Indication of Genetic Factors

In Finland, mortality from coronary heart disease is high, and much higher in the eastern than in the western counties. Both left and right coronary arteries of 141 children who died under one year of age at the Children's Hospital, University of Helsinki, were investigated. Thirty-two of these children formed a western and 41 an eastern group according to the birthplaces of their grandparents in Finland. Correlations were tested between this geographical distribution and some dimensions of the coronary arteries, as well as other clinical variables. The inner vascular layers of the left coronary arteries were found to be thicker in the eastern group (P < 0.05 in analysis of variance and P < 0.01 in regression analysis). No other significant correlations were observed. This association of infants having thick inner vascular layers in the coronary artery with a population group where mortality from coronary heart disease (CHD) is very high supports the hypothesis that the thickenings are prearteriosclerotic. The difference found between the arteries of the western and eastern groups might be due to a difference in the vulnerability of the inner vascular wall to extrinsic deleterious factors. The association substantiates the existence of a genetic component in the etiology of CHD and supports the theory that two separate groups of settlers originally colonized Finland.