Obesity is a public health concern with a strong impact on the health of the population. The aim of this study was to analyze the trend in the prevalence of obesity and to identify changes in this trend in Spain and its 17 autonomous communities (AC) among the population aged ≥ 15 years from 1987 to 2020.

A trend analysis of the prevalence of obesity was conducted with data extracted from the complete historical series of the Spanish National Health Survey and the European Health Survey in Spain using joinpoint regression models. For each period identified in the trend analysis, we estimated the annual percentage change (APC) and its 95% confidence interval (95%CI). The results are presented for crude and standardized prevalences by the direct method accompanied by 95%CI, sex ratios, and relative changes in prevalences between periods.

The prevalence of obesity increased from 7.3% (95%CI, 7.0-7.7) in 1987 to 15.7% (95%CI, 15.1-16.3) in 2020. In men, the prevalence increased until 2009 (APC,4.3; [95%CI, 3.8-5.0]) and then stabilized. In women, the prevalence increased until 2001 (APC,4.2; [95%CI, 2.7-8.8]) and subsequently also stabilized. The prevalence of obesity and its trend varied between AC, with three different patterns being observed with standardized prevalences: AC with a continuous increase, AC with an increase and subsequent stabilization, and AC with an increase and subsequent decrease.

The prevalence of obesity has increased in Spain since 1987, although in the last decade it has remained stable at values above 15%. However, in the group aged 15 to 24 years, the prevalence of obesity showed an increasing trend throughout the study period.