Shellfish and Fatty Fish Intake and Fecundability in a North American Prospective Cohort Study

摘要

Fatty fish and shellfish are important sources of omega-3 fatty acids, which may improve embryo morphology and fecundity. However, they are also sources of persistent organic pollutants and heavy metals, which may adversely affect fecundity. In a French retrospective cohort study of 3,421 pregnant women, shellfish intake ≥2 times/week (relative to <2 times/month) was associated with a 21% reduction in fecundability (average per-cycle probability of conception); fish intake showed little association with fecundability. There have been no prospective studies of these associations. We evaluated intakes of shellfish, fatty fish, and marine fatty acids (sum of eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid) in relation to fecundability in a prospective cohort study of 3,292 female pregnancy planners from the United States and Canada. At enrollment, women completed a baseline questionnaire on sociodemographics, anthropometrics, behavioral factors, and medical history, and a validated food frequency questionnaire (NIH diet history questionnaire II). Pregnancy status was updated bimonthly for 12 months or until pregnancy, whichever came first. We estimated fecundability ratios (FR) and 95% confidence intervals (CI) using proportional probabilities regression models, adjusted for energy, age, body mass index (BMI), smoking, alcohol, physical activity, intercourse frequency and timing, multivitamin use, race/ethnicity, education, marital status, and parity. We restricted analyses to women with <6 menstrual cycles of attempt time at enrollment. Greater shellfish intake was associated with slightly reduced fecundability (≥4 servings/month vs. none: FR=0.87, 95% CI: 0.72-1.07). The shellfish association was stronger among non-users of fish oil supplements (FR=0.77, 95% CI: 0.61-0.98), particularly overweight women (BMI ≥25 kg/m2: FR=0.69, 95% CI: 0.48-1.01). Intakes of fatty fish and marine fatty acids were not appreciably associated with fecundability.