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

24-hour activity composition is associated with lower fall and fracture risk in older men

Physical activity (PA), sedentary behavior (SB), and sleep are each individually associated with falls and fractures, but often are not examined simultaneously. Compositional data analysis examined the combined prospective associations between the proportion of time in PA, SB, and sleep relative to the remaining behaviors with recurrent falls (2+ falls in any yr), any fractures, and major osteoporotic fracture (MOF) from tri-annual questionnaires, with adjudication for fractures, in 2918 older men aged 78.9 ± 5.1 yr in the Osteoporotic Fractures in Men (MrOS) Study. Accelerometers were worn on the right tricep for seven consecutive 24-h periods and measured PA (>1.5 METs), SB (≤1.5 METs), and sleep. Generalized estimating equations evaluated associations with recurrent falls. Cox proportional hazards regression estimated any incident fracture and MOF risk separately. Over 4 yr of follow-up, 1025 (35.2%) experienced recurrent falls; over 10 ± 4 yr of follow-up, 669 (22.9%) experienced incident fractures, and 370 (12.7%) experienced a MOF. Higher proportions of PA relative to SB and sleep were associated with lower odds of recurrent falls [odds ratio (OR): 0.87, 95% CI: 0.76-0.99]. Higher proportions of SB relative to PA and sleep were associated with a higher odds of recurrent falls (OR: 1.38, 95% CI: 1.06-1.81) and a higher risk of any fracture [hazard ratio (HR): 1.42, 95% CI: 1.05-1.92]. Higher proportions of sleep relative to PA and SB were associated with a lower risk of fracture (HR: 0.74, 95% CI: 0.54-0.99). No associations of activity composition with MOF were observed. When accounting for the co-dependence of daily activities, higher proportions of SB relative to the proportion of PA and sleep were associated with higher odds of recurrent falls and fracture risk. Results suggest reducing SB (and increasing PA) may lower fall and fracture risk in older men, which could inform future interventions.

Association of obstructive sleep apnea with bone metabolism in older adults: a hospital-based study

PURPOSE

Obstructive sleep apnea (OSA) significantly affects patients' quality of life; however, the mechanisms, such as its effects on bone mineral density (BMD) and bone turnover marker (BTM) expression, remain unclear. In this study, we investigated the relationships among OSA, BMD, and (BTMs) in older adults.

METHODS

This retrospective study enrolled 260 participants (114 women; 44.5%). Data of an established system (Alice NightOne) were used to diagnose OSA and analyze nocturnal hypoxia. Participants were divided into four groups according to respiratory event index (REI) (control, < 5 times/hour; mild OSA, 5-15 times/hour; moderate OSA 15-30 times/hour; severe OSA ≥ 30 times/hour). BMD were mesured by dual-energy x-ray absorptiometry. BTMs including bone specific alkaline phosphatase (BALP), tartrate-resistant acid phosphatase 5b (TRAP-5b) were collected.

RESULTS

Patients with OSA had higher BMD at first lumbar vertebra, left and right femur than those without (all p < 0.05). REI was positively correlated with BMD at the first lumbar vertebra (r = 0.181, p = 0.006), left femur (r = 0.160, p = 0.014), and right femur (r = 0.243, p < 0.001). In participants with body mass index (BMI) of 18-24 kg/m2 (N = 96), the correlation between REI and BMD at the left femur(r = 0.251, p = 0.019) and right femur (r = 0.258, p = 0.018) remained. Multiple regression analysis showed that OSA was significantly associated with osteoporosis (p = 0.034, 95% confidence interval, 0.092-0.100, odds ratio, 0.092). MSaO2 was positively correlated with TRAP5b (r = 0.560, p = 0.007). In participants with a BMI of ≥ 24 kg/m2(N = 164), MSaO2 was negatively correlated with BALP (r = -0.331, p = 0.034). No significant association between REI and BMD was observed.

CONCLUSIONS

OSA and hypoxia were associated with higher BMD in older adults in BMI of 18-24 kg/m2 but not in participants with a BMI of ≥ 24 kg/m2. This study suggests a negative association between OSA and osteoporosis in non-overweight and obese population. BMI played an important role. The study's findings could help exploration mechanisms of osteoporosis and promoting its treatment.

The role of Klotho and sirtuins in sleep-related cardiovascular diseases: a review study

The prevalence of sleep disorders has been reported from 1.6% to 56.0%, worldwide. Sleep deprivation causes cardiovascular diseases (CVDs) including atherosclerosis, vascular aging, hypertension, heart dysfunction, reduced heart rate variability, and cardiac arrhythmia. Reduced tissue oxygen causes various CVDs by activating pro-inflammatory factors and increasing oxidative stress. Sleep disorders are more important and prevalent in older people and cause more severe cardiovascular complications. On the other hand, the reduction of Klotho level, an age-dependent protein whose expression decreases with age, is associated with age-related diseases. Sirtuins, class III histone deacetylases, also are among the essential factors in postponing cellular aging and increasing the lifespan of organisms, and they do this by regulating different pathways in the cell. Sirtuins and Klotho play an important role in the pathophysiology of CVDS and both have anti-oxidative stress and anti-inflammatory activity. Studies have shown that the levels of Klotho and sirtuins are altered in sleep disorders. In this article, alterations of Klotho and sirtuins in sleep disorders and in the development of sleep-related CVDs were reviewed and the possible signaling pathways were discussed. The inclusion criteria were studies with keywords of different types of sleep disorders and CVDs, klotho, SIRT1-7, and sirtuins in PubMed, Scopus, Embase، Science Direct، Web of Sciences and Google Scholar by the end of 2023. The studies revealed there is a bidirectional relationship between sleep disorders and the serum and tissue levels of Klotho and sirtuins and sleep related-CVDs.

Associations of sleep behaviors and genetic risk with risk of incident osteoporosis: A prospective cohort study of 293,164 participants

BACKGROUND

Unhealthy sleep behaviors are associated with higher risks of osteoporosis (OP), while prospective evidence is limited. This study aimed to prospectively investigate this association, quantify the attributable burden of OP incidence reduction due to unhealthy sleep behaviors, and explore potential modifications by genetic risk factors.

METHODS

This longitudinal cohort study was conducted utilizing data from the UK Biobank, comprising 293,164 participants initially free of OP and with requisite sleep behaviors data at baseline. We followed the participants after recruitment until November 30, 2022, to ascertain incident OP. We assessed the associations of five sleep behaviors including sleep duration, chronotype, insomnia, daytime napping, and morning wake-up difficulties, as well as sleep behavior patterns identified based on the above sleep behaviors, with the risk of OP, using Cox models adjusted for multiple confounders. The analyses were then performed separately among individuals with different OP susceptibility, indexed by standard polygenetic risk scores(PRS) for OP. Our secondary outcome was OP with pathologic fracture. Subgroup and sensitivity analyses were performed. Additionally, attributable risk percent in the exposed population (AR%) and population attributable fraction (PAF) of sleep behaviors were calculated.

RESULTS

Over a median follow-up of 13.7 years, 8253 new-onset OP cases were documented. Unhealthy sleep behaviors, such as long or short sleep duration, insomnia, daytime napping, morning wake-up difficulties, and unhealthy sleep patterns, were associated with elevated risks of OP (HRs ranging from 1.14 to 1.46, all P-value <0.001) compared to healthy sleep behaviors. Similar associations were observed for OP with pathologic fractures. Insomnia exhibited the largest AR% of 39.98 % (95%CI: 36.46, 43.31) and PAF of 33.25 % (95%CI: 30.00, 36.34) among healthy sleep patterns and components. A statistically significant multiplicative interaction was noted between sleep behaviors and OP PRS on OP risk (all P-interaction <0.001).

CONCLUSIONS

Four unhealthy sleep behaviors and sleep behavior patterns were associated to increased OP risk, with insomnia contributing the most to OP incidence, while genetic risk for OP modified this association. These findings underscore the crucial role of adhering to healthy sleep behaviors for effective OP prevention.

An analysis of the potential association between obstructive sleep apnea and osteoporosis from the perspective of transcriptomics and NHANES

BACKGROUND

Obstructive sleep apnea (OSA) and osteoporosis (OP) are prevalent diseases in the elderly. This study aims to reveal the clinical association between OSA and OP and explore potential crosstalk gene targets.

METHODS

Participants diagnosed with OSA in the National Health and Nutrition Examination Survey (NHANES) database (2015-2020) were included, and OP was diagnosed based on bone mineral density (BMD). We explored the association between OSA and OP, and utilized multivariate logistic regression analysis and machine learning algorithms to explore the risk factors for OP in OSA patients. Overlapping genes of comorbidity were explored using differential expression analysis, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, Least Absolute Shrinkage and Selection Operator (LASSO) regression, and Random Forest (RF) methods.

RESULTS

In the OSA population, the weighted prevalence of OP was 7.0%. The OP group had more females, lower body mass index (BMI), and more low/middle-income individuals compared to the non-OP group. Female gender and lower BMI were identified as independent risk factors for OP in OSA patients. Gene expression profiling revealed 8 overlapping differentially expressed genes in OP and OSA patients. KCNJ1, NPR3 and WT1-AS were identified as shared diagnostic biomarkers or OSA and OP, all of which are associated with immune cell infiltration.

CONCLUSION

This study pinpointed female gender and lower BMI as OP risk factors in OSA patients, and uncovered three pivotal genes linked to OSA and OP comorbidity, offering fresh perspectives and research targets.

Association Between Changes in Sleep, Nap Duration and Bone Mineral Density in Mexican Adults

Studies have found associations between sleep, nap duration, and bone mineral density (BMD). However, the longitudinal relationship between sleep, nap duration, and BMD has not been explored. We evaluated the association between the change in sleep and nap duration and BMD in Mexican adults. Data come from 1,337 adult participants of the Health Workers Cohort Study (341 were men and 996 were women, including 450 women < 45 years old and 546 ≥ 45 years old), with two study waves. At each wave, sleep and nap duration was assessed using self-administered questionnaires and BMD in g/cm2 was determined by dual X-ray absorptiometry. We used fixed-effect regression models stratified by sex and adjusted for BMI, diet, physical activity, vitamin supplements, and hormone replacement therapy. Women who changed from < 7 to ≥ 7 h/day of sleep from baseline to follow-up were associated with increases in the total hip (β = 0.012 g/cm2; 95% CI: 0.002, 0.022) and lumbar spine BMD (β = 0.024 g/cm2; 95% CI: 0.009, 0.039). Furthermore, most of these associations were observed in women ≥ 45 years. For women, a changing from 0 to > 60 min/day of napping was associated with a significant increase in total hip BMD of 0.012 g/cm2 (95% CI: 0.004, 0.024) and lumbar spine BMD of 0.027 g/cm2 (95% CI: 0.009, 0.045). No significant associations were observed for men. Our results suggest that increased sleep and nap duration are associated with gains in BMD in Mexican women, emphasizing sleep's role in promoting bone health and supporting established recommendations.

Association of depressive symptoms with incident fractures: the Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT)

This 5-year longitudinal study investigated the relationship between depressive symptoms and fracture risk in a large Japanese cohort. Depressive symptoms were a significant risk factor for hip fractures in women.

PURPOSE

A relationship between depressive symptoms and fractures has not been clearly demonstrated. We aimed to investigate the relationship between depressive symptoms and 5-year fracture risk in the Japan Public Health Center-based Prospective Study for the Next Generation.

METHODS

From 2011 to 2016, 114,092 participants were enrolled, and a follow-up survey was conducted 5 years later. We analyzed 30,552 men and 38,063 women aged 40-74 years who had no past fractures at baseline. Presence of depressive symptoms was defined as a modified 11-item Center for Epidemiological Studies Depression Scale score of 8 or higher, a history of depression, or use of antidepressants. Subjects were asked to report vertebral, upper limb, and/or hip fractures, except for traffic or work accidents, that occurred during the follow-up period. The adjusted odds ratios (AORs) and 95% confidence intervals (CIs) for fracture were analyzed via logistic regression analysis to evaluate the relationship between depressive symptoms and fracture.

RESULTS

Women with depressive symptoms demonstrated a high AOR for hip fractures (AOR: 2.78, 95% CI: 1.30 - 5.92); this result was consistent in post menopause women. In men, this association was not found for any age group or any type of fracture.

CONCLUSIONS

Depressive symptoms in women may increase the risk of hip fractures. Further studies are required to explore this relationship in more detail.

Causal Relationship of Obstructive Sleep Apnea with Bone Mineral Density and the Role of BMI

Background

Observational studies have yielded conflicting evidence concerning the relationships between obstructive sleep apnea (OSA) and bone mineral density (BMD). As the exact causal inferences remain inconclusive, we conducted a two-sample Mendelian randomization (MR) to identify the causal associations between OSA and BMD.

Methods

Single-nucleotide polymorphisms associated with OSA were extracted from the FinnGen study. Summary statistics for 10 BMD measured at different age or skeletal sites were obtained from the publicly available IEU GWAS database. Inverse-variance weighted (IVW) method was chosen as the primary analysis, combined with several sensitivity analyses to evaluate the robustness of results. The study design included two-sample MR and network MR.

Results

Our primary MR analysis revealed that genetically predicted OSA was positively linked to increased forearm BMD (β = 0.24, 95% confidence interval [CI]: 0.06-0.41, p = 0.009) and heel BMD (β=0.10, 95% CI = 0.02-0.18, p = 0.018), while no significant causal relationships were observed between OSA and total body BMD, lumbar spine BMD, or femoral neck BMD (all p > 0.05). Network MR suggests that OSA might act as a mediating factor in the effect of BMI on forearm BMD and heel BMD, with a mediated portion estimated at 73% and 84%, respectively.

Conclusion

Our findings provide support for a causal relationship between genetically predicted OSA and increased forearm BMD and heel BMD. Furthermore, our results suggest that OSA may play a role in mediating the influence of BMI on BMD.

Continuous positive airway pressure treatment improves bone mineral density in men affected by severe obstructive sleep apnea syndrome

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) and low bone mineral density (BMD) are 2 prevalent conditions with a significant negative impact on patients' well-being and quality of life. Recent research has shown low BMD at different bone sites in male patients with OSA. Although the efficacy of continuous positive airway pressure (CPAP) treatment for OSA has been widely demonstrated, the evidence for understanding its impact on BMD and other bone-related outcomes is insufficient. The aim of this observational study was to investigate the effect of 12 months of CPAP treatment on lumbar and femur BMD and bone-related serum biomarkers in male patients with severe OSA.

METHODS

Sixty patients (mean age: 55.1 ± 9.9 years) were consecutively included and underwent BMD measurement with dual-energy x-ray absorptiometry at baseline and after 12 months of CPAP treatment. Vitamin D, parathyroid hormone, and calcium serum levels were examined at the same time points.

RESULTS

A significant increase in BMD in the L1 (P < .001, d = 0.27) and L2 (P < .001, d = 0.26) vertebrae was observed after CPAP treatment, along with an increase in vitamin D (P < .001, d = 0.71) and calcium (P < .001, d = 0.73) levels and a decrease in parathyroid hormone levels (P < .001, d = 0.60). The increase in BMD in L1 was significantly correlated with the decrease in parathyroid hormone serum levels (r = -.50, P < .001).

CONCLUSIONS

Overall, these findings showed that beneficial OSA treatment might restore bone health and support CPAP treatment as a feasible strategy to improve BMD in male patients with severe OSA. Accordingly, diagnosing and targeting OSA may be warranted in the treatment of male patients with undetermined osteopenia and osteoporosis.

CITATION

Carpi M, Cordella A, Placidi F, et al. Continuous positive airway pressure treatment improves bone mineral density in men affected by severe obstructive sleep apnea syndrome. J Clin Sleep Med. 2024;20(1):67-73.

Use of hypnotic-sedative medication and risk of falls and fractures in adults: A self-controlled case series study

OBJECTIVE

To evaluate the risk of falls and fractures in users of benzodiazepines, Z-drugs, or melatonin.

METHODS

We followed 699,335 adults with a purchase of benzodiazepines, Z-drugs, or melatonin in the Danish National Prescription Registry between 2003 and 2016 for falls and fractures in the Danish National Patient Registry between 2000 and 2018. A self-controlled case-series analysis and conditional Poisson regression were used to derive incidence rate ratios (IRR) of falls and fractures during six predefined periods.

RESULTS

In total 62,105 and 36,808 adults, respectively, experienced a fall or fracture. For older adults, the risk of falls was highest during the 3-month pre-treatment period (IRRmen+70 , 4.22 (95% confidence interval, 3.53-5.05), IRRwomen + 70 , 3.03 (2.59-3.55)) compared to the baseline (>1 year before initiation). The risk continued to be higher in the later treatment periods. Contrarily, in men and women aged 40-69 years, the risk was only higher in the 3-month pre-treatment period. The incidence of falls among young men and women was slightly lower after initiation of sedating medication (treatment period, IRRmen15-39 , 0.66 (0.50-0.86), IRRwomen15-39 , 0.65 (0.51-0.83)). Analyses with fractures as outcome yielded similar results.

CONCLUSIONS

Although falls and fractures occur more often in persons using sedative-hypnotic medication, the higher risk of falls and fractures in the pre-treatment period relative to the period directly after treatment, suggests that this association is better explained by other factors that elicited the prescription of this medication rather than the adverse effects of the sedative-hypnotic medication.

Effect of breathing patterns on mandibular cortical bone quality in children and establishment of a preliminary screening model

OBJECTIVE

This retrospective study analyzed breathing patterns and age subgroups effect on cortical bone quality of the mandible in growing subjects, aiming to explore the application value of facial skeletal pattern combined with cortical bone density detection in early screening diagnosis of mouth breathing.

METHODS

One hundred twenty-six participants were divided into four groups: mouth breathing group (7-9, 10-12 years old) and nasal breathing group (7-9, 10-12 years old). The mandibular anterior, middle, and posterior cortical bone mineral density (CBMD), cortical bone width (MCW), ANB, and FMA values were measured. Independent T-test and Mann-Whitney U test were used to compare the measured values. Binary logistic regression was employed to analyze the correlation between measured variables and the children's breathing patterns. ROC analysis was used to determine the ability of the cortical bone density measurements in early screening diagnosis of MB.

RESULTS

Mouth breathing had a negative impact on CBMD and MCW of the pre-mandibular (Pog) in subjects aged 7-9 years and also impacted the development of (Pog) and submandibular (Me) sites in subjects aged 10-12 years. Older children in the nasal breathing group have higher CBMD, MCW, and SNB values and lower FMA values. Single-factor and multiple-factor logistic binary regression analysis showed that FMA, MSPogCBMD, MSPogMCW, and ANB are correlated factors for children at risk of mouth breathing.

CONCLUSION

Mouth breathing pattern is closely associated with decreased mandibular CBMD and MCW values in children aged 7-12, where the anterior (Pog) and inferior (Me) sites of anterior mandible are more significantly affected. Furthermore, in combination with facial skeletal pattern, it provides a basis for the early warning diagnosis of mouth breathing.

Night shift work and serum markers of bone turnover in male shift workers

Night shift work is related to sleep disorders, disruption of circadian rhythm and low serum levels of vitamin D. It is known that all these conditions can adversely affect bone mass. The rate of bone turnover can be assessed through the measurement of molecules called bone turnover markers, including C-terminal telopeptide fragment of type I collagen (CTX) and procollagen type I N-terminal propeptide (P1NP). In this study, we evaluated the serum levels of CTX, P1NP and 25-Hydroxy Vitamin D in 82 male subjects (42 daytime workers and 40 night shift workers) to assess the possible risk of osteoporosis in male shift workers. Serum levels of CTX and P1NP were found to be higher in night shift workers than in daytime workers. No significant difference was found in vitamin D levels between night shift and daytime workers. The increased CTX and P1NP levels reveal a higher rate of bone turnover in night shift workers and thus a possible increased risk of osteoporosis in this category of workers compared with daytime workers. In view of this, our results highlight the importance of further studies investigating the bone health in male night shift workers.

Self-Reported Sleep Disturbances over the Menopausal Transition and Fracture Risk: The Study of Women's Health Across the Nation

Sleep disturbances are common and may impact fracture risk directly by influencing bone turnover or indirectly through shared risk factors or mediators. To investigate the association between self-reported sleep disturbances across the menopausal transition (MT) and fractures, we prospectively studied 3101 women enrolled in the Study of Women's Health Across the Nation (SWAN). At each of 14 study visits spaced approximately 18 months apart, a standardized validated scale ascertained trouble falling asleep, waking up several times during the night, and waking up earlier than planned. Two time-varying exposures were modeled: presence of any of the three disturbances at least three times per week and waking up several times during the night at least three times per week. Base models adjusted for fixed (race/ethnicity, study site) and time-varying characteristics (age, body mass index, and MT stage). Fully adjusted models also included time-varying bone beneficial and detrimental medications, smoking, alcohol, physical activity, diabetes, depression and sleep medications, and depressive symptoms. Women who experienced a fracture were more likely to report a greater frequency of having trouble falling asleep, waking up several times, and/or waking up earlier: 35% versus 30% at baseline, p = 0.02. In the base models, women who had any of the three sleep disturbances at least three times per week had a higher risk of any fracture, odds ratio (OR) = 1.23 (95% confidence intervals, 1.02, 1.48) and nontraumatic fracture, OR = 1.36 (1.03, 1.80). These associations were largely attenuated to nonsignificance in the fully adjusted model. Sensitivity analyses limiting our sample to 2315 SWAN women enrolled in the bone mineral density (BMD) centers yielded similar results. Additional adjustment for femoral neck BMD had no effect on our results. In conclusion, self-reported sleep disturbances were associated with an increased risk of fractures, but these associations likely reflect shared risk factors or factors in the causal pathway. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Dual Role of Fibroblast Growth Factor Pathways in Sleep Regulation

Sleep plays an important function in neuro-immuno-endocrine homeostasis. Sleep disorders have been associated with an increased risk of metabolic and cognitive impairments. Among different factors that have an effect on sleep metabolism, a growing body of literature has investigated growth factors in the course of sleep quality and disorders. A good example of growth factors is fibroblast growth factors (FGFs), which are a large family of polypeptide growth factors. Evidence has shown that FGFs are involved in the modulation of sleep-wake behavior by their receptor subtypes and ligands, e.g., FFG1 plays an important role in the quality of sleep through somnogenic effects, while the high level of FGF23 is associated with secondary disorders in shift workers. Therefore, a controversial effect of FGFs can be seen in the course of sleep in physiologic and pathologic conditions. Further investigation on this topic would help us to understand the role of FGFs in sleep disorders as a therapeutic option and biomarker.

The Use of Continuous Positive Airway Ventilation for Patients With Obstructive Sleep Apnea is Associated With Early Medical and Surgery-related Complications Following Total Hip Arthroplasty: A National Database Study

Background

The objective of this study was to determine the effect size of the use of continuous positive airway pressure (CPAP), as a surrogate in cases of active and more severe diseases, on early medical and surgery-related complications following total hip arthroplasty (THA) within an obstructive sleep apnea (OSA) patient population.

Methods

Patients with OSA who underwent primary THA between 2010 and 2019 were identified using a large national insurance database. Ninety-day incidence of various medical and surgery-related complications and hospital utilization were evaluated for OSA patients who had used CPAP prior to THA and those who did not. Propensity score matching was used to control for patient demographic factors and comorbidities as covariates.

Results

Propensity score matching resulted in 7351 OSA patients who had used CPAP within 6 months of primary THA and 7351 OSA patients who had not. Patients who had used CPAP were at increased 90-day risk of medical complications, as well as 1-year risk of periprosthetic fracture (OR 1.5429; P = .0356), osteolysis (OR 2.4488; P = .0237), aseptic loosening (OR 2.4057; P < .001), and dislocation (OR 1.283; P = .016).

Conclusions

Our findings suggest that OSA patients on CPAP are at increased risk of several 90-day medical complications, 1-year surgical complications, and health-care utilization compared to OSA patients not recently using CPAP.

Level of Evidence

III, Retrospective review.

Disrupted Sleep Architecture Is Associated With Incident Bone Loss in Indian Postmenopausal Women: A Prospective Study

Inadequate sleep has been shown to be detrimental to several body systems, including the bone. We proposed to study the impact of insomnia on bone health in Indian postmenopausal women. In a 2-year prospective study, ambulant community-dwelling postmenopausal women aged >50 years were recruited through simple random sampling. Sleep duration was recorded based on self-reported sleep duration and sleep quality using the Women's Health Initiative Insomnia Rating Scale (WHIIRS). Anthropometry, bone biochemistry including bone turnover markers (C-terminal telopeptide of type 1 collagen [CTX], N-terminal telopeptide of type 1 pro-collagen [P1NP]), bone mineral density (BMD), and trabecular bone score (TBS) were assessed at baseline and at the end of 2 years. Among 190 postmenopausal women with mean (SD) age of 58.2 (6.9) years, 65/190 (34.2%) had insomnia (WHIIRS ≥ 9) and 20/190 (10.5%) developed osteoporosis at any site on follow-up. The percentage decline over 2 years in BMD in women with insomnia was significantly (p < 0.001) higher at femoral neck (2.9 [1.6] versus 1.2 [1.2]%) and lumbar spine (4.5 [2.0] versus 1.6 [1.1]%). The decrement in TBS was also significantly higher (p < 0.001) in women with suboptimal sleep (1.5 [2.1] versus 0.5 [1.0] %) when compared with those with adequate sleep. The increment in CTX (46.4 [32.2] versus 18.9 [26.4]) and decrement in P1NP (35.4 [9.1] versus 16.7 [18.9]), respectively, were also greater (p < 0.001) in women with insomnia compared with those without. On multivariate analysis, insomnia was the sole factor that was predictive (adjusted odds ratio [OR] = 9.3; 95% confidence interval [CI] 2.9-29.6; p < 0.001) of incident osteoporosis. In conclusion, poor sleep quality was associated with incident osteoporosis in Indian postmenopausal women. Optimal sleep may help to retard ongoing bone loss that results from sleep deprivation and requires further research. © 2022 American Society for Bone and Mineral Research (ASBMR).

Skeletal and extraskeletal disorders of biomineralization

The physiological process of biomineralization is complex and deviation from it leads to a variety of diseases. Progress in the past 10 years has enhanced understanding of the genetic, molecular and cellular pathophysiology underlying these disorders; sometimes, this knowledge has both facilitated restoration of health and clarified the very nature of biomineralization as it occurs in humans. In this Review, we consider the principal regulators of mineralization and crystallization, and how dysregulation of these processes can lead to human disease. The knowledge acquired to date and gaps still to be filled are highlighted. The disorders of mineralization discussed comprise a broad spectrum of conditions that encompass bone disorders associated with alterations of mineral quantity and quality, as well as disorders of extraskeletal mineralization (hyperphosphataemic familial tumoural calcinosis). Included are disorders of alkaline phosphatase (hypophosphatasia) and phosphate homeostasis (X-linked hypophosphataemic rickets, fluorosis, rickets and osteomalacia). Furthermore, crystallopathies are covered as well as arterial and renal calcification. This Review discusses the current knowledge of biomineralization derived from basic and clinical research and points to future studies that will lead to new therapeutic approaches for biomineralization disorders.

Orexin-A Reverse Bone Mass Loss Induced by Chronic Intermittent Hypoxia Through OX1R-Nrf2/HIF-1α Pathway

Background

Recent studies suggest that there is a potential connection between obstructive sleep apnea (OSA) and osteoporosis through dysregulation of bone metabolism. Orexin-A, a neuroprotective peptide secreted by the hypothalamus, is at a lower level in the plasma of OSA patients, which regulates appetite, energy expenditure and sleep-wake states. However, the protective effect of orexin-A on bone metabolism in OSA is unclear.

Purpose

To investigate whether the activation of OX1R by orexin-A can reverse bone mass loss induced by chronic intermittent hypoxia (CIH).

Methods

Mice were randomly divided into the normoxia group and CIH group. Within the CIH or normoxia groups, treatment groups were given a subcutaneous injection of either orexin-A or saline vehicle once every day for 4 weeks and then femurs were removed for micro-CT scans. Histology and immunohistochemical staining were performed to observe and calculate the changes in femurs as a result of hypoxia. Cell immunofluorescence and immunohistochemical staining were used to detect the expression of orexin receptors in MC3T3-E1 cells or in bones. CCK-8 assay, ALP assay kit and alizarin red staining were used to detect the viability, alkaline phosphatase (ALP) activity, and capacity of mineralization, respectively. The effect of orexin-A on osteogenic differentiation of MC3T3-E1 cells was evaluated using qRT-PCR, Western blot and cell staining.

Results

CIH led to a decrease in the amount and density of trabecular bone, downregulated OCN expression while increasing osteoclast numbers in femurs and inhibited the expression of RUNX2, OSX, OPN and Nrf2 in MC3T3-E1 cells. Orexin-A treatment alleviated these CIH-induced effects by combining to OX1R. The level of HIF-1α was elevated both in CIH and orexin-A treatment groups.

Conclusion

CIH environment inhibits osteogenesis and orexin-A can reverse bone mass loss induced by CIH through OX1R-Nrf2/HIF-1α pathway.

Sleep Disruption and Bone Health

PURPOSE OF REVIEW

Review recent literature investigating the relationship between bone health and sleep/circadian disruptions (e.g., abnormal sleep duration, night shift work).

RECENT FINDINGS

Short and long sleep are associated with low bone mineral density (BMD). Recent data from observational studies identified an increased risk of fracture in women with short sleep. Studies suggest that age, sex, weight change, and concurrent circadian misalignment may modify the effects of sleep restriction on bone metabolism. Interventional studies demonstrate alterations in bone metabolism and structure in response to circadian disruption that could underlie the increased fracture risk seen with night shift work. The effects of sleep and circadian disruption during adolescence may have lifelong skeletal consequences if they adversely impact bone modeling. Data suggest that short sleep and night shift work negatively impact bone metabolism and health. Rigorous studies of prevalent sleep and circadian disruptions are needed to determine mechanisms and develop prevention strategies to optimize lifelong skeletal health.

Bone mineral density alteration in obstructive sleep apnea by derived computed tomography screening

The association between obstructive sleep apnea (OSA) and bone mineral density (BMD) is poorly elucidated and has contradictory findings. Abdominal computed tomography (CT) for other indications can provide a valuable opportunity for osteoporosis screening. Thus, we retrospectively explored the association between OSA and BMD by examining abdominal CT vertebrae images for a multitude of conditions and indications. We included 315 subjects (174 with OSA and 141 without OSA) who performed at least two CT scans (under similar settings). Both groups had a similar duration between the first and second CT scans of 3.6 years. BMD decreased in those with OSA and increased age. A multivariate linear regression indicated that OSA is associated with BMD alterations after controlling for age, gender, and cardiovascular diseases. Here, we report that OSA is associated with BMD alterations. Further studies are required to untangle the complex affect of OSA on BMD and the possible clinical implications of vertebra-depressed or femoral neck fractures.

Metabolic Bone Diseases and New Drug Developments

Metabolic bone diseases are serious health issues worldwide, since several million individuals over the age of 50 are at risk of bone damage and should be worried about their bone health. One in every two women and one in every four men will break a bone during their lifetime due to a metabolic bone disease. Early detection, raising bone health awareness, and maintaining a balanced healthy diet may reduce the risk of skeletal fractures caused by metabolic bone diseases. This review compiles information on the most common metabolic bone diseases (osteoporosis, primary hyperparathyroidism, osteomalacia, and fluorosis disease) seen in the global population, including their symptoms, mechanisms, and causes, as well as discussing their prevention and the development of new drugs for treatment. A large amount of research literature suggests that balanced nutrition and balanced periodic supplementation of calcium, phosphate, and vitamin D can improve re-absorption and the regrowth of bones, and inhibit the formation of skeletal fractures, except in the case of hereditary bone diseases. Meanwhile, new and improved drug formulations, such as raloxifene, teriparatide, sclerostin, denosumab, and abaloparatide, have been successfully developed and administered as treatments for metabolic bone diseases, while others (romososumab and odanacatib) are in various stages of clinical trials.

The Potential Role of Sleep in Promoting a Healthy Body Composition: Underlying Mechanisms Determining Muscle, Fat, and Bone Mass and Their Association with Sleep

Sleep plays an essential role in human life. While sleep is a state elicited by the brain, its vital role reaches beyond maintaining brain health. Unhealthy sleeping habits have been associated with increased risk for inflammation, obesity, or diabetes. Evidence is emerging that sleep guides processes playing an important role in promoting the regulation of endocrine function involved in tissue regeneration and tissue remodelling. Thereby, sleep presumably is a critical factor contributing to the balance of core body tissues: bone, fat, and muscle mass. Given the increasing prevalence of various chronic diseases and comorbidities due to unhealthy lifestyle choices, sleep could be a key target to promote a healthy body composition up until old age. Here, we review the potential role of sleep and its underlying brain oscillations in body core tissues turnover. Specifically, we discuss potential underlying mechanisms linking sleep to body composition, both during rest and under challenging conditions. Among other described pathways, we highlight the possible role of the growth hormone that was found to be involved in the homeostasis of all core body tissues and has been strongly linked to brain activity dominating deep sleep, the so-called slow waves. Finally, we formulate important questions to be addressed in future research on the effect of sleep on body composition and specifically emphasize the importance of intervention studies to move from correlative to causal evidence.

Risk factors of falls in elderly patients with visual impairment

OBJECTIVE

To examine the risk factors for falls in elderly patients with visual impairment (VI) and assess the predictive performance of these factors.

METHODS

Between January 2019 and March 2021, a total of 251 elderly patients aged 65-92 years with VI were enrolled and then prospectively followed up for 12 months to evaluate outcomes of accidental falls via telephone interviews. Information of demographics and lifestyle, gait and balance deficits, and ophthalmic and systemic conditions were collected during baseline visits. Forward stepwise multivariable logistic regression analysis was performed to identify independent risk factors of falls in elderly patients with VI, and a derived nomogram was constructed.

RESULTS

A total of 143 falls were reported in 251 elderly patients during follow-up, with an incidence of 56.97%. The risk factors for falls in elderly patients with VI identified by multivariable logistic regression were women [odds ratio (OR), 95% confidence interval (CI): 2.71, 1.40-5.27], smoking (3.57, 1.34-9.48), outdoor activities/3 months (1.31, 1.08-1.59), waking up frequently during the night (2.08, 1.15-3.79), disorders of balance and gait (2.60, 1.29-5.24), glaucoma (3.12, 1.15-8.44), other retinal degenerations (3.31, 1.16-9.43) and best-corrected visual acuity (BCVA) of the better eye (1.79, 1.10-2.91). A nomogram was developed based on the abovementioned multivariate analysis results. The area under receiver operating characteristic curve of the predictive model was 0.779.

CONCLUSIONS

Gender, smoking, outdoor activities, waking up at night, disorders of balance and gait, glaucoma, other retinal degeneration and BCVA of the better eye were independent risk factors for falls in elderly patients with VI. The predictive model and derived nomogram achieved a satisfying prediction of fall risk in these individuals.

Relevance of Sleep Disturbances to Orthopaedic Surgery: A Current Concepts Narrative and Practical Review

➤

Sleep disturbances can increase the risk of falls and motor vehicle accidents and may reduce bone density.

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Poor sleep can lead to worse outcomes after fracture, such as chronic pain and delayed recovery.

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Orthopaedic surgeons can play an important role in the screening of sleep disorders among their patients.

Potential impact of pediatric obstructive sleep apnea on mandibular cortical width dimensions

STUDY OBJECTIVES

To analyze differences in mandibular cortical width (MCW) among children diagnosed with obstructive sleep apnea (OSA) or at high- or low-risk for OSA.

METHODS

A total of 161 children were assessed: 60 children with polysomnographically diagnosed OSA, 56 children presenting symptoms suggestive of high-risk for OSA, and 45 children at low risk for OSA. Children at high- and low-risk for OSA were evaluated through the Pediatric Sleep Questionnaire. MCW was calculated using ImageJ software from panoramic radiograph images available from all participants. Differences between MCW measurements in the 3 groups were evaluated using analysis of covariance and Bonferroni post-hoc tests, with age as a covariate. The association between MCW and specific cephalometric variables was assessed through regression analysis.

RESULTS

The participants' mean age was 9.6 ± 3.1 years (59% male and 41% female). The mean body mass index z-score was 0.62 ± 1.3. The polysomnographically diagnosed OSA group presented smaller MCW than the group at low-risk for OSA (mean difference = -0.385 mm, P = .001), but no difference with the group at high-risk for OSA (polysomnographically diagnosed OSA vs high-risk OSA: P = .085). In addition, the MCW in the group at high-risk for the OSA was significantly smaller than the group at low-risk for the OSA (mean difference = -0.301 mm, P = .014). The cephalometric variables (Sella-Nasion-A point angle (SNA) and Frankfort - Mandibular Plane angle (FMA)) explained only 8% of the variance in MCW.

CONCLUSIONS

Reductions in MCW appear to be present among children with OSA or those at high-risk for OSA, suggesting potential interactions between mandibular bone development and/or homeostasis and pediatric OSA.

CITATION

Fernandes Fagundes NC, d'Apuzzo F, Perillo L, et al. Potential impact of pediatric obstructive sleep apnea on mandibular cortical width dimensions. J Clin Sleep Med. 2021;17(8):1627-1634.

Sleep disruptions and bone health: what do we know so far?

PURPOSE OF REVIEW

This review briefly summarizes the growing body of literature addressing the skeletal consequences of sleep and circadian disruption.

RECENT FINDINGS

The most recent data in the field suggest that the diurnal variation in bone turnover markers are because of endogenous circadian rhythmicity linked to clock genes in all bone cells; in a small human intervention study, cumulative sleep restriction with concurrent circadian disruption negatively alter bone turnover markers in a way that could explain the lower BMD and increased fracture risk identified in some prior night shift work studies; abnormal sleep duration and obstructive sleep apnea are associated with low BMD and increased fracture risk in some but not all studies.

SUMMARY

Normal physiology and some animal and human intervention studies suggest that sleep and circadian disruptions, such as night shift work, abnormal sleep durations and obstructive sleep apnea are detrimental to skeletal health. However, additional research in this area is needed to determine which sleep/circadian disturbances are most detrimental to skeletal health, the reversibility of such impairments, and underlying mechanisms.

Sleep disturbance and bone mineral density, risk of falls and fracture: Results from a 10.7-year prospective cohort study

Sleep problems are common in the general population and have been linked to bone health, falls risk and fracture. However, longitudinal studies on sleep-bone health outcomes are lacking and no study has investigated whether an increased risk of fracture is attributable to sleep-related low bone mineral density (BMD) and an increased risk of falls. This study was designed to examine the associations of sleep disturbance with bone mineral density (BMD), risk of falls and fractures over 10.7 years. The analyses were performed in a population-based cohort study with 1099 participants (mean age 62.9 years) enrolled at baseline, and 875, 768 and 563 participants traced at a mean follow-up of 2.6, 5.1 and 10.7 years, respectively. At each visit, self-reported sleep disturbance was recorded. BMD (by dual-energy x-ray absorptiometry), falls risk score and fracture were measured at each visit. The short-form Physiological Profile Assessment was used to measure falls risk score expressed as Z-score. Fractures were self-reported. Mixed-effects model and generalized estimating equations were used for the analyses. In multivariable analysis, there was a dose-response relationship between the extent of sleep disturbance and falls risk score with the strongest association in those reporting the worst sleep disturbance (β = 0.15/unit; 95%CI 0.02-0.28). The worst sleep disturbance was associated with an increased risk of any (relative risk [RR] 1.30/unit; 95%CI 1.01-1.67) and vertebral fracture (RR 2.41/unit; 95%CI 1.00-5.80) compared with those reporting no interrupted sleep. Women but not men with sleep disturbance had a higher risk of vertebral fracture (RR: 2.07 to 6.02, P < 0.05). These were independent of covariates, hip BMD and falls risk. There was no statistically significant association between sleep disturbance and BMD at the hip, spine or total body. Sleep disturbance was independently associated with a greater falls risk score and an increased risk of fractures. Further research is needed to confirm and identify underlying mechanisms for these associations.

A cross-sectional analysis of the association between sleep duration and osteoporosis risk in adults using 2005-2010 NHANES

Controversy remains regarding the relationship between bone health and sleep. In the literature, the effect of sleep on bone density in the clinical setting varies depending on the definition of normal sleep duration, sleep quality, selected population, and diagnostic tools for bone density. The aim of this study was to examine the association between bone mineral density (BMD)assessed by dual-energy X-ray absorptiometry and sleep duration/quality in the defined adult population from the National Health and Nutrition Examination Survey (NHANES) (a national household survey) within a 6-year period (2005–2010) and explore age differences. The basic variables, metabolic diseases, and bone density in the femoral neck as determined through dual-energy X-ray absorptiometry, were segregated, and analyzed according to different sleep durations (1–4, 5–6,7–8, and > 9 h/day) and sleep quality using multinomial regression models. A total of 12,793 subjects were analyzed. Our results reveal that women aged > 50 years with sleep duration < 5 h/day had a 7.35 (CI 3.438–15.715) odds of osteoporosis than those in other groups. This analysis is based on a nationally representative sample using survey and inspection data and clarifies the relationship between bone density and the effect of the combination of sleep quality and duration.

The Effect of Normobaric Intermittent Hypoxia Therapy on Bone in Normal and Disuse Osteopenic Mice

Bromer, Frederik Duch, Mikkel Bo Brent, Michael Pedersen, Jesper Skovhus Thomsen, Annemarie Brüel, and Casper Bindzus Foldager. The effect of normobaric intermittent hypoxia therapy on bone in normal and disuse osteopenic mice. High Alt Med Biol. 22: 225-234, 2021. Background: Systemic intermittent hypoxia therapy (IHT) has been shown to elicit beneficial effects on multiple physiological systems. However, only few studies have investigated the effect of long-term normobaric IHT on bone mass and mechanical and microstructural properties. The aim of the present study was to examine the effect of IHT on bone in both healthy and osteopenic mice. Materials and Methods: Thirty mice were stratified into four groups: Ctrl, Ctrl+IHT, Botox, and Botox+IHT. Osteopenia was induced by injecting Botox into the right hindlimb of the mice causing paralysis and disuse. IHT animals were placed in a normobaric hypoxia-chamber (10% oxygen) for 1 hour twice daily 5 days/week. Animals were sacrificed after 21 days, and DEXA, micro-computed tomography, and mechanical testing were performed on the femora. Results: As expected, Botox resulted in a significant reduction of bone mineral content (-23.4%), area bone mineral density (-19.1%), femoral neck strength (F_max: -54.7%), bone volume fraction (bone volume/tissue volume: -41.8%), and trabecular thickness (-32.4%). IHT had no measurable effect on the bone properties in either healthy or osteopenic mice. Conclusion: The study confirmed that Botox led to loss of bone mass, deterioration of trabecular microstructure, and loss of bone strength. These changes were not influenced by IHT. Notably, IHT had no detrimental effect on bone in either healthy or osteopenic mice. This indicates that IHT of ailments outside of the skeletal system may be administered without causing harm to the bone.

Non-benzodiazepine hypnotic use for sleep disturbance in people aged over 55 years living with dementia: a series of cohort studies

BACKGROUND

Sleep disturbance affects around 60% of people living with dementia and can negatively affect their quality of life and that of their carers. Hypnotic Z-drugs (zolpidem, zopiclone and zaleplon) are commonly used to treat insomnia, but their safety and efficacy have not been evaluated for people living with dementia.

OBJECTIVES

To estimate the benefits and harms of Z-drugs in people living with dementia with sleep disturbance.

DESIGN

A series of observational cohort studies using existing data from (1) primary care linked to hospital admission data and (2) clinical cohort studies of people living with dementia.

DATA SOURCES

Primary care study - Clinical Practice Research Datalink linked to Hospital Episode Statistics and Office for National Statistics mortality data. Clinical cohort studies - the Resource Use and Disease Course in Dementia - Nursing Homes (REDIC) study, National Alzheimer's Coordinating Centre (NACC) clinical data set and the Improving Well-being and Health for People with Dementia (WHELD) in nursing homes randomised controlled trial.

SETTING

Primary care study - 371 primary care practices in England. Clinical cohort studies - 47 nursing homes in Norway, 34 Alzheimer's disease centres in the USA and 69 care homes in England.

PARTICIPANTS

Primary care study - NHS England primary care patients diagnosed with dementia and aged > 55 years, with sleep disturbance or prescribed Z-drugs or low-dose tricyclic antidepressants, followed over 2 years. Clinical cohort studies - people living with dementia consenting to participate, followed over 3 years, 12 years and 9 months, for REDIC, NACC and WHELD, respectively.

INTERVENTIONS

The primary exposure was prescription or use of Z-drugs. Secondary exposures included prescription or use of benzodiazepines, low-dose tricyclic antidepressants and antipsychotics.

MAIN OUTCOME MEASURES

Falls, fractures, infection, stroke, venous thromboembolism, mortality, cognitive function and quality of life. There were insufficient data to investigate sleep disturbance.

RESULTS

The primary care study and combined clinical cohort studies included 6809 and 18,659 people living with dementia, with 3089 and 914 taking Z-drugs, respectively. New Z-drug use was associated with a greater risk of fractures (hazard ratio 1.40, 95% confidence interval 1.01 to 1.94), with risk increasing with greater cumulative dose (p = 0.002). The hazard ratio for Z-drug use and hip fracture was 1.59 (95% confidence interval 1.00 to 2.53) and for mortality was 1.34 (95% confidence interval 1.10 to 1.64). No excess risks of falls, infections, stroke or venous thromboembolism were detected. Z-drug use also did not have an impact on cognition, neuropsychiatric symptoms, disability or quality of life.

LIMITATIONS

Primary care study - possible residual confounding because of difficulties in identifying patients with sleep disturbance and by dementia severity. Clinical cohort studies - the small numbers of people living with dementia taking Z-drugs and outcomes not necessarily being measured before Z-drug initiation restricted analyses.

CONCLUSIONS

We observed a dose-dependent increase in fracture risk, but no other harms, with Z-drug use in dementia. However, multiple outcomes were examined, increasing the risk of false-positive findings. The mortality association was unlikely to be causal. Further research is needed to confirm the increased fracture risk. Decisions to prescribe Z-drugs may need to consider the risk of fractures, balanced against the impact of improved sleep for people living with dementia and that of their carers. Our findings suggest that when Z-drugs are prescribed, falls prevention strategies may be needed, and that the prescription should be regularly reviewed.

FUTURE WORK

More research is needed on safe and effective management strategies for sleep disturbance in people living with dementia.

STUDY REGISTRATION

This study is registered as European Union electronic Register of Post-Authorisation Studies (EU PAS) 18006.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 1. See the NIHR Journals Library website for further project information.

Effects of normobaric cyclic hypoxia exposure on mesenchymal stem-cell differentiation-pilot study on bone parameters in elderly

BACKGROUND

Mesenchymal stem cells (MSC) of bone marrow are the progenitor of osteoblasts and adipocytes. MSC tend to differentiate into adipocytes, instead of osteoblasts, with aging. This favors the loss of bone mass and development of osteoporosis. Hypoxia induces hypoxia inducible factor 1α gene encoding transcription factor, which regulates the expression of genes related to energy metabolism and angiogenesis. That allows a better adaptation to low O2 conditions. Sustained hypoxia has negative effects on bone metabolism, favoring bone resorption. Yet, surprisingly, cyclic hypoxia (CH), short times of hypoxia followed by long times in normoxia, can modulate MSC differentiation and improve bone health in aging.

AIM

To evaluate the CH effect on MSC differentiation, and whether it improves bone mineral density in elderly.

METHODS

MSC cultures were induced to differentiate into osteoblasts or adipocytes, in CH (3% O2 for 1, 2 or 4 h, 4 d a week). Extracellular-matrix mineralization and lipid-droplet formation were studied in MSC induced to differentiate into osteoblast or adipocytes, respectively. In addition, gene expression of marker genes, for osteogenesis or adipogenesis, have been quantified by quantitative real time polymerase chain reaction. The in vivo studies with elderly (> 75 years old; n = 10) were carried out in a hypoxia chamber, simulating an altitude of 2500 m above sea level, or in normoxia, for 18 wk (36 CH sessions of 16 min each). Percentages of fat mass and bone mineral density from whole body, trunk and right proximal femur (femoral, femoral neck and trochanter) were assessed, using dual-energy X-ray absorptiometry.

RESULTS

CH (4 h of hypoxic exposure) inhibited extracellular matrix mineralization and lipid-droplet formation in MSC induced to differentiate into osteoblasts or adipocytes, respectively. However, both parameters were not significantly affected by the other shorter hypoxia times assessed. The longest periods of hypoxia downregulated the expression of genes related to extracellular matrix formation, in MSC induced to differentiate into osteoblasts. Interestingly, osteocalcin (associated to energy metabolism) was upregulated. Vascular endothelial growth factor an expression and low-density lipoprotein receptor related protein 5/6/dickkopf Wnt signaling pathway inhibitor 1 (associated to Wnt/β-catenin pathway activation) increased in osteoblasts. Yet, they decreased in adipocytes after CH treatments, mainly with the longest hypoxia times. However, the same CH treatments increased the osteoprotegerin/receptor activator for nuclear factor kappa B ligand ratio in both cell types. An increase in total bone mineral density was observed in elderly people exposed to CH, but not in specific regions. The percentage of fat did not vary between groups.

CONCLUSION

CH may have positive effects on bone health in the elderly, due to its possible inhibitory effect on bone resorption, by increasing the osteoprotegerin / receptor activator for nuclear factor kappa B ligand ratio.

Effects of Neurological Disorders on Bone Health

Neurological diseases, particularly in the context of aging, have serious impacts on quality of life and can negatively affect bone health. The brain-bone axis is critically important for skeletal metabolism, sensory innervation, and endocrine cross-talk between these organs. This review discusses current evidence for the cellular and molecular mechanisms by which various neurological disease categories, including autoimmune, developmental, dementia-related, movement, neuromuscular, stroke, trauma, and psychological, impart changes in bone homeostasis and mass, as well as fracture risk. Likewise, how bone may affect neurological function is discussed. Gaining a better understanding of brain-bone interactions, particularly in patients with underlying neurological disorders, may lead to development of novel therapies and discovery of shared risk factors, as well as highlight the need for broad, whole-health clinical approaches toward treatment.

Obstructive Sleep Apnea and Risk for Incident Vertebral and Hip Fracture in Women

Recent studies suggest a positive association between obstructive sleep apnea (OSA), a disorder associated with intermittent hypoxia and sleep fragmentation, and derangements in bone metabolism. However, no prospective study to date has investigated the association between OSA and fracture risk in women. We conducted a prospective study examining the relation between OSA and risk of incident vertebral fracture (VF) and hip fracture (HF) in the Nurses' Health Study. History of physician-diagnosed OSA was assessed by self-reported questionnaires. A previous validation study demonstrated high concordance between self-reports and medical record identification of OSA. OSA severity was further categorized according to the presence or absence of self-reported sleepiness. Self-reports of VF were confirmed by medical record review. Self-reported HF was assessed by biennial questionnaires. Cox proportional-hazards models estimated the hazard ratio for fracture according to OSA status, adjusted for potential confounders, including BMI, physical activity, calcium intake, history of osteoporosis, and falls, and use of sleep medications. Among 55,264 women without prior history of fracture, physician-diagnosed OSA was self-reported in 1.3% in 2002 and increased to 3.3% by 2012. Between 2002 and 2014, 461 incident VF cases and 921 incident HF cases were documented. The multivariable-adjusted hazard ratio (HR) for confirmed VF for women with history of OSA was 2.00 (95% CI, 1.29-3.12) compared with no OSA history, with the strongest association observed for OSA with daytime sleepiness (HR 2.86; 95% CI, 1.31-6.21). No association was observed between OSA history and self-reported HF risk (HR 0.83; 95% CI, 0.49-1.43). History of OSA is independently associated with higher risk of confirmed VF but did not have a statistically significant association with self-reported HF in women. Further research is warranted in understanding the role of OSA and intermittent hypoxia in bone metabolism and health that may differ by fracture site. © 2020 American Society for Bone and Mineral Research (ASBMR).

"Take My Bone Away?" Hypoxia and bone: A narrative review

To maintain normal cellular and physiological function, sufficient oxygen is required. Recently, evidence has suggested that hypoxia, either pathological or environmental, may influence bone health. It appears that bone cells are distinctly responsive to hypoxic stimuli; for better or worse, this is still yet to be elucidated. Hypoxia has been shown to offer potentially therapeutic effects for bone by inducing an osteogenic-angiogenic response, although, others have noted excessive osteoclastic bone resorption instead. Much evidence suggests that the hypoxic-inducible pathway is integral in mediating the changes in bone metabolism. Furthermore, many factors associated with hypoxia including changes in energy metabolism, acid-base balance and the increased generation of reactive oxygen species, are known to influence bone metabolism. This review aims to examine some of the putative mechanisms responsible for hypoxic-induced alterations of bone metabolism, with regard to osteoclasts and osteoblasts, both positive and negative.

Comorbid Conditions and GFR Predict Nonvertebral Fractures in Patients With Diabetes in an Ethnic-Specific Manner

CONTEXT

Diabetes mellitus (DM) is associated with an increased risk of fracture, but it is not clear which diabetes and nondiabetes risk factors may be most important.

OBJECTIVE

The aim of the study was to evaluate risk factors for incident major osteoporotic fractures (MOFs) of the hip, wrist, and humerus in African American (AA), Hispanic (HIS), and Caucasian (CA) subjects with DM.

METHODS

This was a retrospective cohort study of 18 210 subjects with DM (7298 CA, 7009 AA and 3903 HIS) at least 40 years of age, being followed at a large healthcare system in Philadelphia, Pennsylvania.

RESULTS

In a global model in CA with DM, MOF were associated with dementia (HR 4.16; 95% CI, 2.13-8.12), OSA (HR 3.35; 95% CI, 1.78-6.29), COPD (HR 2.43; 95% CI, 1.51-3.92), and diabetic neuropathy (HR 2.52; 95% CI, 1.41-4.50). In AA, MOF were associated with prior MOF (HR 13.67; 95% CI, 5.48-34.1), dementia (HR 3.10; 95% CI, 1.07-8.98), glomerular filtration rate (GFR) less than 45 (HR 2.05; 95% CI, 1.11-3.79), thiazide use (HR 0.54; 95% CI, 0.31-0.93), metformin use (HR 0.59; 95% CI, 0.36-0.97), and chronic steroid use (HR 5.03; 95% CI, 1.51-16.7). In HIS, liver disease (HR 3.06; 95% CI, 1.38-6.79) and insulin use (HR 2.93; 95% CI, 1.76-4.87) were associated with MOF.

CONCLUSION

In patients with diabetes, the risk of fracture is related to both diabetes-specific variables and comorbid conditions, but these relationships vary by race/ethnicity.

The Effect of Nursing Intervention-based Levine Conceptual Model Program on Rehabilitation Process among Fracture Patients

Introduction: The nursing intervention program is a strategy for the rehabilitation process among fracture patients The Levine conceptual model program is a practical nursing theory using energy conservation, energy, structural integrity, personal integrity, and social integrity. The study aims to identify the effect of nursing intervention based on Levine's theory of the rehabilitation process among fracture patients.Methods: A quasi-experimental with equivalent control group design was applied in this study. Sixty-two respondents were selected into the experimental group (n=31) and control group (n=31) by using a consecutive sampling technique. The patients' rehabilitation on fracture included sleep disorder, pain, anxiety, and family support as dependent variables. Researchers used the Sleep Quality Scale (SQS) instrument, the Numeric Rating Scale, the Hamilton Anxiety Rating Scale, and the family support scale. Data were analyzed using a Wilcoxon Signed Rank Test.Results: The results showed a significant effect of patients' recovery on fracture among patients after receiving Levine-based nursing intervention than before receiving the intervention (p <0.05). The results of research on the nursing intervention program are based on Levine's conceptual model of sleep disorders, pain, anxiety, and family support (p <0.05). In conclusion, there was significantly different nursing intervention based on Levine in   energy conservation, energy, structural integrity, personal integrity, and social integrity.Conclusion: The nursing intervention program based on Levine's conceptual model could be part of independent nursing intervention to deal with recovery in fracture patients. Based on this description, the researcher is interested in examining the effect of nursing intervention based on Levine’s conceptual model program on rehabilitation process among fracture patients.

Bone metabolism parameters and inactive matrix Gla protein in patients with obstructive sleep apnea†

STUDY OBJECTIVES

The aim of this study was to investigate differences in dual-energy X-ray absorptiometry (DXA) parameters, trabecular bone score (TBS), bone turnover markers and inactive matrix Gla protein (dp-ucMGP) between patients with obstructive sleep apnea (OSA) and healthy controls.

METHODS

This study enrolled 53 male patients diagnosed with OSA, and 50 age- and body mass index (BMI)-matched control subjects. All participants underwent DXA imaging, TBS assessment and blood sampling for biochemical analysis of bone metabolism markers.

RESULTS

Mean apnea-hypopnea index (AHI) score of OSA patients was 43.8 ± 18.8 events/h. OSA patients had significantly higher plasma dp-ucMGP levels in comparison to controls (512.7 ± 71.9 vs. 465.8 ± 50.9 pmol/L, p < 0.001). OSA and control group did not significantly differ regarding standard DXA results, while TBS values were significantly lower in the OSA group (1.24 ± 0.17 vs. 1.36 ± 0.15, p < 0.001). AHI score was a significant independent correlate of plasma dp-ucMGP levels (β ± SE, 1.461 ± 0.45, p = 0.002). In addition, TBS retained a significant relationship with dp-ucMGP values (β ± SE, -93.77 ± 38.1, p = 0.001).

CONCLUSIONS

dp-ucMGP levels are significantly higher in patients with OSA and correlate with disease severity. In addition, TBS values in OSA patients are lower in comparison with the control group and decrease with disease severity.

Upper Airway Obstruction Elicited Energy Imbalance Leads to Growth Retardation that Persists after the Obstruction Removal

Upper airway obstruction can lead to growth retardation by unclear mechanisms. We explored the effect of upper airway obstruction in juvenile rats on whole-body energy balance, growth plate metabolism, and growth. We show that after seven weeks, obstructed animals’ ventilation during room air breathing increased, and animals grew less due to abnormal growth plate metabolism. Increased caloric intake in upper airway-obstructed animals did not meet increased energy expenditure associated with increased work of breathing. Decreased whole-body energy balance induced hindrance of bone elongation following obstruction removal, and array pathways regulating growth plate development and marrow adiposity. This is the first study to show that rapidly growing animals cannot consume enough calories to maintain their energy homeostasis, leading to an impediment in growth in the effort to save energy.

Zinc Homeostasis in Bone: Zinc Transporters and Bone Diseases

Zinc is an essential micronutrient that plays critical roles in numerous physiological processes, including bone homeostasis. The majority of zinc in the human body is stored in bone. Zinc is not only a component of bone but also an essential cofactor of many proteins involved in microstructural stability and bone remodeling. There are two types of membrane zinc transporter proteins identified in mammals: the Zrt- and Irt-like protein (ZIP) family and the zinc transporter (ZnT) family. They regulate the influx and efflux of zinc, accounting for the transport of zinc through cellular and intracellular membranes to maintain zinc homeostasis in the cytoplasm and in intracellular compartments, respectively. Abnormal function of certain zinc transporters is associated with an imbalance of bone homeostasis, which may contribute to human bone diseases. Here, we summarize the regulatory roles of zinc transporters in different cell types and the mechanisms underlying related pathological changes involved in bone diseases. We also present perspectives for further studies on bone homeostasis-regulating zinc transporters.

Short Sleep Is Associated With Low Bone Mineral Density and Osteoporosis in the Women's Health Initiative

Short sleep duration, recognized as a public health epidemic, is associated with adverse health conditions, yet little is known about the association between sleep and bone health. We tested the associations of usual sleep behavior and bone mineral density (BMD) and osteoporosis. In a sample of 11,084 postmenopausal women from the Women's Health Initiative (WHI; mean age 63.3 years, SD = 7.4), we performed a cross-sectional study of the association of self-reported usual hours of sleep and sleep quality (WHI Insomnia Rating Score) with whole body, total hip, femoral neck, and spine BMD using linear regression models. We also studied the association of sleep duration and quality with dual-energy X-ray absorptiometry (DXA)-defined low bone mass (T-score < -2.5 to <-1) and osteoporosis (T-score ≤ -2.5) using multinomial regression models. We adjusted for age, DXA machine, race, menopausal symptoms, education, smoking, physical activity, body mass index, alcohol use, physical function, and sleep medication use. In adjusted linear regression models, women who reported sleeping 5 hours or less per night had on average 0.012 to 0.018 g/cm² significantly lower BMD at all four sites compared with women who reported sleeping 7 hours per night (reference). In adjusted multinomial models, women reporting 5 hours or less per night had higher odds of low bone mass and osteoporosis of the hip (odds ratio [OR] = 1.22; 95% confidence interval [CI] 1.03-1.45, and 1.63; 1.15-2.31, respectively). We observed a similar pattern for spine BMD, where women with 5 hours or less per night had higher odds of osteoporosis (adjusted OR = 1.28; 95% CI 1.02-1.60). Associations of sleep quality and DXA BMD failed to reach statistical significance. Short sleep duration was associated with lower BMD and higher risk of osteoporosis. Longitudinal studies are needed to confirm the cross-sectional effects of sleep duration on bone health and explore associated mechanisms. © 2019 American Society for Bone and Mineral Research.

Rapid suppression of bone formation marker in response to sleep restriction and circadian disruption in men

We describe the time course of bone formation marker (P1NP) decline in men exposed to ~ 3 weeks of sleep restriction with concurrent circadian disruption. P1NP declined within 10 days and remained lower with ongoing exposure. These data suggest even brief exposure to sleep and circadian disruptions may disrupt bone metabolism.

INTRODUCTION

A serum bone formation marker (procollagen type 1 N-terminal, P1NP) was lower after ~ 3 weeks of sleep restriction combined with circadian disruption. We now describe the time course of decline.

METHODS

The ~ 3-week protocol included two segments: "baseline," ≥ 10-h sleep opportunity/day × 5 days; "forced desynchrony" (FD), recurring 28 h day (circadian disruption) with sleep restriction (~ 5.6-h sleep per 24 h). Fasted plasma P1NP was measured throughout the protocol in nine men (20-59 years old). We tested the hypothesis that PINP would steadily decline across the FD intervention because the magnitude of sleep loss and circadian misalignment accrued as the protocol progressed. A piecewise linear regression model was used to estimate the slope (β) as ΔP1NP per 24 h with a change point mid-protocol to estimate the initial vs. prolonged effects of FD exposure.

RESULTS

Plasma P1NP levels declined significantly within the first 10 days of FD ([Formula: see text] = - 1.33 μg/L per 24 h, p < 0.0001) and remained lower than baseline with prolonged exposure out to 3 weeks ([Formula: see text] = - 0.18 μg/L per 24 h, p = 0.67). As previously reported, levels of a bone resorption marker (C-telopeptide (CTX)) were unchanged.

CONCLUSION

Sleep restriction with concurrent circadian disruption induced a relatively rapid decline in P1NP (despite no change in CTX) and levels remained lower with ongoing exposure. These data suggest (1) even brief sleep restriction and circadian disruption can adversely affect bone metabolism, and (2) there is no P1NP recovery with ongoing exposure that, taken together, could lead to lower bone density over time.

Does nesfatin-1 influence the hypothalamic–pituitary–gonadal axis in adult males with obstructive sleep apnoea?

There is growing evidence that obstructive sleep apnoea (OSA) influences the hypothalamic–pituitary–gonadal axis (HPG axis) in men. The aim of the study was to assess the association of nesfatin-1 with HPG axis disturbances in OSA. This is a prospective study with consecutive enrolment. It comprises 72 newly diagnosed OSA patients ((AHI: apnoea-hypopnea index) 18 subjects: 5 ≤ AHI < 15; 24: 15 ≤ AHI < 30; 30: AHI ≥ 30) and a control group composed of 19 patients (AHI < 5). All patients underwent polysomnography and fasting blood collection for nesfatin-1, testosterone, luteinising hormone (LH), high-sensitivity C-reactive protein (hsCRP), aspartate transaminase (AST), alanine aminotransferase (ALT), creatinine and glucose. Groups had similar levels of LH, nesfatin-1 and testosterone (p = 0.87; p = 0.24; p = 0.08). Nesfatin-1 was not correlated to LH (p = 0.71), testosterone (p = 0.38), AHI (p = 0.34) or the oxygen desaturation index (ODI) (p = 0.69) either in the whole group, or in sub-groups. The study did not reveal any association between the HPG axis and nesfatin-1 in OSA adult males. It is possible that nesfatin-1 is not a mediator of HPG axis disturbances in adult patients with OSA.

Association between objective sleep duration and bone mineral density in older postmenopausal women from the Study of Osteoporotic Fractures (SOF)

Methodological limitations preclude determination of the association between sleep duration and bone mineral density (BMD) from existing literature. This was the first study to use objective sleep duration to determine its association with BMD. Nocturnal sleep duration, assessed objectively (actigraphy) or subjectively (questionnaire), was not independently associated with BMD in postmenopausal women.

INTRODUCTION

Both long and short self-reported sleep durations are associated with low bone mineral density (BMD) in men and women. The association between sleep duration measured by actigraphy and BMD in postmenopausal women is unknown.

METHODS

The Study of Osteoporotic Fractures (SOF) ancillary sleep study was used to determine the association between sleep duration and BMD at the total hip and femoral neck in postmenopausal women ≥ 75 years old. Sleep duration was assessed by wrist actigraphy (average 4 nights) and questionnaire. BMD was compared between postmenopausal women with short (< 6 h/night) vs. NIH-recommended (7-8 h/night) sleep durations. Data were analyzed using a 2-sample t test (unadjusted) and multivariate regression model (adjusted). Simple linear regression was used to estimate the difference in BMD per additional hour of sleep when sleep duration was considered as a continuous, rather than dichotomized, variable.

RESULTS

Total hip BMD was higher in women with actigraphically assessed shorter sleep duration in unadjusted models only. No clinically or statistically significant differences in total hip or femoral neck BMD were observed according to nocturnal sleep duration after adjusting for body mass index (BMI) in dichotomized (N = 874) or continuous (N = 1624) sleep duration models or when subjective sleep duration was used. When sleep duration included daytime naps, longer sleep duration was associated with lower total hip BMD (β = - 0.005, p = 0.04).

CONCLUSIONS

Nocturnal sleep duration, whether assessed objectively (actigraphy) or subjectively (questionnaire), was not independently associated with BMD in older postmenopausal women.

Bone turnover is altered during 72 h of sleep restriction: a controlled laboratory study

PURPOSE

The objective of the study was to evaluate how controlled, short-term sleep restriction (SR; 72 h) alters markers of bone formation and resorption and urinary calcium (Ca) output.

METHODS

Ten healthy, sleep-adequate, male soldiers were housed in the research facility one day prior to and for the duration of SR. Diet was controlled to provide adequate energy balance and macronutrient distribution, meeting the recommended dietary allowance (RDA) for Ca. Subjects engaged in light activities to maintain wakefulness and were allowed 2 h of sleep per night (0430-0630 hours). Blood samples were collected each morning at 0 h (baseline) and 24, 48, and 72 h of SR. Serum was assayed for parathyroid hormone (PTH), bone alkaline phosphatase (BAP), tartrate-resistant acid phosphatase (TRAP), and C-terminal telopeptide of type I collagen (CTX). Urine was collected in 24 h increments during SR for measurement of Ca and creatinine (Cr).

RESULTS

BAP was reduced at 24 h (P= 0.015) and resorption markers TRAP and CTX were increased after 48 and 72 h of SR compared to baseline (P < 0.05). The ratio of BAP:TRAP was significantly lower (P= 0.017) at 48 and 72 h of SR. In contrast, total 24 h urinary Ca and Ca/Cr excretion were unchanged.

CONCLUSIONS

Markers of bone formation and resorption are uncoupled in response to as little as 48 h of SR even when Ca intake is at the RDA. Sleep deprivation may be a risk factor for reduced bone health due to perturbations in bone turnover.

[Pathophysiological aspects of neuro-endocrine regulation system in patients with obstructive sleep apnea syndrome]

AIM

To reveal the changes in the pituitary-thyroid, pituitary-gonadal, adrenal components and in the prolactinergic system of neuroendocrine regulation in patients with severe obstructive sleep apnea syndrome (OSAS).

MATERIAL AND METHODS

The study involved 51 men aged 46-55 years. The main group (BG) included 37 patients with severe OSAS. The duration of clinical manifestations of OSAS was 10.5±1.5 years. OSAS was verified on the basis of clinical and functional studies and polysomnographic monitoring in accordance with the AASM criteria (2014). The control group (CG) consisted of 14 age-matched men without sleep-disordered breathing. The body mass index in BG was 34.2±1.8 compared to 28.2±2.1 kg/m² in CG. Serum concentrations of thyroid-stimulating hormone (TTG), free thyroxine (T4), triiodothyronine (T3), cortisol, prolactin, testosterone, luteonizing (LH) and follicle-stimulating (FSH) hormones were determined by the immunoradiological method using the standard DIA test system (Russia) and the analyzer 'Immunotest-800'.

RESULTS

Patients with severe OSAS had decreased concentration of free thyroxine (T4) and decreased activity of thyroid stimulating hormone (TSH) (р<0.001), increased concentration of prolactin and cortisol (р<0.001), decreased concentration of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone compared to the controls (р<0.001).

CONCLUSION

The changes in the hypothalamic-pituitary-gonadal system are a manifestation of disturbances of the mechanisms of self-regulation and compensation that indicates the presence of maladaptive reactions of the neuroendocrine system.

Can Hypoxic Conditioning Improve Bone Metabolism? A Systematic Review

Among other functions, hypoxia-inducible factor plays a critical role in bone–vascular coupling and bone formation. Studies have suggested that hypoxic conditioning could be a potential nonpharmacological strategy for treating skeletal diseases. However, there is no clear consensus regarding the bone metabolism response to hypoxia. Therefore, this review aims to examine the impact of different modes of hypoxia conditioning on bone metabolism. The PubMed and Web of Science databases were searched for experimental studies written in English that investigated the effects of modification of ambient oxygen on bone remodelling parameters of healthy organisms. Thirty-nine studies analysed the effect of sustained or cyclic hypoxia exposure on genetic and protein expression and mineralisation capacity of different cell models; three studies carried out in animal models implemented sustained or cyclic hypoxia; ten studies examined the effect of sustained, intermittent or cyclic hypoxia on bone health and hormonal responses in humans. Different modes of hypoxic conditioning may have different impacts on bone metabolism both in vivo and in vitro. Additional research is necessary to establish the optimal cyclical dose of oxygen concentration and exposure time.

The differences in the relationship between obstructive sleep apnea severity and trabecular bone score in men and women with type 2 diabetes

Aims

Type 2 diabetes mellitus (T2DM) and obstructive sleep apnea (OSA) may adversely affect bone. Gender is a well-established factor influencing bone health. We investigated the impact of OSA on bone mineral density (BMD) and trabecular bone score (TBS) in T2DM.

Methods

Eighty-one T2DM patients [33 men and 48 women] participated. OSA was diagnosed using an overnight monitor, with its severity assessed by an apnea hypopnia index (pAHI). The measurements of hypoxia, including the percentage of total sleep time in which oxygen saturation remains below 90% (pT90), the oxygen desaturation index (pODI) and minimum O₂ (min O₂), were reported. Lumbar spine (L1-4) and femoral neck (FN) BMD were measured using dual-energy X-ray absorptiometry (DXA). TBS was computed from DXA images.

Results

Sixty-five patients (80.2%) had OSA. pAHI, pT90, pODI and min O₂ were not correlated to L1-4 BMD, FN BMD or TBS in all participants by multiple regression analyses adjusting for age, gender and BMI. However, an interaction between gender and pAHI, and gender and pODI were significantly associated with TBS (b = 0.003, p = 0.034 and b = 0.004, p = 0.046, respectively). We therefore reassessed an association between pAHI or pODI and TBS separately between men and women. After adjusting for age and BMI, more severe OSA (higher pAHI) and higher pODI significantly associated with lower TBS (b = -0.002, p = 0.034 and b = -0.003, p = 0.021, respectively) in men. On the other hand, higher pAHI non-significantly associated with better trabecular microarchitecture as indicated by higher TBS (b = 0.002, p = 0.059) in women. When considered only postmenopausal (n = 33), higher pAHI and higher pODI were significantly associated with higher TBS (b = 0.004, p = 0.003 and b = 0.004, p = 0.008, respectively).

Conclusions

In T2DM patients, there is a complex interrelationship among OSA severity, gender and TBS. More severe OSA predicted lower TBS in men, but predicted higher TBS in postmenopausal women.

Sleep Apnea Increases Ninety-Day Complications and Cost Following Primary Total Joint Arthroplasty

BACKGROUND

Sleep apnea (SA) negatively affects bone mineralization, cognition, and immunity. There is paucity in the literature regarding the impact of SA on total joint arthroplasty (TJA). The purpose of this study is to compare complications in patients with and without SA undergoing either total knee (TKA) or total hip arthroplasty (THA).

METHODS

A retrospective review from 2005 to 2014 was conducted using the Medicare Standard Analytical Files. Patients with and without SA on the day of the primary TJA were queried using the International Classification of Diseases, ninth revision codes. Patients were matched by age, gender, Charlson Comorbidity Index), and body mass index. Patients were followed for 2 years after their surgery. Ninety-day medical complications, complications related to implant, readmission rates, length of stay, and 1-year mortality were quantified and compared. Logistic regression was used to calculate odds ratios (OR) with their respective 95% confidence interval and P values.

RESULTS

After the random matching process there were 529,240 patients (female = 271,656, male = 252,106, unknown = 5478) with (TKA = 189,968, THA = 74,652) and without (TKA = 189,968, THA = 74,652) SA who underwent primary TJA between 2005 and 2014. Patients with SA had greater odds of developing medical complications following TKA (OR 3.71) or THA (OR 2.48).

CONCLUSION

The study illustrates an increased risk of developing postoperative complications in patients with SA following primary TJA. Surgeons should educate patients on these adverse effects and encourage the use of continuous positive airway pressure which has been shown to mitigate many postoperative complications.

Sleep-Disordered Breathing Is Associated with Reduced Mandibular Cortical Width in Children

INTRODUCTION

Evidence from the adult population suggests that sleep-disordered breathing (SDB) (i.e., obstructive sleep apnea [OSA]) is negatively associated with bone mineral density. Whether a similar association exists in children with SDB has not been investigated. Using the mandibular cortical width (MCW) as a proxy for skeletal bone density, we investigated if children at risk of SDB or diagnosed with OSA have a reduced mandibular cortical width compared to children without SDB.

METHODS

Two retrospective cross-sectional studies were performed. The first study included comparison of MCW between 24 children with polysomnographically (PSG) diagnosed OSA and 72 age- and sex-matched control children. The second study included a cohort of children in which SDB was suggested by the Pediatric Sleep Questionnaire (PSQ) ( n = 101). MCW was measured from panoramic radiographs.

RESULTS

Multiple-predictors regression analysis from the first study indicated that in children with a severe form of SDB, as induced by OSA severity, there was a negative association with MCW (β = -0.290, P = 0.049). Moreover, PSG-diagnosed OSA children had thinner MCW (2.9. ± 0.6mm) compared to healthy children (3.5 ± 0.6 mm; P = 0.002). These findings were further supported by the second study illustrating that PSQ total scores were negatively associated with MCW (β = -0.391, P < 0.001).

CONCLUSIONS

Findings suggest that children at risk for or diagnosed with SDB exhibit reduced mandibular cortical width that purportedly may reflect alterations in bone homeostasis.

KNOWLEDGE TRANSFER STATEMENT

We report that sleep-disordered breathing (including its severe form, obstructive sleep apnea) in children is associated with reduced mandibular cortical width. This association might be a direct consequence of reduced bone health to sleep-disordered breathing or a reflection that reduced bone formation underlies the development of sleep-disordered breathing. Our findings suggest that mandibular cortical width can be used as an adjunct diagnostic parameter for the diagnosis of sleep-disordered breathing.