Bowel habit in relation to age and gender - Findings from the National Health Interview Survey and clinical implications

Background: Constipation is widely considered to be a common problem among the elderly, as evidenced by the high rate of laxative use in this population. Yet, age-related prevalence studies of constipation generally do not distinguish between actual alteration in bowel movement frequency and subjective self-report of constipation. Objective: To determine the relationship between advancing age and bowel habit. Methods: We employed data collected on 42 375 subjects who participated in the National Health Interview Survey on Digestive Disorders based on interviews with a random nationwide sample of US households. We examined the following characteristics reported by this population according to selected age groupings by decade: constipation, levels of laxative use, and two bowel movements per week or less. Results: Contrary to conventional wisdom, there was no age-related increase in the proportion of subjects reporting infrequent bowel movements. Nonetheless, the prevalence of self-report of constipation increased with advancing age, with a greater proportion of women reporting this symptom than men across all age groups. Laxative use also increased substantially with aging; while women were more likely to use laxatives than men, this effect attenuated with advancing age. A U-shaped relationship was observed between advancing age and bowel habit in men and women; 5.9% of individuals younger than 40 years reported two bowel movements per week or less compared with 3.8% of those aged 60 to 69 years and 6.3% of those aged 80 years or older. This relationship persisted after adjusting for laxative use. Conclusion: These findings suggest that a decline in bowel movement frequency is not an invariable concomitant of aging. In elderly patients who report being constipated, it is essential to take a careful physical, psychological, and bowel history rather than to automatically assume the need for laxative use.