Trends in the prevalence of childhood overweight and obesity according to socioeconomic status: Spain, 1987-2007

BACKGROUND/OBJECTIVES: To ascertain trends in the prevalence of overweight and obesity among Spanish children and adolescents according to the socioeconomic status of the family household and area of residence across the period 1987-2007. SUBJECTS/METHODS: For study purposes, data were drawn from the 1987, 1995, 1997, 2001 and 2007 Spanish National Health Surveys. Overweight and obesity were estimated on the basis of body mass index. The following indicators of socioeconomic status were used: educational level of primary household earner and per capita income of province of residence. The statistical significance of the trend in the prevalence of overweight and obesity was assessed for each category of socioeconomic status. The chi(2) test for trend was used in the case of educational level and a linear regression in the case of per capita income of province of residence. RESULTS: Although the prevalence of overweight and obesity had levelled off among boys and girls aged 5 to 9 years, it nevertheless showed a significant upward trend among those aged 10 to 15 years from families whose primary household earner had a lower educational level. The prevalence of overweight among boys in this last group was 13.1% in 1987 and 31.5% in 2007. From 1997 onwards, the prevalence of overweight and obesity among boys and girls aged 10 to 15 years increased in both the richest and the remaining provinces, although the magnitude of this increase was greater in the latter. Specifically, in these provinces the prevalence increased from 18 to 28.9% over the period of study. CONCLUSIONS: The prevalence of overweight and obesity in the childhood population in Spain has stabilised, except among adolescents, whether from lower-income families or lower-income areas, among whom a rising trend is in evidence.