Trends in adolescent obesity in the Arab ethnic minority in Israel: an age-period-cohort analysis

Background: The goals of the study were to analyze trends, age, period and cohort effects on overweight/obesity among Arab adolescents in Israel. Methods: A retrospective cohort study of 345,852 Arab adolescents aged 14–19 years between the years 2007–2022, and 283,420 Jewish adolescents’ comparison group. Age effect was assessed by examining the effect of the age group (each year between 14 and 19 years), period effect by evaluation of the impact of the time period (two-year periods between 2007 and 2022), and birth cohort effect by estimating the effect of birth cohort (four/five-year birth cohorts between 1988 and 1991 and 2000–2003) on the prevalence of overweight and obesity. Results: There was an increase in the crude prevalence of obesity, and severe obesity (from 13.4% to 22.2%, and from 5.1% to 11.9%, respectively) among Arab adolescents. These numbers exceeded those in the matched Jewish group. The age effect was expressed by the constant decline in the adjusted Odds ratio (aOR) for obesity between the ages 14 (reference age) to 19 years (aOR = 0.30 (95% CI − 0.28–0.31)). The period effect was manifested by an increase in the aOR for obesity, reaching 1.88 (95% CI − 1.76–2.02) in 2021–2022. The cohort effect showed a steep increase in obesity prevalence from the cohort born in 1988–1991 (reference age) to the cohort born from 2000 to 2003 (aOR = 1.67 (95% CI − 1.57–1.77)). Conclusion: The combination of an increasing risk for obesity over time in the younger birth cohorts poses an increasing threat to future generations of adolescents. The findings could help focus future policy for vulnerable adolescent groups.