Trends in relative weight over 1 year in low-income urban youth

Recent cross-sectional data indicate the rates of childhood obesity are plateauing. Few large-scale longitudinal data sets exist, particularly in low-income and minority youth. The purpose of this study was to describe longitudinal changes in relative weight among a large sample of low-income, minority youth over 1 year.

Participants were students from 56 schools in urban, low-income environments. There were 17,727 first- to sixth-graders (64% African-American, 52% male) assessed at baseline, and 13,305 youth (75.1%) were reassessed 1 year later at follow-up. Measured height and weight were used to assess categorical (overweight, obesity, severe obesity) and continuous (BMI, percentile, z-score) measures of relative weight.

Longitudinal data showed that over 1 year, BMI percentile (95% CI.64--0.32, P<0.001) and BMI z-score (95% CI: -0.02--0.01, P<0.001) were significantly lower compared to baseline. The prevalence of overweight and obesity was stable over 1 year. Most (86.0%) youth remained in the same weight category as baseline, 6.8% improved weight category, and 7.2% worsened weight category over 1 year.

These longitudinal data indicate that the relative weight of low-income, urban youth is showing signs of a small improvement over a 1-year follow-up period. The rates of childhood obesity, however, remain remarkably high and require continued, creative public health efforts.