Association of Chinese maternal lifestyle during pregnancy and lactation with vitamin D levels in offspring: a multicenter retrospective cohort Jiangsu study

<i>Background</i>: This study aims to investigate the association between maternal lifestyle during pregnancy and lactation and vitamin D levels in their offspring, providing insights for interventions against vitamin D deficiency. <i>Methods</i>: A stratified random cluster sampling approach was used to recruit children aged 0-5 years in Jiangsu Province. Self-designed questionnaires were utilized to explore maternal lifestyle. Subsequently, the serum 25-hydroxyvitamin D levels were quantified using the enzyme-linked immunosorbent assay technique. <i>Results</i>: We recruited 5243 mother-child pairs. Factors significantly associated with an increased risk of vitamin D deficiency in offspring included maternal vitamin D and calcium supplementation, fish and shrimp intake ≥2 times per week, and <1 hour of outdoor activity per day during pregnancy, and initiation of vitamin D and calcium supplementation after labour and delivery, daily vitamin D and calcium supplementation deficiencies, fish and shrimp intake ≥4 times per week, and <1 hour of outdoor activity per day during lactation, with OR values of 1.26, 1.47, 1.45, 2.31, 1.89, 1.49, and 1.23 and <i>β</i> values of -3.67, -10.44, -5.13, -8.64, -7.55, -5.14, and -2.73, respectively. 25-Hydroxyvitamin D levels were significantly higher in offspring of mothers who started VD and calcium supplementation at 5-12 weeks and 12 weeks or more of pregnancy and in offspring who consumed 250-500 ml of milk per day during pregnancy and 500 ml or more of milk per day by 7.60, 9.58, 8.93, and 9.36 nmol L^-1, respectively, all with <i>P</i> < 0.05. <i>Conclusion</i>: Lower levels of vitamin D in offspring were associated with higher weekly intake of fish and shrimp by mothers during pregnancy and lactation, less daily outdoor activity, vitamin D and calcium supplementation during pregnancy, supplementation started before or early in pregnancy, insufficient milk intake during pregnancy, vitamin D supplementation immediately after delivery, and lack of daily vitamin D and calcium supplementation during lactation.