Effect of tobacco consumption on bone mineral density in healthy young males

Exposure to Cigarette Smoke Impedes Human Osteoblast Differentiation Independently of Nicotine

INTRODUCTION

Tobacco smoking has been implicated in an array of adverse health outcomes, including those that affect adult bone. However, little is known about the impact of tobacco products on developing bone tissue as it develops in the embryo.

AIMS AND METHODS

Here, human embryonic stem cells were differentiated into osteoblasts in vitro and concomitantly exposed to various concentrations of smoke solutions from two conventional, one additive-free and two harm-reduction brands of cigarettes. Differentiation inhibition was determined by calcium assays that quantified matrix mineralization and compared to the cytotoxicity of the tobacco product.

RESULTS

Exposure to mainstream smoke from conventional and additive-free cigarettes caused no inhibition of cell viability or mineralization, while sidestream smoke (SS) concentration-dependently produced cell death. In contrast, mineralization was inhibited only by the highest mainstream concentration of harm-reduction smoke solution. Additionally, sidestream smoke solution from the harm-reduction cigarettes impeded calcification at concentrations lower than those determined to be cytotoxic for conventional products.

CONCLUSIONS

Sidestream smoke impaired in vitro osteogenesis at subtoxic concentrations. In addition, though often perceived as safer, smoke from harm-reduction cigarettes was more potent in inhibiting in vitro osteogenesis than smoke from conventional cigarettes.

IMPLICATIONS

This study adds to a growing list of adverse outcomes associated with pre-natal tobacco exposure. Specifically, in vitro exposure to tobacco products interfered with osteogenic differentiation of human embryonic stem cells, a well-established surrogate model for human embryonic bone development. Contrasting a diverse array of tobacco products unveiled that sidestream smoke was generally more developmentally osteotoxic than mainstream smoke and that harm-reduction products may not be less harmful than conventional products, adverse effects that were seemingly independent of nicotine.

Effect of cigarette smoking on alveolar bone thickness and density in patients undergoing leveling and alignment of crowded lower anterior teeth: a controlled clinical trial

OBJECTIVE

To evaluate the effect of cigarette smoking on the alveolar bone thickness and density in patients undergoing leveling and alignment of crowded lower anterior teeth.

METHODS

This controlled clinical trial involved 17 smokers and 17 nonsmokers with mild to moderate crowding of the anterior mandibular teeth. Two cone-beam computed tomography images of the mandible were taken before and after treatment. The length of each tooth root was calculated in each T0 image, and the root was divided into three equal regions. Three lines were drawn parallel to the line of the cementoenamel junction at these three regions of the root, and the previously drawn lines were used to measure bone thickness and bone density.

RESULTS

The mean changes in cortical bone thickness and bone density were significantly smaller in smokers than nonsmokers. Cortical bone thickness and bone density were significantly lower after than before treatment in both smokers and nonsmokers.

CONCLUSION

In addition to all of its known dangers, cigarette smoking may also harm the alveolar bone by decreasing the bone thickness and density during orthodontic treatment in heavy smokers.

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.

Smoking behavior and circulating vitamin D levels in adults: A meta-analysis

To determine the effect of smoking on circulating vitamin D in adults, we performed a meta-analysis. Literature before 9 May 2021 was retrieved from electronic literature databases such as EMBASE, PubMed, and Cochrane. The quality of the included studies was assessed by two researchers against the Newcastle-Ottawa scale and JBI Evidence-based Health Care Centre criteria. All eligible studies and statistical analyses were performed using STATA 14. Twenty-four studies with 11,340 participants meeting the criteria were included in the meta-analysis. The results of meta-analysis showed that the level of circulating 25(OH)D in smokers was lower than that in nonsmokers. A subgroup analysis based on vitamin D supplement use showed that both smokers who used vitamin D supplements and smokers who did not use vitamin D supplements had lower blood 25(OH)D levels compared with the control group. In addition, subjects were divided into different subgroups according to age for meta-analysis, and the results showed that the serum 25(OH)D level in each subgroup of smokers was lower than that in the control group. This meta-analysis revealed differences in circulating vitamin D levels between smokers and nonsmokers, with smokers likely to have lower circulating vitamin D levels.

Cigarette smoke inhalation impairs angiogenesis in early bone healing processes and delays fracture union

Aims

Cigarette smoking has a negative impact on the skeletal system, causes a decrease in bone mass in both young and old patients, and is considered a risk factor for the development of osteoporosis. In addition, it disturbs the bone healing process and prolongs the healing time after fractures. The mechanisms by which cigarette smoking impairs fracture healing are not fully understood. There are few studies reporting the effects of cigarette smoking on new blood vessel formation during the early stage of fracture healing. We tested the hypothesis that cigarette smoke inhalation may suppress angiogenesis and delay fracture healing.

Methods

We established a custom-made chamber with airflow for rats to inhale cigarette smoke continuously, and tested our hypothesis using a femoral osteotomy model, radiograph and microCT imaging, and various biomechanical and biological tests.

Results

In the smoking group, Western blot analysis and immunohistochemical staining revealed less expression of vascular endothelial growth factor (VEGF) and von Willebrand factor (vWF). The smoking group also had a lower microvessel density than the control group. Image and biochemical analysis also demonstrated delayed bone healing.

Conclusion

Cigarette smoke inhalation was associated with decreased expression of angiogenic markers in the early bone healing phase and with impaired bone healing.

Cite this article:Bone Joint Res. 2020;9(3):99–107.

Network and pathway-based analyses of genes associated with osteoporosis

Osteoporosis (OP) is a disease characterized by bone mass loss, bone microstructure damage, increased bone fragility, and easy fracture. The molecular mechanism underlying OP remains unclear.In this study, we identified 217 genes associated with OP, and formed a gene set [OP-related genes gene set (OPgset)].The highly enriched GOs and pathways showed OPgset genes were significantly involved in multiple biological processes (skeletal system development, ossification, and osteoblast differentiation), and several OP-related pathways (Wnt signaling pathway, osteoclast differentiation, steroid hormone biosynthesis, and adipocytokine signaling pathway). Besides, pathway crosstalk analysis indicated three major modules, with first module consisted of pathways mainly involved in bone development-related signaling pathways, second module in Wnt-related signaling pathway and third module in metabolic pathways. Further, we calculated degree centrality of a node and selected ten key genes/proteins, including TGFB1, IL6, WNT3A, TNF, PTH, TP53, WNT1, IGF1, IL10, and SERPINE1. We analyze the K-core and construct three k-core sub-networks of OPgset genes.In summary, we for the first time explored the molecular mechanism underlying OP via network- and pathway-based methods, results from our study will improve our understanding of the pathogenesis of OP. In addition, these methods performed in this study can be used to explore pathogenesis and genes related to a specific disease.

Long-term use of inhaled glucocorticoids in patients with stable chronic obstructive pulmonary disease and risk of bone fractures: a narrative review of the literature

Patients with chronic obstructive pulmonary disease (COPD) demonstrate a greater osteoporosis prevalence than the general population. This osteoporosis risk may be enhanced by treatment with inhaled corticosteroids (ICSs), which are recommended for COPD management when combined with long-acting bronchodilators, but may also be associated with reduced bone mineral density (BMD). We conducted a narrative literature review reporting results of randomized controlled trials (RCTs) of an ICS versus placebo over a treatment period of at least 12 months, with the aim of providing further insight into the link between bone fractures and ICS therapy. As of 16 October 2017, we identified 17 RCTs for inclusion. The ICSs studied were budesonide (six studies), fluticasone propionate (five studies), mometasone furoate (three studies), beclomethasone dipropionate, triamcinolone acetonide, and fluticasone furoate (one each). We found no difference in the number of bone fractures among patients receiving ICSs versus placebo across the six identified RCTs reporting fracture data. BMD data were available for subsets of patients in few studies, and baseline BMD data were rare; where these data were given, they were reported for treatment groups without stratification for factors known to affect BMD. Risk factors for reduced BMD and fractures, such as smoking and physical activity, were also often not reported. Furthermore, a standardized definition of the term "fracture" was not employed across these studies. The exact relationship between long-term ICS use and bone fracture incidence in patients with stable COPD remains unclear in light of our review. We have, however, identified several limiting factors in existing studies that may form the basis of future RCTs designed specifically to explore this relationship.

Video-based kinetic analysis of calcification in live osteogenic human embryonic stem cell cultures reveals the developmentally toxic effect of Snus tobacco extract

Epidemiological studies suggest tobacco consumption as a probable environmental factor for a variety of congenital anomalies, including low bone mass and increased fracture risk. Despite intensive public health initiatives to publicize the detrimental effects of tobacco use during pregnancy, approximately 10-20% of women in the United States still consume tobacco during pregnancy, some opting for so-called harm-reduction tobacco. These include Snus, a type of orally-consumed yet spit-free chewing tobacco, which is purported to expose users to fewer harmful chemicals. Concerns remain from a developmental health perspective since Snus has not reduced overall health risk to consumers and virtually nothing is known about whether skeletal problems from intrauterine exposure arise in the embryo. Utilizing a newly developed video-based calcification assay we determined that extracts from Snus tobacco hindered calcification of osteoblasts derived from pluripotent stem cells early on in their differentiation. Nicotine, a major component of tobacco products, had no measurable effect in the tested concentration range. However, through the extraction of video data, we determined that the tobacco-specific nitrosamine N'-nitrosonornicotine caused a reduction in calcification with similar kinetics as the complete Snus extract. From measurements of actual nitrosamine concentrations in Snus tobacco extract we furthermore conclude that N'-nitrosonornicotine has the potential to be a major trigger of developmental osteotoxicity caused by Snus tobacco.

A comprehensive overview on osteoporosis and its risk factors

Osteoporosis is a bone disorder with remarkable changes in bone biologic material and consequent bone structural distraction, affecting millions of people around the world from different ethnic groups. Bone fragility is the worse outcome of the disease, which needs long term therapy and medical management, especially in the elderly. Many involved genes including environmental factors have been introduced as the disease risk factors so far, of which genes should be considered as effective early diagnosis biomarkers, especially for the individuals from high-risk families. In this review, a number of important criteria involved in osteoporosis are addressed and discussed.

Dietary Silicon Intake of Korean Young Adult Males and Its Relation to their Bone Status

Accumulated data suggests a positive effect of silicon on bone health; however, limited research exists on the silicon content of foods. To further the understanding of the relationship between dietary silicon intake and bone health, a food composition database of commonly consumed foods in Korea is required. For quantitative data on the intake levels of silicon, we analyzed the silicon content of 365 food items commonly consumed in Korea using inductively coupled plasma-atomic emission spectrometry following microwave-assisted digestion. To investigate the dietary silicon intake status and to examine the potential role of dietary silicon intake in the bone status of men, a total of 400 healthy Korean adult males aged 19-25 were observed for their diet intake and calcaneus bone density using the 24-h recall method and quantitative ultrasound, respectively. Clinical markers reflecting bone metabolism such as serum total alkaline phosphatase, N-mid osteocalcin, and type 1 collagen C-terminal telopeptide concentrations were also analyzed. Silicon intake of the subjects was estimated as 37.5 ± 22.2 mg/day. Major food sources of dietary silicon in the Korean male were cereal and cereal products (25.6 % of total silicon intake), vegetables (22.7 %), beverages and liquors (21.2 %), and milk and milk products (7.0 %). Silicon intake correlated positively with age, weight, energy intake, protein intake, calcium intake, and alcohol intake. After adjusted for age, weight, energy intake, protein intake, calcium intake, alcohol intake, smoking cigarettes, and regular exercise status, daily total silicon intake had no correlation with calcaneus bone density and the bone metabolism markers, but silicon intake from vegetables had a positive correlation with serum total alkaline phosphatase activity, a bone formation maker. These findings show the possible positive relationship between dietary silicon intake from vegetables and the bone formation of young adult males. Further investigation in a larger (Korean) population and correcting for additional nutritional confounders is required to confirm these findings.

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

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

Modifiable Factors Associated With Aging Phenotypes Among Adult Survivors of Childhood Acute Lymphoblastic Leukemia

PURPOSE

Survivors of childhood acute lymphoblastic leukemia (ALL) are at risk for low bone mineral density (BMD) and frail health, outcomes potentially modifiable by altering health behaviors and/or treating endocrine abnormalities. We evaluated associations between lifestyle and hormonal deficits with risk of low BMD and frailty among survivors of ALL.

PATIENTS AND METHODS

Participants included 862 survivors of ALL (median age, 31.3 years [range, 18.4 to 59.7 years]) enrolled in the St Jude Lifetime Cohort study. Bone density was measured using quantitative computed tomography of L1 through L2 vertebrae; low BMD was defined as an age- and sex-standardized z score < -1. The presence of frailty or prefrailty was defined as having at least two of the following: low muscle mass, self-reported exhaustion, low energy expenditure, slow walking speed, and weakness. Hormonal deficiencies were determined according to medical history, medications, and laboratory findings (insulin-like growth factor 1, follicle-stimulating hormone, luteinizing hormone, and testosterone levels). Logistic regression was used to examine associations between lifestyle (smoking, alcohol consumption, and activity levels) and deficiencies in growth hormone (GHD) and/or sex steroids with low BMD and frailty.

RESULTS

Thirty percent of survivors met criteria for low BMD, and 18.6% for frailty/prefrailty. After adjusting for body mass index, low BMD was associated with GHD (odds ratio [OR], 1.59; 95% CI, 1.02 to 2.13) and current smoking (OR, 1.71; 95% CI, 1.02 to 2.85) among men; and GHD (OR, 2.18; 95% CI, 1.26 to 3.78) and moderate alcohol consumption (OR, 2.09; 95% CI, 1.14 to 3.83) among women. After adjusting for current age, the odds of frailty/prefrailty were increased among men with GHD (OR, 2.97; 95% CI, 1.56 to 5.67) and those who smoked (OR, 3.26; 95% CI, 1.65 to 6.43); there were no significant associations among women.

CONCLUSION

The findings suggest that survivors of ALL should receive counseling regarding lifestyle and undergo screening for hormonal deficits to minimize the risk of low BMD and frailty.

Cigarette smoking and testosterone in men and women: A systematic review and meta-analysis of observational studies

Recently Health Canada and the Food and Drug Administration warned about the cardiovascular risk of testosterone, making environmental drivers of testosterone potential prevention targets. Cotinine, a tobacco metabolite, inhibits testosterone breakdown. We assessed the association of smoking with testosterone in a systematic review and meta-analysis, searching PubMed and Web of Science through March 2015 using ("testosterone" or "androgen" or "sex hormone") and ("smoking" or "cigarette"). Two reviewers independently searched, selected, assessed quality and abstracted with differences resolved by consensus or reference to a third reviewer. The initial search yielded 2881 studies; 28 met the selection criteria. In 22 studies of 13,317 men, mean age 18-61years, smokers had higher mean testosterone than non-smokers (1.53nmol/L, 95% confidence interval (CI) 1.11 to 1.96) using a random effects model with inverse variance weighting. In 6 studies of 6089 women, mean age 28-62years, smoking was not clearly associated with testosterone (0.11nmol/L, 95% CI -0.08 to 0.30). Fixed effects models provided similar results, but suggested a positive association in women. Whether products which raise cotinine, such as e-cigarettes or nicotine replacement, also raise testosterone, should be investigated, to inform any regulatory action for e-cigarettes, which emit nicotine into the surrounding air, with relevance for both active and passive smokers.

Evaluation of the effect of selective serotonin reuptake inhibitors on bone mineral density: an observational cross-sectional study

Sixty patients diagnosed with generalized anxiety disorder and treated with either paroxetine, sertraline, or citalopram for at least 12 months were enrolled in this study, and the bone mineral density (BMD) of the patients was compared with that of 40 healthy volunteers. Selective serotonin reuptake inhibitor (SSRI) therapy in generalized anxiety disorder was found to be related with decreased BMD values.

INTRODUCTION

The objectives of this study were to evaluate the effect of SSRI therapy on BMD in postmenopausal women diagnosed with generalized anxiety disorder (GAD) and to identify the effects of the duration of disease and treatment on risk factors for osteoporosis.

METHODS

Sixty patients diagnosed with GAD and treated with paroxetine, sertraline, or citalopram from the SSRI group for at least 12 months were enrolled. Social demographic features, the Hamilton Anxiety Scale (HAS) results, and the Hamilton Depression Scale (HDS) scores of all the patients were assessed. The BMD of the patients was measured by dual-energy X-ray absorptiometry (DXA) at the femoral and lumbar regions. The patients were divided into three groups which are the paroxetine, sertraline, and citalopram groups. The BMD of the patients was compared with that of 40 healthy volunteers.

RESULTS

The L2-L4, total lumbar vertebrae, femoral intertrochanteric, total femoral Z-scores, and femoral Ward's region T-scores of the treatment group were lower than the median T- and Z-scores of the control group (p < 0.05). Of the treatment groups, the femoral neck, trochanteric and intertrochanteric T- and Z-scores, total femoral T- and Z-scores, and femoral Ward's T- and Z-scores of the sertraline group were significantly lower than the BMD values measured at the identical regions in the paroxetine and citalopram groups (p < 0.05).There was a significant negative correlation between the duration of treatment and the BMD values.

CONCLUSION

SSRI therapy in GAD was found to be related with decreased BMD values. Further randomized controlled studies are warranted to determine whether SSRI use is a risk factor for osteoporosis; such studies should investigate these factors by performing BMD assessments before treatment.

Prevention of Osteoporosis and Bone Fragility

The importance of optimal bone growth in childhood and adolescence has been recognized as one of the key strategies in osteoporotic fracture prevention. Low birth size, poor childhood growth, and low peak bone mass at the cessation of growth have been linked to the later risk of osteoporosis and hip fracture. Formerly, the focus was merely on maximizing bone mineral accrual because a high peak bone mineral mass may prevent attainment of a critical “fracture threshold” associated with age-related bone loss and osteoporosis. More recently, the focus has shifted away from bone mineral accrual—as measured by dual-energy X-ray absorptiometry (DXA)—toward the optimization of bone strength. This is partly because of the advances in bone imaging that have enabled estimation of bone strength beyond bone mass. In this review, we briefly describe long-bone growth and structural development and our abilities to assess bone properties by medical imaging tools. In addition, we summarize the evidence of factors contributing to skeletal growth, bone fragility, and the development of strong, healthy bones.

Bone structure and geometry in young men: the influence of smoking, alcohol intake and physical activity

BACKGROUND

The development of osteoporosis is influenced by peak bone mass attained in youth - the influence of lifestyle factors upon which is poorly described, especially amongst males. We sought to address this issue in a large scale study.

METHODS

Hip bone mineral density (dual X-ray absorptiometry, DXA), bone microarchitecture (calcaneal quantitative ultrasound, QUS) and femoral geometry (magnetic resonance imaging, MRI) were characterised in 723 healthy male military recruits (mean ± S.E. age 19.92 ± 0.09 years [range 16-18 years], height 177.67 ± 0.24 cm, weight 73.17 ± 0.37 kg) on entry to UK Army training. Association was sought with prior physical activity, smoking status and alcohol intake.

RESULTS

DXA measures were made in 651, MRI measures in 650, and QUS measures in 572 recruits. Increasing levels of weight-bearing physical activity enhanced periostial bone apposition, increases in both total hip and femoral neck bone mineral density (BMD; p ≤ 0.0001 in both cases), and cortical [p<0.0001] and periostial bone volumes [p=0.016]. Smoking habit was associated with preserved bone geometry, but worse BMD [p=0.0001] and QUS characteristics [p ≤ 0.0005]. Moderate alcohol consumption was associated with greater BMD [p ≤ 0.015].

CONCLUSIONS

Whilst exercise (and perhaps moderate alcohol intake) is beneficial to bone morphometry, smoking is detrimental to bone mineral density in young males notable for the likely short duration of smoking to influence skeletal properties. However, differences in socio-economic status, lifestyle and related environmental factors may to some extent confound our results.

Smoking affects mRNA expression of bone morphogenetic proteins in human periosteum

Periosteum is important for bone homoeostasis through the release of bone morphogenetic proteins (BMPs) and their effect on osteoprogenitor cells. Smoking has an adverse effect on fracture healing and bone regeneration. The aim of this study was to evaluate the effect of smoking on the expression of the BMPs of human periosteum. Real-time polymerase chain reaction was performed for BMP-2,-4,-6,-7 gene expression in periosteal samples obtained from 45 fractured bones (19 smokers, 26 non-smokers) and 60 non-fractured bones (21 smokers, 39 non-smokers). A hierarchical model of BMP gene expression (BMP-2 > BMP-6 > BMP-4 > BMP-7) was demonstrated in all samples. When smokers and non-smokers were compared, a remarkable reduction in the gene expression of BMP-2, -4 and -6 was noticed in smokers. The comparison of fracture and non-fracture groups demonstrated a higher gene expression of BMP-2, -4 and -7 in the non-fracture samples. Within the subgroups (fracture and non-fracture), BMP gene expression in smokers was either lower but without statistical significance in the majority of BMPs, or similar to that in non-smokers with regard to BMP-4 in fracture and BMP-7 in non-fracture samples. In smokers, BMP gene expression of human periosteum was reduced, demonstrating the effect of smoking at the molecular level by reduction of mRNA transcription of periosteal BMPs. Among the BMPs studied, BMP-2 gene expression was significantly higher, highlighting its role in bone homoeostasis.

GSTM1 polymorphism modifies the effect of smoking on calcaneal quantitative ultrasound in young men

Evidence suggests that smoking adversely affects bones. Glutathione S-transferases (GSTs) are important in the detoxification of tobacco smoke compounds. This study investigated the influence of GSTM1 and GSTT1 genetic polymorphisms on the effects on bone induced by tobacco smoking in young men. In total, 231 Chinese men aged 20-39 years were assessed by a cross-sectional study. Calcaneal quantitative ultrasound (QUS) was measured. Smoking information was obtained using a questionnaire. Genotypes were determined for null alleles of GSTM1 and GSTT1. Smoking was inversely associated with speed of sound (SOS) and bone quality index (BQI) among subjects with GSTM1 null genotype (β = -0.28, 95% CI, -34.01 to -8.65 and β = -0.30, 95% CI, -16.41 to -4.49, respectively), but not among those with the allele present (β = -0.02, 95% CI, -15.01 to 12.59 and β = -0.09, 95% CI, -8.75 to 3.02, respectively). P for interaction = 0.04 for SOS and 0.08 for BQI. No interaction was found between the GSTT1 polymorphism and smoking. The results showed that GSTM1 deficiency may increase the adverse effect of smoking on calcaneal QUS in young men, suggesting an interaction between metabolic genes and tobacco smoke in bone detoxification.

Early initiation of smoking and alcohol drinking as a predictor of lower forearm bone mineral density in late adolescence: a cohort study in girls

Background

Adolescence is a critical stage for bone accrual. It is also decisive for the establishment of behaviors such as smoking and alcohol drinking.

Objective

To quantify the short- and long-term associations between smoking and drinking initiation and bone mineral density in adolescent girls.

Methods

We used prospective data from 731 girls identified in public and private schools in Porto, Portugal. Evaluations were conducted when participants were 13 and 17 years old. Bone mineral density (BMD) was measured at the forearm by dual-energy X-ray absorptiometry and weight, height and fat-free mass were measured. Pubertal development status was estimated using menarche age. Self-administered questionnaires were used to collect data on smoking and alcohol drinking, physical exercise and calcium and vitamin D intakes. BMD in early and late adolescence was analyzed as a continuous or dichotomous (Z-score cutoff: −1.0) variable. Associations were calculated using linear or logistic regression.

Results

Over one quarter of these girls had tried smoking by 13, while 59% had drunk alcoholic beverages and 20% had experienced both behaviors by that age. Lower mean BMD at 17 years of age was observed in girls who had ever smoked by 13, as well as in those who reported drinking at that age. There were no significant cross-sectional associations between experience and frequency of smoking or drinking and BMD at 13 years of age. However, we observed significant associations between BMD z-score<−1 in late adolescence and having ever smoked by 13, after adjustment for menarche age and sports practice, (OR = 1.92; 95% CI: 1.21, 3.05) and with ever smoking and drinking in the same period (OR = 2.33; 95% CI: 1.36, 4.00).

Conclusion

Our study adds prospective evidence to the role of early initiation of smoking and alcohol drinking as relevant markers of lower bone mineral density in late adolescence.

Smoking is associated with impaired bone mass development in young adult men: a 5-year longitudinal study

It has previously been shown that smoking is associated with reduced bone mass and increased fracture risk, but no longitudinal studies have been published investigating altered smoking behavior at the time of bone mass acquisition. The aim of this study was to investigate the development of bone density and geometry according to alterations in smoking behavior in a 5-year, longitudinal, population-based study of 833 young men, age 18 to 20 years (baseline). Furthermore, we aimed to examine the cross-sectional, associations between current smoking and parameters of trabecular microarchitecture of the radius and tibia, using high-resolution peripheral quantitative computed tomography (HR-pQCT), in young men aged 23 to 25 years (5-year follow-up). Men who had started to smoke since baseline had considerably smaller increases in areal bone mineral density (aBMD) at the total body (mean ± SD, 0.020 ± 0.047 mg/cm(2) versus 0.043 ± 0.040 mg/cm(2) , p < 0.01) and lumbar spine (0.027 ± 0.062 mg/cm(2) versus 0.052 ± 0.065 mg/cm(2) , p = 0.04), and substantially greater decreases in aBMD at the total hip (-0.055 ± 0.058 mg/cm(2) versus -0.021 ± 0.062 mg/cm(2) , p < 0.01) and femoral neck (-0.077 ± 0.059 mg/cm(2) versus -0.042 ± 0.070 mg/cm(2) , p < 0.01) than men who were nonsmokers at both the baseline and follow-up visits. At the tibia, subjects who had started to smoke had a smaller increment of the cortical cross-sectional area (CSA) than nonsmokers (8.1 ± 4.3 mm(2) versus 11.5 ± 8.9 mm(2) , p = 0.03), and a larger decrement of trabecular volumetric BMD (vBMD) than nonsmokers (-13.9 ± 20.5 mg/mm(3) versus -4.1 ± 13.9 mg/mm(3) , p < 0.001). In the cross-sectional analysis at follow-up (23-25 years of age), smokers had significantly lower trabecular vBMD at the tibia (7.0%, p < 0.01) due to reduced trabecular thickness (8.9%, p < 0.001), as assessed using HR-pQCT, than nonsmokers. In conclusion, this study is the first to report that men who start to smoke in young adulthood have poorer development of their aBMD at clinically important sites such as the spine and hip than nonsmokers, possibly due to augmented loss of trabecular density and impaired growth of cortical cross-sectional area.

The effects of smoking on bone metabolism

Osteoporosis is a common, morbid and costly disorder characterized by deterioration in bone strength. Cigarette smoking is associated with reduced bone mineral density (BMD) and increased fracture risk. There are basic, clinical, and observational studies that define several of the underlying pathophysiologic mechanisms that predispose smokers to bone loss. Such mechanisms include alterations in calciotropic hormone metabolism and intestinal calcium absorption, dysregulation in sex hormone production and metabolism, alterations in adrenal cortical hormone metabolism and in the receptor activator of nuclear factor kappa-B (RANK), receptor activator of nuclear factor kappa-B ligand (RANKL), and osteoprotegerin (OPG) system (RANK-RANKL-OPG system), and direct cellular effects of cigarette use on bone cells. In addition, there is evidence of reversibility in the aforementioned mechanisms with smoking cessation. In summary, cigarette smoking is a reversible risk factor for osteoporosis and osteoporotic fractures through diverse pathophysiologic mechanisms.

The effects of smoke carcinogens on bone

The greatest cause of preventable morbidity and mortality is smoking, and one of the often-underappreciated effects of smoking is profound bone loss. The existing clinical paradigm for smoking is that there is a low turnover osteoporosis. This review highlights findings from recent clinical trials and animal research demonstrating either support or conflict with the existing paradigm. Clinically, it is noted that markers of bone formation are often normal in smokers; these clinical findings conflict with well-conducted animal research demonstrating that carcinogens acting on the aryl hydrogen receptor can significantly reduce osteoblast formation and function. Regarding bone resorption, highlights from recent clinical studies suggest that bone remodeling is increased in smokers. Directly contradicting this enhanced osteoclastogenesis are several animal studies all demonstrating significant inhibition of osteoclast formation and function upon exposure to smoke carcinogens. Future research is needed to clarify whether smoking is truly a low bone remodeling osteoporosis, or an osteoclast-driven bone destruction, with inappropriately normal bone formation.

Bone turnover in passive smoking female rat: relationships to change in bone mineral density

Background

Many studies have identified smoking as a risk factor for osteoporosis, but it is unclear whether passive smoking has an effect on bone mineral density and bone turnover and if such an effect could cause osteoporosis.The purpose of the study was to investigate the effect of passive smoking on bone mineral density (BMD) and bone turnover and the relationship between BMD and bone turnover in female rat.

Methods

Forty-eight female Wistar rats were randomized into six groups: 2-month, 3-month,4-month smoke-exposed rats and their controls. A rat model of passive cigarette smoking was prepared by breeding female rats in a cigarette-smoking box for 2, 3 or 4 months. Serums were analyzed for levels of osteocalcin, bone-specific alkaline phosphatase (b-ALP) and Tartrate-resistant acid phosphatase 5b (TRACP 5b). BMD was assessed at lumbar vertebrae and femur by dual energy X-ray absorptiometry in passive smoking rats and in control rats.

Results

BMD of lumbar spine and femur was lower in 4-month smoke-exposed female rats than that in controls. However, there was no significant difference in serum osteocalcin levels between smoke-exposed rats and controls. Significantly lower b-ALP and higher TRACP 5b were found in the 3-month or 4-month smoke-exposed rats compared to controls. Subsequent analysis showed that b-ALP positively correlated with BMD of the lumbar vertebrae(r = 0.764, P = 0.027) and femur(r = 0.899, P = 0.002) in 4-month smoke-exposed female rats. Furthermore, TRACP 5b levels negatively correlated with BMD of lumbar vertebrae (r = -0.871, P = 0.005) and femur (r = -0.715, P = 0.046) in 4-month smoke-exposed female rats.

Conclusion

Our data suggest that smoke exposure can inhibit bone formation and increase bone resorption. The hazardous effects of passive smoking on bone status are associated with increased bone turnover in female rat.

Impact of smoking on bone mineral density and bone metabolism in elderly men: the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) study

Our cross-sectional analysis of 1,576 men aged ≥65 years examined smoking effects on bone status. Number of smoking years was associated with decreased bone mineral density (BMD), after adjusting for age, height, weight, and number of cigarettes smoked daily. Smoking did not affect biochemical marker serum values for bone turnover.

INTRODUCTION

The impact of smoking on bone status in men has not been conclusively established. We examined how smoking and its cessation influence bone status and metabolism in men.

METHODS

We analyzed 1,576 men among a baseline survey of Japanese men aged ≥65 years, the Fujiwara-kyo Osteoporosis Risk in Men study, conducted during 2007-2008.

RESULTS

Lumbar spine (LS) BMD values among never, former, and current smokers were 1.045 ± 0.194, 1.030 ± 0.189, and 1.001 ± 0.182 g/cm(2) (P = 0.005), respectively, while total hip (TH) BMD values were 0.888 ± 0.120, 0.885 ± 0.127, and 0.870 ± 0.124 (P = 0.078), respectively. The significant trend for LS BMD remained after adjusting for the covariates; age, height, weight, physical activity, milk consumption, and drinking habit (P = 0.036). Among never and ever (current and former) smokers, LS and TH BMD decreased with the number of pack years or the number of smoking years, respectively, adjusted for those covariates. Among ever smokers, LS and TH BMD decreased with the number of smoking years after adjusting for age, height, weight, and number of cigarettes smoked daily. Smoking did not reveal significant effect for serum osteocalcin or tartrate resistant acid phosphatase isoenzyme 5b.

CONCLUSION

The impact of smoking on bone status is mainly associated with the number of smoking years in elderly men.

Effects of smoking on severity of disease in primary hyperparathyroidism

In healthy subjects, smoking is associated with lower plasma levels of parathyroid hormone (PTH) and decreased bone mineral density (BMD). The effect of smoking on PTH, skeletal metabolism, and size/histology of the parathyroid glands in primary hyperparathyroidism (PHPT) is unknown. We investigated, in a cross-sectional study, whether smoking affects PTH levels, BMD, and weight/histology of removed parathyroid tissue in PHPT. We studied 344 (285 women) parathyroidectomized patients with PHPT (24% smokers). Biochemistry was determined at the time of diagnosis. BMD was measured before and after surgical cure. Smoking was associated with lower PTH (9.9 ± 1.8 [SD] vs. 12.2 ± 1.8 pmol/l, P < 0.01) and higher phosphate (0.95 ± 0.17 vs. 0.86 ± 0.17 mmol/l, P < 0.01) levels. Adjustments for between-group differences in age, sex, body weight, plasma creatinine, and 25-hydroxyvitamin D (25OHD) levels did not change the findings. Neither weight of removed adenomatous and hyperplastic tissue nor BMD differed according to smoking status. After adjustment for body weight, age, sex, and 25OHD levels, smokers had slightly lower BMD at the whole body but not at the spine, hip, or forearm. Independent of smoking status, surgical cure caused a significant increase in BMD at all measurement sites. In PHPT smoking is associated with lower plasma PTH and higher phosphate levels. Adjustment for confounders of PTH did not change the results. In contrast to healthy subjects, smoking seems not to decrease BMD in PHPT. Smoking may compromise the correct diagnostic evaluation of borderline hyperparathyroidism. It is unknown to what extent smoking in PHPT affects fracture risk and indication for surgery.

Aetiology and risk factors of musculoskeletal disorders in physically active conscripts: a follow-up study in the Finnish Defence Forces

BACKGROUND

Musculoskeletal disorders (MSDs) are the main reason for morbidity during military training. MSDs commonly result in functional impairment leading to premature discharge from military service and disabilities requiring long-term rehabilitation. The purpose of the study was to examine associations between various risk factors and MSDs with special attention to the physical fitness of the conscripts.

METHODS

Two successive cohorts of 18 to 28-year-old male conscripts (N = 944, median age 19) were followed for six months. MSDs, including overuse and acute injuries, treated at the garrison clinic were identified and analysed. Associations between MSDs and risk factors were examined by multivariate Cox's proportional hazard models.

RESULTS

During the six-month follow-up of two successive cohorts there were 1629 MSDs and 2879 health clinic visits due to MSDs in 944 persons. The event-based incidence rate for MSD was 10.5 (95% confidence interval (CI): 10.0-11.1) per 1000 person-days. Most MSDs were in the lower extremities (65%) followed by the back (18%). The strongest baseline factors associated with MSDs were poor result in the combined outcome of a 12-minute running test and back lift test (hazard ratio (HR) 2.9; 95% CI: 1.9-4.6), high waist circumference (HR 1.7; 95% CI: 1.3-2.2), high body mass index (HR 1.8; 95% CI: 1.3-2.4), poor result in a 12-minute running test (HR 1.6; 95% CI: 1.2-2.2), earlier musculoskeletal symptoms (HR 1.7; 95% CI: 1.3-2.1) and poor school success (educational level and grades combined; HR 2.0; 95% CI: 1.3-3.0). In addition, risk factors of long-term MSDs (>or=10 service days lost due to one or several MSDs) were analysed: poor result in a 12-minute running test, earlier musculoskeletal symptoms, high waist circumference, high body mass index, not belonging to a sports club and poor result in the combined outcome of the 12-minute running test and standing long jump test were strongly associated with long-term MSDs.

CONCLUSIONS

The majority of the observed risk factors are modifiable and favourable for future interventions. An appropriate intervention based on the present study would improve both aerobic and muscular fitness prior to conscript training. Attention to appropriate waist circumference and body mass index would strengthen the intervention. Effective results from well-planned randomised controlled studies are needed before initiating large-scale prevention programmes in a military environment.

Risk factors associated with self-reported training-related injury before arrival at the US army ordnance school

OBJECTIVE

This study examined risk factors for self-reported injury incurred before arrival at Ordnance School for advanced individual training (AIT).

STUDY DESIGN

During AIT in-processing, soldiers (n=27,289 men and 3856 women) completed a questionnaire that collected demographic and lifestyle information, and asked if the soldier currently had an injury that would affect their AIT performance.

METHODS

Potential risk factors for self-reported injury were explored using logistic regression.

RESULTS

For men, self-reported injury was associated with older age [odds ratio (OR) >or=30 years/17-19 years=1.9], race (OR Black/Caucasian=1.2), basic combat training (BCT) site (OR Fort Benning/Fort Jackson=1.7; OR Fort Leonard Wood/Fort Jackson=1.6, OR Fort Knox/Fort Jackson=1.3), smoking on 20 or more days in the 30 days prior to BCT (OR smoker/non-smoker=1.2) and current illness (OR ill/not ill=6.2). For women, increased self-reported injury was associated with older age (OR>or=30 years/17-19 years=2.0), BCT site (OR Fort Leonard Wood/Fort Jackson=1.5) and current illness (OR ill/not ill=5.8).

CONCLUSIONS

Certain demographic characteristics and lifestyle behaviours may be identified as injury risk factors on arrival at Ordnance AIT.

Effect of alcohol consumption on bone mineral density and hormonal parameters in physically active male soldiers

BACKGROUND

Previous studies on the influence of alcohol intake and smoking on bone mineral density (BMD) in men are inconsistent and the effect of these variables on BMD in physically active men is yet to be explored.

OBJECTIVE

To investigate the influence of alcohol intake and smoking on BMD in a cohort of males with well-defined lifestyle conditions.

DESIGN

Men from the armed forces (n=400) having uniform and defined routines were enrolled. BMD was measured by DXA and participants were grouped according to lifestyle variables. Hormonal parameters were measured by immunoassays.

RESULTS

Participants with intake of >24 g/wk of alcohol had significantly higher BMD at femur compared to non-alcohol consumers (p=0.0001) and a linear increase in mean femoral BMD over increasing categories of alcohol intake (p(trend)<0.0001) was observed. Smoking was negatively associated with femoral BMD. In multiple regression analysis, age, BMI, alcohol consumption and smoking were independent predictors of femoral BMD, explaining 10.6% variance. At lumbar spine, age, height and BMI were independent predictors, explaining 9.4% variance in BMD. The concentrations of total testosterone, free testosterone, bioavailable testosterone and PTH were low (p<0.0001) whereas estradiol (p=0.02), free and bioavailable estradiol (p<0.001) were high in alcohol consumers compared to non-consumers. In multiple regression analysis alcohol intake and height explained 5.5% variance in estradiol(.)

CONCLUSIONS

In physically active men with well-defined lifestyle conditions, alcohol consumption was associated with higher femoral BMD, the effect of alcohol is complex and is probably partly mediated by influencing the sex steroid levels.

Does stress shielding occur with the use of long-stem prosthesis in total knee arthroplasty?

A retrospective study conducted to evaluate the possible occurrence of stress shielding with the use of long-stem tibial prosthesis in total knee arthroplasty. Forty-one patients were reviewed (twenty-three standard prosthesis, eighteen long-stem prosthesis) and forty-one unoperated knee of the contralateral limb). Patients underwent bone mineral density assessment with a dual-energy X-ray absorptiometry (DEXA) bone densitometer for the hip and bilateral knees. The mean time interval between surgery and the DEXA assessment was 87.7 months. There was no significant statistical difference (P > 0.05) in the bone mineral density patterns of the tibia with the use of either standard or long-stem prosthesis. The utilization of the long-stem prosthesis to off-load the tibia is not associated with any significant bone mineral density changes or stress shielding.

Effect of cigarette smoking on bone mineral density in healthy Taiwanese middle-aged men

The effect of cigarette smoking in relation to bone mineral density (BMD) remains inconclusive, especially in middle-aged men. This cross-sectional study was conducted to examine the effect of smoking on BMD in 837 healthy Taiwanese males (532 never-smokers, 258 current smokers, 47 former smokers; aged 46-64 yr), recruited at their routine health examination. Subjects with suspected conditions affecting bone metabolism or receiving any medications affecting bone metabolism were excluded. BMD of the lumbar spine (LSBMD) and femoral neck (FNBMD) was measured with dual-energy X-ray absorptiometry. After adjustment for confounding variables (age, weight, physical activity, alcohol consumption, and caffeine intake), we found that the mean value of LSBMD was significantly (2.9%) lower in current smoker compared with never-smokers (p=0.024), but no significant difference was observed in FNBMD. No statistically significant association was observed between former smokers and never-smokers in any of the BMD sites, indicating that quitting smoking did have a positive effect on bone density. Compared with never-smokers, current heavy smokers who consumed at least 20 cigarettes/d (n=94) had 3.8% lower LSBMD (p=0.04), but no significant difference was observed in FNBMD. In the correlation analysis, the duration of smoking was negatively associated with LSBMD (r=-0.166, p=0.004), but no association was shown in FNBMD. Our results suggested that both smoking status and duration of smoking were deleterious factors on the bone density of the lumbar spine, and the effect was cumulative with duration and quantity.

Nutrient intake and bone health status of Korean male college students as related to smoking situations

The purpose of this study was to compare the dietary habits, nutrient intake, bone mineral density (BMD) and bone metabolism in Korean male collegians as related to smoking situation. One hundred sixty one young adult males at the age of 20-26 participated in this study. The subjects were divided into four groups: non smoker (n=42), light smoker (n=34), moderate smoker (n=49) and heavy smoker (n=36). The anthropometric characteristics, smoking situations, dietary habits and nutrient intakes were observed. Bone status of the calcaneus was measured by using quantitative ultrasound (QUS). Bone metabolism markers including serum alkaline phosphatase activity (ALP) and N-mid osteocalcin (OC) were analyzed. There were no significant differences in height, weight, BMI, energy and calcium intake among the four groups. Iron intake of moderate and heavy smoker was significantly lower than that of light smoker. Heavy smokers consumed significantly lower vitamin C than moderate smokers, and their coffee consumption and lifetime alcohol consumption were significantly highest among the 4 groups. QUS parameters and serum ALP were not significantly different among the four groups. Serum OC levels were significantly lower in heavy and non smoker group compared to the moderate smoker group. In conclusion, heavy smokers in young male collegians had undesirable lifestyle and dietary habits, like as high consumption of coffee and alcohol, and low intake of Fe and vitamin C. Although, there was no significant difference in their current bone status from the other groups, these undesirable factors with heavy smoking may affect their bone health in the long term.

Smoking is associated with lower bone mineral density and reduced cortical thickness in young men

CONTEXT

Smoking has previously been associated with reduced areal bone mineral density (aBMD) in elderly subjects, but the association remains controversial in adolescents.

OBJECTIVE

The aim of this study was to determine whether smoking was associated with aBMD or volumetric BMD (vBMD) and bone size in young men.

DESIGN AND SETTING

aBMD was measured using dual x-ray absorptiometry. vBMD and bone size were measured using peripheral quantitative computerized tomography (pQCT). Smoking habits were assessed using questionnaires. Levels of sex steroids, PTH, and 25-OH-vitamin D were measured in serum.

PARTICIPANTS

The population-based Gothenburg Osteoporosis and Obesity Determinants (GOOD) study includes 1068 young men, age 18.9 +/- 0.6 yr (mean +/- SD).

MAIN OUTCOME MEASURE

The main outcome measure was smoking as predictor of bone parameters and serum sex hormone levels.

RESULTS

Of the study subjects, 8.7% smoked daily. Bone parameters were compared between smokers and nonsmokers. Smokers had significantly lower aBMD (dual x-ray absorptiometry) of the total body (crude: -2.1%; adjusted for age, height, weight, calcium intake, and physical activity: -1.8%), lumbar spine (crude: -4.3%; adjusted: -3.3%), and trochanter (crude: -6.6%; adjusted: -5.0%) than nonsmokers. Using peripheral quantitative computerized tomography, we found that smokers had lower cortical thickness of both the radius (crude: -2.8%; adjusted: -2.9%) and tibia (crude: -4.5%; adjusted: -4.0%) than the nonsmokers, whereas no difference was seen for cortical vBMD. Smokers had higher serum levels of total and free testosterone and lower 25-OH-vitamin D than nonsmokers. Adjustment for testosterone and/or 25-OH-vitamin D levels did not alter the associations between smoking and bone parameters.

CONCLUSIONS

We demonstrate that smoking was associated with lower aBMD and reduced cortical thickness in young men.

[Effect of tobacco smoking on leptin serum levels and its relationship with steroid hormones and bone mineral density]

BACKGROUND AND OBJECTIVE

Leptin is an hormone resulting from the obesity gene. Their actions could be important in the pathogenesis of the osteoporosis. The aim of this study is to analyse the influence of tobacco on serum leptin levels, and its relationship with bone mineral density (BMD) and steroid hormones.

SUBJECTS AND METHOD

A group of healthy volunteers were recruited and classified as smokers or non-smokers. A subgroup of smokers ceased smoking during one month. Serum leptin and steroids hormones levels were analysed, and a baseline BMD was measured. In the abstinent group the analysis was repeated at the end of the study.

RESULTS

Fifty-nine healthy volunteers were included (22 of which were smokers). Fifteen smokers remained abstinent for a month. Both groups were similar except in age, being smokers older. Male smokers had lower lumbar BMD (p = 0.017). After adjusting by age, serum leptin levels were higher in smokers than in non-smokers, with statistical differences in women (p = 0.049). Abstinence increased leptin levels, though not reaching statistical significance. An inverse correlation between leptin levels and androstendione in men (r = -0.622; p = 0.001), and a positive correlation with testosterone in women (r = 0.405; p = 0.019) were found. After adjusting by body mass index, only the correlation of leptin levels with androstendione persisted.

CONCLUSIONS

Leptin negatively correlate with sex hormones in young men and is influenced by smoking in young women. Thus, the hormone could be relevant for bone mass regulation in smoker persons.

The influence of cigarette smoke inhalation and its cessation on the tooth-supporting alveolar bone: a histometric study in rats

OBJECTIVE

It has been previously shown that smoking may enhance periodontal breakdown and impair bone healing around titanium implants. However, there is a lack of information concerning the effect of smoking on the tooth-supporting alveolar bone. Thus, the aim of this study was to histometrically evaluate the influence of cigarette smoke inhalation and its cessation on tooth-supporting alveolar bone.

METHODS

Sixty male Wistar rats were randomly assigned to one of the following groups: group 1 - control (n = 15), group 2 - 2 months of cigarette smoke inhalation (n = 13), group 3 - 3 months of cigarette smoke inhalation and 2 months without exposure to cigarette smoke inhalation (n = 16) and group 4 - 5 months of cigarette smoke inhalation (n = 16). Five months after the beginning of cigarette smoke inhalation regime (2 months for group 2), the animals were killed and the mandible was removed and prepared for histological sections. The proportion of mineralized tissue in the furcation area (i.e. a 1000 microm zone under the furcation and between the roots) was obtained.

RESULTS

Data analysis demonstrated that the animals continuously exposed to cigarette smoke inhalation presented a decreased proportion of mineralized tissue (groups 2 and 4), when compared to control and cessation groups (groups 1 and 3) (p < 0.05). Similar levels of proportion of mineralized tissue were observed in groups 1 and 3, showing a beneficial effect of cigarette smoke inhalation cessation on proportion of mineralized tissue.

CONCLUSION

Within the limits of the present study, it can be concluded that cigarette smoke inhalation may affect the tooth-supporting bone as early as 2 months after the initial exposure, and that smoke exposure cessation may revert its negative impact on the alveolar bone.

Effect of Cigarette Smoke Inhalation and Estrogen Deficiency on Bone Healing Around Titanium Implants: A Histometric Study in Rats

BACKGROUND

It has been shown that cigarette smoke inhalation (CSI) and estrogen deficiency (OVX) may affect bone quality around titanium implants; however, their association has not been evaluated. Therefore, this study aimed to verify the effects of CSI associated with OVX on bone healing around titanium implants.

METHODS

The tibia surface of 45 female Wistar rats was surgically exposed, and screw-shaped titanium implants were placed. The animals were randomly assigned to OVX (ovariectomized rats; n = 15), SHAM (sham-operated rats; n = 15), and CSI + OVX (4 months of intermittent cigarette smoke inhalation, starting 2 months before implant placement in ovariectomized rats; n = 15). The implants were placed at the time of OVX or SHAM surgery. After 60 days, the animals were sacrificed and undecalcified sections obtained. The percentages of mineralized tissue (bone density [BD]) in a 500-microm-wide zone lateral to the implant, bone filling (BF) within the limits of the threads, and bone-to-implant contact (BIC) were measured in cortical (zone A) and cancellous (zone B) bone.

RESULTS

In zone A, the CSI + OVX group showed a significant difference regarding BIC and BD (P <0.05) compared to the other groups. In zone B, data analysis showed that the CSI + OVX group presented the lowest percentage of BD and BIC, followed by the OVX and SHAM groups, respectively (P <0.05).

CONCLUSION

Within the limits of the present study, it can be concluded that cigarette smoke inhalation amplified the deleterious effects of estrogen deficiency, affecting both preexisting and newly formed bone in the cortical and cancellous bone around titanium implants.

Inclusion of tobacco exposure as a predictive factor for decreased bone mineral content

Tobacco exposure has been implicated as a risk factor for decreased bone density, which might result in osteoporosis. Cotinine, a metabolite of nicotine, is commonly used as a marker for tobacco exposure (active or passive). The objective of the present study was to compare tobacco exposure with other predictive factors for low bone mineral content (BMC), as determined by dual photon bone absorptiometry (DXA) in a national U.S. sample. Publicly available interview and clinical examination data from the Third National Health and Nutrition Examination Survey, 1988-1994 (NHANES-III) were used. Our data included 14,060 subjects from 19,528 randomly selected representative U.S. households. Clinical laboratory data included serum values for calcium and cotinine. BMC was assessed radiologically by DXA at five proximal femur sites. BMC values were adjusted for age, as well as height, weight, and bone area to correct for bone and body size. We used t tests to compare continuous variables and chi-square tests to explore associations between categorical variables. Multivariate regression models were developed for each gender with appropriate covariates. Intertrochanter BMC explained the most variation (highest R2) and was selected as the basis of the comparison. Serum cotinine had a significant inverse relationship to BMC in both males (p = .0069) and females (p = .0063). Serum cotinine, as a marker for tobacco exposure, is a statistically significant risk factor for decreased BMC in both genders and should be included in multivariate regression models to predict low BMC.

Serum parathyroid hormone (PTH) levels in smokers and non-smokers. The fifth Tromsø study

OBJECTIVE

Smoking is associated with reduced bone density and calcium absorption, and reduced serum levels of vitamin D. A compensatory increase in serum parathyroid hormone (PTH) would therefore be expected as a result of an altered calcium balance. However, reports on PTH levels in smokers are conflicting. As serum PTH levels give important information on the calcium balance, the PTH levels in smokers are of interest.

SUBJECTS AND METHODS

In the fifth Tromsø study, smoking status was recorded and serum PTH measured in 7896 subjects. Intakes of calcium and vitamin D were evaluated with a food-frequency questionnaire. In a follow-up study on 205 subjects, serum 25-hydroxyvitamin D, calcium absorption, and renal excretion of calcium were measured in addition.

RESULTS

The serum PTH levels were significantly lower in smokers than non-smokers (3.1+/-1.4 vs 3.6+/-1.9 pmol/l in males; 3.1+/-1.5 vs 3.6+/-1.8 pmol/l in females (P < 0.001) after correcting for confounding variables, linear regression). In the smokers, there was no association between number of cigarettes smoked and serum PTH. One year after quitting smoking, serum PTH levels were similar to those of people who had never smoked. The smokers had significantly lower intake of vitamin D, lower serum levels of 25-hydroxyvitamin D and lower calcium absorption. The intake of calcium and the renal excretion of calcium were similar to that in non-smokers.

CONCLUSIONS

Smokers have lower serum PTH levels than non-smokers. This cannot be explained by the predictors of serum PTH measured in our study.

Osteoporosis in men: epidemiology, diagnosis, prevention, and treatment

BACKGROUND

Osteoporosis and fragility fractures in men account for substantial health care expenditures and decreased quality of life.

OBJECTIVE

This article reviews the most current information about the epidemiology, diagnosis, prevention, and treatment of osteoporosis in men.

METHODS

Relevant literature was identified through a search of MEDLINE (1966-June 2003) limited to English-language studies in men. The search terms included fractures, bone density, or osteoporosis plus either epidemiology, diagnosis, prevention, control, or therapy. Additional search terms included specific subtopics (eg, bisphosphonates, calcium, exercise, parathyroid hormone). The authors contributed additional relevant publications.

RESULTS

Morbidity after fragility fracture is at least as high in men as in women, and the rate of fracture-related mortality 1 year hip fracture is approximately double in men compared with women. The bioavailable fraction of testosterone slowly declines into the ninth decade in men. There is evidence that the effect of estrogen on bone is greater than that of testosterone in men. Diagnosing osteoporosis in men is complicated by a lack of consensus on how it should be defined. Significant risk factors for osteoporosis or fracture include low bone mineral density, previous fragility fracture, maternal history of fracture, marked hypogonadism, smoking, heavy alcohol intake or alcoholism, low calcium intake, low body mass or body mass index, low physical activity, use of bone-resorbing medication such as glucocorticoids, and the presence of such conditions as hyperthyroidism, hyperparathyroidism, and hypercalciuria. Prevention is paramount and should begin in childhood. During adulthood, calcium (1000-1500 mg/d), vitamin D (400-800 IU/d), and adequate physical activity play crucial preventive roles. When treatment is indicated, the bisphosphonates are the first choice, whereas there is less support for the use of calcitonin or androgen therapy. Parathyroid hormone (1-34) is a promising anabolic therapy. There is also strong evidence for the use of bisphosphonates for the treatment of glucocorticoid-induced osteoporosis.

DHEAS as a new diagnostic tool

Dehydroepiandrosterone sulfate (DHEAS) is a 19-carbon steroid, situated along the steroid metabolic pathway. It is the most abundant circulating steroid hormone in the body and can be converted to either androgens or estrogens. Their physiological and pathological functions have not yet been fully identified. Serum DHEAS concentrations peak at around age 25 years and then decline steadily over the following decades. Due to its long half-life and high concentration in the blood, the levels of DHEAS remain the same 24 h a day. This makes DHEAS a very interesting new diagnostic tool for both scientific research and clinical diagnostics. Moreover, circulating concentrations of DHEAS can be changed by many factors, such as endogenous production, hormone supplementation, many kinds of drugs, and many types of disease states. As research moves forward to better understand the relationships of DHEAS with health and disease, it is essential that studies should be designed to control for the influence of many factors on serum DHEAS concentrations.

Tobacco use and degenerative joint disease of the spine

PURPOSE

To examine differences between tobacco users and nonusers who required surgical treatment for degenerative joint disease (DJD) of the spine.

DATA SOURCES

Two hundred randomly selected medical records of patients who had undergone surgery for DJD of the spine.

CONCLUSIONS

The number of tobacco users in the sample was significantly higher than the number of tobacco users in the general population, indicating greater incidence of DJD among tobacco users. The study demonstrated significant differences between tobacco users and nonusers regarding age, gender, type of occupation, number of imaging studies to diagnosis, and needs for pain management.

IMPLICATIONS FOR PRACTICE

Nurse practitioners who deal with education and treatment of patients at risk for spinal degenerative joint disease must consider tobacco use as a significant factor, especially regarding diagnostic studies and pain management.

Influence of smoking and oral contraceptives on bone mineral density and bone remodeling in young women: a 2-year study

The objective of the study was to explore the influence of menstrual irregularities, oral contraceptives and smoking on bone mineral density (BMD) development and bone turnover with time. Healthy young women (n = 118) were divided into four categories: (a) women neither smoking nor using oral contraceptives; (b) women who were smokers; (c) women using oral contraceptives; (d) women who were smoking and using oral contraceptives. They responded to a validated questionnaire with 34 questions concerning lifestyle and the Sense of Coherence scale (SOC). BMD was measured by dual energy x-ray absorptiometry (DEXA). Deoxypyridinoline (DPD) was measured in urine. Data were analyzed by multiple linear regression analysis. Among smokers, BMD level decreased during a 2-year period and smoking was associated with a larger negative change in BMD. Use of oral contraceptives moderated the negative impact of smoking. Women using oral contraceptives at baseline and with regular bleeding induced by contraceptive pills had a significantly higher BMD at baseline and at follow-up. They also had lower SOC than women who had natural regular bleedings. Use of oral contraceptives in combination with smoking was linked to high alcohol consumption and higher frequency of self-reported body weight reduction, which reduced the negative BMD change in this category. DPD level and difference were strongly associated with estrogen influence. It is concluded that smokers without OCs had a negative BMD development and BMD in young women with irregular menstruations seems to be improved by OC.

Establishment of peak bone mass

Among the main areas of progress in osteoporosis research during the last decade or so are the general recognition that this condition, which is the cause of so much pain in the elderly population, has its antecedents in childhood and the identification of the structural basis accounting for much of the differences in bone strength among humans. Nevertheless, current understanding of the bone mineral accrual process is far from complete. The search for genes that regulate bone mass acquisition is ongoing, and current results are not sufficient to identify subjects at risk. However, there is solid evidence that BMD measurements can be helpful for the selection of subjects that presumably would benefit from preventive interventions. The questions regarding the type of preventive interventions, their magnitude, and duration remain unanswered. Carefully designed controlled trials are needed. Nevertheless, previous experience indicates that weight-bearing activity and possibly calcium supplements are beneficial if they are begun during childhood and preferably before the onset of puberty. Modification of unhealthy lifestyles and increments in exercise or calcium assumption are logical interventions that should be implemented to improve bone mass gains in all children and adolescents who are at risk of failing to achieve an optimal peak bone mass.

Season modifies the relationship between bone and blood lead levels: the Normative Aging Study

Bone serves as a repository for 75% and 90-95% of lead in children and adults, respectively. Bone lead mobilization heightens during times of increased bone turnover, such as pregnancy, lactation, hyperthyroidism, and the rapid growth of childhood. Blood lead levels show seasonal periodicity. Children demonstrate peak blood lead levels in mid-summer and a secondary peak in late winter. Pregnant women demonstrate the highest mean blood lead levels in winter (January-March) and the lowest in summer (July-September). This fluctuation in blood lead levels may be related to seasonal patterns of environmental exposures, but it may also be partially related to the increased mobilization of bone lead stores during the winter months. We performed bone lead measurements using a K-x-ray fluorescent instrument to determine micrograms of lead per gram of bone mineral (parts per million) in middle-aged and elderly men who participated in the Normative Aging Study. We obtained measurements of blood and bone lead during the high sun exposure months of May-August (summer; n = 290); the intermediate sun exposure months of March, April, September, and October (spring/fall; n = 283); and the low sun exposure months of November-February (winter; n = 191). Mean blood lead concentrations were 5.8 microg/dl, 6.1 microg/dl, and 6.6 microg/dl for the summer, spring/fall, and winter, respectively. Mean patella (trabecular bone) lead concentrations were 34.3 microg/gm, 29.7 microg/gm, and 29.0 microg/gm for the summer, spring/fall, and winter time periods, respectively. In multivariate regression models, adjusted for age, smoking, alcohol ingestion, and dietary intake of iron and vitamin C, the authors found a strong interaction between season and bone lead level--with bone lead levels exerting an almost 2-fold greater influence on blood levels during the winter months than the summer months. The authors concluded that elevated blood lead levels in winter may be related to increased mobilization of endogenous bone lead stores, potentially from decreased exposure to sunlight, lower levels of activated vitamin D, and enhanced bone resorption.