Incidence of overweight and obesity in a Mediterranean population-based cohort: the Cornellà Health Interview Survey Follow-up Study (CHIS.FU).

OBJECTIVE To study the changes in body mass index (BMI) in a population-based cohort and their relationship with sociodemographic variables in a Mediterranean-country. METHOD A prospective population-based cohort with 8-year follow-up. The data used derive from the Cornellà-Health-Interview Survey Follow-up (CHIS.FU). 1008 people aged > or = 20 years (females=508; males=500) were interviewed in 1994 and in 2002, providing self-reported weight and height data. The BMI was compared using the Wilcoxon test for paired data. Changes in the BMI were calculated and their relationship with sociodemographic-variables and lifestyles using multivariate Breslow-Cox regression. RESULTS 28.1% of participants had changed from normal-BMI in 1994 to overweight in 2002 (women=25.6%; men=31.6%). 16.8% increased from overweight to obesity (women=25.8%; men=11.2%). The cumulative incidence of overweight: women=26.4%; men=34.0%. The cumulative incidence of obesity: women=29.9%; men=13.1%. The cumulative age and sex-adjusted incidence of overweight showed a significant relationship with marital-status (married: RR=2.0; 95% CI: 1.2-3.4, divorced/widowed: RR=4.0; 95% CI: 1.7-9.3) and moderate alcohol-consumption (RR=1.86; 95% CI: 1.1-3.1). We observed a decreased age-adjusted risk in the incidence of obesity for men (RR=0.49; 95% CI: 0.3-0.8). CONCLUSION The observed changes in the increase in the incidence of obesity and overweight indicated a similar evolution in the obesity epidemic regardless of Mediterranean dietary patterns in our population.