Secular trends in weight, height and BMI in young Swedes: the 'Grow up Gothenburg' studies.

AIM

This study aims to document secular differences in anthropometry (level and variability of weight, height, BMI) in two cohorts born around 1990 and 1974 and examined as young adults.

METHODS

Descriptive results are presented for the complete cohorts. The final analysis age-matched the cohorts (mean, 18.8 years) and employed CDC z-scores to compare means and distributions of weight, height and BMI.

RESULTS

Z-scores for weight, height and BMI were higher in later-born (1990) boys, while in girls weight and height increased over this period without resulting in increased BMI. At the same time, in boys the BMI variances increased, confirming a simultaneous emergence of more overweight and more underweight. In girls, the BMI variance did not increase significantly. Sensitivity analyses, excluding subjects not born in Sweden, confirmed increasing BMI trends in boys.

CONCLUSION

This study documents that gender differences in the recent childhood obesity epidemic can also be observed in young Swedes as they enter adulthood. Comparing two cohorts of high school students born around 1974 or 1990, less favourable trends in weight status were seen in boys than in girls. Finally, secular increases in height, already observed earlier in the 20th century, continued in these more contemporary cohorts.