Hypothesized foetal and early life influences on adult heart disease mortality: an ecological analysis of data for the Republic of Ireland

Spatial disparities in the prevalence of heart disease are frequently explained in terms of adult lifestyle factors (e.g. diet, smoking, alcohol consumption, stress, exercise, etc.). However, research in recent years suggests an alternative explanation: namely, that the risk of heart disease in adult life may be influenced either by living conditions shortly after birth or by foetal development before birth. This paper outlines the evolution of this line of thought, and tests whether these hypotheses are consistent with ecological data for deaths from ischaemic heart disease between 1981 and 1990 and infant deaths between 1916 and 1935 in the Republic of Ireland. Support for the hypotheses is found to be ambiguous. Possible interpretations of these findings are discussed, paying particular attention to the anomalous nature of infant mortality in Ireland between 1916 and 1935.