The contribution of parental BMI to the metabolic health of their offspring: a longitudinal cohort study (EarlyBird 55).

OBJECTIVE: The objective of this study was to establish the extent to which parental factors influence the metabolic health of their offspring. DESIGN: The study was designed as a prospective longitudinal cohort study SUBJECTS: The study's subjects were 226 healthy trios from a 1995 to 1996 birth cohort randomly recruited in the city of Plymouth, UK MEASUREMENTS: Body mass index (BMI) and metabolic z-score (derived from natural log HOMA-IR, triglycerides, total/high-density lipoprotein cholesterol ratio), measured at nine annual time points, from 5 to 13 years. RESULTS: As expected, the metabolic z score was closely related to BMI in both genders and at all ages (r = 0.40-0.57, P < 0.001). Accordingly, there were large and significant differences in the metabolic z-score between children categorized as normal weight or overweight/obese. At 13 years, for example, the metabolic z score of the overweight/obese girls was 14-fold greater than that of the normal-weight girls (P < 0.001). However, parental BMI and metabolic status had little effect on these differences. Indeed, mixed effects modelling showed that, as the child's BMI increased, so the influence of parental factors became less relevant. Time-lag analyses confirmed that weight gain preceded metabolic disturbances in the children. CONCLUSION: The impact of obesity on the metabolic health of contemporary children is a function of their own weight gain, rather than that of their parents, and is therefore potentially preventable.