Early childhood and prepregnancy maternal weight related to weight at 15 years of age
Association of maternal prepregnancy weight and early childhood weight with obesity in adolescence: A population‐based longitudinal cohort study in Japan
Introduction and methods
Obesity in childhood is associated with higher risks of premature onset of illnesses, including diabetes and CV diseases, and death. The prevalence of obesity among children is increasing worldwide. While high birth weight is associated with increased risk of obesity, the link between low birth weight and risk of obesity in childhood is controversial [1-3]. Evidence is currently emerging that obesity in early childhood is an important predictor of obesity in adolescence or adulthood [4,5].
Some studies have also suggested that parental obesity is associated with obesity in children, but prenatal factors that may influence weight later in life are not well understood in the Asian population .
This study therefore studied over a thousand mother-child pairs over a course of 15 year follow-up from birth to adolescence, to examine the association of overweight/obesity at age 15 years (BMI >23.28 for boys and BMI >23.89 for girls, overweight and obesity taken together) with birth weight (low or normal with WHO cut off of 2500g, high: ≥4000g), overweight/obesity in early childhood (overweight: BMI >17.85 for boys and >17.64 for girls at 3 years) and prepregnancy overweight/obesity in mothers.
Data of infancy and school age health check-up data in Japan were used. In Japan, health check-up is mandatory at 1 month, 3 or 4 months, 6 or 7 months, 18 months and 3 years of age, and annually for students at school (check-up data at 15 years used here). Children included in this study were born in Hofu City between April 2000 and March 2003. Maternal pregnancy information was collected by self-administered questionnaires during early pregnancy. Data of 1581 children at 15 years of age and who were followed up since birth were available, with data of their mother’s pregnancy.
- 167 (10.6%) children of 15 years old were overweight/obese, of whom 86 were boys and 81 girls. 130 (8.2%) had low birth weight, and at 3 years 93 (5.9%) had overweight/obesity.
- 14.0% of low birth weight children showed overweight/obesity at 15 years of age compared with 10.7% of those with normal birth weight (P=0.252).
- Children with overweight/obesity compared to normal weight at age 3 years showed higher rates of overweight/obesity at 15 years (33.7% vs. 9.2%, P<0.001).
- Overall analyses in all subjects revealed no association of overweight/obesity at age 15 years with birth weight (adjOR: 0.97, P=0.311) or BMI at 18 months (per 1 kg/m2 increase: aOR: 0.87, P=0.273).
- BMI at age 3 did show a significant association with risk of being overweight/obese at age 15 (per 1 kg/m2 increase: aOR: 2.15, 95%CI: 1.71-2.70, P<0.001), as was maternal prepregnancy BMI (per 1 kg/m2 increase: aOR: 1.17, 95%CI: 1.17-1.24, P<0.001).
- When assessed as categorized weight groups, overweight/obesity at 3 years was significantly associated with a higher risk of overweight/obesity at 15 years (aOR: 4.26, 95%CI: 2.51-7.25, P<0.001). When boy and girls were considered separately, only girls showed a significant association (aOR: 6.48, 95%CI: 3.25-12.9, P<0.001), not boys (aOR: 2.29, 95%CI: 0.92-5.69, P<0.75).
- Prepregnancy BMI was also found to be associated to overweight/obesity at 15 years overall (aOR: 2.46, 95%CI: 1.41-4.30, P=0.002), but in separate analyses this association was only significant in girls (aOR: 2.89, 95%CI: 1.30-6.41, P=0.009), not boys (aOR: 2.18, 95%CI: 0.98-4.8, P=0.057).
- No association was seen between overweight/obesity at age 15 years and low birth weight (aOR: 1.54, P=0.188) or high birth weight (aOR: 2.06, P=0.272).
This longitudinal analysis of Japanese adolescents revealed an association between overweight/obesity at 3 years with a girl’s risk of being overweight/obese at 15 years of age. While prepregnancy overweight/obesity in mothers was also a predictor of overweight/obesity in 15 year old girls, no relation was found between birth weight and being overweight/obese at 15 years.