Prevalence and Determinants of Constipation in the United States: Results from the 2005-2006 National Health and Nutrition Examination Survey (NHANES): 2010 ACG/Radhika Srinivasan Gender-Based Research Award, 2010 Presidential Poster

Abstract

Purpose: Constipation exacts a heavy toll on the healthcare system owing to its cost of treatment, adverse impact on the quality of life and possibly even survival. As such, measuring accurately its burden at the population level is paramount and recent data is lacking. We determined the population-level prevalence of constipation in the United States and its associated factors. Methods: We conducted a cross-sectional study in adults 20 years and older who participated in the NHANES survey between 2005 and 2006 and completed the bowel health questionnaire (BHQ). The BHQ includes the Bristol stool form scale (BSFS) and the stool frequency questionnaire (SFQ). Constipation was defined as either a BSFS score <3 or <3 reported stools per week on the SFQ. Constipated subjects thus defined were compared to the non-constipated subjects. Statistical analysis was done taking into account the complex survey design and incorporating sampling weights. Multivariable adjusted odds of having constipation were derived using survey logistic regression, with age, gender, race/ethnicity, body mass index (BMI), education and income level as the explanatory variables. Results: The overall prevalence of constipation was 8.7% amongst the 4302 study subjects (weighted total N=16,769,379). It was more prevalent in women as compared to men (13% vs. 4%, p<0.0001) and non-Hispanic blacks compared to Non-Hispanic whites (14% vs. 8%, p=0.003). Mexican-Americans had a 10.7% prevalence of constipation. Those over age 60 had a 7.3% prevalence compared to 10.3% in the age group of 20-39 years. Multivariable analysis adjusting for other factors showed that women were 4.4 times more likely to have constipation than men, and non-Hispanic blacks were twice more likely than non-Hispanic whites to be constipated. There was a weak inverse association between age and constipation [OR 0.99 (95%CI 0.98-0.99)]. Subjects with an annual household income less than $20,000 were twice more likely to be constipated than those with an income of $75,000 and above. Education level was also associated with constipation with participants who had no high school education having a greater likelihood of constipation compared to those with some college education and above. A non-significant trend of decreasing association of constipation with increasing BMI was noted. Conclusion: In this population-based study, we report updated estimates of the prevalence of constipation in the United States and identify sub-groups associated with a potential increased risk. Despite medical advances, constipation remains a common cause of morbidity. Sub-groups with a high prevalence may potentially be targeted to reduce the burden of this disorder.