Abstract 14345: Vitamin D and Parathyroid Hormone as Predictors of CVD Morbidity and CVD and All-cause Mortality
Parathyroid hormone (PTH) and vitamin D (25(OH)D) are calciotropic hormones and their metabolisms are closely related, such that a decrease in serum 25(OH)D leads to a rise in serum PTH. Elevated levels of PTH have long been linked to hypertension. However, there is limited evidence from population surveys as to whether elevated PTH is a predictor of cardiovascular disease (CVD).
We tested the hypothesis that serum 25(OH)D and PTH are associated with CVD morbidity and CVD and all-cause mortality.
Data analyses were carried out on a random sample of 2,564 participants aged ≥ 40 years in the Workforce Diabetes Survey, a cross-sectional survey carried out between 1988 and 1990 at work-sites in New Zealand. Blood samples from all participants were collected after a 10-12 hour overnight fast as part of a glucose tolerance test, and stored at -800C until testing. Fasting blood samples were thawed for measurement of 25-hydroxyvitamin D concentrations by isotope-dilution liquid chromatography-tandem mass spectrophotometry, and PTH by immunoassay. Statistical analyses have been weighted for sampling probabilities for having a 25(OH)D measurement.
During 19 years of follow-up, (mean, 14.8 years), we sampled 110 deaths due to CVD and 461 deaths not due to CVD. Vitamin D concentrations were significantly lower in the non-CVD death group compared to the control group (P=0.009), but there were no significant differences in the CVD morbidity or CVD mortality groups. After adjusting for age, sex, ethnicity, season, education, smoking, alcohol, BMI, and PTH, vitamin D concentrations of 51-65, 66-75, 75-90 and ≥ 91 nmol/L were associated with significantly lower hazards ratios for CVD morbidity and all CVD events compared to ≤ 50 nmol/L, but not with all-cause mortality. There was no evidence of significant associations between PTH and CVD deaths, non-CVD deaths and all-cause deaths.
The associations between vitamin D and CVD morbidity and mortality support previous research. Our findings of no significant associations between PTH and CVD deaths and all-cause deaths is in contrast to another study that reported higher PTH levels with both CVD and all-cause deaths.
- © 2013 by American Heart Association, Inc.