Serum 25-hydroxyvitamin D and parathyroid hormone in relation to plasma B-type natriuretic peptide: the Hoorn Study.

Objective: A disturbed vitamin D-parathyroid hormone (PTH)-calcium axis may play a role in thepathogenesis of heart failure. Therefore, we investigated whether lower 25-hydroxyvitamin D (25(OH) D) and higher PTH are cross sectionally and after 8 years of follow-up associated with higher B-type natriuretic peptide (BNP) levels in older men and women. Design and methods: We measured baseline 25(OH) D, PTH, and BNP in 502 subjects in 2000-2001 in the Hoorn Study, a population-based cohort. Follow-up BNP was available in 2007-2009 in 278 subjects. Subjects were categorized according to season-and sex-specific quartiles of 25(OH) D and PTH at baseline. We studied the association of 25(OH) D and PTH quartiles with BNP using linear regression analyses adjusting for confounders. Analyses were stratified by kidney function estimated glomerular filtration rate (eGFR; <= 60 ml/min per 1.73 m(2)) because of significant interaction. Results: At baseline, subjects had a mean age of 69.9 +/- 6.6 years, mean 25(OH) D level was 52.2 +/- 19.5 nmol/l and mean PTH 6.1 +/- 2.4 pmol/l. Cross sectionally, 25(OH) D was associated with BNP in subjects with impaired kidney function (eGFR <= 60 ml/min) only. The association attenuated after adjustment for PTH. PTH was cross sectionally associated with BNP, also in subjects with impaired kidney function only: regression coefficient of highest quartile 9.9 pmol/l (95% confidence interval 2.5, 17.4) with a significant trend across quartiles. Neither 25(OH) D nor PTH was associated with BNP in longitudinal analyses. Conclusion: This study showed overall no strong association between 25(OH) D and BNP. However, PTH was associated with BNP in subjects with impaired kidney function and may point to a potential role in myocardial function.