A cross-sectional association between bone mineral density and parathyroid hormone and other biomarkers in community-dwelling young adults: the CARDIA study

Relationship Between Serum 25-Hydroxyvitamin D and Bone Mineral Density, Fracture Risk, and Bone Metabolism in Adults With Osteoporosis/Fractures

OBJECTIVE

To evaluate the association of serum 25-hydroxyvitamin D (25(OH) D) levels with bone mineral density (BMD), fracture risk, and bone metabolism.

METHODS

This multicenter cross-sectional study recruited menopausal females and males greater than or equal to 50 year old with osteoporosis/fractures between September 2016 and September 2021. Assessment included clinical data, 25(OH)D, intact parathyroid hormone (iPTH), procollagen type 1 amino-terminal propeptide (P1NP), carboxy-terminal collagen crosslinks (CTX), lateral thoracolumbar spine x-rays, and BMD.

RESULTS

A total of 3003 individuals were stratified by 25(OH) D levels: 720 individuals (24%) <20 ng/mL, 1338 individuals (44.5%) 20 to 29 ng/mL, and 945 individuals (31.5%) ≥30 ng/mL. In unadjusted and multivariable models, BMD T-score, except spine, was significantly and positively associated with 25(OH)D levels. 25(OH) D levels were inversely associated with Fracture Risk Assessment Tool scores. Patients with 25(OH)D <20 ng/mL had significantly higher iPTH and bone turnover markers (P1NP and CTX) than patients with 25(OH)D ≧20 ng/mL in all models. When analyzing bone-related markers and BMD, total hip and femoral neck BMD T-scores were positively correlated with 25(OH)D concentrations and BMI but negatively correlated with iPTH, P1NP, CTX, and age. In multivariate models with all bone-related markers, only 25(OH)D levels were significantly associated with total hip and femoral neck BMD.

CONCLUSION

Vitamin D deficiency is significantly associated with decreased total hip and femoral neck BMD and increased fracture risk as assessed by Fracture Risk Assessment Tool. In those with osteoporosis/fractures, vitamin D is implicated in the causal relationship between bone remodeling and BMD. Assessing vitamin D status is imperative for those at risk for osteoporosis/fractures.

Telomere length as a marker of changes in body composition and fractures-an analysis of data from the NHANES 2001-2002

Purpose

There has been an association between changes in body composition, fracture incidence, and age in previous studies. Telomere length (TL) has been proposed as a biomarker of aging. However, the relationship between body composition, fractures, and TL has rarely been studied. Therefore, this study aimed to investigate the correlation between TL and body composition and fractures.Patients and methods: 20950 participants from the 2001-2002 National Health and Nutrition Examination Survey (NHANES) were included in the final analysis. In NHANES, body compositions were measured with DXA, and TL was determined with quantitative PCR. Correlation analysis of TL and body composition was conducted using multivariate weighted linear regression and logistic regression models.

Results

The results showed that TL positively correlated with bone mineral density (BMD) and bone mineral content (BMC) in most body parts. However, BMD and BMC were negatively connected with TL in the upper limbs and skull. Fat content was negatively associated with TL, while muscle content was positively linked to TL. In addition, TL's trend analysis results were consistent with the regression model when transformed from a continuous to a classified variable. An increase in TL was associated with a higher incidence of wrist fractures, while a decrease in spine fractures. The above correlation also has a certain degree of sex specificity.

Conclusion

Our study indicate that TL is associated with body composition as well as fractures, but further research is needed to confirm these contrasting associations in the skull, upper limbs, and wrists.

Suboptimal Plasma Vitamin C Is Associated with Lower Bone Mineral Density in Young and Early Middle-Aged Men: A Retrospective Cross-Sectional Study

Background: This study was conducted to evaluate associations between bone mineral density (BMD) and four selected circulating nutrients, particularly vitamin C, among adults aged 20−49 years. Methods: In this retrospective cross-sectional study, the lumbar spine BMD of 866 men and 589 women were measured by dual-energy X-ray absorptiometry and divided into tertiles, respectively. Logistic regressions were used to identify the predictors of low BMD by comparing subjects with the highest BMD to those with the lowest. Results: Multivariate logistic regressions identified suboptimal plasma vitamin C (adjusted odds ratio (AOR) 1.64, 95% confidence interval (CI) 1.16, 2.31), suboptimal serum vitamin B12 (AOR 2.05, 95% CI 1.02, 4.12), and low BMI (BMI < 23) (AOR 1.68, 95% CI 1.12, 2.53) as independent predictors for low BMD in men. In women, low BMI was the only independent predictor for low BMD. Plasma vitamin C, categorized as suboptimal (≤8.8 mg/L) and sufficient (>8.8 mg/L), was positively significantly correlated with the lumbar spine BMD in men, but there was no association in women. Conclusions: Plasma vitamin C, categorized as suboptimal and sufficient, was positively associated with the lumbar spine BMD in young and early middle-aged men. A well-designed cohort study is needed to confirm the findings.

Spinal Fusion in Pediatric Patients With Low Bone Density: Defining the Value of DXA

BACKGROUND

Children with medical complexity are at increased risk of low bone mineral density (BMD) and complications after spinal fusion compared with idiopathic scoliosis patients. Our aim was to compare treatments and outcomes of children with medical complexity undergoing spinal fusion in those who had dual-energy x-ray absorptiometry (DXA) scans versus those who did not in an effort to standardize the workup of these patients before undergoing spinal surgery.

METHODS

We conducted a retrospective review of patients with low BMD who underwent spinal fusion at a tertiary care pediatric hospital between 2004 and 2016. We consulted with a pediatric endocrinologist to create standard definitions for low BMD to classify each subject. Regardless of DXA status, all patients were given a clinical diagnosis of osteoporosis [at least 2 long bone or 1 vertebral pathologic fracture(s)], osteopenia (stated on radiograph or by the physician), or clinically low bone density belonging to neither category. The last classification was used for patients whose clinicians had documented low bone density not meeting the criteria for osteoporosis or osteopenia. Fifty-nine patients met the criteria, and 314 were excluded for insufficient follow-up and/or not meeting a diagnosis definition. BMD Z -scores compare bone density ascertained by DXA to an age-matched and sex-matched average. Patients who had a DXA scan were also given a DXA diagnosis of low bone density (≤-2 SD), slightly low bone density (-1.0 to -1.9 SD), or neither (>-1.0 SD) based on the lowest BMD Z -score recorded.

RESULTS

Fifty-nine patients were analyzed. Fifty-four percent had at least 1 DXA scan preoperatively. Eighty-one percent of DXA patients received some form of treatment compared with 52% of non-DXA patients ( P =0.03).

CONCLUSIONS

Patients referred for DXA scans were more likely to be treated for low BMD, although there is no standardized system in place to determine which patients should get scans. Our research highlights the need to implement clinical protocols to optimize bone health preoperatively.

LEVEL OF EVIDENCE

Level II-retrospective prognostic study.

Does the relationship between 25-hydroxyvitamin D status and bone mass vary according to skin color in adults? Results of a Brazilian population-based study

Skin color has been indicated as an important factor in determining serum concentrations of 25-hydroxyvitamin D [25(OH)D], and consequently bone health. However, studies are controversial and scarce for mixed populations.

PURPOSE/INTRODUCTION

To analyze the association of 25(OH)D with bone mineral content (BMC) and bone mineral density (BMD); and to investigate the presence of interaction with skin color in Brazilian adults.

METHODS

This is a cross-sectional, population-based study conducted with adult individuals (20-59 years) of both genders. Bone health was assessed by dual energy radiological absortometry. Vitamin D status was measured using serum 25(OH)D. Skin color and other variables in the adjusted model were collected using a questionnaire and anthropometric assessment. Associations and interactions were evaluated using linear regression models stratified according to gender.

RESULTS

Non-white men with vitamin D deficiency (< 20.0 ng/mL) have less bone mass than those with insufficiency and sufficiency for the femoral neck and hip sites. According to the adjusted regression analysis, the deficient status of 25(OH)D in men was associated with worse bone health for the lumbar spine sites (β = - 0.1; p = 0.006), femoral neck (β = - 0.08; p = 0.006), and hip (β = - 0.08; p = 0.009). No statistically significant associations were observed between 25(OH)D and bone health in women. In addition, no statistical interaction was identified between skin color and vitamin D status in relation to bone health (p > 0.05 for all tests) in either gender and for all bone sites evaluated.

CONCLUSION

Deficient vitamin D status is associated with lower bone mass in adults with differences observed according to gender, but not according to skin color.

Effects of PTH and PTH Hypersecretion on Bone: a Clinical Perspective

PURPOSE OF REVIEW

Hyperparathyroidism may be due to an autonomous hypersecretion of parathyroid hormone (PTH) or occurs in response to a number of physiological stimuli. A number of recent findings have provided new insights into the importance of the calcium-parathyroid-vitamin D axis to bone in normal physiology and pathological conditions.

RECENT FINDINGS

PTH is known to affect bone microarchitecture with different effects on cortical and trabecular bone compartments. In trabecular bone, PTH may exert anabolic effects, whereas PTH promotes bone resorption in cortical bone. Vertebral fractures are prevalent in primary hyperparathyroidism (PHPT), and patients seem to fracture at higher values of bone mineral density (BMD) than patients with osteoporosis. This may be explained by changes in bone microarchitecture, which cannot be detected by measuring BMD. Even in mild PHPT, bone seems to benefit from parathyroidectomy. In secondary hyperparathyroidism, bone seems much more susceptible to fracture with insufficient levels of vitamin D compared with a replete vitamin status. If elevated PTH levels cannot be explained by conditions known to cause secondary hyperparathyroidism, the condition is termed normocalcemic PHPT, which also has been associated with an increased risk of fractures. Hyperparathyroidism is harmful to bone, which is why it is of importance to normalize PTH levels either by parathyroidectomy in PHPT or by counteracting conditions known to increase PTH in secondary hyperparathyroidism.

Factors associated with bone mineral content in adults: a population-based study

OBJECTIVE

To determine the association among bone mineral content, sociodemographic, anthropometric and behavioral factors, and health status of Brazilian adults.

METHODS

This was a cross-sectional, population-based study including 701 individuals from both sexes aged between 20 and 59 years. DEXA was used to evaluate dependent variable. The associations were evaluated using linear regression models stratified by sex.

RESULTS

When mean bone mineral content values were compared, we found significant differences related to sex and all the independent variables evaluated. In the adjusted models, we identified an inverse association between bone mineral content and age in both sexes. Among men, to be overweight and/or obese, be highly educated, and have almost sufficiency of 25(OH)D were associated with higher bone mineral content values. On the other hand, among women, to be non-white skin color, overweight and/or obese were associated with better bone health. The main factors associated with low total bone mineral density were advanced age, white skin color, low level of formal education, eutrophy, and 25(OH)D deficiency.

CONCLUSION

Our results may help to identify adults who are at higher risk, and these findings should be used as guidelines for prevention and early diagnosis.

Relationship between 1,25-Dihydroxyvitamin D and Body Composition in Middle-Aged Sedentary Adults: The FIT-AGEING Study

Vitamin D deficiency is a worldwide health problem that, in addition to its well-known negative effects on musculoskeletal health, has been related to a wide range of acute and chronic age-related diseases. However, little is known about the association of body composition with the active, hormonal form of vitamin D, 1,25-dihydroxyvitamin D plasma levels (1,25(OH)₂D). Therefore, the aim of this study was to investigate the association of 1,25(OH)₂D with body composition including lean and fat body mass as well as bone mineral density (BMD) in middle-aged sedentary adults. A total of 73 (39 women) middle-aged sedentary adults (53.7 ± 5.1 years old) participated in the current study. We measured weight and height, and we used dual energy X-ray absorptiometry to measure lean body mass, fat body mass and BMD. Body mass index (BMI), lean mass index (LMI), and fat mass index (FMI) were calculated. 1,25(OH)₂D was measured using a DiaSorin Liaison® immunochemiluminometric analyzer. The results showed a negative association of 1,25(OH)₂D with BMI, LMI and BMD (β = −0.274, R² = 0.075, p = 0.019; β = −0.268, R² = 0.072, p = 0.022; and β = −0.325, R² = 0.105, p = 0.005, respectively), which persisted after controlling for age and sex. No significant differences in 1,25(OH)₂D across body weight status were observed after controlling for the same covariates. In summary, our results suggest that 1,25(OH)₂D could be negatively associated with BMI, LMI and BMD whereas no association was found with FMI in middle-aged sedentary adults.

Meta-analysis across Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium provides evidence for an association of serum vitamin D with pulmonary function

The role that vitamin D plays in pulmonary function remains uncertain. Epidemiological studies reported mixed findings for serum 25-hydroxyvitamin D (25(OH)D)-pulmonary function association. We conducted the largest cross-sectional meta-analysis of the 25(OH)D-pulmonary function association to date, based on nine European ancestry (EA) cohorts (n 22 838) and five African ancestry (AA) cohorts (n 4290) in the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium. Data were analysed using linear models by cohort and ancestry. Effect modification by smoking status (current/former/never) was tested. Results were combined using fixed-effects meta-analysis. Mean serum 25(OH)D was 68 (sd 29) nmol/l for EA and 49 (sd 21) nmol/l for AA. For each 1 nmol/l higher 25(OH)D, forced expiratory volume in the 1st second (FEV1) was higher by 1·1 ml in EA (95 % CI 0·9, 1·3; P<0·0001) and 1·8 ml (95 % CI 1·1, 2·5; P<0·0001) in AA (P race difference=0·06), and forced vital capacity (FVC) was higher by 1·3 ml in EA (95 % CI 1·0, 1·6; P<0·0001) and 1·5 ml (95 % CI 0·8, 2·3; P=0·0001) in AA (P race difference=0·56). Among EA, the 25(OH)D-FVC association was stronger in smokers: per 1 nmol/l higher 25(OH)D, FVC was higher by 1·7 ml (95 % CI 1·1, 2·3) for current smokers and 1·7 ml (95 % CI 1·2, 2·1) for former smokers, compared with 0·8 ml (95 % CI 0·4, 1·2) for never smokers. In summary, the 25(OH)D associations with FEV1 and FVC were positive in both ancestries. In EA, a stronger association was observed for smokers compared with never smokers, which supports the importance of vitamin D in vulnerable populations.

Determinants of bone mineral density in young Australian women; results from the Safe-D study

The study aimed to explore determinants of bone parameters in young women. Most bone parameters were associated with height and lean mass. Bone parameters were not associated with vitamin D status. Future research should address whether interventions aimed at improving lean mass are beneficial to bone health in young women.

INTRODUCTION

The implementation of prevention strategies during young adulthood may be crucial for osteoporosis prevention in later life, yet literature examining the determinants of bone health in premenopausal women is limited. We aimed to assess determinants of bone health, including serum 25-hydroxyvitamin D (25OHD), in females aged 16-25 years, living in Victoria, Australia, recruited through Facebook advertising.

METHODS

Serum 25OHD was measured by liquid chromatography-tandem mass spectrometry and bone health was measured using dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) in 326 participants.

RESULTS

Mean (± standard deviation) serum 25OHD was 69 ± 28 nmol/L and the prevalence of vitamin D deficiency (serum 25OHD <50 nmol/L) was 26%. Seven percent of participants (n = 23) reported taking a vitamin D supplement. Two percent of participants had low lumbar spine bone mineral density (Z-score <-2.0), 5% at the hip and 7% at the femoral neck. Serum 25OHD levels were not associated with DXA bone parameters, nor with pQCT bone parameters. Most bone parameters were positively associated with height and lean mass.

CONCLUSION

Vitamin D status was not associated with bone health in young women in the current study. Our findings suggest that targeting other modifiable factors, such as lean body mass, is likely to be beneficial to bone health in young women. Longitudinal studies examining the association between vitamin D status and bone health in young women are necessary to confirm our findings. In addition, whether raising 25OHD levels is advantageous for young women's bone health is yet to be determined.

Smoking habits and parathyroid hormone concentrations in young adults: The CARDIA study

Conflicting results have been reported concerning a relationship between smoking and serum PTH. Our study objective was to examine whether smoking was associated with serum PTH independent of correlates of PTH among young adults, and explore potential mechanisms. This was a cross-sectional study of healthy individuals, 24-36 years old, examined during 1992 through 1993 in California, USA (a subset of Coronary Artery Risk Development in Young Adults study). Linear regression was used to obtain adjusted means of PTH according to smoking habit (current, former, never). Biomarkers for calcium metabolism and bone turnover (including serum concentrations of osteocalcin, bone-specific alkaline phosphatase, and 24-hour urinary excretion of calcium) and bone mineral density were similarly compared by smoking. 376 participants were analyzed (171 women, 181 black). Over half reported never smoking. We observed lower PTH in current smokers compared to non-smokers and found no evidence of an interaction by race and sex. PTH was lowest in current smokers, intermediate in former smokers, and highest in never smokers (geometric mean PTH: 23.6, 26.7, 27.4 pg/mL, respectively: P for trend, 0.006) after adjusting for potential confounders including calcium intake. Among the biomarkers, serum osteocalcin concentration and 24-hour urinary excretion of calcium were lowest in current smokers. We observed no smoking-related difference in bone mineral density. In this community-based sample of young adult men and women, smoking was associated with significantly lower PTH concentration. The mechanism and clinical implication of the finding, however, remains uncertain.

Associations of 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D With Bone Mineral Density, Bone Mineral Density Change, and Incident Nonvertebral Fracture

Relationships between 1,25-dihydroxyvitamin D (1,25(OH)2 D) and skeletal outcomes are uncertain. We examined the associations of 1,25(OH)2 D with bone mineral density (BMD), BMD change, and incident non-vertebral fractures in a cohort of older men and compared them with those of 25-hydroxyvitamin D (25OHD). The study population included 1000 men (aged 74.6 ± 6.2 years) in the Osteoporotic Fractures in Men (MrOS) study, of which 537 men had longitudinal dual-energy X-ray absorptiometry (DXA) data (4.5 years of follow-up). A case-cohort design and Cox proportional hazards models were used to test the association between vitamin D metabolite levels and incident nonvertebral and hip fractures. Linear regression models were used to estimate the association between vitamin D measures and baseline BMD and BMD change. Interactions between 25OHD and 1,25(OH)2 D were tested for each outcome. Over an average follow-up of 5.1 years, 432 men experienced incident nonvertebral fractures, including 81 hip fractures. Higher 25OHD was associated with higher baseline BMD, slower BMD loss, and lower hip fracture risk. Conversely, men with higher 1,25(OH)2 D had lower baseline BMD. 1,25(OH)2 D was not associated with BMD loss or nonvertebral fracture. Compared with higher levels of calcitriol, the risk of hip fracture was higher in men with the lowest 1,25(OH)2 D levels (8.70 to 51.60 pg/mL) after adjustment for baseline hip BMD (hazard ratio [HR] = 1.99, 95% confidence interval [CI] 1.19-3.33). Adjustment of 1,25(OH)2 D data for 25OHD (and vice versa) had little effect on the associations observed but did attenuate the hip fracture association of both vitamin D metabolites. In older men, higher 1,25(OH)2 D was associated with lower baseline BMD but was not related to the rate of bone loss or nonvertebral fracture risk. However, with BMD adjustment, a protective association for hip fracture was found with higher 1,25(OH)2 D. The associations of 25OHD with skeletal outcomes were generally stronger than those for 1,25(OH)2 D. These results do not support the hypothesis that measures of 1,25(OH)2 D improve the ability to predict adverse skeletal outcomes when 25OHD measures are available. © 2015 American Society for Bone and Mineral Research.

Obstructive sleep apnea and metabolic bone disease: insights into the relationship between bone and sleep

Obstructive sleep apnea (OSA) and low bone mass are two prevalent conditions, particularly among older adults-a section of the U.S. population that is expected to grow dramatically over the coming years. OSA, the most common form of sleep-disordered breathing, has been linked to multiple cardiovascular, metabolic, hormonal, and inflammatory derangements and may have adverse effects on bone. However, little is known about how OSA (including the associated hypoxia and sleep loss) affects bone metabolism. In order to gain insight into the relationship between sleep and bone, we review the growing information on OSA and metabolic bone disease and discuss the pathophysiological mechanisms by which OSA may affect bone metabolism/architecture.

Preservation of volumetric bone density and geometry in trans women during cross-sex hormonal therapy: a prospective observational study

Although trans women before the start of hormonal therapy have a less bone and muscle mass compared with control men, their bone mass and geometry are preserved during the first 2 years of hormonal therapy, despite of substantial muscle loss, illustrating the major role of estrogen in the male skeleton.

PURPOSE

The aim of this study is to examine the evolution of areal and volumetric bone density, geometry, and turnover in trans women undergoing sex steroid changes, during the first 2 years of hormonal therapy.

METHODS

In a prospective observational study, we examined 49 trans women (male-to-female) before and after 1 and 2 years of cross-sex hormonal therapy (CSH) in comparison with 49 age-matched control men measuring grip strength (hand dynamometer), areal bone mineral density (aBMD), and total body fat and lean mass using dual X-ray absorptiometry (DXA), bone geometry and volumetric bone mineral density, regional fat, and muscle area at the forearm and calf using peripheral quantitative computed tomography. Standardized treatment regimens were used with oral estradiol valerate, 4 mg daily (or transdermal 17-β estradiol 100 μg/24 h for patients >45 years old), both combined with oral cyproterone acetate 50 mg daily.

RESULTS

Prior to CSH, trans women had lower aBMD at all measured sites (all p < 0.001), smaller cortical bone size (all p < 0.05), and lower muscle mass and strength and lean body mass (all p < 0.05) compared with control men. During CSH, muscle mass and strength decreased and all measures of fat mass increased (all p < 0.001). The aBMD increased at the femoral neck, radius, lumbar spine, and total body; cortical and trabecular bone remained stable and bone turnover markers decreased (all p < 0.05).

CONCLUSIONS

Although trans women, before CSH, have a lower aBMD and cortical bone size compared with control men, their skeletal status is well preserved during CSH treatment, despite of substantial muscle loss.