ASSOCIATION OF PARITY AND GRAVIDITY WITH CAROTID INTIMA-MEDIA THICKNESS: THE OHASAMA STUDY

Abstract

Abstract Objective: We aimed to investigate if any of parity, gravidity and menstrual factors are associated with carotid atherosclerosis diagnosed by ultrasound imaging. Design and method: We identified 543 women aged 60 years or older from the general population of Ohasama, a rural Japanese community, who answered a questionnaire on parity and gravidity and age at menarche, were free of previous cardiocerebrovascular disease. The carotid atherosclerosis was assessed based on the presence of focal carotid plaque and mean common carotid intima-media thickness (IMT) by using ultrasound imaging. Information on possible confounding factors including self-measured blood pressure at home (home BP) was simultaneously obtained. Results: Plaque lesion was observed in 138 (25%) and the median of IMT was 0.68 mm with interquartile range of 0.63–0.75. Means of home systolic and diastolic BP levels were 129.5 ± 14.2 mmHg and 74.0 ± 8.4 mmHg, respectively. Multivariate logistic regression models showed that compared with women who had two children, women who had three children (OR 1.82, 95%CI, 1.12–2.96) and women who had four or more children (OR 2.60, 95%CI, 1.47–4.58) were more likely to have an increased risk with the presence of focal carotid plaque adjusting for age (p < 0.001), body mass index (p = 0.012), hypertensive drug use (p = 0.319), home systolic BP levels (p = 0.364), impaired glucose tolerance (p = 0.230) and hyperlipidemia (p = 0.808), and current smoker (p = 0.955) and drinker (p = 0.294). Adjusting for these covariates, the highest quartile of gravidity (4- vs. 2) was associated with an increased risk of the plaques lesion (OR 2.03; 95%CI: 1.14–3.62) and youngest age quartile of age at menarche (13- y/o vs. 14 years) was associated with a decreased risk of the presence of plaque (OR, 0.51, 95%CI: 0.28–0.92). Multivariate general linear regression model showed that the wall thickness of carotid artery appeared slightly thicker among women who had highest parity quartile (b = 0.036, p = 0.009) adjusting for same covariates. The wall thickness of carotid artery was not associated with both gravidity (p = 0.089) and age at menarche (p = 0.113). Conclusions: Higher parity and gravidity, and younger age at menarche were associated with carotid atherosclerosis, independent of major confounding factors including age and home BP levels.