25-Hydroxyvitamin D, cholesterol, and ultraviolet irradiation.

Vitamin D deficiency may have implications for cardiovascular health. The purpose of this study was to determine the relationship of 25-hydroxyvitamin D (25[OH]D) to cholesterol and lipoprotein particles and to determine whether increasing 25(OH)D through ultraviolet (UV) irradiation impacted on these parameters in healthy young men and women. This was a randomized trial of 51 adults exposed to suberythemal doses of whole-body irradiation using UV lamps that emitted UV-A and UV-B radiation, compared with a control group, twice weekly for 12 weeks. 25-Hydroxyvitamin D, cholesterol, and lipoprotein subfractions were measured at baseline and after 12 weeks. There was a significant (P < .03) positive association between 25(OH)D and apolipoprotein A-I (Apo A-I) and lipoprotein A-I (Lp A-I). The ratio of low-density lipoprotein to high-density lipoprotein was significantly (P < or = .044) negatively correlated with 25(OH)D levels. The levels of 25(OH)D increased significantly in the treated compared with control group (P < .05). Overall, there were no significant differences between the treated and control groups in any lipoproteins or apolipoproteins after administration of UV irradiation. Subgroup analysis for Apo A-II confined to those with 25(OH)D insufficiency (25[OH]D <75 nmol/L [30 ng/mL]) revealed decreases in Apo A-II in the treated group and increases in the control group that were statistically significantly different between the groups (P = .026). We found a significant positive correlation between 25(OH)D and Apo A-I and Lp A-I and a significant negative correlation between 25(OH)D and the ratio of low-density lipoprotein to high-density lipoprotein. In those with vitamin D insufficiency, we found small decreases in Apo A-II in the treated relative to the control group. Overall, though, twice weekly exposure to UV radiation resulting in an increase in serum 25(OH)D had no significant impact on lipoprotein composition.

Bone mineral density and turnover in non-corticosteroid treated African American children with juvenile rheumatoid arthritis.

OBJECTIVE: To determine bone mineral content (BMC), bone mineral density (BMD), Z scores, and markers of bone turnover in African American children with juvenile rheumatoid arthritis (JRA). METHODS: Eight children with JRA with no prior exposure to corticosteroids were evaluated. Lumbar spine (L1-L4) and total body and total hip BMC and BMD were determined using dual x-ray absorptiometry (DXA), and Z scores (BMD) were calculated. Serum samples of markers of bone turnover including pyridinoline (PYR), N-terminal propeptide of type I procollagen (P1NP), osteocalcin (OC), and bone-specific alkaline phosphatase (BSAP) were measured. RESULTS: The mean Z score (BMD) at the lumbar spine (L1-L4) in patients with JRA was -1.2+/-0.8. Z scores for total body and total hip were within 1 standard deviation of normal compared with healthy historical controls matched for age, sex, and race. CONCLUSION: BMD was normal for chronological age (defined as Z score >or= 2.0) in African American children with JRA who had not previously been treated with corticosteroids. Further studies are needed on the effects of JRA on skeletal health in African American children.

Effects of a low sodium diet on bone metabolism.

Osteoporosis is a serious public health problem, and dietary interventions may potentially be helpful in preventing this disorder. The purpose of this study was to determine the effects of a low sodium diet on bone metabolism in postmenopausal women. This was a longitudinal study to determine the effects of a low sodium (2-g/day) diet on bone. Forty postmenopausal African-American and Caucasian women were enrolled in a 2-g/day sodium diet for 6 months. Sodium and calcium excretion, bone turnover, and calcitropic hormones (intact parathyroid hormone (PTH) and 1,25 dihydroxyvitamin D) were measured before and 6 months after the intervention. In women who had baseline sodium excretions equal to or greater than the average sodium intake in the United States (> or =3.4 g/day), the low sodium diet resulted in significant decreases in sodium excretion (P = 0.01), in calcium excretion (P = 0.01), and in a biomarker of bone turnover, aminoterminal propeptide of type I collagen (P = 0.04). However, there were no significant changes in calcitropic hormones, including intact PTH (P = 0.97) or 1,25 dihydroxyvitamin D (P = 0.49) with the low sodium diet. These findings suggest that in postmenopausal women with sodium intakes > or =3.4 g/day, a low sodium diet may have benefits for skeletal health.

Training requirements for DXA technologists in the United States.

The purposes of this study were to determine, by state, the requirements for dual-energy X-ray absorptiometry(DXA) operators' training, knowledge of these state requirements, and factors that predicted state and International Society of Clinical Densitometry (ISCD) certification of DXA technologists. Seventeen states required registered technologist (RT) certification or authorized/licensed limited certification for DXA operators, 16 had no certification requirements, 12 required RT certification, and 5 had state-specific requirements. There were 9745 surveys mailed toDXA users including 50% Hologic Inc., 50% GE Lunar, and 100% Norland; 3148 surveys are included in this analysis. Among responders who indicated that their state did not have any certification requirements (n=1673), 1095(65.5%) were incorrect; there were requirements. Possession of state and ISCD certification was significantly correlated with the number of patients scanned per week (p

The relationship of antiresorptive drug use to structural findings and symptoms of knee osteoarthritis.

OBJECTIVE: To examine the cross-sectional association between use of medications that have a bone antiresorptive effect (estrogen, raloxifene, and alendronate) and both the structural features of knee osteoarthritis (OA), assessed by magnetic resonance imaging (MRI) and radiography, and the symptoms of knee OA in elderly women. METHODS: Women in the Health, Aging and Body Composition Study underwent MRI and radiography of the knee if they reported symptoms of knee OA, and women without significant knee symptoms were selected as controls. MR images of the knee were assessed for multiple features of OA using the Whole-Organ MRI scoring method, and radiographs were read for Kellgren and Lawrence grade and individual features of OA. Concurrent medication use and knee symptoms were assessed by interview, and knee pain severity was evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). RESULTS: There were 818 postmenopausal women from whom we obtained MR images of the knee and data on medication use. Among these women, 214 (26.2%) were receiving antiresorptive drugs. We found no significant association between overall use of antiresorptive drugs and the presence of knee pain and radiographic changes of OA of the knee. Use of alendronate, but not estrogen, was associated with less severity of knee pain as assessed by WOMAC scores. Both alendronate use and estrogen use were associated with significantly less subchondral bone attrition and bone marrow edema-like abnormalities in the knee as assessed by MRI, as compared with women who had not received these medications. CONCLUSION: Elderly women being treated with alendronate and estrogen had a significantly decreased prevalence of knee OA-related subchondral bone lesions compared with those reporting no use of these medications. Alendronate use was also associated with a reduction in knee pain according to the WOMAC scores.

Association between bone mineral density and the use of nonsteroidal anti-inflammatory drugs and aspirin: impact of cyclooxygenase selectivity.

UNLABELLED: BMD was examined in users of NSAIDs (by COX selectivity) and aspirin in the Health ABC cohort (n = 2853). Significantly higher BMD was found in users of relative COX-2 selective NSAIDs with aspirin (COX-2/ASA) compared with nonusers. This suggests a role for COX-2/ASA in osteoporosis. INTRODUCTION: The purpose of this study was to determine the relationship of nonsteroidal anti-inflammatory drug (NSAID) use, by cyclo-oxygenase selectivity (COX), and aspirin use on bone mineral density (BMD) in participants from the Health, Aging, and Body Composition (Health ABC) population-based cohort. It is known that NSAIDs inhibit the COX enzyme and decrease production of prostaglandins, which are involved in regulation of bone turnover. COX has two isoforms, COX-1 and COX-2. Production of prostaglandins associated with bone loss is primarily mediated through the COX-2 pathway. In addition, aspirin may have effects on bone independent of the prostaglandin pathway. MATERIALS AND METHODS: NSAID (by COX selectivity) and aspirin use and BMD were assessed in 2853 adults (49.5% women, 50.5% men: 43.1% black, 56.9% white; mean age: 73.6 years) from the Health ABC cohort. For the purposes of this analysis, relative COX-1 selective NSAIDs were defined as having a ratio of COX-1 IC50 to COX-2 IC50 of > 1 in whole blood, and relative COX-2 selective NSAIDs were defined as having a ratio of COX-1 IC50 to COX-2 IC50 of < 1 in whole blood. Analysis of covariance was used to compare BMD across each NSAID use and aspirin use category adjusting for age, race, gender, weight, height, study site, calcium and vitamin D supplementation, Womac score, history of rheumatoid arthritis, history of arthritis other than rheumatoid, and smoking status. RESULTS: After adjustment for possible confounders, current use of relative COX-2 selective NSAIDs with aspirin was associated with higher BMD at the whole body (4.2%, 1.2-7.3 CI) and total hip (4.6%, 0.5-8.8 CI) by DXA and at both trabecular (34.1%, 15.4-52.7 CI) and cortical spine (12.8%, 2.3-23.3 CI) by quantitative computed tomography. CONCLUSIONS: Our data suggest that the combination of relative COX-2 selective NSAIDs and aspirin is associated with higher BMD at multiple skeletal sites in men and women.

The relationship of sodium intake to calcium and sodium excretion and bone mineral density of the hip in postmenopausal African-American and Caucasian women.

During the past several decades in the United States, there has been a shift in dietary habits, with an increased consumption of processed foods that are high in sodium. It is known that calcium and sodium metabolism are linked and that higher sodium intakes may increase calcium excretion. Epidemiological studies in patients with idiopathic hypercalciuria suggest that hypercalciuria is linked to low bone mass. However, the relationship of sodium intake to bone mineral density (BMD) is controversial in Caucasians and has not been explored in African-Americans. To determine the consequences of sodium intake on bone in African-American and Caucasian postmenopausal women, sodium and calcium excretion and BMD of the total hip were measured in 50 Caucasian and 39 African-American postmenopausal women. After adjustment for race and urine volume, sodium excretion was a significant predictor of calcium excretion (P < 0.01). This relationship was modulated by calcium intake (P < 0.01), but not by race (P = 0.63). There was no significant effect of sodium excretion (P = 0.42) or calcium excretion (P = 0.90) on BMD of the total hip after adjusting for race and urine volume. Sodium excretion is a significant predictor of calcium excretion in both postmenopausal African-American and Caucasian women. The relationship between sodium and calcium excretion is modulated by calcium intake, and the relationship is strongest at low calcium intakes (< or =1000 mg/day). However, sodium excretion in the range of 53.75-283.33 mmole/g/total volume (mmole/g/TV) is not a significant predictor of total hip BMD in elderly African-American and Caucasian postmenopausal women.