Long-term trends in the body mass index and obesity risk in Estonia: an age-period-cohort approach.

Abstract

To analyse the age, period and cohort effects on the mean body mass index (BMI) and obesity over the past two decades in Estonia. Study used data from nationally representative repeated cross-sectional surveys on 11,547 men and 16,298 women from 1996 to 2018. The independent effects of age, period and cohort on predicted mean BMI and probability of obesity (BMI ≥ 30kg/m2) were modelled using hierarchical age-period-cohort analysis. Curvilinear association between age and mean BMI was found for men, whereas the increase in mean BMI was almost linear for women. The predicted mean BMI for 40-year-old men had increased by 6% and probability of obesity by 1.8 times over 1996-2018; the period effects were slightly smaller for women. Men from the 1970s birth cohort had higher mean BMI compared to the average, whereas no significant cohort effects were found for obesity outcome. Population-level BMI changes in Estonia during 1996-2018 were mostly driven by period rather than cohort-specific changes.