Trends in thin body stature among Japanese male adolescents, 2003-2012.

BACKGROUND

The desire for thin body stature and unhealthy eating behaviours have spread among Japanese boys. The prevalence of thinness in boys is expected to increase; however, recent trends have not been reported.

AIM

To describe changes in the distribution of body mass index (BMI) of Japanese boys, from 2003 to 2012.

SUBJECTS AND METHODS

BMI distribution changes were studied in 2599 relatively affluent Japanese children and adolescents, aged 12.5-17.5 years, during 2003-2012. The 2003 and 2004 data were combined and compared to the combined 2011 and 2012 data. Tukey mean-difference plots were used to study the direction and magnitude of shifts in BMI distributions.

RESULTS

Prevalence of thinness has progressively increased from 2.8-4.7% in 2003-2004 to 5.1-7.6% in 2011-2012 in Japanese boys. Tukey plots showed that the increases in the prevalence of thinness are related to shifts in the entire distribution of BMI in the sample.

CONCLUSION

Thin body stature was documented in increasing proportion of Japanese male adolescents. BMI z-scores decreased across the entire BMI centile spectrums, indicating that the whole school population may be at risk of thinness.