Body mass index in Australian children: Recent changes and relevance of ethnicity

Abstract

Aim - To determine changes over time in the body mass index (BMI) profile of Australian primary schoolchildren and to assess the effects of sex and ethnicity. Methods - Height and weight were measured in 3645 children (1869 girls and 1596 boys), aged 5-12 years from 39 schools in southeastern Sydney during 1994-7. Levels in the four largest ethnic groups of the population were compared with those measured by the 1985 Australian Council on Health, Physical Education, and Recreation (ACHPER) survey. Results - The study population was 59.9% white (north European), 8.5% Mediterranean white, 7.7% Asian, 7.7% other, and 16.2% mixed (mainly Asian-white (36%) and Arab- white (24.7%)). There were sufficient numbers in four groups for analysis and comparison with the ACHPER survey: Mediterranean white, other white, mixed ethnicity, and Asian children. The age and sex adjusted BMI was highest in Mediterranean white, then white, mixed race, and Asian children. There were minimal differences between sexes within each group. However, boys had an age and sex adjusted BMI 1.5-6.5% higher (mean, 3.9%) than in ACHPER in 1985, as did white girls (mean increase, 2.4%). Conclusions - BMI in southeastern Sydney schoolchildren is related strongly to ethnicity and age; in boys and white girls it is on average 3.9% and 2.4% greater, respectively, than that recorded in the 1985 ACHPER survey. We suggest that this 10 year increase reflects a general trend in developed countries. Because increased BMI in childhood tracks to adulthood and is then associated with adverse effects on health, these findings signal a need for prevention.