Plasma parathyroid hormone and the risk of cardiovascular mortality in the community

Diseases with elevated levels of parathyroid hormone (PTH) such as primary and secondary hyperparathyroidism are associated with increased incidence of cardiovascular disease and death. However, data on the prospective association between circulating PTH levels and cardiovascular mortality in the community are lacking.

The Uppsala Longitudinal Study of Adult Men (ULSAM), a community-based cohort of elderly men (mean age, 71 years; n=958), was used to investigate the association between plasma PTH and cardiovascular mortality. During follow-up (median, 9.7 years), 117 participants died of cardiovascular causes. In Cox proportional-hazards models adjusted for established cardiovascular risk factors (age, systolic blood pressure, diabetes, smoking, body mass index, total cholesterol, high-density lipoprotein cholesterol, antihypertensive treatment, lipid-lowering treatment, and history of cardiovascular disease), higher plasma PTH was associated with higher risk for cardiovascular mortality (hazard ratio for 1-SD increase in PTH, 1.38; 95% confidence interval, 1.18 to 1.60; P<0.001). This association remained essentially unaltered in participants without previous cardiovascular disease and in participants with normal PTH (<6.8 pmol/L) with no other signs of a disturbed mineral metabolism (normal serum calcium, 2.2 to 2.6 mmol/L; normal glomerular filtration rate, >50 mL . min(-1) . 1.73 m(-2) and without vitamin D deficiency, plasma 25-OH vitamin D >37.5 nmol/L). Interestingly, elevated plasma PTH (>5.27 pmol/L) accounted for 20% (95% confidence interval, 10 to 26) of the population-attributable risk proportion for cardiovascular mortality.

Plasma PTH levels predict cardiovascular mortality in the community, even in individuals with PTH within the normal range. Further studies are warranted to evaluate the clinical implications of measuring PTH in cardiovascular risk prediction and to elucidate whether PTH is a modifiable risk factor.