Background and purpose: Metabolic and hormonal changes associated with pregnancy and childbirth are assumed to contribute to the development of cardiovascular disease among women. We analyzed the association of parity with common carotid intima-media thickness (IMT), which has a predictive value of subsequent myocardial infarction and stroke.
Methods: The Study of Health in Pomerania (SHIP), an epidemiological study of the general population in the northeast of Germany, included 1195 women aged 45 to 79 years. Mean and maximum far-wall IMT of the common carotid arteries were assessed by high-resolution ultrasound. All women were comprehensively characterized as to their reproductive history as well as to socioeconomic, behavioral, and biological risk factors.
Results: There was a U-shaped association between the number of children (from 0 to > or =4) and mean and maximum IMT. Nulliparous women had the highest age-adjusted mean (0.81 mm [95% CI, 0.78 to 0.84]) and maximum IMT (1.04 mm [95% CI, 1.00 to 1.09]), and women with single parity the lowest (mean IMT, 0.73 [95% CI, 0.72 to 0.74]; maximum IMT, 0.91 mm [95% CI, 0.89 to 0.93]; P<0.001 versus nulliparity for both parameters). Stepwise multivariate adjustment for socioeconomic factors, lifestyle variables, and biological variables attenuated the magnitude of this association yet significance remained.
Conclusions: Nulliparity and higher number of children are associated with increased carotid IMT. These findings add support to the hypothesis of a link between the reproductive history of women and cardiovascular disease.