Background: Mothers bearing small offspring are at increased risk of cardiovascular disease (CVD) mortality. The cardiovascular risk for fathers of small offspring is, however, inconclusive. Very few studies with sufficiently large sample sizes have been conducted to specifically differentiate the maternal/paternal CVD risk in association with offspring birth weight in the same population.
Methods: This study followed 1,400,383 primigravida and their spouses with singleton births registered in Taiwan between 1978 and 1987 to the end of 2006. By linking to the mortality registry, the hazards ratio (HR) of parental cardiovascular mortality was measured in relation to lower offspring birth weights.
Results: The covariate-adjusted HR and 95% confidence interval (CI) of CVD mortality for 1 standard deviation higher offspring birth weight was reduced (HR = 0.89; 95% CI: 0.85-0.94) for mothers, but less obvious for fathers (HR = 0.97; 95% CI: 0.95-1.00). Analyses of the categorical offspring birth weights revealed that the association between bearing low-birth-weight offspring (<2500 g) and CVD mortality was also stronger in mothers (adjusted HR = 1.85; 95% CI: 1.67-2.18) than in fathers (adjusted HR = 1.13; 95% CI: 1.03-1.24). On standardizing the birth weight for gestational age, the observed associations persisted, although these associations were relatively weak.
Conclusions: This large cohort analysis confirmed that the bearing of smaller size infants is associated with a stronger elevated risk for CVD mortality in mothers than in fathers. Women who have had a lower birth-weight offspring can be targeted for CVD-prevention measures.