Girls, boys and obesity

A recent study published in the Pediatric Obesity journal suggests that young girls who are either overweight or obese during childhood were more likely to remain obese as they progressed into young adulthood compared to boys.

The research study, led by Professor Shane Norris of the MRC Developmental Pathways for Health Research Unit at the University of the Witwatersrand reported that boys that were overweight during childhood (between the ages of four and eight) were two times more likely to become obese by the time they attained late adolescence (16 -18 years).

According to findings – in the study titled "Sex differences in obesity incidence: 20-year prospective cohort in South Africa" –  from the Soweto-based research unit in Johannesburg, if the boys were already obese as children, they were 20 times more likely to become obese adolescents.

The likelihood of becoming obese adolescents was more profound in girls; the study reported overweight girls to be seven times and obese girls to be 42 times more likely to remain obese by the time they were adolescents. Equally importantly, the researchers suggest that timely interventions particularly in girls, may reduce the risk of overweight and obesity especially due to the persistence of obesity across the age groups in girls.

The study also highlighted that obesity incidence was higher in girls between the ages 11 - 12 and 13 – 15 (11.2 cases/1 000 person-years) compared to boys between the ages 4 – 8 and 11 – 12 (6.8 cases/1 000 person-years).

The researchers speculate that this gender difference may be attributed to various factors, which include the onset of puberty, a period when females acquire more body fat than males, who gain more amounts of muscle and bone in addition to becoming more physically active.

While the rates of overweight and obesity in boys do not represent a significant public health concern, the investigators stressed that the figures seen in girls, particularly during adolescence, were comparable to those of high-income countries and underscored the urgency to find effective interventions targeted at fighting obesity during childhood and puberty.

This research adds to the body of evidence resulting from data obtained from the Birth-to-Twenty Plus cohort, to describe the rise in obesity incidence from infancy through late adolescence and to encourage the promotion of healthy nutrition and weight among female south African children.