Maternal nativity and sleep-related infant injury deaths in New York City

Rates of Sudden Unexpected Infant Death (SUID) and its Subcategories in the U.S.: The Effect of Maternal Race, Ethnicity and Nativity

OBJECTIVE

This study aimed to estimate (1) rates of SUID and its subcategories among infants of U.S.-born and foreign-born women, and (2) the extent to which maternal race/ethnicity modifies the relationship between maternal nativity and SUID rates.

METHODS

Stratified and adjusted (for traditional demographic, clinical, and behavioral risk factors) Poisson regression analyses were performed on the National Center for Health Statistics linked 2021-2022 live birth-infant death database. Rates of SUID and its subcategories-sudden infant death syndrome (SIDS), accidental suffocation or strangulation in bed (ASSB), and unknown causes-were calculated for infants of women in the four largest U.S. racial/ethnic groups.

RESULTS

Infants of U.S.-born women (n = 5,600,507) had an over three-fold greater SUID rate than infants of foreign-born women (n = 1,594,547): 115.5/100,000 vs. 34.8/100,000, RR = 3.3 (3.0, 3.6). Strikingly, the nativity disparity existed among infants of Non-Hispanic Asian (n = 431,532), Non-Hispanic Black (n = 1,025,573), Hispanic (n = 1,820,734) and Non-Hispanic White (n = 3,722,820) women: RR = 2.4 (1.7, 3.5), 4.9 (4.0, 6.1), 2.3 (2.0, 2.6), and 3.2 (2.5, 4.1), respectively. Maternal nativity disparities in SUID persisted after adjustment, overall (adjRR = 2.5 (2.3, 2.8)) and within each racial/ethnic group. Non-Hispanic Black infants had the widest disparity (adjRR = 3.3 (2.7, 4.1)). Similar results were observed for SIDS, ASSB, and unknown causes.

CONCLUSIONS FOR PRACTICE

Infants of U.S.- vs. foreign-born women have higher rates of SUID and its subcategories independent of traditional risk factors. This nativity disparity is widest among Non-Hispanic Black women. These findings warrant further attention and research regarding differences in environment, infant sleep practices and SUID death investigation among foreign-born and U.S.-born women.

Maternal Obesity and Risk of Sudden Unexpected Infant Death

Importance

Rates of maternal obesity are increasing in the US. Although obesity is a well-documented risk factor for numerous poor pregnancy outcomes, it is not currently a recognized risk factor for sudden unexpected infant death (SUID).

Objective

To determine whether maternal obesity is a risk factor for SUID and the proportion of SUID cases attributable to maternal obesity.

Design, Setting, and Participants

This was a US nationwide cohort study using Centers for Disease Control and Prevention National Center for Health Statistics linked birth-infant death records for birth cohorts in 2015 through 2019. All US live births for the study years occurring at 28 weeks' gestation or later from complete reporting areas were eligible; SUID cases were deaths occurring at 7 to 364 days after birth with International Statistical Classification of Diseases, Tenth Revision cause of death code R95 (sudden infant death syndrome), R99 (ill-defined and unknown causes), or W75 (accidental suffocation and strangulation in bed). Data were analyzed from October 1 through November 15, 2023.

Exposure

Maternal prepregnancy body mass index (BMI; calculated as weight in kilograms divided by height in meters squared).

Main Outcome and Measure

SUID.

Results

Of 18 857 694 live births eligible for analysis (median [IQR] age: maternal, 29 [9] years; paternal, 31 [9] years; gestational, 39 [2] weeks), 16 545 died of SUID (SUID rate, 0.88/1000 live births). After confounder adjustment, compared with mothers with normal BMI (BMI 18.5-24.9), infants born to mothers with obesity had a higher SUID risk that increased with increasing obesity severity. Infants of mothers with class I obesity (BMI 30.0-34.9) were at increased SUID risk (adjusted odds ratio [aOR], 1.10; 95% CI, 1.05-1.16); with class II obesity (BMI 35.0-39.9), a higher risk (aOR, 1.20; 95% CI, 1.13-1.27); and class III obesity (BMI ≥40.0), an even higher risk (aOR, 1.39; 95% CI, 1.31-1.47). A generalized additive model showed that increased BMI was monotonically associated with increased SUID risk, with an acceleration of risk for BMIs greater than approximately 25 to 30. Approximately 5.4% of SUID cases were attributable to maternal obesity.

Conclusions and Relevance

The findings suggest that infants born to mothers with obesity are at increased risk of SUID, with a dose-dependent association between increasing maternal BMI and SUID risk. Maternal obesity should be added to the list of known risk factors for SUID. With maternal obesity rates increasing, research should identify potential causal mechanisms for this association.

Nativity and perinatal outcome disparities in the United States: Beyond the immigrant paradox

In the United States (US), epidemiologists have long documented paradoxically lower rates of adverse perinatal health outcomes among immigrant birthing people than what might be expected in light of socioeconomic and language barriers to healthcare, especially as compared to their US-born racial and ethnic counterparts. However, researchers have also documented significant variability in this immigrant birth paradox when examining within and across racial and ethnic subgroups. This review paper summarizes fifty years of research regarding differences in low, preterm birth, and infant mortality in the US, according to the nativity status of the birthing person. While there is ample evidence of the importance of nativity in delineating a pregnant person's risk of adverse infant outcomes, this review also highlights the relative paucity of research exploring the intersection of acculturation, ethnic enclaves, and structural segregation. We also provide recommendations for advancing the study of perinatal outcomes among immigrants.

The Role of Breastfeeding in Racial and Ethnic Disparities in Sudden Unexpected Infant Death: A Population-Based Study of 13 Million Infants in the United States

Sudden unexpected infant death (SUID) disproportionately affects non-Hispanic Black (NHB) and American Indian/Alaskan Native infants, who have lower rates of breastfeeding than other groups. Using 13,077,880 live-birth certificates and 11,942 linked SUID death certificates from 2015 through 2018, we calculated odds ratios and adjusted risk differences of SUID in infants who were not breastfed across 5 racial/ethnic strata in the United States. We analyzed mediation by not breastfeeding in the race/ethnicity-SUID association. The overall SUID rate was 0.91 per 1,000 live births. NHB and American Indian/Alaskan Native infants had the highest disparity in SUID relative to non-Hispanic White infants. Overall, not breastfeeding was associated with SUID (adjusted odds ratio (aOR), 1.14; 95% confidence interval (CI): 1.10, 1.19), and the adjusted risk difference was 0.12 per 1,000 live births. The aOR of not breastfeeding for SUID was 1.07 (95% CI: 1.00, 1.14) in NHB infants and 1.29 (95% CI: 1.14, 1.46) in Hispanic infants. Breastfeeding minimally explained the higher SUID risk in NHB infants (2.3% mediated) and the lower risk in Hispanic infants (2.1% mediated) relative to non-Hispanic White infants. Competing risks likely explain the lower aOR seen in NHB infants of not breastfeeding on SUID, suggesting that social or structural determinants must be addressed to reduce racial disparities in SUID.

Prevalence and Predictors of Postpartum Maternal and Infant Bed-Sharing Among Chinese-Canadian Women

Objective/Background: Our primary objective was to describe and identify predictors of any and predominant bed-sharing at 4 and 12 weeks postpartum among Chinese-Canadian mothers. Participants: We conducted a longitudinal study of 570 Chinese immigrant and Canadian-born women in Toronto, Ontario. Methods: Any bed-sharing, defined as sharing a bed or mattress for any part of the night on any night in the previous week, and predominant bed-sharing, defined as sharing a bed or mattress for most of the night, on more than half the nights of the previous week, were evaluated at 4 and 12 weeks postpartum. Predictors of bed-sharing, evaluated in multivariable logistic regression models, were background (age, parity, education, household size, delivery mode, social support), cultural (immigrant status, acculturative stress, acculturation, postpartum ritual uptake), and postpartum variables (mental health, breastfeeding problems, fatigue, sleep knowledge, plans for bed-sharing, perceptions of infant sleep problems, cognitions about infant sleep). Results: One in five women (20.7%) reported bed-sharing as the predominant sleep location for their infant at 4 weeks postpartum, with nearly half (45.6%) reporting any bed-sharing at this time. The prevalence of any bed-sharing remained relatively stable at 12 weeks postpartum (46.5%), while predominant bed-sharing increased to 30.1%. The most consistent predictors of any and predominant bed-sharing at 4 and 12 weeks postpartum were lower education level, greater acculturative stress, and predelivery plans to bed-share. Conclusions: These findings have implications for the development of clinical recommendations given to expectant and new parents to promote infant sleep practices that are consistent with American Academy of Pediatrics recommendations.

Racial and Ethnic Differences in Injury Prevention Behaviors Among Caregivers of Infants

INTRODUCTION

African American and Latino children experience higher rates of traumatic injury and mortality, but the extent to which parents of different races and ethnicities disparately enact injury prevention behaviors has not been fully characterized. The objective of this study is to evaluate the association between caregiver race/ethnicity and adherence to injury prevention recommendations.

METHODS

This was a cross-sectional analysis of caregiver-reported baseline data from the Greenlight study, a cluster-randomized pediatric obesity prevention trial. Data were collected between 2010 and 2012 in four academic pediatric practices and analyzed in 2015. Non-adherence to injury prevention recommendations was based on five domains: car seat safety, sleeping safety, fire safety, hot water safety, and fall prevention.

RESULTS

Among 864 caregiver-infant pairs (17.7% white, non-Hispanic; 49.9% Hispanic; 27.7% black, non-Hispanic; 4.7 % other, non-Hispanic), mean number of non-adherent injury prevention behaviors was 1.8 (SD=0.9). In adjusted regression, Hispanic caregivers had higher odds of non-adherence to car seat safety (AOR=2.1, 95% CI=1.2, 3.8), and lower odds of non-adherence with fall prevention (AOR=0.4, 95% CI=0.3, 0.7) compared with whites. Black, non-Hispanic caregivers had higher odds of non-adherence to car seat safety (AOR=2.4, 95% CI=1.3, 4.4) and sleeping safety (AOR=2.1, 95% CI=1.3, 3.2), but lower odds of fall prevention non-adherence (AOR=0.5, 95% CI=0.3, 0.8) compared with whites.

CONCLUSIONS

A high prevalence of non-adherence to recommended injury prevention behaviors is common across racial/ethnic categories for caregivers of infants among a diverse sample of families from low-SES backgrounds.