1. ¹Departments of Internal Medicine, Uppsala, Sweden
2. ²Departments of Geriatrics, Uppsala, Sweden
3. ³Departments Internal Medicine, Sundby Hospital, Copenhagen, Denmark

Correspondence: Lars Lind, MD, Lars Lind, MD, Department of Internal Medicine, University Hospital, S-751 85 Uppsala, Sweden.

Received 4 March 1994; Accepted 3 April 1995.

Abstract

A previous study has shown that serum levels of the active vitamin D metabolite 1,25-(OH)₂-vitamin D were inversely related to blood pressure levels while the prohormone 25-OH-vitamin D was found to be related to insulin metabolism. Also other clinical and experimental data support the view that vitamin D metabolism is involved in blood pressure regulation and other metabolic processes.

The present study was conducted in order to see if the above mentioned relationships between the vitamin D endocrine system and blood pressure, as well as other cardiovascular risk factors, could be found in a cross-section population-based study. Serum levels of 1,25-(OH)₂-vitamin D, 25-OH-vitamin D, and blood pressure were therefore measured in 34 middle-aged men and metabolic cardiovascular risk factors were evaluated by means of intravenous glucose and fat tolerance tests, euglycemic hyperinsulinemic clamp, lipoprotein measurements, and lipoprotein lipase activity determinations.

Serum levels of 1,25-(OH)₂-vitamin D were found to be inversely correlated to the blood pressure (r = -0.42, P < .02), VLDL triglycerides (r = -0.47, P < .005), and to triglyceride removal at the intravenous fat tolerance test (r = 0.34, P < .05), while serum levels of 25-OH-vitamin D were correlated to fasting insulin (r = -0.35, P < .05), insulin sensitivity during clamp (r = 0.54, P < .001), and lipoprotein lipase activity both in adiposal tissue (r = 0.48, P < .005) and skeletal muscle (r = 0.38, P < .03).

These findings highlight the question for a role of vitamin D metabolism and intake in a metabolic syndrome involving hypertension as well as hyperlipidemia and insulin resistance.