Marques-Vidal et al. BMC Public Health 2011, 11:772 http://www.biomedcentral.com/1471-2458/11/772 R E S E A R C H A R T I C L E Open Access Ten-year trends in overweight and obesity in the adult Portuguese population, 1995 to 2005 Pedro Marques-Vidal1*, Fred Paccaud1 and Paula Ravasco2 Abstract Background: There is little information regarding the trends in body mass index (BMI) and obesity in the overall Portuguese population, namely if these trends are similar according to educational level. In this study, we assessed the trends in the prevalence of overweight and obesity in the Portuguese population, overall and by educational level. Methods: Cross-sectional national health interview surveys conducted in 1995-6 (n = 38,504), 1998-9 (n = 38,688) and 2005-6 (n = 25,348). Data were derived from the population and housing census of 1991 and two geographically-based strata were defined. The sampling unit was the house, and all subjects living in the sampling unit were surveyed. Height and weight were self-reported; the effects of gender, age group and educational level were also assessed by self-reported structured questionnaires. Bivariate comparisons were performed using Chi- square or analysis of variance (ANOVA). Trends in BMI levels were assessed by linear regression analysis, while trends in the prevalence of obesity were assessed by logistic regression. Results: Mean (±standard deviation) BMI increased from 25.2 ± 4.0 in 1995-6 to 25.7 ± 4.5 kg/m2 in 2005-6. Prevalence of overweight remained stable (36.1% in 1995-6 and 36.4% in 2005) while prevalence of obesity increased (11.5% in 1995-6 and 15.1% in 2005-6). Similar findings were observed according to age group. Mean age-adjusted BMI increase (expressed in kg/m2/year and 95% confidence interval) was 0.073 (0.062, 0.084), 0.016 (0.000, 0.031) and 0.073 (0.049, 0.098) in men with primary, secondary and university levels, respectively; the corresponding values in women were 0.085 (0.073, 0.097), 0.052 (0.035, 0.069) and 0.062 (0.038, 0.084). Relative to 1995-6, obesity rates increased by 48%, 41% and 59% in men and by 40%, 75% and 177% in women with primary, secondary and university levels, respectively. The corresponding values for overweight were 6%, 1% and 23% in men and 5%, 7% and 65% in women. Conclusion: Between 1995 and 2005, obesity increased while overweight remained stable in the adult Portuguese population. Although higher rates were found among lesser educated subjects, the strong increase in BMI and obesity levels in highly educated subjects is of concern. Backgound Obesity is now a pandemic condition, affecting approxi- mately half a billion people worldwide [1]. Portugal is a South European country characterized by a high preva- lence of overweight (39.4% to 41.8%) and obesity (14.2% to 21.3%) [2,3], ranking among the highest in Europe [4] which has prompted the government to launch a nation- wide obesity prevention program [5,6]. There is no population-based data regarding overweight and obesity * Correspondence: Pedro-Manuel.Marques-Vidal@chuv.ch 1Institute of Social and Preventive Medicine (IUMSP), CHUV and Faculty of biology and medicine, Lausanne, Switzerland Full list of author information is available at the end of the article before 1995, but two studies conducted on male con- scripts (mean age 18 years) showed an increase in over- weight and obesity from 8.1% in 1960 to 18.0% in 1990 in the Lisbon region [7] and from 10.5% in 1986 to 21.3% in 2000 in Portugal [8]. In previous studies, we have shown that the prevalence of overweight and obe- sity were increasing in the Portuguese population [9] and that, in Switzerland, this increase in the prevalence of obesity was larger in low education strata of the population [10], a finding also observed in a prospective study conducted in an urban Portuguese population [11]. Still, to our knowledge, no information regarding these trends according to educational levels has ever © 2011 Marques-Vidal et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.