Prolactin Levels and the Risk of Future Coronary Artery Disease in Apparently Healthy Men and Women

BACKGROUND: Prolactin is increasingly recognized to play a stimulatory role in the inflammatory response. Because inflammation is considered of crucial importance in the development of atherosclerosis, we aimed to evaluate whether prolactin levels are associated with the occurrence of coronary artery disease (CAD). METHODS AND RESULTS: We performed a nested case-control study in the prospective EPIC-Norfolk cohort. Cases were apparently healthy men and women, aged 45 to 79 years, who developed fatal or nonfatal CAD (n=882). Controls remained free of CAD (n=1490). Overall, systemic prolactin levels did not differ between cases and controls, and people in the highest prolactin tertile did not have a significantly increased risk of developing future CAD (in men, odds ratio, 1.21; 95% CI, 0.92 to 1.61; in women, odds ratio, 1.12; 95% CI, 0.76 to 1.64). However, in a separate immunohistochemical study, the presence of prolactin receptors could be demonstrated in postmortem human coronary artery plaques (preliminary data). CONCLUSIONS: Elevated systemic prolactin levels do not predict CAD in the general population. However, prolactin receptors were found in human coronary artery plaques. This observation may indicate a role of prolactin within atherosclerotic plaques. More studies are needed to define the possible role of prolactin in atherosclerotic plaque development.