title: Association of low dietary intake of fiber and liquids with constipation: evidence from the National Health and Nutrition Examination Survey.
abstract: OBJECTIVE
  Epidemiological studies support an association of self-defined constipation with fiber and physical activity, but not liquid intake. The aims of this study were to assess the prevalence and associations of dietary fiber and liquid intake to constipation.
  
  
  METHODS
  Analyses were based on data from 10,914 adults (≥20 years) from the 2005-2008 cycles of the National Health and Nutrition Examination Surveys. Constipation was defined as hard or lumpy stools (Bristol Stool Scale type 1 or 2) as the "usual or most common stool type." Dietary fiber and liquid intake from total moisture content were obtained from dietary recall. Co-variables included: age, race, education, poverty income ratio, body mass index, self-reported general health status, chronic illnesses, and physical activity. Prevalence estimates and prevalence odds ratios (POR) were analyzed in adjusted multivariable models using appropriate sampling weights.
  
  
  RESULTS
  Overall, 9,373 (85.9%) adults (4,787 women and 4,586 men) had complete stool consistency and dietary data. Constipation rates were 10.2% (95% confidence interval (CI): 9.6, 10.9) for women and 4.0% (95% CI: 3.2, 5.0) for men (P<.001). After multivariable adjustment, low liquid consumption remained a predictor of constipation among women (POR: 1.3, 95% CI: 1.0, 1.6) and men (POR: 2.4, 95% CI: 1.5, 3.9); however, dietary fiber was not a predictor. Among women, African-American race/ethnicity (POR: 1.4, 95% CI: 1.0, 1.9), being obese (POR: 0.7, 95% CI: 0.5,0.9), and having a higher education level (POR: 0.8, 95% CI: 0.7, 0.9) were significantly associated with constipation.
  
  
  CONCLUSIONS
  The findings support clinical recommendations to treat constipation with increased liquid, but not fiber or exercise.
authors.affiliation: Birmingham/Atlanta Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Department of Veterans Affairs Medical Center, Birmingham, AL 35233, USA. amarkland@aging.uab.edu
authors.forename: Alayne D
authors.initials: AD
authors.lastname: Markland
authors.forename: Olafur
authors.initials: O
authors.lastname: Palsson
authors.forename: Patricia S
authors.initials: PS
authors.lastname: Goode
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Burgio
authors.forename: Jan
authors.initials: J
authors.lastname: Busby-Whitehead
authors.forename: William E
authors.initials: WE
authors.lastname: Whitehead
mesh_terms: D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D000368:Aged; D003248:Constipation / Q000453:epidemiology* / Q000209:etiology*; D004043:Dietary Fiber / Q000008:administration & dosage*; D004327:Drinking Behavior; D004522:Educational Status; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D009765:Obesity / Q000150:complications; D012307:Risk Factors; D012737:Sex Factors; D014481:United States / Q000453:epidemiology; D014868:Water Deprivation