The Changing Epidemiology of Sudden Infant Death Syndrome: A 15-Year Overview Comparing Italian and European Data.

Background and Aims: Sudden Infant Death Syndrome (SIDS) represents a prominent cause of infant death in many countries. Epidemiological data has been variable over time because the related International Classification of Diseases (ICD) code is not consistent throughout countries and has changed over the years. The prevalence of SIDS is unclear, with estimates that do not reflect the number of patients who actually died from SIDS. This paper aims to assess the trend of SIDS in Italy and Europe during 2011-2018, and factors contributing to epidemiological data. Data for Italy were also integrated with an individual-level analysis over the period 2003-2018. Methods: A two-pronged analysis was performed starting from the Italian National Institute of Statistics and experimental data. The individual characteristics of SIDS infants were detailed in association with biomedical, socioeconomic, and cultural variables. Results: Total infant mortality has been continuously declining in Italy, from 4.15‰ in 2003 to 3.05‰ in 2018 (-26.5%) with rates significantly lower than the European average in the same period (mean Italy 3.05‰ vs. mean Europe 4.11‰). Considering only SIDS, the 28 European countries show an average value of 0.15/1000 deaths/births (2011-2018), with a decreasing temporal trend. Italy displays an average rate 75% lower (0.04/1000 births). The seasonality of the syndrome highlights a prevalence during cold months (60.7%) and no evidence of a significant effect of mother's age at birth was found. The mean age at death is prevalent in the postneonatal period. No statistically significant effects on Italian SIDS mortality have been found regarding economical, educational, and cultural aspects related to the care of infants. Conclusion: The data suggest a likely effect of different ways of classification of SIDS-related deaths, although a different approach to the prevention campaigns could be responsible for data variability among countries. Results also suggest an urgent need to get insight into previously unexplored aspects, such as neuroanatomical, genetic, metabolic, and proteomic aspects, focusing especially on high-risk groups to further clarify the etiopathogenesis of this syndrome.