Abstract

BACKGROUND: The aim of our study was to determine whether alterations ofthe vitamin D-endocrine system and the renin-angiotensin-aldosterone system occur in male obesity andinfluence each other.MATERIAL/METHODS: 32 obese male subjects and 21 age-matched healthy male subjectswere 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 reninactivity, and urinary calcium, magnesium, and phosphorus.RESULTS: Serum total Ca and ionized calciumwere slightly, but not significantly lower in obese subjects compared to controls, whereas serum magnesiumphosphorus and PTH levels were significantly higher in the obese subjects. Mean urinary calcium and Mgwere not significantly different, while urinary P was significantly higher in obese subjects. Mean serum25OHD was significantly lower in obese subjects. Supine and upright aldosterone and renin were unrelatedto BMI or fat mass. Supine aldosterone correlated with serum total calcium, ionized calcium and supinerenin activity, but not with other minerals, PTH or 25OHD, whereas upright aldosterone did not correlatewith other parameters. Supine renin activity did not correlate with any parameters, whereas upright renincorrelated 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 increasedserum Mg, P, PTH and urinary P and lower supine aldosterone and 25OHD, but unchanged serum and urinaryCa.

Keywords: Body Mass Index, Calcium, Case-Control Studies, Homeostasis, Magnesium, Obesity, Parathyroid Hormone, Renin-Angiotensin System