Influence of sociodemographic factors in the prevalence of obesity in Spain. The SEEDO'97 Study

European Journal of Clinical Nutrition (2001) 55, 430±435 ß 2001 Nature Publishing Group All rights reserved 0954±3007/01 $15.00 www.nature.com/ejcn Original Communication In¯uence of sociodemographic factors in the prevalence of obesity in Spain. The SEEDO'97 Study J Aranceta1*, C Perez-Rodrigo1, L Serra-Majem2, L Ribas3, J Quiles-Izquierdo4, J Vioque4, M Foz5 and Spanish Collaborative Group for the Study of Obesity{ 1 Community Nutrition Unit, Department of Public Health, Municipality of Bilbao, Bilbao, Spain; 2Department of Preventive Medicine and Public Health, Faculty of Medicine, University of Las Palmas de Gran Canaria, Las Palmas, Spain; 3Group of Community Nutrition, Department of Public Health, Faculty of Medicine, University of Barcelona, Barcelona, Spain; 4Department of Public Health, University Miguel Hernandez, Campus San Juan, Alicante, Spain; and 5Department of Internal Medicine, Germans Trias i Pujol University Hospital, Badalona, Spain Objective: To analyse the in¯uence 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 de®ned as body mass index 30 kg=m2. The protocol used in each survey was in accordance with the recommendations of the Spanish Society for the Study of Obesity (SEEDO). Logisitic regression models were designed to analyse the in¯uence 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 ˆ 1.40 (95% CI 1.39 ± 1.41) for men and OR ˆ 1.86 (95% CI 1.85 ± 1.87) for women. Logisitic regression analysis adjusted for age showed higher obesity rates among low educated people, OR ˆ 1.80 (95% CI 1.78 ± 1.81) in men and OR ˆ 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 ˆ 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. Descriptors: epidemiology; prevalence; adults; cross-sectional studies; sociodemographic factors European Journal of Clinical Nutrition (2001) 55, 430±435 Introduction *Correspondence: J Aranceta, Community Nutrition Unit, Municipal Department of Public Health, Luis BrinÄas 18, 4th ¯oor, 48013 Bilbao, Spain. E-mail: { The members of The Spanish Collaborative Group for the Study of Obesity are: J Aranceta, M Barbany, D Bellido, M Carrillo, S DuraÂn, ML FernaÂdez-Soto, X Formiguera, M Foz, P GarcõÂa-Luna, JL Griera, JF MartõÂnez Valls, E MorejoÂn, B Moreno, L Serra-Majem, M Serrano RõÂos y FJ TeÂbar. Guarantor: Spanish Society for the Study of Obesity (SEEDO). Contributors: The Members of The Spanish Collaborative Group for the Study of Obesity contributed to the design of the study. Received 22 February 2000; revised 2 January 2001; accepted 17 January 2001 Overweight and obesity are becoming a new epidemic in Western developed countries and are major public health problems because of their impact on co-morbidity and associated health cost. This problem is often underestimated but the potential impact on health outcomes is comparable to that of tobacco (Aranceta, 1998; WHO, 1998). Obesity is a major risk factor for the development of coronary heart disease, hypertension, type 2 diabetes and dislipidaemia and has been related to some hormonedependent cancers as well (Pi-Sunyer, 1993; Khan & Bowman, 1999). Sociodemographic factors and obesity J Aranceta et al Recent data in the USA show an absolute increase of 8% in the prevalence of obesity in recent years, from 25% estimated in NHANES II (1976 ± 1980) to 35% in NHANES III (1990 ± 1994), thus a relative increase of 40% (Kuczmarski et al, 1994). In several countries the cost of obesity has been estimated to account for between 5 and 7% of the annual health budget (Wolf & Colditz, 1994; Birmingham et al, 1999; Bernard Krief, 1999). Data regarding the prevalence of obesity in Spain are based on regional Nutritional Surveys (Aranceta et al, 1994, 1995; Serra Majem et al, 1996; Quiles Izquierdo & Vioque, 1996) and local surveys of cardiovascular risk factors (Tormo DõÂaz et al, 1995). Some estimates have been based on data from the National Health Survey considering self-reported height and weight (GutierrezFisac et al, 1994). The Spanish Society for the Study of Obesity (SEEDO) supported the SEEDO'97 Study. The results of this study provide a global estimate of the prevalence of obesity in the country based on pooled population data. The SEEDO'97 Study considered data from regional surveys carried out during a time frame of 4 y using the same methodology and similar protocol, including anthropometric measurements and socio-demographic variables (Aranceta et al, 1998b). Although there is limited knowledge of factors which may in¯uence the variation in the prevalence of obesity, it is generally accepted that environmental factors as well as lifestyle play an important role in the onset of obesity, acting on a genetic substrate (Bouchard, 1996). A better understanding of population-based data is required in order to analyse key underlying factors, thus contributing to the development of effective public health intervention strategies targeted to prevent or diminish the problem. Therefore, the aim of this study is to analyse the in¯uence of social and cultural factors on the prevalence of obesity in the Spanish adult population aged 25 ± 60 y, based on available population data. Subjects and methods Sample This study considers cross-sectional data from four regional population nutrition surveys carried out between 1990 and 1994 in random samples of the Basque Country (Aranceta et al, 1995), the Region of Madrid (Aranceta et al, 1994), Catalunya (Serra Majem et al, 1996) and the Region of Valencia (Quiles Izquierdo & Vioque, 1996), which were unique Spanish population studies of obesity recognised by the SEEDO. All the samples were drafted by multi-step strati®ed random sampling procedures by age, gender and (...truncated)