Body mass index in rural first grade schoolchildren: progressive increase in boys

Childhood overweight is a global health problem. Monitoring of childhood body mass index (BMI) may help identify critical time periods during which excess body weight is accumulated.

To examine changes in mean BMI and the prevalence of at-risk-for overweight in repeated cross-sectional samples of rural first grade schoolchildren between 1999 and 2004.

BMI was determined in 479 first graders from a rural Wyoming school district. BMI and gender-specific BMI-for-age percentiles were determined and evaluated over the 6 years. Children were also classified as normal or at-risk-for overweight according to CDC classification procedures.

From 1999 to 2004, there was a significant increase in the average BMI of first graders, 15.8+/-2.2 kg/m2 versus 16.8+/-2.2 kg/m2, respectively (P<.05). First grade boys had a progressive increase in BMI from 1999 to 2004 (15.6+/-2.2 kg/m2 compared to 17.3+/-2.2 kg/m2, respectively), but no change was evident for first grade girls. There was an approximate 4-fold increase in the percentage of rural first grade boys classified as at-risk-for overweight between 1999 and 2004.

A progressive increase in the BMI and the significant increase in prevalence of at-risk-for overweight in rural first grade boys highlight the need for future gender and age group-specific investigations. Focus should be given to primary prevention programs targeting potentially vulnerable time periods when excess weight gain may be occurring.