OBJECTIVES: Studies examining the time trend in social inequalities in obesity have yielded diverse results. The aim of this study is to investigate whether social inequalities in obesity have increased overtime in Belgium.

METHODS: We used data from three national cross-sectional health interview surveys (1997 n=7953, 2001 n=8887, and 2004 n=9709) to estimate age-standardized obesity prevalence and a series of summary measures reflecting health inequalities in men and women aged 18 years and older.

RESULTS: For males, a clear socioeconomic gradient was observed between obesity and education. This gradient witnessed a large increase between the years 1997 and 2004. For instance, the relative index of inequality increased from 1.92 (95% CI: 1.16-3.18) to 3.71 (95% CI: 2.49-5.54). Social inequalities in female obesity indicate a different pattern. Our results revealed a very steep socioeconomic gradient for female obesity, but overtime, no significant change was observed. The relative index of inequality for female obesity was 4.04 (95% CI: 2.47-6.63) in 1997 and 4.03 (95% CI: 2.75-5.90) in 2004.

CONCLUSIONS: Using three comparable nation-wide population-based surveys, our study has shown that in Belgium from 1997 to 2004, the socioeconomic gradient in obesity has increased for males and persisted for females.