Breastfeeding and post-perinatal infant deaths in the United States, A national prospective cohort analysis.

Background: Reducing infant mortality is a major public health goal. The potential impact of breastfeeding on infant deaths is not well studied in the United States (US). Methods: We analyzed linked birth-death certificates for 3,230,500 US births that occurred in 2017, including 6,969 post-perinatal deaths from 7-364 days of age as the primary outcome, further specified as late-neonatal (7-27 days) or post-neonatal (28-364 days) deaths. The primary exposure was 'ever breastfed' obtained from birth certificates. Multiple logistic regression examined associations of ever breastfeeding with post-perinatal deaths and specific causes of deaths, controlling for maternal and infant factors. Findings: We observed an adjusted reduced odds ratio (AOR)= 0·74 with 95% confidence intervals (CI)=0·70-0·79 for the association of breastfeeding initiation with overall infant deaths (7-364 days), AOR=0·60 (0·54-0·67) for late-neonatal deaths, and AOR=0·81 (0·76-0·87) for post-neonatal deaths. In race/ethnicity-stratified analysis, significant associations of breastfeeding initiation with reduced odds of overall infant deaths were observed for Hispanics [AOR=0·64 (0·55-0·74)], non-Hispanic Whites [AOR=0·75 (0·69-0·81)], non-Hispanic Blacks [AOR=0·83 (0·75-0·91)], and non-Hispanic Asians [AOR=0·51 (0·36-0·72)]. Across racial/ethnic groups, effect sizes for late-neonatal deaths were consistently larger than those for post-neonatal deaths. Significant effects of breastfeeding initiation were observed for deaths due to infection [AOR=0·81(0·69-0·94)], Sudden Unexpected Infant Death [AOR=0·85 (0·78-0·92)], and necrotizing enterocolitis [AOR=0·67 (0·49-0·90)]. Interpretation: Breastfeeding initiation is significantly associated with reduced odds of post-perinatal infant deaths in multiple racial and ethnic groups within the US population. These findings support efforts to improve breastfeeding in infant mortality reduction initiatives.

Heatwave Events and Mortality Outcomes in Memphis, Tennessee: Testing Effect Modification by Socioeconomic Status and Urbanicity.

Heatwave studies typically estimate heat-related mortality and morbidity risks at the city level; few have addressed the heterogeneous risks by socioeconomic status (SES) and location within a city. This study aimed to examine the impacts of heatwaves on mortality outcomes in Memphis, Tennessee, a Mid-South metropolitan area top-ranked in morbidity and poverty rates, and to investigate the effects of SES and urbanicity. Mortality data were retrieved from the death records in 2008-2017, and temperature data from the Applied Climate Information System. Heatwave days were defined based on four temperature metrics. Heatwave effects on daily total-cause, cardiovascular, and respiratory mortality were evaluated using Poisson regression, accounting for temporal trends, sociodemographic factors, urbanicity, and air pollution. We found higher cardiovascular mortality risk (cumulative RR (relative risk) = 1.25, 95% CI (confidence interval): 1.01-1.55) in heatwave days defined as those with maximum daily temperature >95th percentile for more than two consecutive days. The effects of heatwaves on mortality did not differ by SES, race, or urbanicity. The findings of this study provided evidence to support future heatwave planning and studies of heatwave and health impacts at a coarser geographic resolution.

Associations Between Breastfeeding Initiation and Infant Mortality in an Urban Population.

Background: Breastfeeding promotion and support are not universally accepted in the United States as a strategy to reduce infant mortality. We investigated associations between breastfeeding and infant mortality in an urban population with high infant mortality and low breastfeeding rates. Methods: A retrospective epidemiologic study linked birth-infant death data for 148,679 live births in Shelby County, Tennessee from January 2004 to December 2014. Births <500 g, deaths ≤7 days, deaths because of congenital anomalies or malignant neoplasms, and records with missing breastfeeding status were excluded. Main outcomes were infant death before the first birthday, neonatal death <28 days, and postneonatal death ≥28 days by ever or never breastfed. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for breastfeeding initiation were adjusted for maternal factors and infant factors. Results: Initiation of breastfeeding was associated with a significant reduction in total infant mortality (OR = 0.81, 95% CI = 0.68-0.97, p = 0.023). Neonatal mortality was also significantly reduced with any breastfeeding (OR = 0.49, 95% CI = 0.34-0.72, p = 0.001). Postneonatal mortality was not significantly associated with breastfeeding initiation in the overall population (OR = 0.95, 95% CI = 0.78-1.17, p = 0.65), but was significant in the nonblack population (OR = 0.63, 95% CI = 0.41-0.98, p = 0.039). An association was observed between breastfeeding initiation and infant mortality from infectious disease (OR = 0.49, 95% CI = 0.32-0.77, p = 0.002). Conclusions: In an urban area with high infant mortality and low breastfeeding rates, initiation of breastfeeding was significantly associated with reductions in overall infant mortality, neonatal mortality, and infection-related deaths. Breastfeeding promotion, protection, and support should be an integral strategy of infant mortality reduction initiatives.