Geographic Origin as a Determinant of Carotid Artery Intima-Media Thickness and Brachial Artery Flow-Mediated Dilation

Abstract

People living in eastern Finland have approximately 40% higher coronary heart disease mortality rates than western Finns. Whether this is because of genetic or environmental factors is unknown. We examined the effect of geographic family origin on subclinical atherosclerosis among young Finns. As part of a longitudinal follow-up study, we measured carotid intima-media thickness (IMT) in 2264 and brachial flow-mediated dilation (FMD) in 2109 white adults, aged 24 to 39 years. Subjects from eastern Finland had greater IMT and lower FMD compared with western subjects. These differences accentuated when the subjects' family origin (grandparents' birthplace) was taken into account and remained significant after adjusting for several environmental factors. Among subjects with all grandparents born in eastern or western Finland, IMTs were (mean+/-SEM) 0.592+/-0.003 versus 0.565+/-0.005 mm (P<0.0001), respectively. The corresponding FMD values were 7.61+/-0.15% versus 8.75+/-0.26%; P<0.01. The number of grandparents born in eastern Finland was directly related to IMT (P<0.0001) and inversely to FMD (P<0.05). Young adults originating from eastern Finland have greater carotid IMT and lower brachial FMD than western Finns. Consistent with a hereditable component predisposing to or protecting from atherosclerosis, these differences accentuated when subjects' family origin was taken into account. We studied whether an east-west difference exists in markers of subclinical atherosclerosis in 2264 Finns aged 24 to 39 years. Subjects with family origin in eastern Finland had greater carotid IMT and lower brachial FMD compared with western subjects, suggesting that hereditable factors play a role in excess atherosclerosis risk in eastern Finland.