An Empirical Dietary Inflammatory Pattern and Fecundability in a Multiethnic Asian Preconception Cohort

Background: Inflammation is known to adversely affect fertility but few studies have related dietary inflammatory potential to conception in women without known infertility. Objectives: This study aimed to empirically derive a dietary inflammatory pattern score for Singaporean women (EDIP-SGW) and examined its association with fecundability in women from the Singapore PREconception Study of long-Term maternal and child Outcomes (S-PRESTO) study. Methods: The EDIP-SGW score was calculated based on a dietary pattern (derived from food frequency questionnaire data using reduced rank regression) most predictive of 2 inflammatory markers: high-sensitivity C-reactive protein and glycoprotein acetyls. We validated the score in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) study. Fecundability (measured by time-to-pregnancy in menstrual cycles within a year of enrolment) for increasing EDIP-SGW score was estimated using discrete-time proportional hazards models adjusted for covariates (n = 890). Interaction with insulin resistance [homeostatic model assessment for insulin resistance (HOMA-IR)] was explored. Results: Increasing concentrations of high-sensitivity C-reactive protein and glycoprotein acetyls were observed across EDIP-SGW score quartiles in both the S-PRESTO and GUSTO, demonstrating the score's validity. Fecundability was 34% lower in the highest quartile of EDIP-SGW scores compared with the lowest quartile (fecundability ratio: 0.66, 95% confidence interval: 0.48, 0.93), and each SD increase in EDIP-SGW score was associated with a 13% lower fecundability [0.87 (0.77, 0.99)]. Among women with low HOMA-IR (<2.5), those in the highest quartile of EDIP-SGW scores appeared to have a 34% lower fecundability [0.66 (0.46, 0.94); P-interaction = 0.004], but this was not evident in women with high HOMA-IR (>= 2.5). Conclusions: A proinflammatory diet is associated with lower fecundability in multiethnic Asian women without known infertility. Further studies are needed to clarify the role of insulin resistance in this relationship.