Polymorphisms in the gene coding for low-density lipoprotein receptor-related protein 5 (LRP5) contribute to variation in bone mass in the general population. Whether this is due to influence on bone mass acquisition or on bone loss thereafter has not been established.
We studied the association of LRP5 polymorphisms with peak bone mass in young men. The study included 235 Finnish men, aged 18.3 to 20.6 years. Lifestyle factors and fracture history were recorded. Bone mineral content (BMC), density (BMD) and scan area were measured for the lumbar spine and proximal femur by dual energy X-ray absorptiometry (DXA). Blood and urine were collected for determination of bone turnover markers, serum 25-OHD and PTH. Genomic DNA was extracted from peripheral blood for genetic analysis of LRP5. Ten single nucleotide polymorphisms in LRP5 were analyzed and correlated with bone parameters.
Only the A1330V polymorphism of LRP5 significantly associated with bone parameters. In comparison with subjects with the AlaAla genotype (n=215), those with AlaVal genotype (n=20) had lower femoral neck BMC (P=0.029) and BMD (P=0.012), trochanter BMC (P=0.0067) and BMD (P=0.015), and total hip BMC (P=0.0044) and BMD (P=0.0089). Fracture history was similar for the genotypes.
The polymorphic valine variant at position 1330 of LRP5 was significantly associated with reduced BMC and BMD values in healthy young Finnish men. The results provide evidence for the crucial role of LRP5 in peak bone mass acquisition.
The calcium, phosphorus, and parathyroid hormone targets recommended by the Canadian Society of Nephrology (CSN) encompass a wider range of values as compared to the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) guidelines. We sought to compare mineral metabolism parameters within the Manitoba Renal Program (MRP) to the CSN and NKF-K/DOQI guidelines. Medication use was also examined.
All hemodialysis patients in Manitoba were evaluated. Values for serum albumin, phosphorus, calcium, intact parathyroid hormone (PTH) and pertinent medications were collected.
Five hundred and forty-six patients were included in the analysis. Fifty-three per cent to 81% of MRP patients met individual CSN targets. However, only 26% of patients achieved all targets, despite high usage of phosphate (85.5% calcium carbonate, 16.1% sevelamer, 1.3% aluminum) and PTH-lowering drug therapies (30.2% calcitriol, 2.7% cinacalcet).
Only a small proportion of patients were able to achieve all three CSN mineral metabolism targets simultaneously. The majority of outliers presented with hyperphosphatemia or hypoparathyroidism.
Many studies have shown the indigenous elderly population and Asian immigrants to be groups at particular risk of vitamin D deficiency and osteomalacia, but there are no data on the risks in elderly Asians. In this community-based study a group of elderly Asians was compared with control groups of elderly and young whites and young Asians. Levels of 25-hydroxyvitamin D3 (25-OHD3) were significantly lower (p
Parathyroid hormone (PTH) may be an important determinant of cortical bone remodeling in the elderly. Vitamin D status is one of the determining factors in this relationship. The aim of this study was to quantify the relationship between serum PTH, vitamin D and bone mineral density (BMD) in elderly women in Reykjavik (64 degrees N), where daily intake of cod liver oil is common and mean calcium intake is high. In PTH correlated inversely with 25(OH)D (r = -0.26, p
OBJECTIVE: To explore the relation between serum parathyroid hormone (PTH) and bone mineral density (BMD), adjusted for lifestyle factors including smoking. DESIGN: Cross-sectional study. METHODS: The Troms? Study is a population-based study performed for the fifth time in 2001. Serum PTH was measured and the subjects filled in a questionnaire covering lifestyle factors. BMD at the hip, distal and ultradistal forearm was measured. RESULTS: Complete datasets were available in 1442 men and 1368 women. Age, body mass index and serum PTH were strong predictors of BMD level at the hip in both genders. No significant relation was seen between serum PTH and BMD at the distal or ultradistal forearm. When smokers and non-smokers were analysed separately, the relation between PTH and BMD at the hip was significant in current non-smokers only. In males, current non-smokers had significantly higher BMD at all three measurement sites compared with current smokers. Male former smokers had values in between current and never smokers. There was a significant and negative relation between number of years smoked and BMD at the hip. In male former smokers, there was an increase in BMD with increasing years since smoking cessation. CONCLUSION: Serum PTH is negatively associated with BMD at the hip, and the relation seems to be masked, or diminished, by smoking. Smoking reduces BMD at the hip, distal and ultradistal forearm in males, and the effect appears to be mainly time and not dose dependent.
Very few studies have evaluated both parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] and their effects on bone mass in children.
We studied the associations of serum 25(OH)D and intact PTH (iPTH) with bone mineral content (BMC) and bone mineral density (BMD) at different bone sites and the relation between serum 25(OH)D and iPTH in early pubertal and prepubertal Finnish girls.
The subjects were 10-12-y-old girls (n = 193) at Tanner stage 1 or 2, who reported a mean (+/- SD) dietary calcium intake of 733 +/- 288 mg/d. 25(OH)D, iPTH, tartrate-resistant acid phosphatase 5b (TRAP 5b), urinary calcium excretion, BMC, areal BMD, and volumetric BMD were assessed by using different methods.
Thirty-two percent of the girls were vitamin D deficient [serum 25(OH)D
A number of single nucleotide polymorphisms (SNPs) related to height have been detected. Calcium metabolism is important for the skeleton and accordingly also for adult height. Therefore, in the present study, nine SNPs related to the vitamin D receptor (VDR) gene and serum levels of 25-hydroxyvitamin D (25(OH)D), calcium, phosphate and parathyroid hormone (PTH) were related to height in 9471 subjects. Relation with height was evaluated with linear regression for trend across SNP genotypes with age and gender as covariates. After correcting for multiple testing, significant associations with height were found for two SNPs related to the VDR gene (rs1544410 (Bsml) and rs7975232 (Apal)), one SNP related to serum 25(OH)D (rs3829251 at the DHCR7/NADSYN1 gene), one SNP related to serum calcium (rs1459015 at the PTH gene) and one SNP related to serum phosphate (rs1697421 at the ALPL gene). For rs3829251, the mean differences in height between major and minor homozygotes were 1.5-2.0 cm (P
The relationship between serum levels of calcium, parathyroid hormone (PTH) and risk of venous thromboembolism (VTE) has not been addressed in population-based cohorts. We investigated the associations between serum levels of calcium and PTH, with future risk of VTE in a general adult population.
A total of 27 712 subjects (25-87 years) who participated in Tromsø 4 (1994-1995) and Tromsø 5 (2001-2002) surveys were included in the study, and total calcium and PTH were measured in 27 685 and 8547 subjects respectively. Incident VTE was recorded through December 31, 2012. Cox-regression models with calcium and PTH as time-varying exposures were used to calculate hazard ratios (HR) of VTE by quartiles of calcium and PTH. Quartiles of calcium and PTH were also combined to assess the effect of discordants of both PTH and calcium (e.g. highest and lowest quartiles of both calcium and PTH) on VTE risk using the middle two quartiles as reference.
There were 712 VTEs during 15.0 years of median follow-up. Serum levels of calcium and PTH were not associated with risk of VTE. However, subjects with discordant high serum levels of both calcium and PTH (calcium =2.45?mmol/L and PTH =4.0?pmol/L) had increased risk of VTE compared to those in subjects with normal calcium and PTH (multivariable HR: 1.78, 95% CI: 1.12-2.84).
Serum levels of calcium and PTH separately were not associated with future risk of VTE, but subjects with high levels of both calcium and PTH had increased risk of VTE compared to those in subjects with normal levels.
OBJECTIVE--To evaluate benign familial hyperphosphatasemia involving serum alkaline phosphatase (SAP) in pups. DESIGN--Pups with markedly increased SAP activity were evaluated and compared with unaffected siblings, and with other unaffected Siberian Husky pups from the same colony. ANIMALS--8 related litters of Siberian Husky pups (n = 56). PROCEDURE--At ages 11 and 16 weeks, pups were given physical examinations and blood was obtained for hematologic and serum biochemical analyses (including electrolytes and isoenzymes of alkaline phosphatase), ionized calcium concentration, and serum parathyroid hormone concentration. Diet, growth and health performance, skeletal radiographs, and genealogical data also were evaluated. RESULTS--Of 42 pups tested, 17 had markedly high total SAP values. Mean total SAP activity of affected pups at ages 11 and 16 weeks was over 5 times greater than mean total SAP activity of unaffected siblings and other unaffected Siberian Husky pups of the same age (P
This study aims to quantify bone mineral density (BMD) changes following surgery in patients with primary hyperparathyroidism (PHPT) and to assess their relationship with clinical and biochemical variables.
A historic cohort of 236 PHPT patients with DXA scans pre- and 1-year postoperatively, clinical data, and biochemical data was analyzed.
The mean age was 60 years (range 19-86) and 81 % of the patients were women. A significant postoperative 2.6 % (95 % CI, 2.1; 3.1) increase in lumbar spine BMD was seen. The increase in BMD was positively associated with preoperative plasma PTH (p?=?0.002), Ca(2+) (p?