Maternal calcium supplementation and cardiovascular risk factors in twin offspring

Background There is evidence that maternal calcium supplementation may result in lower offspring blood pressure. We hypothesized that maternal calcium supplementation also influences other cardiovascular risk factors. Methods In the Tasmanian Infant Health Study, supplements reportedly taken in pregnancy were recorded. Twin children of 147 participating mothers were seen at mean age 9 years. Blood pressure was measured in all 294 children and fasting blood samples taken from 230 (78%) for glucose and insulin, triacylglycerol, total cholesterol (T-C) and HDL cholesterol (HDL-C). LDL cholesterol (LDL-C) was calculated. Results Children of supplemented mothers (n = 110, 77 had venipuncture) had lower geometric mean triacylglycerol, T-C, and LDL-C than other children. After adjustment for potential confounding factors, geometric mean ratios were 0.86 (95% CI: 0.75, 0.98), 0.94, (95% CI: 0.90, 0.99) and 0.90, (95% CI: 0.83, 0.98) respectively. The association with T-C and LDL-C was seen principally among children with BMI > 17.5: estimated ratios 0.85 (95% CI: 0.79, 0.92) for total cholesterol and 0.79 (95% CI: 0.70, 0.90) for LDL cholesterol (P for interaction 0.001 and 0.009 respectively). There was no significant association between maternal calcium supplementation and child size at birth and follow up, blood pressure, fasting glucose or insulin or HDL-C. Conclusions Maternal calcium supplementation may confer health benefits on twin offspring, especially if they are relatively fat. Calcium availability could permanently programme lipid metabolism during fetal life, directly or by influencing maternal lipid profile. Our findings need to be replicated in other studies and in singletons. If confirmed, our findings could have important implications for population health.