Prevalence of gastro-oesophageal reflux disease in Spain and associated factors.

BACKGROUND: The prevalence of gastro-oesophageal reflux disease (GERD), has not been characterized in Spain. Aim To measure the prevalence of GERD in Spain, and the factors associated with it, by means of a primary care-based study. METHODS: An epidemiological, multicentre, cross-sectional, population-based study. A self-administered questionnaire was sent out to randomly selected patients. Data were statistically analysed to provide the prevalence of GERD and to compare it with that of gastro-oesophageal reflux symptoms. Factors associated with GERD were studied using logistic regression models. RESULTS: The response rate was 45%. The prevalence of GERD was 15% (95% CI: 13.2-16.2). When compared with gastro-oesophageal reflux symptoms patients, those with GERD experienced more intense symptoms (moderate-severe: 35% vs. 8%, P < 0.001) and suffered heartburn more frequently both at day and night (48% vs. 25%, P < 0.001) and for longer period of times (69% vs. 62%, P = 0.057). A body mass index of >25% (odds ratio: 1.07; 95% CI: 1.03-1.11) was the only independent variable associated with GERD. The risk of suffering GERD increases by 7% for each kg/m(2) that the body mass index increases. CONCLUSIONS: The prevalence of GERD among the Spanish population is 15%. Body mass index is the only risk factor significantly associated with GERD.