multiple logistic regression analysis.