The biological and social determinants of childhood obesity: comparison of two cohorts 50 years apart

Objective; To determine whether the same relationships between early life risk factors and socioeconomic status with childhood BMI are observed in a modern cohort (2000) compared with an historic cohort (1947). Study design; The relationships between early life factors and SES with childhood BMI were examined in two prospective birth cohorts from the same region, born 50 years apart: 711 children in the 1947 Newcastle Thousand Families Study (NTFS) and 475 from the 2000 Gateshead Millennium Study (GMS). The associations between birthweight, breastfeeding, rapid infancy growth (0-12 months), early life adversity (0-12 months) and parental SES (birth and childhood) with childhood BMI z-scores, and whether overweight/obese (BMI >91 st centile using UK 1990) aged 9 were examined using linear regression, path analyses and logistic regression. Results; In the NTFS, the most advantaged children were taller than the least (+0.91 height z-score, P = .001), whereas in GMS they had lower odds of overweight/obese than the least (0.35 (0.14, 0.86)). Rapid infancy growth was associated with increased BMIz in both cohorts, and with increased likelihood of overweight/obese in GMS. Conclusions; This suggests that children exposed to socioeconomic disadvantage or who have rapid infancy growth in modern environments are now at lower risk of growth restriction, but greater risk of overweight.