Maternal gestational weight gain and offspring vitamin D level: a multicentre retrospective cohort study

Background This study examined the association between maternal gestational weight gain (GWG) and offspring vitamin D levels. Methods In this retrospective cohort study, 0–5-year-old children attending routine health checks at 12 centres across 10 cities in Jiangsu Province (April 2014–March 2015) were enrolled via stratified random cluster sampling. Serum 25(OH)D was measured by ELISA. Results Among 1,984 mother–offspring pairs, GWG ≤10 kg was associated with an increased risk of vitamin D deficiency (<50 nmol/L) in the unadjusted model ( OR = 1.550, 95% CI : 1.196–2.008), and this association remained significant in Model 1 ( OR = 1.820, 95% CI : 1.357–2.441), Model 2 ( OR = 1.545, 95% CI : 1.060–2.253), and Model 3 ( OR = 1.882, 95% CI : 1.228–2.883). For vitamin D insufficiency (50–<75 nmol/L), GWG >19 kg was associated with an increased risk in the unadjusted model ( OR = 1.309, 95% CI : 1.026–1.670) and in Model 1 ( OR = 1.312, 95% CI : 1.021–1.685), Model 2 ( OR = 1.872, 95% CI : 1.305–2.684), and Model 3 ( OR = 1.609, 95% CI : 1.054–2.456). This association was statistically significant in Model 3 but was no longer significant after FDR correction. Conclusion To our knowledge, this is the first multicentre study to report an association between GWG ≤10 kg and an increased risk of vitamin D deficiency in offspring, and between GWG >19 kg and an increased risk of vitamin D insufficiency. However, the latter association did not remain significant after FDR correction in sensitivity analyses based on Model 3 and requires confirmation in further studies.