Bone disease in chronic alcoholism: the value of plasma osteocalcin measurement

Impact of heavy alcohol consumption on cortical bone mechanical properties in male rhesus macaques

Chronic heavy alcohol consumption may influence the skeleton by suppressing intracortical bone remodeling which may impact the quality of bone and its mechanical properties. However, this aspect has not been thoroughly assessed in either humans or animal models whose cortical bone microstructure resembles the microstructure of human cortical bone. The current study is the first to investigate the effects of chronic heavy alcohol consumption on various mechanical properties of bone in a non-human primate model with intracortical remodeling. Male rhesus macaques (5.3 years old at the initiation of treatment) were induced to drink alcohol and then given the choice to voluntarily self-administer water or ethanol (4 % w/v) for approximately 14 months, followed by three abstinence phases (lasting 34, 41, and 39-46 days) with approximately 3 months of ethanol access in between. During the initial 14 months of open-access, monkeys in the alcohol group consumed an average of 2.9 ± 0.8 g/kg/d ethanol (mean ± SD) resulting in a blood ethanol concentration of 89 ± 47 mg/dl in longitudinal samples taken at 7 h after the daily sessions began. To understand the impact of alcohol consumption on material properties, various mechanical tests were conducted on the distal tibia diaphysis of 2-5 monkeys per test group, including dynamic mechanical analysis (DMA) testing, nano-indentation, microhardness testing, compression testing, and fracture resistance curve (R-curve) testing. Additionally, compositional analyses were performed using Fourier-transform infrared (FTIR) spectroscopy. Significant differences in microhardness, compressive stress-strain response, and composition were not observed with alcohol consumption, and only minor differences were detected in hardness and elastic modulus of the matrix and osteons from nanoindentation. Furthermore, the R-curves of both groups overlapped, with similar crack initiation toughness, despite a significant decrease in crack growth toughness (p = 0.032) with alcohol consumption. However, storage modulus (p = 0.029) and loss factor (p = 0.015) from DMA testing were significantly increased in the alcohol group compared to the control group, while loss modulus remained unchanged. These results indicate that heavy alcohol consumption may have only a minor influence on the material properties and the composition of cortical bone in young adult male rhesus macaques.

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.

Twelve months of voluntary heavy alcohol consumption in male rhesus macaques suppresses intracortical bone remodeling

Chronic heavy alcohol consumption is a risk factor for cortical bone fractures in males. The increase in fracture risk may be due, in part, to reduced bone quality. Intracortical (osteonal) bone remodeling is the principle mechanism for maintaining cortical bone quality. However, it is not clear how alcohol abuse impacts intracortical bone remodeling. This study investigated the effects of long-duration heavy alcohol consumption on intracortical bone remodeling in a non-human primate model. Following a 4-month induction period, male rhesus macaques (Macaca mulatta, n=21) were allowed to voluntarily self-administer water or alcohol (4% ethanol w/v) for 22h/d, 7 d/wk for 12months. Control monkeys (n=13) received water and an isocaloric maltose-dextrin solution. Tetracycline hydrochloride was administered orally 17 and 3days prior to sacrifice for determination of active mineralization sites. Animals in the alcohol group consumed 2.7±0.2g alcohol/kg/d (mean±SE) during the 12months of self-administration, resulting in a mean daily blood alcohol concentration of 77±9mg/dl from samples taken at 7h after the start of a daily session. However, blood alcohol concentration varied widely from day to day, with peak levels exceeding 250mg/dl, modeling a binge-drinking pattern of alcohol consumption. The skeletal response to alcohol was determined by densitometry, microcomputed tomography and histomorphometry. Significant differences in tibial bone mineral content, bone mineral density, and cortical bone architecture (cross-sectional volume, cortical volume, marrow volume, cortical thickness, and polar moment of inertia) in the tibial diaphysis were not detected with treatment. However, cortical porosity was lower (1.8±0.5 % versus 0.6±0.1 %, p=0.021) and labeled osteon density was lower (0.41±0.2/mm(2)versus 0.04±0.01/mm(2), p<0.003) in alcohol-consuming monkeys compared to controls, indicating a reduced rate of intracortical bone remodeling. In concordance, plasma CTx was lower (2.5±0.3ng/ml versus 1.7±0.1ng/ml, p=0.028) in the alcohol group. These results suggest that chronic heavy alcohol consumption may negatively impact bone health, in part, by suppressing intracortical bone remodeling.

Association of gene polymorphisms with intervertebral disc degeneration and vertebral osteophyte formation

STUDY DESIGN

Cross-sectional cohort study of elderly people.

OBJECTIVES

To examine the factors influencing osteophyte formation without lumbar disc degeneration and to estimate the implications of osteophytes from the viewpoint of low back pain and gene polymorphisms.

SUMMARY OF BACKGROUND DATA

The degenerative changes that occur in the intervertebral discs are the point of departure of osteophyte formation. Several studies on factors associated with genetic susceptibility to spinal osteophyte formation, such as VDR and TGF-beta1. However, there are no detailed studies concerning osteophytes not accompanied with disc degeneration.

METHODS

A total of 387 elderly persons were recruited, and disc degeneration and osteophyte formation were evaluated. The cases with osteophyte formation were classified into 3 groups: osteophyte formation with disc height narrowing (n = 217), osteophyte formation without disc height narrowing (n = 99), and control group defined as the cases without osteophyte formation (n = 71). Twelve genotypes were characterized. Correlations between these degenerative factors and the polymorphisms were analyzed.

RESULTS

The prevalence of low back pain was significantly greater in the group of osteophyte formation with disc height narrowing than the other 2 groups. In the polymorphism of alcohol dehydrogenase (ADH2), prevalence of osteophyte formation without disc height narrowing was less in His/Arg (odds ratio = 0.57, P = 0.041) and Arg/Arg (odds ratio = 0.41, P = 0.18) than His/His.

CONCLUSIONS

Patients with osteophyte formation preceding intervertebral disc narrowing had a lower risk of low back pain compared with those without osteophytes. The 47Arg polymorphism in the ADH2 may act to suppress osteophyte formation unaffected by disc degeneration.

Depressive symptoms as a risk factor for osteoporosis and fractures in older Mexican American women

INTRODUCTION AND HYPOTHESIS

Despite higher rates of depression, lower hormone replacement therapy (HRT) use, and inadequate knowledge of factors associated with osteoporosis, Mexican Americans have been understudied with regards to the association between depression, osteoporosis, and fractures. We hypothesized that depression increases the risk for osteoporosis and fractures among older Mexican American women.

METHODS

Seven years of prospective data (1993-2001) from the Hispanic Established Populations for Epidemiologic Studies of the Elderly were analyzed for 1,350 women in the Southwest United States who had complete data for at least the first follow-up interview.

RESULTS

Respondents (mean age:75) were generally poorly educated, had low income, and reported poor or fair health. High levels of depressive symptoms were reported by 31%, while new diagnosis of osteoporosis and new fractures were reported by 18 and 13%, respectively. Logistic regression analyses showed that predictors of newly diagnosed osteoporosis included age, high school (HS) education, ever having been an alcoholic, early menopause, hormone replacement therapy, and high levels of depressive symptoms. Factors predictive of new fractures included age, HS education, diabetes, early menopause, and high levels of depressive symptoms.

CONCLUSIONS

Depressive symptoms were associated with increased risk of osteoporosis and new fractures, even after controlling for other predictive factors.

Alcohol-induced bone loss and deficient bone repair

BACKGROUND

Chronic consumption of excessive alcohol eventually results in an osteopenic skeleton and increased risk for osteoporosis. Alcoholics experience not only increased incidence of fractures from falls, but also delays in fracture healing compared with non-alcoholics. In this review the term "alcohol-induced bone disease" is used to refer to these skeletal abnormalities. Alcohol-induced osteopenia is distinct from osteoporoses such as postmenopausal osteoporosis and disuse osteoporosis. Gonadal insufficiency increases the rate of bone remodeling, whereas alcohol decreases this rate. Thus, histomorphometric studies show different characteristics for the bone loss that occurs in these two disease states. In particular, alcohol-induced osteopenia results mainly from decreased bone formation rather than increased bone resorption. Human, animal and cell culture studies of the effects of alcohol on bone strongly suggest alcohol has a dose-dependent toxic effect on osteoblast activity. The capacity of bone marrow stromal cells to differentiate into osteoblasts has a critical role in the cellular processes involved in the maintenance of the adult human skeleton by bone remodeling. Chronic alcohol consumption suppresses osteoblastic differentiation of bone marrow cells and promotes adipogenesis. In fracture healing, the effect of alcohol is to suppress synthesis of an ossifiable matrix, possibly due to inhibition of cell proliferation and maldifferentiation of mesenchymal cells in the repair tissue. This results in the deficient bone repair observed in animal studies, characterized by repair tissue of lower stiffness, strength and mineral content. Current knowledge of cellular effects and molecular mechanisms involved in alcohol-induced bone disease is insufficient to develop interventional strategies for its prevention and treatment.

OBJECTIVES

The objectives of this review are 1) to identify the characteristics of alcohol-induced bone loss and deficient bone repair as revealed in human and animal studies, 2) to determine the current understanding of the cellular effects underlying both skeletal abnormalities, and 3) to suggest directions for future studies to resolve current ambiguities regarding the cellular basis of alcohol-induced bone disease.

Skeletal response to alcohol

This review briefly assesses the well-established effects of alcohol consumption on bone and mineral metabolism and addresses areas of controversy that need additional research. Alcohol consumption is a risk factor for osteoporosis based on the frequent finding of a low bone mass, decreased bone formation rate, and increased fracture incidence in alcoholics. Alcohol also has been shown to reduce bone formation in healthy humans and animals and to decrease proliferation of cultured osteoblastic cells. On the other hand, it has been difficult to demonstrate alcohol-induced bone loss and increased fracture rate in population-based studies. Indeed, most population-based studies have shown a positive association between alcohol and bone mass and no change or a decrease in fracture risk. Overall, the evidence generally supports a detrimental effect of chronic alcohol abuse on the skeleton of men and a neutral or generally beneficial effect of light to moderate alcohol consumption, especially in older women. This latter putative beneficial effect may be due to a reduction in the age-related increase in bone remodeling associated with postmenopausal bone loss. Specific areas of research are recommended to clarify the dose and sex effects of alcohol consumption and to determine cellular and molecular mechanisms of action. The goals of this proposed research emphasis are to determine the degree of risk for the range of alcohol consumption, to set guidelines of consumption compatible with maintaining bone health, and to develop appropriate countermeasures to prevent or reverse the detrimental skeletal effects of alcohol abuse.

Moderate alcohol consumption suppresses bone turnover in adult female rats

Chronic alcohol abuse is a major risk factor for osteoporosis but the effects of moderate drinking on bone metabolism are largely uninvestigated. Here, we studied the long-term dose-response (0, 3, 6, 13, and 35% caloric intake) effects of alcohol on cancellous bone in the proximal tibia of 8-month-old female rats. After 4 months of treatment, all alcohol-consuming groups of rats had decreased bone turnover. The inhibitory effects of alcohol on bone formation were dose dependent. A reduction in osteoclast number occurred at the lowest level of consumption but there were no further reductions with higher levels of consumption. An imbalance between bone formation and bone resorption at higher levels of consumption of alcohol resulted in trabecular thinning. Our observations in rats raise the concern that moderate consumption of alcoholic beverages in humans may reduce bone turnover and potentially have detrimental effects on the skeleton.

Alcohol consumption inhibits osteoblastic cell proliferation and activity in vivo

To better understand the effect of alcohol consumption on the bone remodeling process in vivo, we used a rodent animal model system to compare osteoblast activity and number in alcohol-fed, pair-fed, and chow-fed animals. Adult, virgin female Sprague-Dawley rats were assigned to alcohol-fed, pair-fed, and chow groups based on weights. Alcohol animals were fed a liquid diet containing 35% ethanol-derived calories for 6 weeks. Pair-fed animals were matched to test animals on the basis of initial weight and fed an isocaloric diet equivalent to that consumed by the alcohol-matched animals on the previous day with alcohol replaced by maltose-dextrin. Right tibias were fixed and embedded in methyl methacrylate for sectioning. Sections (5 microm) were stained for cement lines and packets were measured using histomorphometric techniques on a BioQuant morphometric system. Alcohol-fed animals exhibited statistically significant decreases in the amount of bone surface containing active osteoblasts and a decrease in mean wall thickness. Osteocalcin values were significantly reduced from pair-fed levels and slightly, but not significantly, reduced from chow-fed animals.

Effects of ethanol on gene expression in rat bone: transient dose-dependent changes in mRNA levels for matrix proteins, skeletal growth factors, and cytokines are followed by reductions in bone formation

Several studies were performed in female rats to determine dose and time course changes in mRNA levels for matrix proteins in bone after a single administration of ethanol. As expected, dose-dependent transient increases in blood ethanol were measured. Additionally, there was mild hypocalcemia with no change in immunoreactive parathyroid hormone. Coordinated dose-dependent increases in mRNA for type 1 collagen, osteonectin, and osteocalcin were noted in the proximal tibial metaphysis 6 hr after ethanol was given, with the peak values occurring at a dose of 1.2 g/kg (0.4 ml). Similar increases in mRNA levels for matrix proteins were noted in lumbar vertebrae after ethanol treatment. The changes were specific for bone; ethanol had no effect on mRNA levels for matrix proteins in the uterus or liver, although the mRNA concentrations tended to be reduced in uterus. Message levels for several cytokines implicated in the regulation of bone turnover were also assayed; mRNA levels for transforming growth factor-beta1, transforming growth factor-beta2, interferon-gamma, and interleukin-6 were unchanged at doses ranging from 0.14 to 1.7 g/kg. At the highest dose of ethanol, the mRNA level for tumor necrosis factor-alpha was elevated while the level for insulin-like growth factor-1 was reduced. The time course effects of ethanol (0.4 ml dose) were determined in a separate experiment. Ethanol resulted in a transient increase in mRNA levels for the three bone matrix proteins assayed. However, matrix protein synthesis, as determined by incorporation of 3H-proline into the proximal tibial metaphysis, was not changed after 6 hr. The changes in mRNA levels for the matrix proteins were preceded by brief, transient decreases in mRNA levels for interleukin-1beta, interferon-gamma, and migration inhibitory factor, and followed by a more prolonged decrease in the mRNA level for insulin-like growth factor-1. A subsequent study was performed to determine the effects of repetitive daily treatment with ethanol on rat bone. After 7 days, there were highly significant decreases in the mRNA level for type 1 collagen, as well as decreased bone formation. These results suggest that ethanol may alter bone metabolism by disturbing signal transduction pathways that regulate the expression of genes for bone matrix proteins, skeletal growth factors, and cytokines.

Alcohol, osteoporosis, and bone regulating hormones

The mechanism of the production of ethanol-associated osteopenia seems to be a direct effect of alcohol on bone cells and an indirect or modulating effect through mineral regulating hormones such as vitamin D metabolites, parathyroid hormone, and calcitonin. The modulating effects of these hormones on bone and mineral metabolism in acute and chronic alcohol consumption is discussed herein.

Alcohol-induced bone disease: impact of ethanol on osteoblast proliferation

The habitual consumption of even moderate quantities of alcohol (1 to 2 drinks/day) is clearly linked with reduced bone mass (osteopenia). Biochemical and histological evaluation of patients with alcoholic bone disease reveal a marked impairment in bone formation in the face of relatively normal bone resorption. Experiments using well-defined osteoblastic model systems indicate that the observed reductions in bone formation result from a direct, antiproliferative effect of ethanol on the osteoblast itself. As bone remodeling and mineralization are dependent on osteoblasts, it follows that the deleterious effect of alcohol on these cells would result in slowed bone formation, aberrant remodeling of skeletal tissue and, ultimately, osteopenia and fractures. The skeletal consequences of alcohol intake during adolescence, when the rapid skeletal growth ultimately responsible for achieving peak bone mass is occurring, may be especially harmful. The specific subcellular mechanisms whereby ethanol inhibits cell proliferation are, as yet, unknown. During the last few years, attention has shifted from nonspecific membrane perturbation effects to actions on certain signaling proteins. Specifically, there is increasing evidence that ethanol may exert significant effects on transmembrane signal transduction processes that constitute major branches of cellular control mechanisms. At present, abstinence is the only effective therapy for alcohol-induced bone disease. An improved understanding of the pathogenesis of alcohol-induced bone disease may eventually result in alternative therapeutic avenues for those who are unable to abstain.

Secondary osteoporosis

Secondary osteoporosis is diagnosed when there is a well-established disease-related risk factor for fracture or low bone mass. Secondary osteoporosis is associated with a substantial minority of osteoporotic fractures in women perhaps with a majority of osteoporotic related fractures in men. This chapter does not review all the possible causes of low bone mass and fractures but picks out some of the more important causes of, with an emphasis on the main iatrogenic cause, that is corticosteroid induced osteoporosis. It also highlights some of the possible causes which could be avoidable. Where appropriate the methods of prevention and treatment of secondary osteoporosis are reviewed.

Alcohol consumption inhibits bone growth and development in young actively growing rats

Adolescence is an age of widespread alcohol abuse, but the effect of alcohol consumption on bone formation has not been studied in the young population. This study addresses the effect of alcohol on the early phases of bone growth and development in an animal model. Four-week-old, female Sprague-Dawley rats were divided into three groups. Alcohol-treated animals were fed a modified Lieber-DeCarli diet ad libitum containing 35% ethanol-derived calories, whereas the pair-fed animals (weight-matched to ethanol rats) received an isocaloric liquid diet in which maltose-dextrin substituted calories supplied by ethanol. Chow animals were fed a standard rat chow ad libitum. Proximal tibiae (primarily cancellous bone) and femora (primarily cortical bone) were removed for analysis after 2, 4, 6, or 8 weeks on the diets. Serum was collected for analysis of calcium levels, osteocalcin, corticosterone, growth hormone, parathyroid hormone, and 25-hydroxyvitamin D. The most rapid weight gain occurred between 6 and 8 weeks of age, it was significantly delayed in alcohol and pair-fed animals. Almost all morphological parameters of bone were lower in the alcohol groups. No significant difference in serum calcium levels, osteocalcin, or growth hormone levels were found, and small difference in calciotropic hormone levels was found between groups. The results indicated that chronic alcohol consumption during the age of bone development reduces bone density and peak bone mass in both cortical and cancellous bone. The mechanism whereby this effect occurs is not fully understood, but, our results suggest that the negative impact of alcohol on growing bone is not due to the secondary effects of altered bone mineral regulating hormones.

Bone mass improves in alcoholics after 2 years of abstinence

To evaluate the effect of abstinence on bone mass and bone mineral metabolism in chronic alcoholics, a 2 year longitudinal follow-up study was carried out in a group of 30 chronic alcoholic males who started a rehabilitation program. Lumbar and femoral bone mineral density (BMD) and serum levels of osteocalcin and 25-hydroxyvitamin D were measured at entry and after 1 and 2 years in all patients. Circulating cortisol and parathyroid hormone were measured in 14 and 6 patients, respectively, at entry and every year. Testosterone was measured in 18 patients at entry and after 1 year. At entry, lumbar BMD was significantly lower in alcoholics (1.06 +/- 0.03 g/cm2) than in age-matched healthy men (1.22 +/- 0.03 g/cm2; p < 0.001). Circulating osteocalcin and vitamin D levels were also significantly lower in alcoholics than in controls. Lumbar and femoral neck BMD increased in alcoholics after 2 years of abstinence (lumbar BMD, mean +/- SEM, 1.06 +/- 0.03 to 1.10 +/- 0.04 g/cm2, p < 0.05; femoral BMD, 0.82 +/- 0.02 to 0.84 +/- 0.02 g/cm2; p < 0.02). Moreover, lumbar BMD increased in alcoholics (2.9 +/- 1.4%) and decreased in controls (-1.1 +/- 0.2%; p < 0.02). Femoral BMD also increased in alcoholics (2.8 +/- 1.0%) but the expected mean decrease of -0.92% was found in healthy age-matched males. Baseline low osteocalcin levels (5.1 +/- 0.6 ng/ml) increased after 1 year (8.6 +/- 0.5 ng/ml, p < 0.001) and 2 years of abstinence (9.5 +/- 0.7 ng/ml, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol-induced bone disease in the absence of severe chronic liver damage

To define and identify metabolic bone disease and mineral alterations induced by chronic heavy alcoholism in patients without severe liver damage, we studied a prospective series of unselected patients admitted to a 300-bed general hospital in Barcelona (Spain). A total of 26 chronic heavy drinkers of more than 150 g/day for at least 3 years were included. A general analytic and hormonal study, including liver biopsy in cases with any abnormality in liver function tests, and plasma and urine biochemistry with calcium regulating hormones and osteocalcin levels were determined. A transiliac bone biopsy after double-tetracycline labeling, with histomorphometric study of undecalcified bone, was performed. Statistical analysis was adjusted by age and sex by means of logistic regression. A total of 26 (20 men and 6 women) chronic alcohol abusers were studied. After adjustment for age and sex, alcoholic patients showed slight but significantly increased concentrations of plasma calcium (9.56 +/- 0.56; OR = 17.93; 95% CI 3.17-101.48) and decreased cPTH (0.36 +/- 0.11; OR = 0.097; 95% CI 0.018-0.528) compared with controls. Osteocalcin values were low (1.49 +/- 0.89, normal range 1.8-6.6). There was a significant decrease in bone volume, BV/TV (12.56 +/- 5.29; OR = 0.06; 95% CI 0.01-0.34), with increased resorption surfaces, ES/BS (4.28 +/- 2.43; OR = 9.86; 95% CI 2.16-45.07), and increased osteoclast number, N.Oc/TA (0.21 +/- 0.37; OR = 6.41; 95% CI 1.27-32.25).(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanisms of hypocalcemia and markers of bone turnover in alcohol-intoxicated drinkers

Studies of hypocalcemia and osteoporosis frequently encountered in heavy users of alcohol have previously been performed on alcoholic people who have already recovered from alcohol intoxication. Bone and mineral metabolism during and after the intoxication may be different. We measured serum parameters of bone and mineral metabolism in 26 alcohol-intoxicated men and in 19 healthy control men. Although serum ionized calcium was 12% (P < 0.0001) lower in the patients than in the controls, serum intact parathyroid hormone was similar in the study groups. As reflected by decreased serum levels of osteocalcin (-43%; P < 0.001), bone formation was depressed in the patients. Serum cross-linked carboxyterminal telopeptide of human type I collagen (ICTP), a novel parameter of bone matrix degradation, was 9% higher in the patients (P = 0.03) than controls. The positive correlation between serum osteocalcin and ICTP in the controls (r = 0.59, P < 0.01) was absent in the patients (r = 0.05, P = 0.8). We conclude that in alcohol-intoxicated alcohol users, the parathyroid glands do not respond normally to a hypocalcemic stimulus, and that depressed bone formation is uncoupled from accelerated bone resorption.

Is alcohol an osteoporosis-inducing agent for young and middle-aged women?

The effects of alcohol abuse on the bone of women have scarcely been investigated, although women are more prone than men to osteoporosis. We studied 19 noncirrhotic female alcoholics (aged 24 to 48 years) hospitalized for 2 weeks for withdrawal and three groups of control women (n = 182). Sixteen patients and all control subjects had regular menstrual cycles. Forearm bone mineral content (BMC) and axial bone mineral density (BMD) were measured by single-photon absorptiometry and dual-energy x-ray absorptiometry, respectively. Parameters of bone metabolism were analyzed at the beginning and end of the withdrawal period. BMC and BMD did not differ between patients and controls at any of the five measurement sites. On admission, bone formation of the alcoholics was depressed as reflected by osteocalcin levels (-48%, P < .01); it normalized during abstention (P < .01). Urinary hydroxyproline, a parameter of bone resorption, and serum intact parathyroid hormone were at the control level throughout the observation period. Serum ionized calcium level increased by 4% (P < .0001), and serum free fatty acid (FFA) levels decreased by 30% (P < .05) during withdrawal; there was an inverse correlation between changes in these two parameters (r = -.49, P < .05). On admission, serum concentrations of 25-hydroxyvitamin D3 [25-OH-D3] and 1,25-dihydroxyvitamin D3 [1,25-(OH)2-D3] were reduced by 46% (P < .001) and 16% (P = .16); these did not normalize during abstention. In conclusion, provided that liver cirrhosis and gonadal dysfunction are not contributing, even heavy drinking does not seem to decrease bone mass in young and middle-aged women.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol-induced bone disease: relationship to age and parathyroid hormone levels

Alcohol abuse leads to osteopenia and fractures. Epidemiological evidence suggests that older alcoholics are at substantially greater risk of fractures than younger alcoholics. To examine the interaction of age and alcohol abuse on bone mineral homeostasis, we studied 27 subjects with a history of 10 more years of alcohol abuse ranging in age from 26-68 years. They were evaluated for disordered bone mineral homeostasis by assessing bone density (by quantitative computed tomography of the lumbar spine), histomorphometry of a transcortical biopsy from the iliac crest, serum levels of vitamin D metabolites and parathyroid hormone, and serum and urine levels of bone minerals. Seventeen of the subjects were found to have spinal compression fractures by routine radiologic procedures. The older the subject the more likely the subject was to have such a fracture. Bone densitometry indicated a marked reduction in spinal bone density with 15 subjects below 2 SD of normal aged-matched controls. Bone density fell sharply with the age of the subject. Histomorphometry of iliac crest bone biopsies revealed no evidence of osteomalacia, but total resorption surfaces were increased. Consistent with the lack of osteomalacia were the normal levels of the vitamin D metabolites. The increased total resorption surfaces were correlated with high normal or elevated levels of parathyroid hormone as indicated both by radioimmunoassay and by urinary cAMP levels. Bone formation and active bone resorption (resorption surfaces containing osteoclasts) did not correlate with parathyroid hormone levels, however, but correlated negatively with age.(ABSTRACT TRUNCATED AT 250 WORDS)

Concentration and hydroxyapatite binding capacity of plasma osteocalcin in chronic alcoholic men: effect of a three-week withdrawal therapy

Plasma concentrations of osteocalcin (OC) were studied in 40 chronic alcoholic men (age range: 21-56 years) before and after 3 weeks of ethanol withdrawal therapy and in 50 non-alcoholic controls selected in respect to age and sex. Plasma OC level in alcoholic subjects was significantly lower than in the controls (3.0 +/- 2.6 micrograms/l and 4.7 +/- 2.8 micrograms/l, respectively). After 21 days of withdrawal therapy, plasma OC level was significantly higher than at the day of admission (5.8 +/- 3.5 micrograms/l, P < 0.001). This level was not statistically different from that of the controls. We also demonstrated that the hydroxyapatite binding capacity of plasma OC before as well as after the withdrawal period was not different from that of the controls. The acetaldehyde adduction of purified bovine OC in vitro did not change any of its immunoactivity and hydroxyapatite binding capacity. The results emphasize the fact that the decrease of plasma osteocalcin in chronic alcoholics is reversible within 3 weeks of alcohol withdrawal and that the circulating protein seems to be similar to that present in controls.

Bone mineral density and abstention-induced changes in bone and mineral metabolism in noncirrhotic male alcoholics

BACKGROUND AND PURPOSE

Abuse of alcohol may derange bone metabolism and cause osteoporosis. Due to confounding factors associated with alcohol abuse, however, the effect of alcohol itself on bone loss remains obscure. The influence of alcohol intake on bone and mineral metabolism is rather well known, but how the metabolism normalizes during withdrawal has rarely been investigated. The aims of the present study were to evaluate the alcohol-induced changes of bone and mineral metabolism and their recovery during abstention, and to reassess any possible link between alcohol abuse and osteoporosis.

PATIENTS AND METHODS

We studied 27 non-cirrhotic male alcoholics hospitalized for 2 weeks for withdrawal. For comparison, three groups of control subjects were examined. Serum and urinary parameters of bone and mineral metabolism as well as intestinal absorption of calcium were determined at the beginning and end of the treatment period. Bone mineral density (BMD) was measured by dual-energy x-ray absorptiometry at four axial sites (lumbar spine, femoral neck, Ward's triangle, trochanter).

RESULTS

On admission, bone formation in the alcoholics was reduced as reflected by decreased serum levels of osteocalcin (-28%; p < 0.05) and procollagen I carboxyterminal propeptide (-17%; p < 0.05). Both parameters normalized within 2 weeks of abstention (p < 0.0001 and p < 0.01, respectively). Urinary hydroxyproline, a parameter of bone resorption, was at the control level on admission and increased slightly during abstention (p < 0.05). Serum ionized calcium increased by 3% (p < 0.0001) during withdrawal. Concomitantly, serum free fatty acids (FFA) decreased by 38% (p < 0.001), and there existed an inverse correlation (r = -0.50, p < 0.05) between changes in ionized calcium and FFA. Serum levels of intact parathyroid hormone and vitamin D metabolites were similar in patients and controls throughout the whole observation period. Intestinal absorption of calcium measured by stable strontium was 37% higher in alcoholics than in controls (p < 0.001); it decreased to nearly normal toward the end of the treatment period. Mean axial BMD did not differ between patients and controls at any of the four measurement sites. However, BMD decreased parallel with duration of drinking history in the alcoholics at all axial sites (p < 0.05 to < 0.01, analysis of covariance with age and weight as covariates).

CONCLUSIONS

Decreased bone formation, which is uncoupled from ongoing bone resorption, recovers completely during 2 weeks of abstention. In the absence of confounding factors, the central BMD is normal in noncirrhotic male alcoholics, although the negative effect of alcohol on BMD is evident when duration of excessive drinking is taken into account.

Alcoholism-associated spinal and femoral bone loss in abstinent male alcoholics, as measured by dual X-ray absorptiometry

Although alcoholism is a known risk factor for osteoporosis, there are few published reports on alcoholism-associated bone loss. To study alcoholism-associated bone loss, this study used a dual X-ray absorptiometry (DXA) densitometer to measure lumbar and femoral bone mineral density (BMD) in a previously little-studied population: 32 relatively healthy, nonhospitalized, Caucasian, alcoholic men with a period of abstinence longer than that previously studied (median abstinence 4.0 months, range 3 days-36 months). DXA is a new, highly precise densitometric method with many advantages over the methods used in previous studies. The subjects had statistically significant bone loss at three sites: lumbar spine, femoral neck, and Ward's triangle (multiple correction adjusted two-tailed P < 0.008). Compared to the mean BMD of sex-, age-, and race-matched norms, the subjects' average femoral neck, Ward's triangle, and lumbar BMDs were, respectively, 0.56, 0.69, and 0.57 standard deviations (SDs) below the normative values.

Effects of 3 weeks' moderate alcohol intake on bone and mineral metabolism in normal men

To study the effects of prolonged moderate alcohol intake on bone and mineral metabolism, 60 g/day of ethanol was administered to 10 healthy male volunteers during 3 weeks. The drinking period was preceded and followed by an abstinence period of 3 weeks. The serum level of osteocalcin decreased by 30% towards the end of the alcohol period (P less than 0.01), recovering by 25% after the termination of drinking (P less than 0.01). The serum level of intact parathyroid hormone increased to the end of the drinking period (P less than 0.05). After stopping drinking it came back to baseline (P less than 0.05) within a week. The serum levels of 25(OH)D3, 1,25(OH)2D3, 24,25(OH)2D3, the serum and urinary levels of calcium, and the intestinal absorption of calcium measured by stable strontium remained practically unchanged throughout the whole observation period. We conclude that prolonged moderate alcohol intake impairs osteoblastic function, leading to lowered serum levels of osteocalcin, but it does not derange vitamin D metabolism.

Osteocalcin: diagnostic methods and clinical applications

Osteocalcin is a small (Mr 5800), very interesting bone specific protein, synthesized by osteoblasts and measured in plasma as a biochemical indicator of bone formation. Many immunoassays for osteocalcin have been developed, including radio- and enzymoimmunoassays, with the use of monoclonal and polyclonal antibodies. These are used in many different clinical settings, including bone, kidney, and liver diseases. However, there is a wide range of published values for plasma osteocalcin concentrations in control and patient samples and this has hindered a more widespread adoption of osteocalcin measurement by clinicians. This review discusses how various immunoassays for osteocalcin may contribute to the wide variation of published values and suggests approaches for the development of standardized assays. For example, epitope specificity and immunoreactivity with multiple forms of osteocalcin and osteocalcin peptides in plasma are discussed. It also includes a recent update on interesting clinical applications of osteocalcin.

Alcohol and bone

Abuse of alcohol is considered to be an important risk factor for fractures and osteoporosis. Alcohol abuse is associated with deleterious changes in bone structure detected by histomorphometry, and with a decrease in bone mineral density. These changes may also be produced by factors commonly associated with alcohol abuse, e.g., nutritional deficiencies, liver damage, and hypogonadism. Thus the etiology of alcohol-associated bone disease is multifactorial. Alcohol has, however, clear-cut direct effects on bone and mineral metabolism. Acute alcohol intoxication causes transitory hypoparathyroidism with resultant hypocalcemia and hypercalciuria. Prolonged moderate drinking elevates serum parathyroid hormone (PTH) levels, whereas chronic alcoholics are characterized by low serum levels of vitamin D metabolites with resultant malabsorption of calcium, hypocalcemia, and hypocalciuria. Independently of whether alcohol consumption is of short duration, social, or heavy and chronic, it seems to suppress the function of osteoblasts, as evidenced by low serum levels of osteocalcin. It has recently been reported, however, that alcohol can also have a beneficial effect on bone. Among postmenopausal women, moderate alcohol consumption correlates positively with central and peripheral bone mineral density, and with serum estradiol levels.

Deranged vitamin D metabolism but normal bone mineral density in Finnish noncirrhotic male alcoholics

To study the effect of prolonged ethanol consumption on calcium metabolism and on the prevalence of osteoporosis we examined 38 Finnish noncirrhotic male alcoholics (30-55 years of age) with dietary interviews and biochemical measurements and by measuring the bone mineral content of the forearm using single photon absorptiometry (SPA) and the bone mineral density of the spine, humerus and proximal femur using nonquantified computer tomography (CT) and dual-energy x-ray absorptiometry (DEXA). In comparison two groups of healthy controls were studied. The mean daily dietary intake of calcium was 1.3 g in the patients and 1.2 g in the controls. The dietary intake of vitamin D was equal in the study groups, too. The serum levels of calcium, phosphate and parathyroid hormone did not show any difference between the patients and controls but in the alcoholics the urinary excretion of calcium was reduced by 42% (p less than 0.0001) as compared to the controls. The serum levels of 25-hydroxyvitamin D3, 1,25-dihydroxyvitamin D3, and 24,25-dihydroxyvitamin D3 were reduced in the alcoholics by 40% (p less than 0.0001), 23% (p less than 0.01), and 48% (p less than 0.0001), respectively, as compared to the controls. The alcoholic men had normal levels of serum testosterone and they did not have hypercortisolism. The bone mineral content of the dominant forearm measured by SPA was similar in the study groups as were the bone mineral densities (BMD) of the lumbar and humeral areas measured by CT. The BMD at the lumbar, femoral neck, Ward's triangle and trochanter sites measured by DEXA did not differ, either.(ABSTRACT TRUNCATED AT 250 WORDS)