Background: Childhood obesity increases the risk for adult obesity and cardio metabolic disease.
Objective and hypotheses: The aim with the present study was to investigate longitudinal changes of childhood body mass index (BMI), overweight, and obesity in boys born 1946 until present time, using the population-based BMI Epidemiology STudy (BEST) cohort in Gothenburg, Sweden.
Method: We collected detailed growth data (height and weight) from archived school health records for boys born every five years between 1946 and 2006 (n=1,584 for reference birth cohort 1946, n=425 for each birth cohort 19512006, total n=6,684). BMI at eight years of age was calculated for all included individuals.
Results: Childhood BMI at eight years of age increased 0.18 kg/m2 (95% confidence interval 0.16; 0.20) per decade increase in birth year during 19462006. The increase was statistically significant from birth year 1971, peaked 1991, and after birth year 1991, an apparent reduction was seen. Next, we aimed to thoroughly explore the trend after birth year 1991 and therefore expanded birth cohorts 1991 (n=1,566), 2001 (n=6,478), and 2006 (n=6,515). Importantly, a significant decrease in mean BMI (P<0.01), overweight prevalence (P<0.01), and obesity prevalence (P<0.05) was seen after 1991. In boys categorized to Sweden as country of birth, a substantial reduction in overweight (−28.6%, P<0.001) and obesity (−44.3%, P<0.001) prevalence was observed between birth year 1991 and birth year 2006.
Conclusion: Using the unique population-based BEST cohort, we provide clear evidence of a childhood obesity epidemic that increased statistically significant from birth year 1971, peaked birth year 1991, and declined afterwards. This is the first long-term study describing both the rise and the recent fall of childhood obesity. As childhood obesity is strongly associated with subsequent adult obesity, we propose that a similar reduction in adult obesity prevalence might be expected during the coming decades.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology