The Association between Obesity, Constipation, and Functional Constipation in Iranian Adults

Constipation is a common disorder of the gastrointestinal tract which affects the quality of life (QOL) of patients. However, findings of studies on the relationship between obesity and constipation are conflicting. The aim of the present study was to assess the relationship of general and central obesity with constipation and functional constipation in a large group of Iranian adults.
This cross-sectional study was conducted on 4457 adults, through obtaining anthropometric measures using a validated self-report questionnaire. The subjects were classified into three categories of normal weight, overweight, and obese based on their body mass index (BMI) and normal, central overweight, and central obesity based on their waist circumference. The prevalence of constipation, functional constipation, and its components was investigated according to Rome III criteria.
Findings: The prevalence of constipation and functional constipation among the study population was 33.6% and 15.3%, respectively. After adjustment for potentially confounding factors, obese individuals were at a 32% greater risk of constipation compared to those with normal BMI (OR: 1.32; 95% CI: 1.03-1.71). There was no significant association between general obesity and functional constipation. Gender-stratified analysis revealed a significant association between overweight and obesity, and constipation among women in the crude model; overweight women (OR: 1.21; 95% CI: 1.02-1.45) and obese women compared to women with normal BMI (OR: 1.65; 95% CI: 1.26-2.15) were 21% and 65% more likely to have constipation. Although significant associations were found between abdominal obesity, and constipation and functional constipation in the crude model, these associations disappeared with adjustment for confounding factors. Gender-stratified analysis revealed no significant associations between abdominal obesity, and risk of constipation or functional constipation in men or women.
General obesity was associated with a significant increase in the risk of constipation, while abdominal obesity was not associated with constipation and functional constipation. General obesity was related to increased risk of constipation in women. However, no significant association was found between constipation and functional constipation, and obesity or abdominal obesity in men.