The obesity epidemic has become a major public health problem in both industrialized countries and the developing world. Recent studies suggest that the major development of persistent adiposity is established already at pre-adolescence.
The fact that obesity is mainly determined before puberty implies that preschool detection of children at risk is essential along with individual prevention programs.
A Swedish study reports a protocol that detects with high precision which pre-adolescent children will be obese later using only weight and height data.
The protocol selects boys having a body mass index (BMI) above the international standard for obesity at both age 4 and age 5, and girls having a BMI higher than 20 at the age 5 for individual weight-reduction programs. The protocol does not require additional tests or equipment, and can thereby be used in any child healthcare setting where the growth of preschool children is monitored.
Already in its present form, the protocol can save sizeable societal costs accrued by obesity and reduce suffering among the affected individuals and their families. The researchers will still continue to refine the protocol in order to increase the share of detected obese pre-adolescents without loosing the high precision.
This extension of the protocol is likely to require inclusion of new observation in the routine health monitoring of pre-school children, such as family heredity for obesity and eating behaviours.
The study analyzed data obtained for child health surveillance up to age 5 from 5778 children born in a Swedish county in 1991. The basic data set included age, sex, and weight and height measurements from the regular checkups between ages 1.5 and 5. Data not routinely collected in the child health centre setting were disregarded. The children were at age 10 randomly assigned to protocol derivation and validation cohorts and assessed for obesity according to IOTF criteria.
The accuracy of predicting obesity in the validation cohort was measured using decision precision, specificity, and sensitivity. The decision protocol selected 1.4% of preschool children as being at obesity risk. The precision of the protocol at age 10 was 82% for girls and 80% for boys, and the specificity was 100% for both boys and girls. The sensitivity was higher for girls (41%) than for boys (21%). The relative risk for obesity at age 10 estimated by the odds ratio for individuals selected by the protocol compared to non-selected peers was 212.6 (95% confidence interval 56.6 to 798.4) for girls and 120.3 (95% CI 24.5 to 589.9) for boys.
A simple and inexpensive decision protocol based on BMI values proved to have high precision and specificity for identification of preschool children at risk for obesity persisting into adolescence, while the sensitivity was low especially for boys. Implementation and further evaluations of the protocol in child health centre settings are warranted.