Analysis of Covariance on Association between Staple Foods Consumption and Irritable Bowel Syndrome (IBS) Prevalence.

<p>Confounding factors include age (continuous variable), sex, body mass index (continuous variable), smoking status (never, former, current), drinking frequency (never, sometimes, every day), occupation (desk work), educational levels (≥college), sleep duration (6–8 hours/day), physical activity (≥23 metabolic equivalent hours/week), and depressive symptoms (self-rating depression scale ≥45 points). Data on the consumption of staple foods were log-transformed prior to multivariate statistical analyses due to their abnormal distribution and back-transformed for data presentation. Data were shown as means and 95% confidence interval. Of the 1 082 subjects, 212 had IBS.