Association between birth weight and mortality in adulthood in a cohort from North-West Italy

Objective: Yearly, around 15 % of newborns worldwide are underweight. Studies found associations between low birth weight and various health conditions or mortality for all and specific causes, such as cardiovascular. Moreover, high birth weight was a risk factor for developing or dying from certain conditions, such as cancer. This study aims to investigate the association between birth weight and adult mortality from different causes through the Turin Longitudinal Study (TLS), containing information on a cohort of subjects born in the 1920s and followed from 1971 to 2013. Study design: Data were obtained from the TLS, a health-administrative cohort. Methods: Around 3500 subjects born at the Sant'Anna hospital (Turin, Italy) were enrolled. Different outcomes were investigated: all-cause mortality, and death from traumatisms, cancer, cardiovascular, respiratory, nervous system, and digestive apparatus diseases. Regarding exposures, birth weights <2500g, <2800g, and ≥4000g were assessed. Survival and Competing Risk analyses were performed, fitting Cox, Cause-Specific, and Subdistribution Proportional Hazards models. Results: After exclusions, 2992 individuals were considered. Low birth weight was a risk factor for death from all causes and cardiovascular diseases. Stratifying by sex, it was associated with mortality from cardiovascular conditions among females and from nervous system diseases in males. Conclusions: In this research, it emerged that low birth weight is a risk factor for death from all-cause mortality and some specific causes, such as cardiovascular and nervous system diseases. These findings support the need to implement policies to reduce the number of subjects born with non-normal weight.