Background: The aim of our study was to determine whether alterations of the vitamin D-endocrine system and the renin-angiotensin-aldosterone system occur in male obesity and influence each other.
Material/methods: 32 obese male subjects and 21 age-matched healthy male subjects were enrolled in the study. The parameters measured included serum total calcium (Ca), ionized calcium, magnesium (Mg), phosphorus (P), 25-hydroxyvitamin D (25-OHD), supine and upright aldosterone and renin activity, and urinary calcium, magnesium, and phosphorus.
Results: Serum total Ca and ionized calcium were slightly, but not significantly lower in obese subjects compared to controls, whereas serum magnesium phosphorus and PTH levels were significantly higher in the obese subjects. Mean urinary calcium and Mg were not significantly different, while urinary P was significantly higher in obese subjects. Mean serum 25OHD was significantly lower in obese subjects. Supine and upright aldosterone and renin were unrelated to BMI or fat mass. Supine aldosterone correlated with serum total calcium, ionized calcium and supine renin activity, but not with other minerals, PTH or 25OHD, whereas upright aldosterone did not correlate with other parameters. Supine renin activity did not correlate with any parameters, whereas upright renin correlated with serum Mg and PTH. There were significant correlations between PTH and BMI or fat mass. Urinary Mg was also related to both BMI and fat mass.
Conclusions: Male obesity is associated with increased serum Mg, P, PTH and urinary P and lower supine aldosterone and 25OHD, but unchanged serum and urinary Ca.