Area-Level Infant Mortality Exposure in Early Life and Later Life Stroke: The Role of Modifiable Risk Factors and Place of Birth

A growing literature suggests that early life conditions may contribute to the risk of later life stroke. In this paper we explore the role that infant mortality (as a proxy for environmental and socioeconomic conditions) plays in later life self-reported stroke and stroke mortality, while also considering other contextual factors such as state of birth. We use a sample of 244,041 individuals aged 60 and above with the NIH-AARP Diet and Health Study with 16 years of mortality follow-up, allowing us to examine the role that infant mortality rates, along with other known risk factors, play in ones individual risk of stroke mortality and self-reported stroke. We show using logistic regression models for stroke incidence and cox proportional hazard models for stroke mortality, that infant mortality rates are associated with later life stroke mortality among males, net of controls for education, and stroke risk factors, and with self-reported stroke among females, prior to controlling for risk factors. However, upon controlling for state of birth, these associations dissipate. Our findings suggest that early life factors in the form of infant mortality are important considerations when studying the risk of stroke death for males, for reporting a history of strokes among females and how failure to consider these early life contextual influences may overstate these associations with morbidity and mortality.