Optimal dietary calcium intake in HIV treated patients: no femoral osteoporosis but higher cardiovascular risk.

BACKGROUND & AIMS: We performed a cross-sectional study on adult HIV-infected patients, on HAART, without calcium or vitamin D supplementation to evaluate if the cardiovascular risk or the presence of osteoporosis may be predictive factors of an optimal daily calcium intake (DCI>1000 mg/day). METHODS: Patients underwent a dual-energy X-ray absorptiometry, measured biochemical parameters and compiled a validated questionnaire for the assessment of DCI. Osteoporosis (OP) was defined according to the WHO classification at either the vertebral spine or femoral neck. Cardiovascular risk was assessed by the 10-year Framingham cardiovascular risk score. RESULTS: 200 HIV-infected patients evaluated: 171 (86%) males with a median age of 48.1 (42.3-53.8) years and 10.6 (4.3-13.6) years of HAART exposure. DCI was 889 (589-1308) mg/day and 79 (40%) patients had an optimal DCI. Framingham risk>20% was found in 13 (6.7%) patients and femoral OP was diagnosed in 12 (6%) pts. By multivariate analysis, optimal DCI was more likely in patients with a Framingham risk>20% [OR = 5.547, 95% CI:1.337, p = 0.025] and less likely in patients with femoral osteoporosis [OR = 0.159, 95% CI: 0.018-0.790, p = 0.047]. CONCLUSIONS: We found that an optimal dietary calcium intake was more likely in patients with high cardiovascular risk and no femoral osteoporosis.

Heritability and demographic analyses in the large isolated population of Val Borbera suggest advantages in mapping complex traits genes.

BACKGROUND: Isolated populations are a useful resource for mapping complex traits due to shared stable environment, reduced genetic complexity and extended Linkage Disequilibrium (LD) compared to the general population. Here we describe a large genetic isolate from the North West Apennines, the mountain range that runs through Italy from the North West Alps to the South. METHODOLOGY/PRINCIPAL FINDINGS: The study involved 1,803 people living in 7 villages of the upper Borbera Valley. For this large population cohort, data from genealogy reconstruction, medical questionnaires, blood, anthropometric and bone status QUS parameters were evaluated. Demographic and epidemiological analyses indicated a substantial genetic component contributing to each trait variation as well as overlapping genetic determinants and family clustering for some traits. CONCLUSIONS/SIGNIFICANCE: The data provide evidence for significant heritability of medical relevant traits that will be important in mapping quantitative traits. We suggest that this population isolate is suitable to identify rare variants associated with complex phenotypes that may be difficult to study in larger but more heterogeneous populations.

Intestinal calcium absorption is associated with bone mass in stone-forming women with idiopathic hypercalciuria.

BACKGROUND: Patients with idiopathic hypercalciuria are predisposed to osteoporosis despite their high enteral calcium absorption. Conversely, low calcium absorption has been reported in patients with osteoporosis. Because bone loss occurs earlier in women, this work explores the relationship between bone mineral density (BMD) and calcium absorption in premenopausal and postmenopausal hypercalciuric stone-forming women. METHODS: BMD and intestinal calcium absorption were compared in 64 hypercalciuric and 42 normocalciuric calcium stone-forming women. Calcium absorption was assessed by using strontium as a surrogate marker for calcium. Strontium was administered to patients as an oral load, then measured in blood to calculate absorption after 60 minutes. Femoral and lumbar-spine BMD were measured by dual-energy x-ray absorptiometry. RESULTS: Strontium absorption was significantly increased in hypercalciuric stone formers, whereas BMD z score was decreased in hypercalciuric patients at the lumbar spine, but not the femur. The increase in strontium absorption was detected in both postmenopausal (n = 29) and premenopausal (n = 35) hypercalciuric patients. The decrease in lumbar-spine BMD was confirmed in postmenopausal, but not premenopausal, hypercalciuric patients. Strontium absorption was greater in hypercalciuric patients with a lumbar-spine BMD z score of -2 or less (n = 10) than in those with a score greater than -2 (n = 54). Multiple stepwise regression showed that lumbar-spine BMD was related negatively to intestinal strontium absorption and age in hypercalciuric patients. CONCLUSION: Results of the strontium absorption test suggest that the increase in calcium absorption is associated with a decrease in lumbar-spine BMD in hypercalciuric stone-forming women. Hypercalciuric stone-forming women with high calcium intestinal absorption denote a group of patients predisposed to loss of bone mass.