Background: With the exception of studies on folic acid, little evidence is available concerning other nutrients in the pathogenesis of congenital heart defects (CHDs). Fatty acids play a central role in embryonic development, and the B-vitamins riboflavin and nicotinamide are co-enzymes in lipid metabolism.
Aim of the study: To investigate associations between the maternal dietary intake of fats, riboflavin and nicotinamide, and CHD risk in the offspring.
Methods: A case-control family study was conducted in 276 mothers of a child with a CHD comprising of 190 outflow tract defects (OTD) and 86 non-outflow tract defects (non-OTD) and 324 control mothers of a non-malformed child. Mothers filled out general and food frequency questionnaires at 16 months after the index-pregnancy, as a proxy of the habitual food intake in the preconception period. Nutrient intakes (medians) were compared between cases and controls by Mann-Whitney U test. Odds ratios (OR) for the association between CHDs and nutrient intakes were estimated in a logistic regression model.
Results: Case mothers, in particular mothers of a child with OTD, had higher dietary intakes of saturated fat, 30.9 vs. 29.8 g/d; P < 0.05. Dietary intakes of riboflavin and nicotinamide were lower in mothers of a child with an OTD than in controls (1.32 vs. 1.41 mg/d; P < 0.05 and 14.6 vs. 15.1 mg/d; P < 0.05, respectively). Energy, unsaturated fat, cholesterol and folate intakes were comparable between the groups. Low dietary intakes of both riboflavin (<1.20 mg/d) and nicotinamide (<13.5 mg/d) increased more than two-fold the risk of a child with an OTD, especially in mothers who did not use vitamin supplements in the periconceptional period (OR 2.4, 95%CI 1.4-4.0). Increasing intakes of nicotinamide (OR 0.8, 95%CI 0.7-1.001, per unit standard deviation increase) decreased CHD risk independent of dietary folate intake.
Conclusions: A maternal diet high in saturated fats and low in riboflavin and nicotinamide seems to contribute to CHD risk, in particular OTDs.