Association between Chlamydophila pneumoniae infection and risk of coronary heart disease for Japanese: The JPHC study

Abstract

BackgroundChlamydophila pneumoniae infection is considered a risk factor for atherosclerosis and coronary heart disease in western countries. However, evidence of it being a risk for Japanese is very limited because of a lower risk of coronary heart disease than for western people. The aim of this study was to examine further the association between C. pneumoniae infection and risk of coronary heart disease in Japanese. MethodsWe conducted a nested case–control study of 49,011 Japanese men and women who participated in The Japan Public Health Center (JPHC) study. By the end of 2004, 196 cases of coronary heart disease and 155 cases of myocardial infarction had been documented among the participants. Two controls were selected for each case. For these subjects, we examined the association between serum anti C. pneumoniae IgA and IgG on the one hand and risk of coronary heart disease on the other. ResultsConcentration of C. pneumoniae IgA antibody was positively associated with risk of coronary heart disease and more specifically myocardial infarction. Subjects with the highest quartile of IgA antibody showed 2.29 (95%CI, 1.21–4.33) times higher risk of coronary heart disease and 2.58 (95%CI, 1.29–5.19) times higher risk of myocardial infarction than those with lowest quartile. However, no such association was detected for IgG antibody. ConclusionC. pneumoniae infection was found to be positively associated with risk of coronary heart disease.