Maternal central obesity and birth size: a Mendelian randomization analysis

Area of Science:

• Reproductive biology
• Human genetics
• Pediatrics

Background:

• Maternal central obesity is linked to offspring birth size, but causal links are unclear.
• Observational studies suggest associations with birth weight, length, and head circumference.
• Mendelian randomization (MR) can investigate causal relationships.

Purpose of the Study:

• To determine the causal effect of maternal central obesity on birth size.
• To assess the impact of maternal central obesity on puberty height growth.
• Utilizing Mendelian randomization (MR) analysis for causal inference.

Main Methods:

• Two-sample MR analysis using public genome-wide data.
• Instrumental variables included SNPs for hip circumference (HIP), waist circumference, and waist-to-hip ratio, adjusted for BMI.
• Inverse-variance-weighted approach applied to estimate causal effects.

Main Results:

• Maternal hip circumference (HIP) showed a causal association with increased birth length and birth weight.
• Higher genetically predicted maternal HIP was strongly associated with greater puberty heights.
• No causal association was found between maternal waist circumference or waist-to-hip ratio and the studied outcomes.

Conclusions:

• Genetic predisposition to higher maternal hip circumference causally increases offspring birth size, independent of maternal BMI.
• Maternal hip circumference is causally linked to offspring birth size and puberty height.
• No causal link was identified between maternal waist circumference, waist-to-hip ratio, and offspring birth size.