Maternal Smoking, Vaping and Infant Sleep Practices in Sudden Unexpected Death in Infancy: A New Zealand Case Series

BACKGROUND: New Zealand's sudden unexpected death in infancy (SUDI) rates remain high, and ethnic disparities appear to be increasing. This study describes the characteristics and circumstances of these deaths. METHODS: Coronial data identified 101 SUDI cases in 2022-2023. Sociodemographic factors, sleep environment, and maternal smoking and/or vaping were analysed and compared with previous years. RESULTS: The SUDI rate was 0.87/1000 live births. Rates among Māori (1.97/1000) and Pacific (0.91/1000) infants were higher than those among Europeans (0.17/1000). 72.3% of cases occurred while direct bed sharing. Maternal smoking was reported in 51.5% of cases, vaping in 30.3%, and smoking and/or vaping in 72.7%. Vaping was more likely in bed-sharing than non-bed-sharing deaths (p = 0.003). Compared with New Zealand studies from 1987 to 1990 and 2012 to 2015, current cases show increasing proportions of Māori and Pacific infants, older mothers, back sleeping and direct bed sharing. CONCLUSIONS: SUDI rates remain unacceptably high with widening ethnic disparities. The proportion of deaths associated with direct bed sharing is striking and is increasing. Vaping appears to be an emerging SUDI risk factor, especially when combined with direct bed sharing. Further studies examining the association of vaping with SUDI are urgently needed.