Objective: To analyse the influence of social and cultural factors in the prevalence of obesity in the Spanish adult population aged 25--60 y based on available population data.
Design: Pooled analysis of four cross-sectional nutrition surveys.
Subjects: A total of 5388 free-living subjects aged 25--60 y, respondents of the Nutritional Surveys carried out in four Spanish regions (Catalunya, Basque Country, Madrid and Valencia) from 1990 to 1994. The samples were pooled together and weighted to build a national random sample.
Measurements: Weight and height were measured on each individual by trained observers. Age, gender, educational level, occupation, habitat (rural/urban) and region were considered. Obesity was defined as body mass index > or = 30 kg/m(2). The protocol used in each survey was in accordance with the recommendations of the Spanish Society for the Study of Obesity (SEEDO). Logistic regression models were designed to analyse the influence of sociodemographic factors in the prevalence of obesity in men and women.
Results: The prevalence of obesity was higher in older age groups in men and women, odds ratio (OR) for every 10 y OR=1.40 (95% CI 1.39--1.41) for men and OR=1.86 (95% CI 1.85--1.87) for women. Logistic regression analysis adjusted for age showed higher obesity rates among low educated people, OR=1.80 (95% CI 1.78--1.81) in men and OR=2.36 (95% CI 2.29--2.42) in women (P<0.001). Among men the odds ratio for the prevalence of obesity in rural areas was OR=1.87 (95% CI 1.86--1.89), compared to cities. The geographical distribution showed higher obesity rates in the southeast.
Conclusion: This study supports that obesity is a multifactorial problem. Older women with low educational level and low income seem to be the most susceptible group to weight gain. Therefore, Public Health Programs should consider this type of environmental factor when planning strategies aimed at preventing or reducing the problem of obesity in western societies.