Increased aortic intima-media thickness in 11-year-old healthy children with persistent Chlamydia pneumoniae seropositivity.

OBJECTIVE The relationship between Chlamydia pneumoniae (Cpn) infection and arterial measures of preclinical atherosclerosis has remained controversial. Because atherogenesis begins in early life, we examined whether carotid and aortic intima-media thickness (IMT) and brachial artery endothelial function are associated with Cpn seropositivity in children. METHODS AND RESULTS Cpn-specific IgG and IgA antibodies were assessed by enzyme immunoassay in 199 healthy children followed-up annually from 7 to 11 years of age. Carotid (cIMT) and aortic IMT (aIMT), and brachial artery flow-mediated dilatation (FMD) were measured in 137 of the 199 children at the age of 11 years using high-resolution ultrasound. Children with persistent IgG and/or IgA seropositivity to Cpn had significantly increased aIMT compared with seronegative children (IgG< or =45 and IgA< or =12 enzyme immunounits) or children with transient Cpn seropositivity (seronegative, 0.496 [0.054]; transient, 0.494 [0.061]; and persistent, 0.532 [0.086] mm; P<0.05 for trend). This trend was not explained by traditional atherosclerotic risk factors or pubertal stage. cIMT and FMD were not associated with Cpn seropositivity. CONCLUSIONS Eleven-year-old children with persistent Cpn seropositivity show increased aIMT but not cIMT, suggesting that Cpn may affect the aortic wall, the site where the earliest atherosclerotic lesions are known to occur, in otherwise healthy children.