Pre-pregnancy obesity and offspring IQ at 5 years
Maternal obesity has become an increasingly alarming issue, as it is associated with an increased risk of numerous obstetric complications, in addition to long-term metabolic conditions for the offspring. Pre-pregnancy obesity has been associated with offspring neurodevelopment as well. However, the effects on child cognition are less clear, as previous studies have been limited in their ability to control for important maternal factors that may bias the associations observed. More importantly, this relationship has been minimally studied in children born preterm, though these children are already vulnerable to cognitive deficits in a step-wise manner with decreasing gestational age.
This study aimed to determine whether pre-pregnancy body mass index (BMI) is associated with offspring intelligence quotient (IQ) up to 5 years and whether this relationship varied with gestational age.
Data from two French birth cohorts, EDEN (all gestational ages; n=1100) and EPIPAGE-2 (preterm-born children between 24-34 weeks of gestation; n=2629), were used for this study. Pre-pregnancy weight and height were used to calculate pre-pregnancy BMI. The Wechsler Preschool and Primary Scale of Intelligence was used to assess child IQ around 5 years. Multivariable models were used to determine the association between pre-pregnancy BMI and offspring IQ around 5 years.
Lower intellectual functioning (full-scale IQ<85) was observed in 8.1% of children from EDEN and 19.6% of children from EPIPAGE-2. Pre-pregnancy obesity was associated with an approximate 3-point decrease in full-scale IQ scores in both cohorts, while pre-pregnancy overweight was associated with more modest decreases (less than 2-points).
Though a 3-point decrease in full-scale IQ may appear relatively minor, this change corresponds to the same difference in IQ between a child born at term and a child born at 8 months in the EDEN cohort. These differences may be significant from a public health perspective, since even modest variation in population-level IQ scores, despite little clinical significance for the individual, could have relevant effects on human capital. In addition, due to the high prevalence of maternal obesity, this would affect many children at a population level.
Link to the full text here: https://onlinelibrary.wiley.com/doi/10.1111/ppe.13157
By Courtney DOW
Photo credits: Tammi Dow via Adobe AI
