Trends in obesity prevalence and changes in adiposity across ethnic groups: findings from a population-based prospective cohort study in Amsterdam, the Netherlands (HELIUS study)

Background and aim Obesity has reached epidemic proportions worldwide, with large differences across regions. European data on obesity trends among ethnic groups is scarce, particularly regarding the influence of age and socioeconomic status on these trends, which is crucial for guiding targeted interventions. In this study, we assessed the prevalence of obesity and changes in body mass index (BMI) and waist circumference (WC) over time and the effects of key sociodemographic factors on these changes using longitudinal data from a large multi-ethnic cohort.Methods Using baseline and follow-up data from 10 484 participants in the HEalthy Life in an Urban Setting (HELIUS) study, representing Dutch, South-Asian Surinamese, African Surinamese, Ghanaian, Moroccan and Turkish populations; age-adjusted obesity prevalence; BMI and WC changes over an average follow-up of 6.3 (SD 1.2) years were calculated. Linear mixed models were used to assess changes in BMI and WC over time, adjusting for age, sex and socio-economic position. Key analyses were stratified by age (younger <50 years, older ≥50 years).Results Median age of the baseline population was 48.0 years (IQR 38.0, 56.0), with 56.7% being women. Age-adjusted prevalence of obesity increased from 23.6% at baseline to 28.7% at follow-up, with steeper increases in ethnic minority groups compared with the Dutch origin group. The steepest increase in BMI and WC was observed in younger migrants, especially in those of Ghanaian and African-Surinamese descent. In older participants, only individuals of Ghanaian and Turkish descent showed a further increase in BMI over time.Conclusion Obesity is increasingly prevalent in ethnic minority groups under 50 years, potentially raising obesity-related health risks and underscoring the need for targeted interventions to prevent further complications.