Time-Varying Associations between Food Insecurity and Infant and Maternal Health Outcomes

Food insecurity (FI) is dynamic for families and adversely affects infant and maternal health. However, few studies have examined the longitudinal impact of FI on infant and maternal health. We aimed to examine the relation between food insecurity in the first year of life and infant and maternal health outcomes. We hypothesized FI would be associated with poorer infant and maternal health outcomes. We conducted a retrospective cohort study of 364 infants 12–15 months and their caregivers receiving care at a single primary care clinic. The exposure of interest was food insecurity measured during well-child checks using a validated 2-item screening tool. The primary outcome was infant weight-for-length z score. Secondary outcomes included infant log-transformed ferritin, infant hemoglobin, infant lead concentrations, and maternal depression, assessed by the Edinburgh Postnatal Depression Scale. Unadjusted and adjusted effects were estimated using generalized mixed linear models, and the linear effect of visit time was tested using likelihood ratios. In adjusted models, no overall association between FI and infant weight-for-length z score was observed; however, FI male infants had lower weight-for-length z scores than female infants (P = 0.05). FI infants had 14% lower log ferritin concentrations per month of exposure to FI. FI was positively associated with maternal depression (IRR 5.01 [95% CI 2.21–11.3]). Food insecurity can have longitudinal and demographically-varied associations with infant and maternal outcomes that warrant further exploration.