Certain factors induce substantial, persisting risk of higher BMI in childhood
Factors including parental body mass index (BMI), low socioeconomic position (SEP) and smoking during pregnancy exert a strong, persisting influence on childhood BMI and weight, regardless of birthweight and infancy BMI, study reports.
Researchers looked at family triads with available data on maternal, paternal and child BMI at ages 7 years (n=29,374) and 11 years (n=18,044) from the Danish National Birth Cohort. Data were obtained from maternal interviews and medical health examinations. Path analysis facilitated estimation of the direct and indirect effects of prenatal risk factors on childhood BMI z-scores (BMIz per unit score of the risk factor).
At age 7 years, the strongest direct effects on BMIz were produced by maternal and paternal BMI (0.19 and 0.14, respectively), low SEP (0.08), maternal smoking (0.12), and higher BMIz at 5 and 12 months (up to 0.19).
At age 11 years, similar effects were observed. However, the direct effects of BMIz at age 5 and 12 months were mediated through BMI at age 7 (0.62).
Results were similar for the risk of overweight at ages 7 and 11 years. In a child with average height and BMI, the sum of the direct effects could be translated to approximate absolute measures: 2.4 kg at 7 years and 5.7 kg at 11 years.
The findings show that certain factors produce a substantial and persisting risk of a higher BMI and of overweight in childhood, researchers said. These may play an important role in the fight against overweight and obesity in children.