Estimate of body composition by Hume's equation: validation with DXA.

We investigated how the Hume's equation, using the antipyrine space, could perform in estimating fat mass (FM) and lean body mass (LBM). In 100 (40 male ad 60 female) subjects, we estimated FM and LBM by the equation and compared these values with those measured by a last generation DXA device. The correlation coefficients between measured and estimated FM were r = 0.940 (p < 0.0001) and between measured and estimated LBM were r = 0.913 (p < 0.0001). The Bland-Altman plots demonstrated a fair agreement between estimated and measured FM and LBM, though the equation underestimated FM and overestimated LBM in respect to DXA. The mean difference for FM was 1.40 kg (limits of agreement of -6.54 and 8.37 kg). For LBM, the mean difference in respect to DXA was 1.36 kg (limits of agreement -8.26 and 6.52 kg). The root mean square error was 3.61 kg for FM and 3.56 kg for LBM. Our results show that in clinically stable subjects the Hume's equation could reliably assess body composition, and the estimated FM and LBM approached those measured by a modern DXA device.

Carotid intima-media thickness is not associated with vitamin D and PTH levels in patients admitted to an Internal Medicine Department.

Vitamin D (25OHD) and/or parathyroid hormone (PTH) levels have been associated with common carotid intima-media thickness (IMT). We investigated such associations in inpatients consecutively admitted to an Internal Medicine Department. In 168 consecutive patients admitted to our department, 25 hydroxyvitamin D (25OHD) was measured by means of RIA and PTH by means of ICMA, whereas IMT by means of ultrasonography. The main cardiovascular risk factors were also explored. In patients with either diabetes, or hypertension, or both, 25OHD values were not significantly lower than in other patients. No difference was found among the IMT values across tertiles of 25OHD level, as like as in the 25OHD, PTH, PTH/25OHD ratio values of patients either grouped by tertiles of IMT, or categorized according to IMT of <0.9, 0.9-1.5, and >1.5 mm. IMT did not significantly associate with 25OHD, PTH, and PTH/25OHD ratio, whereas it positively associated with age (r = 0.281; p < 0.001) and BMI (r = 0.138; p = 0.074), and negatively with eGFR (r = -154; p = 0.046). Multiple regression models showed that IMT was significantly associated to age and BMI, while 25OHD, PTH, or PTH/25OHD ratio did not increase the significance of the models. IMT assessment does not seem to be associated with 25OHD and PTH levels in unselected inpatients.