Moderate ingestion of alcohol is associated with acute ethanol-induced suppression of circulating CTX in a PTH-independent fashion

Association between alcohol intake and bone mineral density: results from the NHANES 2005-2020 and two-sample Mendelian randomization

We used the data from the NHANES cross-sectional study among 14,113 participants and indicated a positive correlation between alcohol intake frequency and bone mineral density in different body sites. Mendelian randomization was conducted, and no causal relationship is significant between these two variables. The study can provide some suggestions on the daily consumption of alcohol for osteoporosis patients.

PURPOSE

The effect of alcohol intake on bone mineral density (BMD) remains unclear. This study explored the association and causality between alcohol intake and BMD.

METHODS

Based on the 2005-2020 National Health and Nutrition Examination Survey including 14,113 participants, we conducted co-variate-adjusted multilinear regression analyses to explore the association between alcohol intake levels and spine or femur BMD. To evaluate the causal association between alcohol intake frequency and bone mineral density, the inverse variance weighted approach of two-sample Mendelian randomization (MR) was used with genetic data from the Medical Research Council Integrative Epidemiology Unit (462,346 cases) for alcohol intake frequency and the Genetic Factors for Osteoporosis Consortium (28,496 cases) for lumbar spine and femur neck BMD (32,735 cases).

RESULTS

Compared with non-drinkers, total femur BMDs but not total spine BMD increased with daily alcohol intake in males (β = 3.63*10-2 for mild drinkers, β = 4.21*10-2 for moderate drinkers, and β = 4.26*10-2 for heavy drinkers). By contrast, the higher total spine BMD in females was related to higher alcohol intake levels (β = 2.15*10-2 for mild drinkers, β = 2.59*10-2 for moderate drinkers, and β = 3.88*10-2 for heavy drinkers). Regarding the two-sample MR results, no causal relationship was observed between alcohol intake frequency and lumbar spine BMD (odds ratio [OR] = 1.016, P = 0.789) or femur neck BMD (OR = 1.048, P = 0.333).

CONCLUSION

This study suggests a positive association between alcohol intake frequency and BMD, although the causal relationship was not significant.

Clinical Indicators of Bone Deterioration in Alcoholic Liver Cirrhosis and Chronic Alcohol Abuse: Looking beyond Bone Fracture Occurrence

Although previous studies indicated that chronic alcohol abuse (CAA) and alcoholic liver cirrhosis (ALC) are associated with increased bone fragility, understanding bone fragility determinants is still modest in these individuals. We used a comprehensive individualized clinical fracture risk assessment approach (vertebral osteodensitometry, femoral osteodensitometry and geometry, and serum bone turnover biomarkers) to compare adult male patients with ALC who have not previously had femoral or vertebral fractures (n = 39), patients with CAA (without liver cirrhosis, n = 78) who have not previously had femoral or vertebral fractures and healthy age- and sex-matched controls (n = 43). Our data suggested that intertrochanteric bone mineral density was significantly lower in ALC and CAA patients than in controls. Also, the trabecular bone score was considerably lower in ALC patients compared with CAA and control individuals. The most significant inter-group differences in femoral geometry were noted on the femoral shaft. Patients with ALC and CAA have a higher 10-year risk of major osteoporotic fractures compared to the controls. Analysis of bone turnover biomarkers showed increased osteoprotegerin and beta-C-terminal telopeptide serum concentrations and decreased insulin growth factor-1 concentrations in patients with ALC compared to CAA and control groups. Our data revealed that bone alterations are present in patients with ALC and CAA even if they did not sustain a nontraumatic bone fracture, but it is also indicative that current bone-assessing clinical methods are not entirely reliable. Thus, future studies should focus on developing a reliable integrative clinical tool that can be used to accurately predict and prevent bone fracture occurrences in patients with ALC and CAA.

Pathophysiology and Therapeutic Management of Bone Loss in Patients with Critical Illness

Patients with critical illnesses are at higher risk of comorbidities, which can include bone mineral density loss, bone turnover marker increase, and fragility fractures. Patients admitted to intensive care units (ICUs) have a higher risk of bone fractures. Since hypermetabolism is a characteristic of ICU patients, such patients are often rapidly affected by systemic deterioration, which often results in systemic wasting disease. Major risk factors for ICU-related bone loss include physical restraint, inflammation, neuroendocrine stress, malnutrition, and medications. A medical history of critical illness should be acknowledged as a risk factor for impaired bone metabolism. Bone loss associated with ICU admission should be recognized as a key component of post-intensive care syndrome, and further research that focuses on treatment protocols and prevention strategies is required. Studies aimed at maintaining gut integrity have emphasized protein administration and nutrition, while research is ongoing to evaluate the therapeutic benefits of anti-resorptive agents and physical therapy. This review examines both current and innovative clinical strategies that are used for identifying risk factors of bone loss. It provides an overview of perioperative outcomes and discusses the emerging novel treatment modalities. Furthermore, the review presents future directions in the treatment of ICU-related bone loss.

Impact of Alcohol on Bone Health in People Living With HIV: Integrating Clinical Data From Serum Bone Markers With Morphometric Analysis in a Non-Human Primate Model

People living with HIV (PLWH) represent a vulnerable population to adverse musculoskeletal outcomes due to HIV infection, antiretroviral therapy (ART), and at-risk alcohol use. Developing measures to prevent skeletal degeneration in this group requires a grasp of the relationship between alcohol use and low bone mass in both the PLWH population and its constituents as defined by sex, age, and race. We examined the association of alcohol use with serum biochemical markers of bone health in a diverse cohort of PLWH enrolled in the New Orleans Alcohol Use in HIV (NOAH) study. To explore the effects of alcohol on bone in the context of HIV and ART and the role of estrogen, we conducted a parallel, translational study using simian immunodeficiency virus (SIV)+/ART+ female rhesus macaques divided into four groups: vehicle (Veh)/Sham; chronic binge alcohol (CBA)/Sham; Veh/ovariectomy (OVX); and CBA/OVX. Clinical data showed that both osteocalcin (Ocn) and procollagen type I N-propeptide (PINP) levels were inversely associated with multiple measures of alcohol consumption. Age (>50 years) significantly increased susceptibility to alcohol-associated suppression of bone formation in both female and male PLWH, with postmenopausal status appearing as an additional risk factor in females. Serum sclerostin (Scl) levels correlated positively with measures of alcohol use and negatively with Ocn. Micro-CT analysis of the macaque tibias revealed that although both CBA and OVX independently decreased trabecular number and bone mineral density, only OVX decreased trabecular bone volume fraction and impacted cortical geometry. The clinical data implicate circulating Scl in the pathogenesis of alcohol-induced osteopenia and suggest that bone morphology can be significantly altered in the absence of net change in osteoblast function as measured by serum markers. Inclusion of sophisticated tools to evaluate skeletal strength in clinical populations will be essential to understand the impact of alcohol-induced changes in bone microarchitecture. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Ethanol alters the relationship between IGF-1 and bone turnover in male macaques

Insulin-like growth factor 1 (IGF-1) influences bone turnover. Transient decreases in IGF-I levels and/or bioavailability may contribute to the detrimental effects of alcohol on bone. The goals of this non-human primate study were to i) evaluate the 20-h response of bone turnover markers to ethanol consumption and ii) assess how ethanol consumption influences the relationship between IGF-1 and these markers. Osteocalcin (bone formation), carboxyterminal cross-linking telopeptide of type 1 collagen (CTX, bone resorption), IGF-1, and IGF binding protein 1 (IGFBP-1) were measured in plasma from male rhesus macaques (N = 10, 8.4 ± 0.3 years) obtained at 12:00, 16:00, and 06:00 h during two phases: pre-ethanol (alcohol-naïve) and ethanol access. During the ethanol access phase, monkeys consumed 1.5 g/kg/day ethanol (4% w/v) beginning at 10:00 h. Osteocalcin and CTX were lower, and the ratio of osteocalcin to CTX was higher at each time point during ethanol access compared to the pre-ethanol phase. Pre-ethanol marker levels did not vary across time points, but markers varied during ethanol access. IGF-1 levels, but not IGFBP-1 levels, varied during the pre-ethanol phase. In contrast, IGF-1 levels were stable during ethanol access but IGFBP-1 levels varied. There were positive relationships between IGF-1 and turnover markers during the pre-ethanol phase, but not during ethanol access. In conclusion, chronic ethanol consumption reduces levels of bone turnover markers and blocks the normal positive relationship between IGF-1 and turnover markers and alters the normal relationship between IGF-1 and IGFBP-1. These findings support the hypothesis that chronic alcohol consumption leads to growth hormone/IGF-1 resistance.

Current Status of the Diagnosis and Management of Osteoporosis

Osteoporosis has been defined as the silent disease of the 21st century, becoming a public health risk due to its severity, chronicity and progression and affecting mainly postmenopausal women and older adults. Osteoporosis is characterized by an imbalance between bone resorption and bone production. It is diagnosed through different methods such as bone densitometry and dual X-rays. The treatment of this pathology focuses on different aspects. On the one hand, pharmacological treatments are characterized by the use of anti-resorptive drugs, as well as emerging regenerative medicine treatments such as cell therapies and the use of bioactive hydrogels. On the other hand, non-pharmacological treatments are associated with lifestyle habits that should be incorporated, such as physical activity, diet and the cessation of harmful habits such as a high consumption of alcohol or smoking. This review seeks to provide an overview of the theoretical basis in relation to bone biology, the existing methods for diagnosis and the treatments of osteoporosis, including the development of new strategies.

Binge Ethanol Exposure in Mice Represses Expression of Genes Involved in Osteoblast Function and Induces Expression of Genes Involved in Osteoclast Differentiation Independently of Endogenous Catalase

Excessive ethanol consumption is a risk factor for osteopenia. Since a previous study showed that transgenic female mice with overexpression of catalase are partially protected from ethanol-mediated trabecular bone loss, we investigated the role of endogenous catalase in skeletal ethanol toxicity comparing catalase knockout to wild-type mice. We hypothesized that catalase depletion would exacerbate ethanol effects. The mice were tested in a newly designed binge ethanol model, in which 12-week-old mice were exposed to 4 consecutive days of gavage with ethanol at 3, 3, 4, and 4.5 g ethanol/kg body weight. Binge ethanol decreased the concentration of serum osteocalcin, a marker of bone formation. The catalase genotype did not affect the osteocalcin levels. RNA sequencing of femoral shaft RNA from males was conducted. Ethanol exposure led to significant downregulation of genes expressed in cells of the osteoblastic lineage with a role in osteoblastic function and collagen synthesis, including the genes encoding major structural bone proteins. Binge ethanol further induced a smaller set of genes with a role in osteoclastic differentiation. Catalase depletion affected genes with expression in erythroblasts and erythrocytes. There was no clear interaction between binge ethanol and the catalase genotype. In an independent experiment, we confirmed that the binge ethanol effects on gene expression were reproducible and occurred throughout the skeleton in males. In conclusion, the binge ethanol exposure, independently of endogenous catalase, reduces expression of genes involved in osteoblastic function and induces expression of genes involved in osteoclast differentiation throughout the skeleton in males.

Dose-response effects of alcohol on biochemical markers of bone turnover in non-human primates: Effects of species, sex and age of onset of drinking

Purpose

Alcohol consumption suppressed bone turnover in male non-human primates; however, it is unclear the extent to which this effect depends upon biological variables. Using archived plasma samples, we investigated whether sex, age of onset of alcohol intake, and species influence the effects of graded increases in alcohol consumption on bone turnover markers.

Methods

91 male and female macaques (rhesus and cynomolgus), ranging in age from 4 years (adolescent) to 10 years (adult) were required to increase their consumption of ethanol in 30-day increments: 0 g/kg/day, followed by 0.5 g/kg/day, 1.0 g/kg/day, and, finally, 1.5 g/kg/day. Plasma osteocalcin (formation), plasma CTX (resorption) and osteocalcin to CTX ratio (turnover balance) were measured during these intervals to assess the dose-response effects of alcohol.

Results

We detected no relationship between dose and osteocalcin when all monkeys were combined, but there was a significant effect of sex (lower levels in females) and interactions between alcohol dose and sex (osteocalcin levels increased with dose in rhesus females). In contrast, we detected a negative linear dose-response relationship for ethanol and CTX. We did not detect a relationship between dose and osteocalcin to CTX ratio overall, but there was a significant positive relationship detected in females (no change in males). Increased age predicted lower biomarker levels for both osteocalcin and CTX. Species was a significant predictor for osteocalcin and the osteocalcin to CTX ratio in these models.

Conclusion

These findings indicate that age, sex, and species influence bone turnover and support the concept that factors beyond quantity of alcohol affect skeletal response to alcohol consumption.

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Age, sex, and species influenced markers of bone turnover in non-human primates.

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Ethanol consumption resulted in a dose-dependent reduction in CTX.

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Ethanol consumption resulted in increased osteocalcin in rhesus females.

Environmental Factors That Affect Parathyroid Hormone and Calcitonin Levels

Calciotropic hormones, parathyroid hormone (PTH) and calcitonin are involved in the regulation of bone mineral metabolism and maintenance of calcium and phosphate homeostasis in the body. Therefore, an understanding of environmental and genetic factors influencing PTH and calcitonin levels is crucial. Genetic factors are estimated to account for 60% of variations in PTH levels, while the genetic background of interindividual calcitonin variations has not yet been studied. In this review, we analyzed the literature discussing the influence of environmental factors (lifestyle factors and pollutants) on PTH and calcitonin levels. Among lifestyle factors, smoking, body mass index (BMI), diet, alcohol, and exercise were analyzed; among pollutants, heavy metals and chemicals were analyzed. Lifestyle factors that showed the clearest association with PTH levels were smoking, BMI, exercise, and micronutrients taken from the diet (vitamin D and calcium). Smoking, vitamin D, and calcium intake led to a decrease in PTH levels, while higher BMI and exercise led to an increase in PTH levels. In terms of pollutants, exposure to cadmium led to a decrease in PTH levels, while exposure to lead increased PTH levels. Several studies have investigated the effect of chemicals on PTH levels in humans. Compared to PTH studies, a smaller number of studies analyzed the influence of environmental factors on calcitonin levels, which gives great variability in results. Only a few studies have analyzed the influence of pollutants on calcitonin levels in humans. The lifestyle factor with the clearest relationship with calcitonin was smoking (smokers had increased calcitonin levels). Given the importance of PTH and calcitonin in maintaining calcium and phosphate homeostasis and bone mineral metabolism, additional studies on the influence of environmental factors that could affect PTH and calcitonin levels are crucial.

Chronic ethanol consumption does not reduce true bone density in male Wistar rats

Osteoporosis is characterized by reduced bone mineral density (BMD) and increased bone fragility, which may be modified by lifestyle behaviors. In observational studies, chronic moderate ethanol consumption is associated with higher BMD, but results are inconsistent and underlying mechanisms are unknown. To understand the influence of chronic ethanol consumption on true bone density (Archimedes principal), bone mechanical properties (Young's Modulus of bend), and osteogenic gene expression, 12-month-old male Wistar rats were randomly assigned to a control group or ethanol intervention (20% ethanol in drinking water on alternate days) group for 13 weeks and tibiae and femurs were collected. Blood was collected to assess alcohol content and antioxidant enzyme activities. We hypothesized that chronic ethanol consumption would increase true bone density and mechanical properties and increase osteoblastic gene expression and serum antioxidant enzyme activity. Ethanol consumption did not influence femoral or tibial true bone density but did result in lower tibial Young's modulus of bend (p = 0.0002). However, there was no influence of ethanol on other measures of mechanical properties. Femoral pro-osteoclastic gene expression of Dkk1 was lower (p = 0.0006) and pro-osteoblastic gene expression of Ctnnb1 was higher (p = 0.02) with ethanol consumption. We observed no differences in circulating antioxidant activities between groups, other than a tendency for greater (p = 0.08) glutathione peroxidase in the ethanol group. Results showed chronic ethanol consumption did not influence true bone density, only modestly reduced tibial mechanical properties (lower Young's modulus of bend), and moderately impacted expression of genes within the femur known to regulate both osteoblast and osteoclast activities.

Inhibitory effects of orthosilicic acid on osteoclastogenesis in RANKL-stimulated RAW264.7 cells

Numerous studies have reported on the positive effects of silicon (Si) on bone metabolism, particularly on the stimulatory effects of Si on osteoblast cells and on bone formation. Inhibitory effects of Si on osteoclast formation and bone resorption have also been demonstrated in vitro and are suggested to be mediated indirectly via stromal and osteoblast cells. Direct effects of Si on osteoclasts have been less studied and mostly using soluble Si, but no characterisation of the Si treatment solutions are provided. The aims of the present study were to (a) further investigate the direct inhibitory effects of Si on osteoclastogenesis in RANKL-stimulated RAW264.7 cells, (b) determine at what stage during osteoclastogenesis Si acts upon, and (c) determine if these effects can be attributed to the biologically relevant soluble orthosilicic acid specie. Our results demonstrate that silicon, at 50 μg/ml (or 1.8 mM), does not affect cell viability but directly inhibits the formation of TRAP+ multinucleated cells and the expression of osteoclast phenotypic genes in RAW264.7 cells. The inhibitory effect of Si was clearly associated with the early stages (first 24 hr) of osteoclastogenesis. Moreover, these effects can be attributed to the soluble orthosilicic acid specie.

Effects of graded increases in ethanol consumption on biochemical markers of bone turnover in young adult male cynomolgus macaques

Chronic heavy alcohol use is often associated with reduced bone mineral density and altered bone turnover. However, the dose response effects of ethanol on bone turnover have not been established. This study examined the effects of graded increases of ethanol consumption on biochemical markers of bone turnover in young adult male cynomolgus macaques (Macaca fascicularis). For this study, 6.6-year-old (95% CI: 6.5, 6.7) male macaques were subjected to three 30-day sessions of increased ethanol intake over a 90-day interval. During the first 30 days, the monkeys drank a predetermined volume of ethanol corresponding to 0.5 g/kg/day, followed by 1.0 g/kg/day and 1.5 g/kg/day. Osteocalcin, a marker of bone formation, and carboxyterminal cross-linking telopeptide of type 1 collagen (CTX), a marker of resorption, were measured during each 30-day session. In addition, the ratio of osteocalcin to CTX was determined as a surrogate measure of global turnover balance. Mean osteocalcin decreased by 2.6 ng/mL (1.8, 3.5) for each one-half unit (0.5 g/kg/day) increase in dose (p < 0.001). Mean CTX decreased by 0.13 ng/mL (0.06, 0.20) for each one-half unit increase in dose (p < 0.001). Furthermore, there was an inverse relationship between dose and the ratio of osteocalcin to CTX, such that the mean ratio decreased by 0.9 (0.3, 1.5) for each one-half unit increase in dose (p = 0.01). In summary, male cynomolgus macaques had decreased blood osteocalcin and CTX, and osteocalcin to CTX ratio during the 90-day interval of graded increases in ethanol consumption, indicative of reduced bone turnover and negative turnover balance, respectively. These findings suggest that over the range ingested, ethanol resulted in a linear decrease in bone turnover. Furthermore, the negative bone turnover balance observed is consistent with reported effects of chronic alcohol intake on the skeleton.

Effects of the Non-Alcoholic Fraction of Beer on Abdominal Fat, Osteoporosis, and Body Hydration in Women

Several studies have shown that binge drinking of alcoholic beverages leads to non-desirable outcomes, which have become a serious threat to public health. However, the bioactive compounds in some alcohol-containing beverages might mitigate the negative effects of alcohol. In beer, the variety and concentration of bioactive compounds in the non-alcoholic fraction suggests that its consumption at moderate levels may not only be harmless but could also positively contribute to an improvement of certain physiological states and be also useful in the prevention of different chronic diseases. The present review focuses on the effects of non-alcoholic components of beer on abdominal fat, osteoporosis, and body hydration in women, conditions selected for their relevance to health and aging. Although beer drinking is commonly believed to cause abdominal fat deposition, the available literature indicates this outcome is inconsistent in women. Additionally, the non-alcoholic beer fraction might improve bone health in postmenopausal women, and the effects of beer on body hydration, although still unconfirmed seem promising. Most of the health benefits of beer are due to its bioactive compounds, mainly polyphenols, which are the most studied. As alcohol-free beer also contains these compounds, it may well offer a healthy alternative to beer consumers.

Impact of Alcohol on Bone Health, Homeostasis and Fracture repair

Purpose of review

Alcohol use continues to rise globally. We review the current literature on the effect of alcohol on bone health, homeostasis and fracture repair to highlight what has been learned in people and animal models of alcohol consumption.

Recent findings

Recently, forkhead box O (FoxO) has been found to be upregulated and activated in mesenchymal stem cells (MSC) exposed to alcohol. FoxO has also been found to modulate Wnt/β-catenin signaling, which is necessary for MSC differentiation. Recent evidence suggests alcohol activates FoxO signaling, which may be dysregulating Wnt/β-catenin signaling in MSCs cultured in alcohol.

Summary

This review highlights the negative health effects learned from people and chronic and episodic binge alcohol consumption animal models. Studies using chronic alcohol exposure or alcohol exposure then bone fracture repair model have explored several different cellular and molecular signaling pathways important for bone homeostasis and fracture repair, and offer potential for future experiments to explore additional signaling pathways that may be dysregulated by alcohol exposure.

Soluble silica stimulates osteogenic differentiation and gap junction communication in human dental follicle cells

Several studies have indicated that dietary silicon (Si) is beneficial for bone homeostasis and skeletal health. Furthermore, Si-containing bioactive glass biomaterials have positive effects on bone regeneration when used for repair of bone defects. Si has been demonstrated to stimulate osteoblast differentiation and bone mineralisation in vitro. However, the mechanisms underlying these effects of Si are not well understood. The aim of the present study was to investigate the effects of soluble Si on osteogenic differentiation and connexin 43 (CX43) gap junction communication in cultured pluripotent cells from human dental follicles (hDFC). Neutral Red uptake assay demonstrated that 25 μg/ml of Si significantly stimulated hDFC cell proliferation. Dosages of Si above 100 μg/ml decreased cell proliferation. Alizarin Red staining showed that osteogenic induction medium (OIM) by itself and in combination with Si (25 μg/ml) significantly increased mineralisation in hDFC cultures, although Si alone had no such effect. The expression of osteoblast-related markers in hDFC was analysed with RT-qPCR. OSX, RUNX2, BMP2, ALP, OCN, BSP and CX43 genes were expressed in hDFC cultured for 1, 7, 14 and 21 days. Expression levels of BMP-2 and BSP were significantly upregulated by OIM and Si (25 μg/ml) and were also induced by Si alone. Notably, the expression levels of OCN and CX43 on Day 21 were significantly increased only in the Si group. Flow cytometric measurements revealed that Si (50 μg/ml) significantly increased CX43 protein expression and gap junction communication in hDFC. Next-generation sequencing (NGS) and bioinformatics processing were used for the identification of differentially regulated genes and pathways. The influence of OIM over the cell differentiation profile was more prominent than the influence of Si alone. However, Si in combination with OIM increased the magnitude of expression (up or down) of the differentially regulated genes. The gene for cartilage oligomeric matrix protein (COMP) was the most significantly upregulated. Genes for the regulator of G protein signalling 4 (RGS4), regulator of G protein signalling 2 (RGS2), and matrix metalloproteinases (MMPs) 1, 8, and 10 were also strongly upregulated. Our findings reveal that soluble Si stimulates Cx43 gap junction communication in hDFC and induces gene expression patterns associated with osteogenic differentiation. Taken together, the results support the conclusion that Si is beneficial for bone health.

Determinants of Bone Health Status in a Multi-Ethnic Population in Klang Valley, Malaysia

Background and objectives: Studies on osteoporosis risk factors are limited in Malaysia, so this study assesses the factors associated with bone health assessed using dual-energy X-ray absorptiometry (DXA) among Malaysians aged ≥40 years. Subjects and Methods: Data on demography, medical history, dietary and lifestyle practices of 786 Malaysians (51.4% women) aged ≥40 years recruited in Klang Valley were obtained. Their body composition and bone health were determined using DXA. The association between risk factors and bone health status was assessed using binary logistic regression. Results: The prevalence of suboptimal bone health and osteoporosis was higher in women (59.4% and 16.1%) than men (40.8% and 8.4%). Overall, the predictors of suboptimal bone health and osteoporosis among the subjects were increased age and higher fat mass. Lower monthly income was positively associated with osteoporosis. Being menopausal was a risk factor for both suboptimal bone health and osteoporosis in women. Women with no formal education were more likely to get osteoporosis. Being a smoker and Chinese were positively related to suboptimal bone health among men. Meanwhile, predictors of osteoporosis among men were regular alcohol and dairy product consumption, higher fat mass and having a tertiary education. Conclusions: This study calls for immediate and effective interventions for middle-aged and elderly populations with risk factors to halt the progression of bone loss.

Bone-Loading Physical Activity and Alcohol Intake but not BMI Affect Areal Bone Mineral Density in Young College-Aged Korean Women: A Cross-Sectional Study

The purpose of this cross-sectional study was to determine the differences in areal bone mineral density (aBMD) based on alcohol consumption behaviors, bone-loading history as assessed by a bone-specific physical activity questionnaire (BPAQ), and the body mass index (BMI). College-aged female students (N = 112) were recruited from the universities in Seoul and Gyeonggi province, South Korea. The aBMD of the lumbar spine and non-dominant side of the proximal femur (total hip, TH; femoral neck, FN; femoral trochanter, FT) were measured using dual energy X-ray absorptiometry (DXA). Alcohol consumption was determined by the frequency and amount of alcohol intake during the past 12 months using a self-reported questionnaire. The X-scan plus II was used to measure height (cm), body mass (kg), fat-free mass (FFM, kg), and % body fat. Drinking two or more times alcohol per week was associated with greater aBMD of the TH (p = 0.04–0.002) and FN (p = 0.043) compared to a lower frequency of alcohol consumption and 2–4 times per month, respectively. Based on the drinking amount per occasion, there were no significant group differences (p > 0.05) in aBMD at any of the sites. The highest group of total BPAQ had greater aBMD of the TH, FN, and FT versus the lowest (p = 0.023–0.009) and mid of total BPAQ groups (p = 0.004–0.009). Additionally, the highest group had greater aBMD of the lumbar spine compared to the mid group (p = 0.001). No significant group differences in aBMD at any of the sites were noted based on the BMI (p > 0.05). Young college-aged women with greater bone-loading physical activity showed greater aBMD at the TH, FN, FT, and lumbar spine, while a moderate alcohol intake was associated with greater aBMD of the TH and FN. These findings have clinical implications for young women who may not participate in high-impact physical activity and are binge drinkers.

Reduced Serum Osteocalcin in High-Risk Alcohol Using People Living With HIV Does Not Correlate With Systemic Oxidative Stress or Inflammation: Data From the New Orleans Alcohol Use in HIV Study

BACKGROUND

HIV infection is now largely a chronic condition as a result of the success of antiretroviral therapy. However, several comorbidities have emerged in people living with HIV (PLWH), including alcohol use disorders and musculoskeletal disorders. Alcohol use has been associated with lower bone mineral density, alterations to circulating bone turnover markers, and hypocalcemia. The pathophysiological basis of bone loss in the PLWH population is unclear but has been suggested to be linked to oxidative stress and inflammation. To test the hypothesis that PLWH consuming excessive alcohol have altered markers of bone turnover and/or calcium homeostasis in association with oxidative stress, we correlated measurements of alcohol consumption with markers of oxidative stress and inflammation, serum calcium concentrations, and measurements of bone turnover, including c-terminal telopeptide cross-links (CTX-1) and osteocalcin.

METHODS

Data were drawn from cross-sectional baseline data from the ongoing New Orleans Alcohol Use in HIV (NOAH) study, comprised of 365 in care PLWH. Alcohol consumption measures (Alcohol Use Disorders Test, 30-day timeline follow-back calendar, and phosphatidylethanol [PEth]) were measured in a subcohort of 40 subjects selected based on highest and lowest PEth measurements. Multivariate linear regression was performed to test the relationships between alcohol consumption and systemic oxidative stress (4-hydroxynonenal; 4-HNE) and inflammation (c-reactive protein; CRP).

RESULTS

Serum calcium and CTX-1 did not differ significantly between the high and low-PEth groups. Individuals in the high-PEth group had significantly lower serum osteocalcin (median low-PEth group: 13.42 ng/ml, inter-quartile range [IQR] 9.26 to 14.99 ng/ml; median high-PEth group 7.39 ng/ml, IQR 5.02 to 11.25 ng/ml; p = 0.0005, Wilcoxon rank-sum test). Osteocalcin negatively correlated with PEth (Spearman r = -0.45, p = 0.05) and self-reported measures after adjusting for covariates. Alcohol consumption showed mild, but significant, positive associations with serum 4-HNE, but not with CRP. Osteocalcin did not correlate with either 4-HNE or CRP.

CONCLUSIONS

In this subcohort of PLWH, we detected significant associations between at-risk alcohol use and osteocalcin, and at-risk alcohol use and serum 4-HNE, suggesting suppression of bone formation independent of increased systemic oxidative stress with increasing alcohol consumption.

Voluntary Chronic Heavy Alcohol Consumption in Male Rhesus Macaques Suppresses Cancellous Bone Formation and Increases Bone Marrow Adiposity

BACKGROUND

Chronic heavy alcohol consumption is an established risk factor for bone fracture, but comorbidities associated with alcohol intake may contribute to increased fracture rates in alcohol abusers. To address the specific effects of alcohol on bone, we used a nonhuman primate model and evaluated voluntary alcohol consumption on: (i) global markers of bone turnover in blood and (ii) cancellous bone mass, density, microarchitecture, turnover, and microdamage in lumbar vertebra.

METHODS

Following a 4-month induction period, 6-year-old male rhesus macaques (Macaca mulatta, n = 13) voluntarily self-administered water or ethanol (EtOH; 4% w/v) for 22 h/d, 7 d/wk, for a total of 12 months. Control animals (n = 9) consumed an isocaloric maltose-dextrin solution. Tetracycline hydrochloride was administered orally 17 and 3 days prior to sacrifice to label mineralizing bone surfaces. Global skeletal response to EtOH was evaluated by measuring plasma osteocalcin and carboxyterminal collagen cross-links (CTX). Local response was evaluated in lumbar vertebra using dual-energy X-ray absorptiometry, microcomputed tomography, static and dynamic histomorphometry, and histological assessment of microdamage.

RESULTS

Monkeys in the EtOH group consumed an average of 2.8 ± 0.2 (mean ± SE) g/kg/d of EtOH (30 ± 2% of total calories), resulting in an average blood EtOH concentration of 88.3 ± 8.8 mg/dl 7 hours after the session onset. Plasma CTX and osteocalcin tended to be lower in EtOH-consuming monkeys compared to controls. Significant differences in bone mineral density in lumbar vertebrae 1 to 4 were not detected with treatment. However, cancellous bone volume fraction (in cores biopsied from the central region of the third vertebral body) was lower in EtOH-consuming monkeys compared to controls. Furthermore, EtOH-consuming monkeys had lower osteoblast perimeter and mineralizing perimeter, no significant difference in osteoclast perimeter, and higher bone marrow adiposity than controls. No significant differences between groups were detected in microcrack density (2^nd lumbar vertebra).

CONCLUSIONS

Voluntary chronic heavy EtOH consumption reduces cancellous bone formation in lumbar vertebra by decreasing osteoblast-lined bone perimeter, a response associated with an increase in bone marrow adiposity.

Bone Effects of Binge Alcohol Drinking Using Prepubescent Pigs as a Model

BACKGROUND

Although chronic alcohol consumption in adults is an established risk factor for osteoporotic fractures, there is a huge gap in our knowledge about bone effects of binge drinking in adolescents. The aim of this pilot study was therefore to assess skeletal effects of binge alcohol drinking using prepubescent pigs as a large animal model.

METHODS

Piglets aged 2 months were offered alcohol orally as a mixture of hard liquor and apple juice. Those with the highest propensity to drink alcohol were included in the experiment and received 1.4 g alcohol/kg bodyweight 2 times per week for 2 months (alcohol group); control piglets received apple juice in an identical manner. At the age of 4 months, the animals were euthanized; trabecular and cortical bone samples from the femur, the tibia, the humerus, and the fourth vertebral body harvested during necropsy were assessed by microcomputed tomography and dynamic histomorphometry. In addition, blood chemistry and blood alcohol determinations were performed.

RESULTS

Blood alcohol levels assessed 1 hour after alcohol administration were 0.99‰ ± 0.15, 1.12‰ ± 0.2, and 1.14‰ ± 0.18 at the ages of 2, 3, and 4 months, respectively. In the alcohol group, serum calcium and phosphate levels were decreased. In the femur, trabecular number and connectivity density were lower in the alcohol than in the control group, and in the humerus and the fourth vertebral bodies, an opposite pattern was seen for trabecular number and connectivity density, respectively. Cortical density was higher in the humerus and trabecular density higher in the tibia of the alcohol group compared to the control group. Cortical porosity was lower in the humerus of the alcohol group. No significant differences were seen for trabecular thickness, trabecular separation, bone volume fraction, and static and dynamic histomorphometric parameters.

CONCLUSIONS

In this pilot study, we have assessed skeletal effects of binge alcohol drinking by using prepubescent pigs as a promising large animal model. Binge drinking has bone effects that are site-specific. However, these data have to be verified in a larger study population.

Influence of Chronic Alcohol Use on Osteoblastic Differentiation of Bone Marrow Cells, Bone Properties, and Hepatic and Renal Morphology of Rats

Chronic alcohol exposure can affect the osteoblastic activity and the proliferation and differentiation of cells due to its toxic effect, which can affect negatively bone repair and bone microarchitecture. The aim of this study was to evaluate the effects of chronic use of 20% alcohol on rats regarding osteoblastic differentiation, extrinsic and intrinsic properties of the tibia, and hepatic and renal morphology. Wistar rats were divided into three groups (n = 9) in accordance with a 24-week diet. After euthanasia, kidneys, liver, and tibias were removed for analysis and femurs mesenchymal cells were collected. The results showed that chronic use of 20% alcohol influenced neither the alkaline phosphatase production nor total protein (p > 0.05) in rats, with similar formation of nodules in all groups (p > 0.05). However, significant changes in the liver and kidneys and adverse effects on the mechanical properties of the tibia were observed. According to the results, it can be concluded that the chronic use of alcohol for 24 weeks had no negative influence on the activity and differentiation of osteoblasts, but the mechanical properties of the tibia were impaired and the organs responsible for metabolism and excretion were also affected due to the consumption of alcohol.

Association between alcohol consumption and bone mineral density in elderly Korean men and women

In this cross-sectional study based on Korean elderly men and women, heavy alcohol intake for men was related to low whole-body BMD and light alcohol intake for women was associated with high whole-body, lumbar, and total femur BMD.

PURPOSE

Alcohol is a risk factor of osteoporosis but previous studies on its effect on bone health has been controversial. The aim of this study was to evaluate the association between alcohol intake and bone mineral density in Korean elderly men and women.

METHODS

Based on the Fourth and Fifth Korean National Health and Nutrition Examination Surveys (KNHANES), 2657 men and 2080 women 50 to 79 years of age were included. Bone mineral density (BMD) was measured using dual energy X-ray absorptiometry (DXA). Alcohol consumption was determined by self-administered questionnaires and classified into four groups according to sex: non-drinkers (0 g/day), light drinking (1-19 g/day men, 1-9 g/day women), moderate drinking (20-39 g/day men, 10-29 g/day women), and heavy drinking (≥ 40 g/day men, ≥ 20 g/day women). The adjusted mean values calculated by linear regression analysis for BMD were determined according to the amount of alcohol consumed.

RESULTS

Light drinkers had the highest whole-body BMD for both men (mean 1.164, SD 0.047-1.281) and women (mean 1.046, SD 0.912-1.180). Among men, mean whole-body BMD for heavy drinkers was significantly lower than that among light drinkers (P = 0.031). Among women, BMD for light drinkers was significantly higher in the whole body, lumbar, and total femur than that for non-drinkers (P < 0.001, P = 0.026, P = 0.040, respectively).

CONCLUSIONS

Heavy alcohol intake may be associated with lower BMD in men while light alcohol intake may associate with higher BMD among women. Future longitudinal studies investigating the effect of alcohol consumption on bone mineral density are needed to validate the findings of this study.

Gender Differences and Socioeconomic Factors Related to Osteoporosis: A Cross-Sectional Analysis of Nationally Representative Data

BACKGROUND

Osteoporosis has been considered a disease that primarily affects women, but recently male osteoporosis is also attracting attention. This study aims to comparatively analyze socioeconomic and other factors that are related to the prevalence of osteoporosis in both men and women.

MATERIALS AND METHODS

This study used data from the Korean Community Health Survey conducted in 2013. To determine factors related to osteoporosis prevalence, researchers applied a binary logistic regression model, first for all research participants, then separately for male and female participants.

RESULTS

Women were more likely than men to have osteoporosis (odds ratio 12.33, 95% confidence interval 11.55-13.17). Factors related to osteoporosis prevalence included age, education level, region, economic activity, alcohol consumption, salt intake, depression, and body mass index in both genders. Low education and income levels were more highly associated with osteoporosis prevalence in women than in men.

CONCLUSIONS

Most of the factors were not gender specific, but some socioeconomic determinants varied by gender. Future studies that will focus on the effects of socioeconomic factors on osteoporosis, as well as gender-related differences in prevention and control of osteoporosis, are needed.

Alcohol: A Simple Nutrient with Complex Actions on Bone in the Adult Skeleton

BACKGROUND

Alcohol is an important nonessential component of diet, but the overall impact of drinking on bone health, especially at moderate levels, is not well understood. Bone health is important because fractures greatly reduce quality of life and are a major cause of morbidity and mortality in the elderly. Regular alcohol consumption is most common following skeletal maturity, emphasizing the importance of understanding the skeletal consequences of drinking in adults.

METHODS

This review focuses on describing the complex effects of alcohol on the adult skeleton. Studies assessing the effects of alcohol on bone in adult humans as well as skeletally mature animal models published since the year 2000 are emphasized.

RESULTS

Light to moderate alcohol consumption is generally reported to be beneficial, resulting in higher bone mineral density (BMD) and reduced age-related bone loss, whereas heavy alcohol consumption is generally associated with decreased BMD, impaired bone quality, and increased fracture risk. Bone remodeling is the principal mechanism for maintaining a healthy skeleton in adults and dysfunction in bone remodeling can lead to bone loss and/or decreased bone quality. Light to moderate alcohol may exert beneficial effects in older individuals by slowing the rate of bone remodeling, but the impact of light to moderate alcohol on bone remodeling in younger individuals is less certain. The specific effects of alcohol on bone remodeling in heavy drinkers are even less certain because the effects are often obscured by unhealthy lifestyle choices, alcohol-associated disease, and altered endocrine signaling.

CONCLUSIONS

Although there have been advances in understanding the complex actions of alcohol on bone, much remains to be determined. Limited evidence implicates age, skeletal site evaluated, duration, and pattern of drinking as important variables. Few studies systematically evaluating the impact of these factors have been conducted and should be made a priority for future research. In addition, studies performed in skeletally mature animals have potential to reveal mechanistic insights into the precise actions of alcohol and associated comorbidity factors on bone remodeling.

Alcohol consumption and hip fracture risk

SUMMARY

The present meta-analysis shows that a nonlinear association between alcohol consumption and the risk of hip fracture was observed. Light alcohol consumption was inversely significantly associated with hip fracture risk, whereas heavy alcohol consumption was associated with an elevated hip fracture risk.

INTRODUCTION

Previous studies examining the association between alcohol consumption and the risk of hip fracture have reported conflicting findings. Therefore, we conducted a meta-analysis of prospective cohort studies to assess the association between alcohol consumption and the risk of hip fracture.

METHODS

PubMed and EMBASE were searched for prospective cohort studies on the relationship between alcohol consumption and the risk of hip fractures. Relative risks (RR) with 95% confidence intervals (CI) were derived using random-effects models throughout the whole analysis.

RESULTS

Eighteen prospective cohort studies were included with 3,730,424 participants and 26,168 hip fracture cases. Compared with non-drinkers, the pooled RR of hip fractures for alcohol consumption was 1.03 (95% CI, 0.91-1.15), with high heterogeneity between studies (P<0.001, I2=72.6%). A nonlinear relationship between alcohol consumption and the risk of hip fracture was identified (P nonlinearity=0.003). Compared with non-drinkers, the pooled RRs of hip fractures were 0.88 (95% CI, 0.83-0.89) for light alcohol consumption (0.01-12.5 g/day), 1.00 (95% CI, 0.85-1.14) for moderate alcohol consumption (12.6-49.9 g/day), and 1.71 (95% CI, 1.41-2.01) for heavy alcohol consumption (≥50 g/day).

CONCLUSIONS

There was no evidence of publication bias. In conclusion, a nonlinear association between alcohol consumption and the risk of hip fracture was observed in this meta-analysis. Further, light alcohol consumption was inversely significantly associated with hip fracture risk, whereas heavy alcohol consumption was associated with an elevated hip fracture risk.

Work- and travel-related physical activity and alcohol consumption: relationship with bone mineral density and calcaneal quantitative ultrasonometry

A number of healthy workers rarely exercise because of a lack of time or resources. Physical activity related to work and everyday travel may be more feasible, but evidence of its beneficial effect on bone health is scarce. We assessed if this form of physical activity was associated with higher bone mineral density (BMD) and stiffness index (SI) when adjusted for recreational physical activity, age, body mass index, smoking, alcohol consumption, education, and serum level of 25-hydroxyvitamin D. Healthy workers, aged 25-54 yr, of the Electricity Generating Authority of Thailand were surveyed. The outcomes were BMD (lumbar spine, femoral neck, and total hip) and calcaneal SI. Physical activity was estimated using the global physical activity questionnaire and considered active when >600 metabolic equivalent tasks (min). Of 2268 subjects, 74% were men. Active male subjects had significantly higher BMD at the femoral neck and total hip (p<0.005). However, the association was not significant with male lumbar spine BMD, male SI, or any bone parameters in women (p>0.05). In men, work and travel physical activity seems beneficial to male bone health; hence, it should be encouraged. Furthermore, smoking appeared harmful while moderate alcohol consumption was beneficial.

Soluble silica inhibits osteoclast formation and bone resorption in vitro

Several studies have suggested that silicon (Si) may be essential for the normal development of connective tissue and the skeleton. Positive effects of Si from the diet as well as from Si-containing biomaterials, such as bioactive glass 45S5 (BG), have been demonstrated. Studies have reported that Si stimulates osteoblast proliferation and differentiation. However, the effects of Si on osteoclasts have not been directly addressed. The purpose of the present in vitro study was to clarify if Si has regulatory effects on osteoclast formation and bone resorption. The effects of BG, BG dissolution extracts and Si containing cell culture medium were investigated in a mouse calvarial bone resorption assay and osteoclast formation assays (mouse bone marrow cultures and RAW264.7 cell cultures). We conclude from our results that Si causes significant inhibition of osteoclast phenotypic gene expressions, osteoclast formation and bone resorption in vitro. In conclusion, the present study suggests that Si has a dual nature in bone metabolism with stimulatory effects on osteoblasts and inhibitory effects on osteoclasts. This suggested property of Si might be interesting to further explore in future biomaterials for treatments of bone defects in patients.

Intraperitoneal injection of ethanol results in drastic changes in bone metabolism not observed when ethanol is administered by oral gavage

BACKGROUND

Chronic alcohol abuse is associated with increased risk of osteoporosis while light-to-moderate alcohol intake correlates with reduced osteoporosis risk. Addition of alcohol to a liquid diet is often used to model chronic alcohol abuse. Methods to model intermittent drinking (including binge drinking and light-to-moderate consumption) include (i) intragastric administration of alcohol by oral gavage or (ii) intraperitoneal (ip) administration of alcohol by injection. However, it is unclear whether the latter 2 methods produce comparable results. The purpose of this investigation was to determine the skeletal response to alcohol delivered daily by oral gavage or ip injection.

METHODS

Ethanol (EtOH) or vehicle was administered to 4-month-old female Sprague-Dawley rats once daily at 1.2 g/kg body weight for 7 days. Following necropsy, bone formation and bone architecture were evaluated in tibial diaphysis (cortical bone) and proximal tibial metaphysis (cancellous bone) by histomorphometry. mRNA was measured for bone matrix proteins in distal femur metaphysis.

RESULTS

Administration of alcohol by gavage had no significant effect on body weight gain or bone measurements. In contrast, administration of the same dose of alcohol by ip injection resulted in reduced body weight, total suppression of periosteal bone formation in tibial diaphysis, decreased cancellous bone formation in proximal tibial metaphysis, and decreased mRNA levels for bone matrix proteins in distal femur.

CONCLUSIONS

Our findings raise concerns regarding the use of ip injection of EtOH in rodents as a method for modeling the skeletal effects of intermittent exposure to alcohol in humans. This concern is based on a failure of the ip route to replicate the oral route of alcohol administration.

Silicon: a review of its potential role in the prevention and treatment of postmenopausal osteoporosis

Physicians are aware of the benefits of calcium and vitamin D supplementation. However, additional nutritional components may also be important for bone health. There is a growing body of the scientific literature which recognizes that silicon plays an essential role in bone formation and maintenance. Silicon improves bone matrix quality and facilitates bone mineralization. Increased intake of bioavailable silicon has been associated with increased bone mineral density. Silicon supplementation in animals and humans has been shown to increase bone mineral density and improve bone strength. Dietary sources of bioavailable silicon include whole grains, cereals, beer, and some vegetables such as green beans. Silicon in the form of silica, or silicon dioxide (SiO2), is a common food additive but has limited intestinal absorption. More attention to this important mineral by the academic community may lead to improved nutrition, dietary supplements, and better understanding of the role of silicon in the management of postmenopausal osteoporosis.

Association of regional body composition with bone mineral density in HIV-infected and HIV-uninfected women: women's interagency HIV study

OBJECTIVE

To understand how regional body composition affects bone mineral density (BMD) in HIV-infected and HIV-uninfected women.

METHODS

Dual energy x-ray absorptiometry was used to measure regional lean and fat mass and BMD at lumbar spine (LS), total hip (TH), and femoral neck (FN) in 318 HIV-infected and 122 HIV-uninfected Women's Interagency HIV Study participants at baseline and 2 and 5 years later. Total lean and fat mass were measured using bioimpedance analysis. Multivariate marginal linear regression models assessed the association of HIV status and body composition on BMD change.

RESULTS

Compared with HIV-uninfected women, HIV-infected women were older (44 vs. 37 years), more likely to be Hepatitis C virus-infected (32% vs. 14%), and postmenopausal (26% vs. 3%) and had lower baseline total fat mass, trunk fat, and leg fat. In multivariate models, increased total lean mass was independently associated with increased BMD at LS, TH, and FN, and total fat mass was associated with increased BMD at TH and FN (all P < 0.05). When total fat was replaced in multivariate models with trunk fat and leg fat, increased trunk fat (and not leg fat) was associated with increased TH and FN BMD (P < 0.001).

CONCLUSIONS

Total fat and lean mass are strong independent predictors of TH and FN BMD, and lean mass was associated with greater LS BMD. Regardless of HIV status, greater trunk fat (and not leg fat) was associated with increased TH and FN BMD, suggesting that weight-bearing fat may be a more important predictor of BMD in the hip.

The role of diet in osteoporosis prevention and management

Diet, a modifiable osteoporosis risk factor, plays an important role in the acquisition and maintenance of bone mass. The influence of diet on bone begins in childhood; even maternal diet can influence bone mass in the offspring. A good general nutritional status and adequate dietary protein, calcium, vitamin D, fruits, and vegetables have a positive influence on bone health, while a high caloric diet and heavy alcohol consumption have been associated with lower bone mass and higher rates of fracture. The evidence for a role of other minerals and vitamins in skeletal health is not as strong, but recent evidence suggests that vitamins C and K might also have an effect on bone.

Moderate alcohol intake lowers biochemical markers of bone turnover in postmenopausal women

OBJECTIVE

Epidemiological studies indicate that higher bone mass is associated with moderate alcohol consumption in postmenopausal women. However, the underlying cellular mechanisms responsible for the putative beneficial effects of alcohol on bone are unknown. Excessive bone turnover, combined with an imbalance whereby bone resorption exceeds bone formation, is the principal cause of postmenopausal bone loss. This study investigated the hypothesis that moderate alcohol intake attenuates bone turnover after menopause.

METHODS

Bone mineral density was determined by dual-energy x-ray absorptiometry in 40 healthy postmenopausal women (mean ± SE age, 56.3 ± 0.5 y) who consumed alcohol at 19 ± 1 g/day. Serum levels of the bone formation marker osteocalcin and the resorption marker C-terminal telopeptide (CTx) were measured by immunoassay at baseline (day 0) and after alcohol withdrawal for 14 days. Participants then consumed alcohol and were assayed on the following morning.

RESULTS

Bone mineral density at the trochanter and total hip were positively correlated to the level of alcohol consumption. Serum osteocalcin and CTx increased after abstinence (4.1 ± 1.6%, P = 0.01 and 5.8 ± 2.6%, P = 0.02 compared with baseline, respectively). Osteocalcin and CTx decreased after alcohol readministration, compared with the previous day (-3.4 ± 1.4%, P = 0.01 and -3.5 ± 2.1%, P = 0.05, respectively), to values that did not differ from baseline (P > 0.05).

CONCLUSIONS

Abstinence from alcohol results in increased markers of bone turnover, whereas resumption of alcohol reduces bone turnover markers. These results suggest a cellular mechanism for the increased bone density observed in postmenopausal moderate alcohol consumers. Specifically, the inhibitory effect of alcohol on bone turnover attenuates the detrimental skeletal consequences of excessive bone turnover associated with menopause.

Prevalence, awareness, and treatment of osteoporosis among Korean women: The Fourth Korea National Health and Nutrition Examination Survey

PURPOSE

This study aimed to assess the factors associated with the prevalence, awareness, and treatment of osteoporosis in a representative sample of Korean women.

METHODS

Data were obtained from dual energy X-ray absorptiometry measurement of the lumbar vertebrae and femoral neck, and from a standardized questionnaire in 2870 Korean women aged 50years and older who participated in the Fourth Korea National Health and Nutrition Examination Survey 2008-2009. Osteoporosis was defined by World Health Organization T-score criteria, and awareness and treatment were defined by self-report of an osteoporosis diagnosis and self-report of current anti-osteoporotic medication use, respectively. We assessed the relationship between multiple risk factors and prevalence, awareness, and treatment.

RESULTS

Osteoporosis was reported in 39.1% of Korean women. Among those with osteoporosis, only 37.5% were aware of their diagnosis and 23.5% received pharmacological treatment. Despite higher prevalence among respondents who were older, of lower body weight, calcium intake, physical activity, and education levels, the awareness and treatment rates of these groups were similar or lower than that of the low-risk controls in multivariate logistic regression models. Moreover, easily identifiable risk factors (e.g., history of fracture, falls, height loss, familial osteoporosis) were not associated with awareness and treatment. Participants who had undergone health screening in the previous 2years exhibited increased awareness and treatment rates independently of other demographic factors.

CONCLUSIONS

Osteoporosis was highly prevalent in this Korean study but was underdiagnosed and undertreated. Routine health screenings could be an effective strategy to increase osteoporosis awareness and treatment.

Alcohol and bone: review of dose effects and mechanisms

Alcohol is widely consumed across the world. It is consumed in both social and cultural settings. Until recently, two types of alcohol consumption were recognized: heavy chronic alcohol consumption or light consumption. Today, there is a new pattern of consumption among teenagers and young adults namely: binge drinking. Heavy alcohol consumption is detrimental to many organs and tissues, including bones, and is known to induce secondary osteoporosis. Some studies, however, have reported benefits from light alcohol consumption on bone parameters. To date, little is known regarding the effects of binge drinking on bone health. Here, we review the effects of three different means of alcohol consumption: light, heavy, and binge drinking. We also review the detailed literature on the different mechanisms by which alcohol intake may decrease bone mass and strength. The effects of alcohol on bone are thought to be both direct and indirect. The decrease in bone mass and strength following alcohol consumption is mainly due to a bone remodeling imbalance, with a predominant decrease in bone formation. Recent studies, however, have reported new mechanisms by which alcohol may act on bone remodeling, including osteocyte apoptosis, oxidative stress, and Wnt signalling pathway modulation. The roles of reduced total fat mass, increased lipid content in bone marrow, and a hypoleptinemia are also discussed.

Cortical bone is more sensitive to alcohol dose effects than trabecular bone in the rat

OBJECTIVE

While chronic alcohol consumption is known to decrease bone mineral content (BMC), bone mineral density (BMD), and negatively modify trabecular bone microarchitecture, the impact of alcohol on cortical microarchitecture is still unclear. The aim of this study was to investigate the effects of various doses of alcohol on bone density, trabecular and cortical parameters and bone strength in rats.

METHODS

Forty-eight male Wistar rats were divided into four groups: control (C), alcohol 25% v/v (A25), alcohol 30% v/v (A30) and alcohol 35% v/v (A35). Rats in the alcohol groups were fed a solution composed of ethanol and water for 17 weeks while the control group drank only water. Bone quality and quantity were evaluated through the analysis of density, trabecular and cortical bone microarchitectural parameters, osteocalcin and N-Telopeptide concentrations and a 3-point bending test.

RESULTS

Bone density along with trabecular and cortical thickness were lower in alcohol groups compared to C. BMD was lower in A35 vs. A30 and cortical thickness was lower in A35 vs. A25 and A30. Pore number was increased by alcohol and the porosity was greater in A35 compared to C. N-Telopeptide concentration was decreased in alcohol groups compared to control whereas no differences were observed in osteocalcin concentrations. Maximal energy to failure was lower in A25 and A35 compared to C.

CONCLUSION

Chronic ethanol consumption increases cortical bone damage in rats and may have detrimental effects on bone strength. These effects were dose-dependent, with greater negative effects proportionate to greater alcohol doses.

Low bone accrual is associated with osteocyte apoptosis in alcohol-induced osteopenia

INTRODUCTION

Alcohol is known to decrease bone mineral density (BMD) and to induce trabecular microarchitecture deterioration. However, little is known about the effects of chronic alcohol consumption on osteocytes in situ. The aim of this study was to assess the effects of a high alcohol dose on osteocytes in an alcohol-induced osteopenia model.

MATERIALS AND METHODS

24 male Wistar rats, 2-months old were separated in 2 groups: Control (C) or Alcohol (A35). The rats in the A35 group drank a beverage composed of 35% ethanol v/v mixed to water for 17 weeks. BMD was assessed by DXA, while the microarchitecture was analyzed using μCT. Bone remodeling was studied measuring serum concentration of osteocalcin, NTx and TRAP. Bone marrow adiposity, osteoblastic lineage differentiation, osteocyte morphology and apoptosis were assessed using bright field, epifluorescence, transmission electron and confocal microscopy.

RESULTS

BMD, trabecular thickness, TRAP and NTx concentration were significantly decreased in A35, while cortical thickness was thinner. There were 10 fold more cells stained with cleaved caspase-3, and 35% more empty lacunae in A35, these data indicating a large increase in osteocyte apoptosis in the A35 group. The number of lipid droplets in the marrow was increased in A35 (7 fold). Both the osteocyte apoptosis and the fat bone marrow content strongly correlated with femur BMD (p=0.0017, r = -0.72 and p=0.002, r = -0.70) and whole body BMD.

CONCLUSION

These data suggest that low BMD is associated with osteocyte apoptosis and bone marrow fat content in alcohol-induced osteopenia.

Acute calcium ingestion attenuates exercise-induced disruption of calcium homeostasis

PURPOSE

Exercise is associated with a decrease in bone mineral density under certain conditions. One potential mechanism is increased bone resorption due to an exercise-induced increase in parathyroid hormone (PTH), possibly triggered by dermal calcium loss. The purpose of this investigation was to determine whether calcium supplementation either before or during exercise attenuates exercise-induced increases in PTH and C-terminal telopeptide of Type I collagen (CTX; a marker of bone resorption).

METHODS

Male endurance athletes (n = 20) completed three 35-km cycling time trials under differing calcium supplementation conditions: 1) 1000 mg of calcium 20 min before exercise and placebo during, 2) placebo before and 250 mg of calcium every 15 min during exercise (1000 mg total), or 3) placebo before and during exercise. Calcium was delivered in a 1000-mg·L(-1) solution. Supplementation was double-blinded, and trials were performed in random order. PTH, CTX, bone-specific alkaline phosphatase (BAP; a marker of bone formation), and ionized calcium (iCa) were measured before and immediately after exercise.

RESULTS

CTX increased and iCa decreased similarly in response to exercise under all test conditions. When compared with placebo, calcium supplementation before exercise attenuated the increase in PTH (mean ± SE: 55.8 ± 15.0 vs 74.0 ± 14.2 pg·mL(-1), P = 0.04); there was a similar trend (58.0 ± 17.4, P = 0.07) for calcium supplementation during exercise. There were no effects of calcium on changes in CTX, BAP, and iCa.

CONCLUSIONS

Calcium supplementation before exercise attenuated the disruption of PTH. Further research is needed to determine the effects of repeated increases in PTH and CTX on bone (i.e., exercise training) and whether calcium supplementation can diminish any exercise-induced demineralization.