Interaction between current smoking, leanness, and physical inactivity in the prediction of hip fracture

The positive impact of smoking cessation on fracture risk in a nationwide cohort study

Many studies sought to demonstrate the association between smoking and fracture risk. However, the correlation between smoking and fractures remains controversial. This study aimed to examine the impact of smoking and smoking cessation on the occurrence of fractures using prospective nationwide cohort data. We enrolled those who underwent a National Health Insurance Service (NHIS) health checkup in 2009-2010 who had a previous health checkup 4-year prior (2005-2006). The study population of 4,028,559 subjects was classified into three groups (non-smoker, smoking cessation, current smoker). The study population was also analyzed according to fracture type (all fractures, vertebral fracture, hip fracture). Lastly, the smoking cessation group and current smoker group were divided into four subgroups based on a lifetime smoking amount cut-off of 20 pack-years (PY). Multivariate-adjusted hazard ratios (HRs) of fracture were examined through a Cox proportional hazards model. After multivariable adjustment, non-smokers showed the lowest risk of fracture (HR = 0.818, CI 0.807-0.828, p < 0.0001) and smoking cessation significantly lowered the risk of fracture (HR 0.938, 95% CI 0.917-0.959, p < 0.0001) compared to current smokers. Regardless of 20PY, all smoking cessation subgroups showed significantly less risk of fractures than current smokers with ≥ 20PYs. Smoking increases the risk of fracture, and smoking cessation lowers the risk of fracture.

Smoking and fracture risk in men: a meta-analysis of cohort studies, using both frequentist and Bayesian approaches

Past studies indicate that men are more likely to smoke and be at higher risk of smoking-related conditions than women. Our research aimed, through meta-analysis, to assess the association between smoking and fracture risk in men. The following databases were searched, including MEDLINE, EMBASE, Scopus, PsycINFO, ISI Web of Science, Google Scholar, WorldCat, and Open Grey, for identifying related studies. A random-effects model was used to pool the confounder-adjusted relative risk (R.R.). Frequentist and Bayesian hierarchical random-effects models were used for the analysis. The heterogeneity and publication bias were evaluated in this study. Twenty-seven studies met the inclusion criteria. Overall, smoking is associated with a significantly increased risk of fracture in both the frequentist approach (R.R., 1.37; 95% confidence interval: 1.22, 1.53) and the Bayesian approach (R.R., 1.36; 95% credible interval: 1.22, 1.54). Significant heterogeneity was observed in the meta-analysis (Higgin's I² = 83%) and Cochran's Q statistic (p < 0.01). A significant association was also observed in multiple pre-specified sensitivity and subgroup analyses. Similar results were observed in the group containing a large sample size (≥ 10,000 participants), and the group has a small sample size (< 10,000 participants); the pooled R.R was 1.23 (95% confidence interval, 1.07–1.41) and 1.56 (95% confidence interval, 1.37–1.78), respectively. With the Bayesian method, the effect size was 1.23 (95% credible interval, 1.05, 1.45) for the large sample size group and 1.57 (95% credible interval, 1.35, 1.82) for the small sample size group. Smoking is associated with a significant increase in fracture risk for men. Thus, smoking cessation would also greatly reduce fracture risk in all smokers, particularly in men.

Regular Exercise and Weight-Control Behavior Are Protective Factors against Osteoporosis for General Population: A Propensity Score-Matched Analysis from Taiwan Biobank Participants

The rising prevalence of osteoporosis, which can lead to osteoporotic fractures, increases morbidity, mortality, and socioeconomic burden. Multiple factors influencing bone mass have already been identified. The aim of this study was to investigate whether exercise habits and weight-control behaviors can lower the incidence of osteoporosis in the general population. This retrospective study recruited all participants aged 35–70 years who underwent dual-energy X-ray absorptiometry (DXA) from Taiwan Biobank (TWB). The final analysis consisted of 3320 eligible participants divided into two groups; demographic characteristics, prevalence of clinical symptoms, comorbidities, and daily behavior were collected using a self-reported questionnaire. After propensity score matching with a 1:1 ratio, 1107 out of 2214 individuals were classified into the osteoporosis group. Age, body fat rate, body shape, diabetes mellitus, and social status were found to affect the incidence of osteoporosis. Subjects with a habit of regular exercise and weight-control behavior showed decreased odds of osteoporosis. (odds ratio: 0.709 and 0.753, 95% confidence interval: 0.599–0.839 and 0.636–0.890). In the general population, regular exercise or weight-control behavior lowers the incidence of osteoporosis.

Modifiable lifestyle factors associated with fragility hip fracture: a systematic review and meta-analysis

INTRODUCTION

Among the various hip fracture predictors explored to date, modifiable risk factors warrant special consideration, since they present promising targets for preventative measures. This systematic review and meta-analysis aims to assess various modifiable risk factors.

MATERIAL AND METHODS

We searched four online databases in September 2017. We included studies that reported on modifiable lifestyle risk factors for sustaining fragility hip fractures. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS). The inclusion criteria consisted of (1) adult patients with osteoporotic hip fracture, (2) original study, (3) availability of full text articles in English, and (4) report of a modifiable lifestyle risk factor.

RESULTS

Thirty-five studies, containing 1,508,366 subjects in total, were included in this study. The modifiable risk factors that were significantly associated with an increased risk of hip fracture were the following: weight < 58 kg (128 lbs) (pooled OR 4.01, 95% CI 1.62-9.90), underweight body mass index (BMI) (< 18.5) (pooled OR 2.83, 95% CI 1.82-4.39), consumption of ≥ 3 cups of coffee daily (pooled OR 2.27, 95% CI 1.04-4.97), inactivity (pooled OR 2.14, 95% CI 1.21-3.77), weight loss (pooled OR 1.88, 95% CI 1.32-2.68), consumption of ≥ 27 g (approx. > 2 standard drinks) alcohol per day (pooled OR 1.54, 95% CI 1.12-2.13), and being a current smoker (pooled OR 1.50, 95% CI 1.22-1.85). Conversely, two factors were significantly associated with a decreased risk of hip fracture: obese BMI (> 30) (pooled OR 0.58, 95% CI 0.34-0.99) and habitual tea drinking (pooled OR 0.72, 95% CI 0.66-0.80).

CONCLUSION

Modifiable factors may be utilized clinically to provide more effective lifestyle interventions for at risk populations. We found that low weight and underweight BMI carried the highest risk, followed by high coffee consumption, inactivity, weight loss, and high daily alcohol consumption.

The impact of smoking on outcomes following anterior cervical fusion-nonfusion hybrid surgery: a retrospective single-center cohort study

BACKGROUND

There is mixed evidence for the impact of cigarette smoking on outcomes following anterior cervical surgery. It has been reported to have a negative impact on healing after multilevel anterior cervical discectomy and fusion, however, segmental mobility has been suggested to be superior in smokers who underwent one- or two-level cervical disc replacement. Hybrid surgery, including anterior cervical discectomy and fusion and cervical disc replacement, has emerged as an alternative procedure for multilevel cervical degenerative disc disease. This study aimed to examine the impact of smoking on intermediate-term outcomes following hybrid surgery.

METHODS

Radiographical and clinical outcomes of 153 patients who had undergone continuous two- or three-level hybrid surgery were followed-up to a minimum of 2-years post-operatively. The early fusion effect, 1-year fusion rate, the incidence of bone loss and heterotopic ossification, as well as the clinical outcomes were compared across three smoking status groups: (1) current smokers; (2) former smokers; (3) nonsmokers.

RESULTS

Clinical outcomes were comparable among the three groups. However, the current smoking group had a poorer early fusion effect and 1-year fusion rate (P < 0.001 and P < 0.035 respectively). Both gender and smoking status were considered as key factors for 1-year fusion rate. Upon multivariable analysis, male gender (OR = 6.664, 95% CI: 1.248-35.581, P = 0.026) and current smoking status (OR = 0.009, 95% CI: 0.020-0.411, P = 0.002) were significantly associated with 1-year fusion rate. A subgroup analysis demonstrated statistically significant differences in both early fusion process (P < 0.001) and the 1-year fusion rate (P = 0.006) across the three smoking status groups in female patients. Finally, non-smoking status appeared to be protective against bone loss (OR = 0.427, 95% CI: 0.192-0.947, P = 0.036), with these patients likely to have at least one grade lower bone loss than current smokers.

CONCLUSIONS

Smoking is associated with poor outcomes following hybrid surgery for multilevel cervical disc disease. Current smokers had the poorest fusion rate and most bone loss, but no statistically significant differences were seen in clinical outcomes across the three groups.

Quantitative CT-Based Methods for Bone Microstructural Measures and Their Relationships With Vertebral Fractures in a Pilot Study on Smokers

Osteoporosis causes fragile bone, and bone microstructural quality is a critical determinant of bone strength and fracture risk. This study pursues technical validation of novel CT-based methods for assessment of peripheral bone microstructure together with a human pilot study examining relationships between bone microstructure and vertebral fractures in smokers. To examine the accuracy and reproducibility of the methods, repeat ultra-high-resolution (UHR) CT and micro-CT scans of cadaveric ankle specimens were acquired. Thirty smokers from the University of Iowa COPDGene cohort were recruited at their 5-year follow-up visits. Chest CT scans, collected under the parent study, were used to assess vertebral fractures. UHR CT scans of distal tibia were acquired for this pilot study to obtain peripheral cortical and trabecular bone (Cb and Tb) measures. UHR CT-derived Tb measures, including volumetric bone mineral density (BMD), network area, transverse trabecular density, and mean plate width, showed high correlation (r > 0.901) with their micro-CT-derived values over small regions of interest (ROIs). Both Cb and Tb measures showed high reproducibility-intra-class correlation (ICC) was greater than 0.99 for all Tb measures except erosion index and greater than 0.97 for all Cb measures. Female sex was associated with lower transverse Tb density (p < 0.1), higher Tb spacing (p < 0.05), and lower cortical thickness (p < 0.001). Participants with vertebral fractures had significantly degenerated values (p < 0.05) for all Tb measures except thickness. There were no statistically significant differences for Cb measures between non-fracture and fracture groups. Vertebral fracture-group differences of Tb measures remained significant after adjustment with chronic obstructive pulmonary disease (COPD) status. Although current smokers at baseline had more fractures-81.8% versus 63.2% for former smokers-the difference was not statistically significant. This pilot cross-sectional human study demonstrates CT-based peripheral bone microstructural differences among smokers with and without vertebral fractures. © 2021 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Current and former smokers and hip fractures

The purpose of this review is to examine the correlation between tobacco smoking and hip fractures. The literature that was used for this article was based on studies that investigated not only the direct correlation between smoking and hip fractures but also the effect of smoking on bone mineral density. In general, the incidence of hip fracture was found to be higher in current smokers in both genders. Compared with never smokers, former smokers had a slightly higher risk of hip fracture that was inversely proportional to the cessation span. The relative risk (RR) of hip fracture in current male smokers was higher than the RR for nonsmokers (never and former smokers). In postmenopausal women former and current smoking increased the RR. In premenopausal and postmenopausal women, cessation of smoking decreases the risk of hip fracture. Risk rises with greater cigarette consumption. Risk declines among former smokers, but the benefit is not observed until 10 years after cessation.

Effect of Cigarette Smoking on Risk of Hip Fracture in Men: A Meta-Analysis of 14 Prospective Cohort Studies

BACKGROUND

Several observational studies have suggested an association between cigarette smoking and risk of hip fracture. However, no formal systematic review or meta-analysis was performed to summarize this risk in men.

MATERIALS AND METHODS

A search was applied to MEDLINE, EMBASE, and web of science (up to November 1 2016). All prospective cohort studies assessing risk of hip fracture with the factor of cigarette smoking in men without language restriction were reviewed, and qualities of all included studies were assessed using the Newcastle-Ottawa Scale. Two authors independently assessed literatures and extracted information eligibility, and any disagreement was resolved by consensus. Newcastle-Ottawa quality assessment scale was used to evaluate studies' quality in meta-analyses. We calculated the RR with 95% CIs in a random-effects model as well as the fixed-effects model using the metan command in the STATA version 12.0 (StataCorp, USA).

RESULTS

Fourteen prospective cohort studies were eligible for the present analysis. A meta-analysis of 12 prospective studies showed that the relative risk (RR) for current male smoking was 1.47 [95% confidence interval (CI) (1.28-1.66), p = 0.54; I2 = 0%]. Subgroup analyses show study characteristics (including geography region, length of follow-up, size of cohorts and study quality) did not substantially influence these positive associations. Eight studies reported the RRs for former smokers compared with never smokers and the pooled RR was 1.15 [95% CI, (0.97-1.34), (I2 = 0%, p = 0.975)].

CONCLUSIONS

The present meta-analysis of 14 prospective studies suggests that, compared with never smokers, cigarette smoking increases risk of hip fracture in man, specifically in current smokers. However, further larger prospective cohorts with more power or meta-analysis of individual patient data are needed to confirm this association.

Smoking, smoking cessation, and fracture risk in elderly women followed for 10 years

This study examines the impact of smoking and smoking cessation on fracture risk in 75-year-old women followed for 10 years. Smoking increased fracture risk, especially for vertebral fractures. Smoking cessation decreased the risk for vertebral fractures but not for other fracture types.

INTRODUCTION

The purpose of this study was to examine effects of smoking and smoking cessation on fracture risk.

METHODS

This prospective observational population-based study followed 1033 women during 10 years from age 75. Data regarding smoking were collected at age 75. Hazard ratios (HRs) and 95 % confidence intervals for fracture were calculated using competing risks proportional hazards regression.

RESULTS

Both former smokers and current smokers had an increased risk for any fracture (HR 1.30; 1.03-1.66, and HR 1.32; 1.01-1.73, respectively) and any osteoporotic fracture (hip, proximal humerus, distal radius, vertebra) (HR 1.31; 1.01-1.70 and HR 1.49; 1.11-1.98, respectively) compared to non-smokers. Former smokers had an increased risk for proximal humerus fractures (HR 2.23; 1.35-3.70), and current smokers had an increased risk for vertebral fractures (HR 2.30; 1.57-3.38) compared to non-smokers. After adjustment for weight, previous fractures, alcohol habits, bone mineral density (BMD), use of corticoids, vitamin D, bisphosphonates, and previous falls, former smokers had an increased risk for proximal humerus fracture (HR 2.07; 1.19-3.57) and current smokers had an increased risk for osteoporotic (HR 1.47; 1.05-2.05) and vertebral fractures (HR 2.50; 1.58-3.95) compared to non-smokers. Former smokers had a decreased risk for vertebral fractures, but not for other types of fractures, compared to current smokers.

CONCLUSIONS

Smoking increased the risk for fracture among elderly women, especially vertebral fractures. Smoking cessation decreased the risk for vertebral fractures but not for other types of fractures.

The relationship between weight change and risk of hip fracture: meta-analysis of prospective studies

The relationship between weight change and risk of hip fracture is still controversial. We searched PubMed and Embase for studies on weight change and risk of hip fracture. Eight prospective studies were included. The weight loss studies included 85592 participants with 1374 hip fractures, and the weight gain studies included 80768 participants with 732 hip fractures. Weight loss is more likely a risk factor of hip fracture, with an adjusted RR (Relative Risk) (95% CI) of 1.84 (1.45, 2.33). In contrast, weight gain can decrease the risk of hip fracture, with an adjusted RR (95% CI) of 0.73 (0.61, 0.89). Dose-response meta-analysis shows that the risk of hip fracture is an ascending curve, with an increase of weight loss above the line of RR = 1; this trend is consistent with the results of forest plots that examine weight loss and hip fracture. For weight gain and risk of hip fracture, the descending curve below the line of RR = 1; this trend is consistent with the results of forest plots that examine weight gain and hip fracture. Our meta-analysis suggests that weight loss may be a risk factor for hip fracture and that weight gain may be a protective factor for hip fracture.

Cigarette smoking and risk of hip fracture in women: a meta-analysis of prospective cohort studies

BACKGROUND AND OBJECTIVES

Whether cigarette smoking can increase the risk of hip fracture in women is unclear. This meta-analysis, which pooled results from 10 prospective cohort studies, was performed to derive a more precise estimation between cigarette smoking and the risk of hip fracture in women.

MATERIALS AND METHODS

Pubmed, Cochrane Central Register of Controlled Trials and ISI Web of Science were systematically searched to identify relevant studies. A meta-analysis was performed to examine the association among 10 studies. The pooled risk estimates were calculated by using both random- and fixed-effects model. Heterogeneity among articles and their publications bias were also tested. All of the statistical analyses were performed using the software programs STATA (version 12.0).

RESULTS

Relative risk was significantly increased in current female smokers (pooled RR, 1.30; 95%CI, 1.16-1.45). The association was significant among the high-dose smokers (more than 15 cigarettes per day) while not among the low-does smokers (less than 15 cigarettes per day). Omission of any single study had little effect on the pooled risk estimate. Former smokers had a similar RR of hip fracture (RR, 1.02; 95%CI, 0.93-1.11) to published papers. Smoking cessation for ≥10 years leads to a significant decline in risk.

CONCLUSIONS

Smoking is associated with an increased hip fracture risk in women. Cessation of smoking for ≥10 years had a decreased impact on risk of hip fracture. Given the inconsistency among the studies in the choice of adjustments, the associations between cigarette smoking and risk of hip fracture in women await further investigation.

Smoking and body fat mass in relation to bone mineral density and hip fracture: the Hordaland Health Study

Lower bone mineral density (BMD) in smokers may be attributable to lower body weight or fat mass, rather than to a direct effect of smoking. We analyzed the effects of smoking exposure, assessed by plasma cotinine, and body fat on BMD and the risk of subsequent hip fracture. In the community-based Hordaland Health Study (HUSK), 3003 participants 46-49 years and 2091 subjects 71-74 years were included. Cotinine was measured in plasma and information on health behaviors was obtained from self-administered questionnaires. BMD and total body soft tissue composition were measured by dual X-ray absorptiometry. Information on hip fracture was obtained from computerized records containing discharge diagnoses for hospitalizations between baseline examinations 1997-2000 through December 31st, 2009. In the whole cohort, moderate and heavy smokers had stronger positive associations between fat mass and BMD compared to never smokers (differences in regression coefficient (95% CI) per % change in fat mass = 1.38 (0.24, 2.52) and 1.29 (0.17, 2.4), respectively). In moderate and heavy smokers there was a nonlinear association between BMD and fat mass with a stronger positive association at low compared to high levels of fat mass (Davies segmented test, p<0.001). In elderly women and men, heavy smokers had an increased risk of hip fracture compared to never smokers (hazard ratio = 3.31, 95% CI: 2.05, 5.35; p<0.001). In heavy smokers there was a tendency of a lower risk of hip fracture with higher percentage of fat mass. The deleterious effect of smoking on bone health is stronger in lean smokers than in smokers with high fat mass.

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.

Clinical review. Risk factors for low bone mass-related fractures in men: a systematic review and meta-analysis

CONTEXT

Testing men at increased risk for osteoporotic fractures has been recommended.

OBJECTIVE

The aim of this study was to estimate the magnitude of association and quality of supporting evidence linking multiple risk factors with low bone mass-related fractures in men.

DATA SOURCES

We searched MEDLINE, EMBASE, Web of Science, SCOPUS and Cochrane CENTRAL through February 2010. We identified further studies by reviewing reference lists from selected studies and reviews.

STUDY SELECTION

Eligible studies had to enroll men and quantitatively evaluate the association of risk factors with low bone density-related fractures.

DATA EXTRACTION

Reviewers working independently and in duplicate determined study eligibility and extracted study description, quality, and outcome data.

DATA SYNTHESIS

Fifty-five studies provided data sufficient for meta-analysis. The quality of these observational studies was moderate with fair levels of multivariable adjustment and adequate exposure and outcome ascertainment. Statistically significant associations were established for age, low body mass index, current smoking, excessive alcohol use, chronic corticosteroid use, history of prior fractures, history of falls, history of hypogonadism, history of stroke, and history of diabetes. Statistical heterogeneity of the meta-analytic estimates of all associations was significant except for chronic corticosteroid use. None of these associations were of large magnitude (i.e. adjusted odds ratios were generally <2). No evidence supporting a particular effective testing or screening strategy was identified.

CONCLUSIONS

Multiple risk factors for fractures in men were identified, but their usefulness for stratifying and selecting men for bone density testing remains uncertain.

Fracture risk and prevention: a multidimensional approach

Although physical therapists commonly manage neuromusculoskeletal disorders and injuries, their scope of practice also includes prevention and wellness. In particular, this perspective article proposes that physical therapists are well positioned to address the client's skeletal health by incorporating fracture prevention into clinical practice with all adults. Fracture prevention consists primarily of maximizing bone strength and preventing falls. Both of these initiatives require an evidence-based, multidimensional approach that customizes interventions based on an individual's medical history, risk factors, and personal goals. The purposes of this perspective article are: (1) to review the role of exercise and nutrition in bone health and disease; (2) to introduce the use of the Fracture Risk Assessment Tool (FRAX®) into physical therapist practice; (3) to review the causes and prevention of falls; and (4) to propose a role for the physical therapist in promotion of bone health for all adult clients, ideally to help prevent fractures and their potentially devastating sequelae.

Poor trabecular microarchitecture in male current smokers: the cross-sectional STRAMBO study

Current smoking (but not past smoking) is associated with higher risk of fracture independent of areal bone mineral density (aBMD); however, the pathophysiologic mechanism underlying this association is not clear. In 810 men aged 60-87, aBMD was measured by dual-energy X-ray absorptiometry. Bone microarchitecture at the distal radius and distal tibia was assessed by high-resolution peripheral quantitative computed tomography using the Xtreme CT Scanco device. Current smokers (n = 47) had lower trabecular volumetric density (Dtrab), lower trabecular number (TbN), more heterogenous trabecular network (higher trabecular spacing standard deviation [TbSpSD]), as well as higher urinary deoxypyridinoline and higher C-reactive protein levels in comparison with 261 men who never smoked (adjusted for age, weight, height, time spent outdoors, physical activity, and intake of alcohol, caffeine, and calcium). Abnormal values (lower Dtrab and TbN, higher TbSpSD, deoxypyridinoline, and C-reactive protein) were found mainly in 21 current smokers who smoked eight or more cigarettes per day. Cortical parameters and aBMD did not differ from the never-smokers. In 502 former smokers, aBMD and all bone microarchitectural parameters did not differ from the never-smokers. At the tibia (not radius), Dtrab decreased, whereas TbSpSD slightly increased across quartiles of smoking intensity (number of pack-years). In conclusion, older men who are moderate current smokers have poor trabecular (but not cortical) microarchitecture, which is not reflected by a decrease in aBMD.

The masticatory system under varying functional load. Part 2: Effect of reduced masticatory load on the degree and distribution of mineralization in the rabbit mandible

A reduction in mechanical loading of the mandible brought about by mastication of soft food is assumed to decrease the remodelling rate of bone, which, in turn, might increase the degree of bone mineralization. The effect of a reduction in masticatory functional load on the degree and distribution of mineralization of mandibular bone was investigated in male juvenile New Zealand White rabbits. The experimental animals (n=8) had been raised on a diet of soft pellets from 8 to 20 weeks of age, while the controls (n=8) had been fed pellets of normal hardness. The degree of mineralization of bone (DMB) was assessed at the attachment sites of various jaw muscles, the condylar head, and the alveolar process. Differences between groups and among sites were tested for statistical significance using a Student's t-test and one-way analysis of variance, respectively. The DMB did not differ significantly between the experimental and control animals at any of the sites assessed. However, in the rabbits that had been fed soft pellets, both cortical bone at the attachment sites of the temporalis and digastric muscles and cortical bone in the alveolar process had a significantly higher DMB than cortical bone at the attachment site of the masseter muscle, while there were no significant differences among these sites in the control animals. The results suggest that a moderate reduction in masticatory functional load does not significantly affect the remodelling rate and the DMB in areas of the mandible that are loaded during mastication but might induce a more heterogeneous mineral distribution.

Strontium ranelate: an effective solution for diverse fracture risks

Osteoporosis is listed by the WHO among the ten most frequent and socio-economically important, chronic diseases of mankind. The term osteoporosis however comprises a number of different pathophysiological conditions and clinical situations of weakened bones with increased risk of fragility fractures. A modern anti-osteoporotic drug should provide qualified study results proving therapeutic efficacy over this broad range of daily clinical appearances of osteoporosis. The decision for treatment in the individual patients depends no longer only on bone mineral density. Today, the major criterion for decision making is the prospective 10-year risk for fractures. Since this risk is calculated on the basis of age, sex, bone mineral density, prevalent fractures, and a number of other contributing risk factors (Kanis et al., Osteoporos Int 12:989-995, 2001; Kanis et al., Osteoporos Int 19:385-397, 2008), it seems to be of interest to have a look whether the fracture-reducing potency of a drug is influenced by these risk factors. The purpose of this review is to analyze whether the fracture-reducing efficacy of strontium ranelate in patients with osteoporosis can be achieved independently of sex, etiology of osteoporosis, and the major diagnostically relevant risk factors.

OSTEOPOROSIS DIAGNOSIS AND TREATMENT

Articles that update the state of knowledge regarding osteoporosis run the risk of quickly becoming obsolete because research and studies on osteoporosis today are arousing great interest among researchers, the pharmaceutical and medical equipment industries, governments and even WHO. All orthopedists know about osteoporosis because of its most deleterious effect: osteoporotic fracture. Osteoporosis without fractures does not arouse suspicion because this is a pathological condition with a nonspecific clinical profile. Osteoporotic fractures have an economic cost (from treatment), a social cost (from its sequelae) and a medical cost (from deaths). Many fractures could be avoided through diagnosing osteoporosis prior to the first fracture and thus many temporary and permanent disabilities could be avoided and many lives saved. Awareness of the risk factors for osteoporosis raises suspicions and bone densitometry aids in diagnosis. Treatment should be based on the physiopathology of the disease. Hence, for prevention or treatment of osteoporosis, the activity of osteoclasts should be diminished or the activity of osteoblasts should be increased, or both. Treatment that reduces the incidence of fractures by improving the bone geometry and microarchitecture would be ideal. Newly formed bone tissue needs to have good cell and matrix quality, normal mineralization, a good ratio between mineralized (mechanically resistant) and non-mineralized (flexible) bone, and no accumulated damage. The ideal treatment should have a positive remodeling rate and fast and long-lasting therapeutic effects. Such effects need to be easily detectable. They need to be safe.

Male risk factors for hip fracture-a 30-year follow-up study in 7,495 men

SUMMARY

Risk factors for hip fracture were studied in 7,495 randomly selected men during 30 years; 451 men had a hip fracture. High degree of leisure-time, but not work-related, physical activity, high occupational class, and high body mass index (BMI) protected against hip fracture. Smoking, tall stature, interim stroke, and dementia increased the risk.

PURPOSE

The purpose was to prospectively study risk factors for hip fracture in men.

METHODS

We studied midlife determinants of future hip fractures in 7,495 randomly selected men aged 46-56 years in Gothenburg, Sweden. The subjects were investigated in 1970-1973 and followed for over 30 years. Questionnaires were used regarding lifestyle factors, psychological stress, occupational class, and previous myocardial infarction, stroke, and diabetes mellitus. Alcohol problems were assessed with the aid of registers. Using the Swedish hospital discharge register, data were collected on intercurrent stroke and dementia diagnoses and on first hip fractures (X-ray-verified).

RESULTS

Four hundred fifty-one men (6%) had a hip fracture. Age, tall stature, low occupational class, tobacco smoking, alcoholic intemperance, and interim stroke or dementia were independently associated with the risk of hip fracture. There were inverse associations with leisure-time physical activity, BMI, and coffee consumption. The gradient of risk for one standard deviation of multivariable risk decreased with time since measurement yet was a good alternative to dual energy X-ray absorptiometry measurements.

CONCLUSIONS

High degree of leisure-time physical activity, high occupational class, and high BMI protected against hip fracture. However, work-related physical activity was not protective. Smoking, tall stature, and interim stroke or dementia increased the risk.

Hip fractures and femoral bone mineral density in male former elite athletes

INTRODUCTION

We studied whether vigorous physical activity in young adulthood is associated with higher femoral bone density and lower risk of hip fracture at older age in men.

MATERIALS

A cohort of former male elite athletes (n=2147) and matched control subjects (n=1467) were studied for their leisure physical activity, and for fragility fractures at the hip (proximal femur) by Cox regression. Areal bone mineral densities (aBMD) at femoral neck and trochanter region were measured using dual-energy X-ray absorptiometry in a subgroup of the former athletes (n=87; median age 59 years) and in a population-based control group (n=194) and compared by general linear models.

RESULTS

After their active sporting careers, the former athletes participated in leisure physical activity more than the matched control subjects (p<0.0001). The hazard ratio (HR) of osteoporotic hip fracture adjusted for the occupational group was 0.77 (95% CI 0.45 to 1.32, p=0.34) in the athletes compared with the control subjects. The mean age at the time of the fracture event was 76.9 years (95% CI 73.2 to 78.8) for the athletes and 70.6 years (95% CI 67.1 to 72.9) for the matched control subjects (p=0.005). Adjusted for age and body mass index, aBMD at the proximal femur was significantly higher in the former athletes compared with the population-based control group (p<0.0001 for both measurement sites).

CONCLUSIONS

Osteoporotic hip fractures were sustained at a significantly older age among former athletes compared with control subjects. Clear skeletal benefits of long-term physical loading were also observed in comparative DXA measurements of aBMD.

The effects of smoking on bone health

Osteoporotic fractures are a major public health problem in most developed countries and an increasing concern in much of the developing world. This healthcare burden will increase significantly worldwide over the next 20 years due to aging of the population. Smoking is a key lifestyle risk factor for bone loss and fractures that appears to be independent of other risk factors for fracture such as age, weight, sex and menopausal status. This review discusses the effects of smoking on bone health in pre-menopausal and post-menopausal women and men. Data from twin studies and the three main published meta-analyses are presented. Possible mechanisms by which smoking affects bone mass are reviewed. Despite smoking being a major lifestyle risk factor for osteoporosis, the mechanisms underlying smoking-associated bone loss and fracture risk remain poorly understood. The effect appears dose-dependent, and may be, at least partially, reversible. However, more work is required to confirm and characterize the reversibility of smoking-associated bone defects. Finally, strategies for quitting smoking are discussed. Encouragement of lifestyle alterations, including smoking cessation, should be a major component of any bone therapeutic programme.

Leisure physical activity and the risk of fracture in men

BACKGROUND

Data from previous studies are inconsistent, and it is therefore uncertain whether, to what extent, and at what level leisure physical activity influences the risk of osteoporotic fractures in men.

METHODS AND FINDINGS

A cohort of 2,205 men, 49-51 y of age, was enrolled in a longitudinal, population-based study. Leisure physical activity and other lifestyle habits were established at baseline and at ages 60, 70, 77, and 82 y. During 35 y of follow-up, 482 men had at least one fracture. Cox's proportional hazards regression was used to determine hazard ratios (HRs) of fracture associated with time-dependent physical activity habits and covariates. Men with a sedentary lifestyle (HR 2.56, 95% confidence interval 1.55-4.24) or men who walked or bicycled only for pleasure (HR 1.61, 95% confidence interval 1.10-2.36) had an increased adjusted risk of hip fracture compared with men who participated in regular sports activities for at least 3 h/wk. At the end of follow-up, 8.4% of the men with a high physical activity, 13.3% of the men with a medium physical activity, and 20.5% of the men with a low physical activity had suffered a hip fracture. According to the estimation of population-attributable risk, one third of all hip fractures could be prevented by participation in regular sports activities. High activity also conferred a reduced overall fracture risk.

CONCLUSIONS

Our data indicate that regular sports activities can reduce the risk of fractures in older men.

Epidemiology of osteoporosis

Osteoporosis and related fractures represent a major, and growing, public health concern for the United States and worldwide. The pathogenesis of osteoporosis is complex, requiring attention to the different life phases involved in growth, maintenance, and loss of bone, in addition to non-skeletal factors associated with falls and fractures. While the current clinical definition is based upon bone density measurements, other determinants of skeletal strength, particularly bone quality, are important to identify for future areas of research and prevention efforts. This epidemiologic review describes the definition, pathogenesis, and risk factors, as well as the frequency and impact of osteoporosis, with particular emphasis upon hip fracture.

Effects of age, grip strength and smoking on forearm volumetric bone mineral density and bone geometry by peripheral quantitative computed tomography: comparisons between female and male

Peripheral quantitative computed tomography (pQCT) is useful to measure volumetric bone mineral density (vBMD) distinguishing trabecular from cortical bones as well as quantity of bone geometry. In the present study, we examined the effects of age, grip strength and smoking on vBMD, bone geometry and bone strength index (polar strength strain index (SSIp)), and then compared with the differences between female and male by employing pQCT in Japanese 252 female and 230 male subjects. Age was negatively correlated with vBMD, cortical area (Ct.Ar) and cortical thickness (Ct.Th) as well as SSIp in both sexes, and the correlation coefficients were higher in female, compared with those in male. Although age was correlated with endocortical circumferences (En.Le) in both sexes, periosteal circumferences (Ex.Le) were correlated with age only in male. Volumetric BMD, Ct.Ar, Ct.Th and SSIp were significantly lower in the group with vertebral fractures, although En.Le and Ex.Le were similar between subjects with and without vertebral fractures. Grip strength was positively correlated with vBMD, Ct.Ar, Ct.Th as well as SSIp. The extent of correlation was much higher in female, compared with that in male. Ct.vBMD, Ct.Ar, Ct.Th and SSIp, but not trabecular vBMD, were significantly lower in the group with high Brinkman index (number of cigarettes smoked per day) x (duration of smoking (years)) in female. These parameters were not significantly different between groups with high and low Brinkman index in male. In conclusion, the present study demonstrated that age, grip strength and smoking affected forearm vBMD, bone geometry and bone strength index by pQCT. These effects were greater in female, compared with those in male.

Quantitative ultrasound: use in screening for susceptibility to stress fractures in female army recruits

QUS measurements were made on 4139 female Army recruits at the beginning of basic training (BT). QUS predicted stress fracture in female recruits as well as it predicts hip fracture in elderly women. Recruits with low QUS values and a history of smoking and not exercising had an extremely high risk of stress fracture.

INTRODUCTION

Stress fractures during basic military training (BT) cause morbidity for the recruits and expense for the Military Services. Females have a higher incidence than males. If recruits at high risk for stress fracture could be accurately identified before they began BT, the military might find it advantageous to provide adaptive training programs for them. Currently no accurate methods of risk identification are available. We measured quantitative ultrasound (QUS) in a population sample of female Army recruits to determine if QUS is a useful tool for determining soldiers at high risk of stress fracture during BT.

MATERIALS AND METHODS

We recruited 93% of the population of female recruits entering BT at Fort Leonard Wood, MO, during a 10-month period. We measured calcaneal QUS and administered a risk factor questionnaire at baseline and ascertained stress fractures during the 8 weeks of BT. Logistic regression was used to calculate relative risk (RR) of stress fracture. The area under the receiver-operating characteristic (ROC) curve was also analyzed to determine the sensitivity and specificity of speed of sound (SOS) in predicting stress fracture.

RESULTS

The incidence of stress fracture was 4.7%. SOS was significantly related to the risk of stress fracture. (p < 0.000) The area under the ROC curve was 0.70. The relative risk (RR) of fracture of those in the lowest quintile (Q1) of SOS was 6.7. The highest risk of stress fracture was found in the subgroup of white women in Q1 of SOS who smoked and didn't exercise (RR, 14.4). Over 16% of the fractures occurred in this subgroup, which indicates that about six of these women would need to be assigned to an alternate BT regimen to prevent one stress fracture.

CONCLUSIONS

The combination of QUS measurements with evaluation of individual risk factors can identify recruits who are at the very highest risk of stress fracture. The military may find these data helpful to determine the cost-effectiveness of alternate BT regimens.

Simple Computer Model for Calculating and Reporting 5-Year Osteoporotic Fracture Risk in Postmenopausal Women

PURPOSE

To devise, validate, and test a software model that improves how clinicians calculate individual risk for osteoporotic fracture and expected treatment benefit.

METHODS

We developed a simple model of seven easily ascertained items plus bone mineral density (BMD) that calculates absolute fracture risk and expected absolute risk reduction after treatment. Baseline clinical variables and longitudinal fracture data from two large osteoporosis cohort studies validated the model's accuracy in predicting fracture risk. We then surveyed 298 clinicians to evaluate the likelihood they would prescribe alendronate in three hypothetical cases, first given the clinical data alone and then with model-derived data on fracture risk and expected treatment benefit.

RESULTS

We found a strong linear relationship with the model's predicted fracture risk and observed fracture rates in two large observational cohorts but the model overestimated risk 2-3 fold. The model predicted a 1:200 5-year risk for spinal fracture and a 1:40 risk for nonspinal fracture in an index case of a younger, thin, osteopenic woman. Given this hypothetical history with BMD t-scores, 26% of clinicians were likely to prescribe alendronate; when also given model-calculated 5-year fracture risks with or without treatment, only 13% were likely to prescribe alendronate (p < 0.001). For 2 other osteoporosis patients in whom risk was much higher, further information on fracture risk and expected treatment benefit did not alter prescribing.

CONCLUSIONS

Reporting absolute fracture risk with and without treatment promises to be most useful in women with osteopenia, a common clinical dilemma in younger postmenopausal women.

Effect of different masticatory functional and mechanical demands on the structural adaptation of the mandibular alveolar bone in young growing rats

The influence of masticatory functional and mechanical demands on the structural adaptation of the alveolar bone has not been investigated in both animals and humans. The effect of two experimental factors, the insertion of a bite-opening appliance and the alteration of food consistency, was investigated in young growing rats, with a particular emphasis on three-dimensional (3D) bone microstructure. Thirty-six male albino rats were divided into two equal groups, fed with either the standard hard diet or soft diet, at the age of 4 weeks. After 2 weeks, half of the animals in both groups had their upper molars fitted with an upper posterior bite block, an appliance similar to those used in clinical orthodontics. The remaining animals served as a control. After another 4 weeks, the animals were sacrificed, and their left hemimandibles were excised. Bone mineral density (BMD) and bone microstructure parameters of the alveolar process were subsequently measured, using dual-energy X-ray absorptiometry (DXA) and micro-computed tomography (micro-CT). The alveolar process width was also measured. Both experimental factors led to significant shape and structure modification of the mandibular alveolar bone in the growing rat. The bite block applied a continuous light force, which was associated with an inhibition of alveolar process vertical growth and a significant increase of cortical thickness. Soft diet and the consequent reduction of the intermittent forces applied to the alveolar bone during mastication resulted in a reduction of bone mineral density, accompanied by decreased trabecular bone volume and thickness. This rat model could prove to be a useful tool for the in vivo investigation of the role of muscular forces on the shape and structure adaptation of bone.

Vitamin D deficiency, bone mineral density and weight in patients with advanced pulmonary disease

OBJECTIVE

To study the influence of underweight, body composition and vitamin D deficiency on bone mineral density in patients with advanced pulmonary disease.

DESIGN

Cross-sectional study with time span for inclusion set at 5 years.

SETTING

The clinical work and biochemical analyses were carried out at Rikshospitalet University Hospital, Norway. Analyses for vitamin D metabolites and bone markers were carried out at Aker University Hospital, and bone measurements at Clinic of Osteoporosis.

SUBJECTS

Seventy-one candidates for lung transplantation (63% chronic obstructive pulmonary disease, 42 underweight and 29 normal weight) were included.

MAIN OUTCOME MEASURES

Body composition, bone mineral density at lumbar spine and femur neck, serum concentration of calcidiol and vitamin D intake.

RESULTS

Subnormal calcidiol levels were present in 52% of the underweight patients and 69% of the normal-weight patients. The resulting models of linear regression showed that for the lumbar spine T scores model, the total variation of 16.7% was explained by group (underweight/normal weight), sex and age. For the femur neck T scores model, the total variation of 20.4% was explained by the interaction of underweight and vitamin D deficiency (with borderline significance) and by arm muscle circumference percentage of standard. In patients with normal calcidiol levels, the median intake of vitamin D was 17 microg in the underweight patients and 11 microg in the normal-weight patients.

CONCLUSIONS

Vitamin D deficiency was common in both underweight and normal-weight patients, but only in the underweight patients, an association between vitamin D deficiency and reduced femur neck T scores was indicated.

Fracture risk associated with smoking: a meta-analysis

OBJECTIVES

To assess fracture risk associated with smoking.

DESIGN

Systematic review.

DATA SOURCES

Cohort, case-control, and cross-sectional studies identified by searching PubMed and EMBASE, and by recursive screening of reference lists.

SUBJECTS

Fifty studies including 512 399 subjects were included.

MAIN OUTCOME MEASURE

Fracture occurrence in current, previous, and never smokers.

RESULTS

Fracture risk was significantly increased in current smokers for all fracture types combined (pooled relative risk 1.26, 95% CI 1.12-1.42) and for hip (1.39, 95% CI 1.23-1.58) and spine fractures (1.76, 95% CI 1.10-2.82), but not for wrist fractures (0.86, 95% CI 0.46-1.60). In previous smokers the estimate was significantly lower for as well all types of fractures (1.02, 95% CI 0.85-1.22, P = 0.03 compared with current smokers), as for hip fractures (1.19, 95% CI 1.06-1.34, P = 0.04). There was a trend towards higher risk estimates in previous smokers for hip fractures in case-control studies than in cohort studies. A similar difference between case-control and cohort studies was not present for current smokers. There was a geographical heterogeneity: the risk of hip fractures associated with current smoking increased with latitude, i.e. the risk was higher in Northern Europe and the USA than in Southern Europe and countries close to the equator.

CONCLUSIONS

Smoking is associated with an increased overall fracture risk, an increased risk of hip and spine but not wrist fractures. Cessation of smoking seems associated with a decrease in fracture risk. The impact of smoking varied geographically with an increase with latitude.

Factors related to occurrence of hip fracture during a fall on the hip

Recently, it has been shown that hip fractures can be effectively prevented by use of hip protectors. To determine who would gain most benefit from use of hip protectors, we conducted a study with the aim to clarify factors that contribute to the occurrence of fracture in individuals who fall on their hip. Hip fracture patients were compared with individuals who had fallen on their hip without sustaining a fracture. The study group consisted of 123 consecutive hip fracture patients aged 70 years or over (mean age 82 years, female 82 years and male 80 years). The control group comprised 132 individuals (mean age 81 years, female 81 years and male 80 years) obtained from a prospective study on falls, who had experienced a fall that caused a visible soft tissue injury (bruise or wound) at the hip or gluteal region without sustaining a fracture. Patients were questioned about associated diseases, medications, place of residence, walking ability, need for locomotor aids and some activities in daily living (ADL). Patients who sustained a hip fracture were more likely to be women, living in long-term institutional care, using neuroleptics, dependent in ADL and had more history of previous stroke with hemiparesis, more Parkinsonism and lower body mass indexes (BMI) than those who did not sustain a fracture on fall on the hip. According to a logistical regression model, institutional residence, low BMI and history of stroke with hemiplegic status differed between fracture cases and controls. Institutional residence, low BMI and history of hemiplegic stroke discriminate hip fracture patients from fallers who sustain a soft tissue injury on the hip region. In clinical practice, patients who have these characteristics would be potential candidates to use hip protectors and other preventive measures.

Evaluating and managing osteoporosis in men

Osteoporosis affects approximately 10 million Americans; of these, 2 million are men. An estimated 3.5 million additional men are at risk of developing the disease. Individuals with osteoporosis commonly incur fractures of the spine, hip, and forearm. The clinical spectrum of osteoporosis is similar in men and women; however, differences exist in skeletal development, age-related bone loss, modifiable and nonmodifiable risk factors, and secondary causes. Prevention and early detection is achieved through identification of risk factors and secondary causes. Treatment options include risk factor reduction, correction of underlying disease, and use of pharmacologic and nonpharmacologic therapies.

Determination of bone mineral density of the hip and spine in human pedigrees by genetic and life-style factors

In 40 human pedigrees with 563 subjects, we evaluated the contribution of genetic and life-style factors (exercise, smoking, and alcohol consumption) and the interactions between non-genetic factors in determining bone mineral density (BMD) of the hip and spine. In our analysis, we adjusted for age, weight, height, menopausal status in females, life-style factors, and the significant interactions among these factors. For the spine and hip BMD, heritabilities (h(2)) (+/- SE) were, respectively, 0.68 (0.21) and 0.86 (0.28) in males and 0.64 (0.13) and 0.67 (0.14) in females. Exercise had significant beneficial effects for male spine BMD and female hip BMD. Alcohol consumption experienced in our sample had significant beneficial effects on hip BMD in both sexes. Although the main effect of smoking was not significant, there were significant interaction effects between smoking and other important factors (e.g., exercise, weight, alcohol consumption). For example, for female spine BMD, exercise had significant beneficial effects in smokers; however, its effect in non-smokers was non-significant. This result indicates that exercise may reduce deleterious effects of smoking (if any) on BMD, but may have minor effects in increasing BMD in non-smokers. The various interaction effects among risk factors explicitly revealed here for the first time indicate that the detailed effects and direction of individual risk factors may depend on the presence and magnitude of other factors. Weight invariably affected BMD of the hip and spine in both sexes. Age effects were significant for hip BMD, but not for male spine BMD.

Smoking and bone metabolism in elderly women

Cigarette smoking has been implicated as a risk factor for osteoporosis. In the present study, the relationship between smoking and bone mineral density, calcitropic hormones, calcium absorption, and biochemical indices related to bone and mineral metabolism was examined at baseline, in subjects recruited for an osteoporotic study. The subjects included 489 elderly women, aged 65-77 years. After exclusions (thiazide users), 54 women constituted the smoking group and 390 women were classified as nonsmokers. The effect of frequency of smoking was also examined in this population (33 light smokers [<1 pack/day] and 21 heavy smokers [>1 pack/day]). Adjusted mean total body bone mineral density was 4% lower (0.968 +/- 0.019 vs. 1.009 +/- 0.004) and the total hip density was 6% lower (0.778 +/- 0.024 vs. 0.826 +/- 0.006) in heavy smokers compared with nonsmokers. At the other sites measured (spine, midradius, femoral neck, trochanter, and Ward's triangle), a similar nonsignificant trend was observed. The adjusted mean calcium absorption corrected for weight was lower (13%) both in light and heavy smokers compared with nonsmokers, and serum 25-hydroxyvitamin D was significantly lower (16%) in heavy smokers than nonsmokers. Serum parathryroid hormone (PTH) was higher in heavy smokers, but was not significantly different from that of nonsmokers. A significant increase in bone remodeling markers, serum osteocalcin (4.35 +/- 0.271 vs. 3.79 +/- 0. 066) and urine N-telopeptide/creatinine (NTx/Cr) ratio (74.5 +/- 5. 75 vs. 49.8 +/- 1.4) was seen in heavy smokers compared with nonsmokers. These results suggest that smoking lowers bone mineral density, and is a result of decreased calcium absorption associated with secondary hyperparathyroidism and increased bone resorption.

Cigarette smoking and exercise-related injuries among young men and women

BACKGROUND

We evaluate whether a recent history of cigarette smoking is a risk factor for exercise-related injuries sustained during Army basic training, controlling for factors such as demographic, physical fitness, and health variables.

METHODS

We conducted an observational cohort study in 1087 male and 915 female Army recruits undergoing 8-week basic military training. Data were collected from questionnaires, anthropometric measurements, physical fitness tests, company training logs, and medical records of all clinic visits.

RESULTS

During the 8-week training period, 33% of men and 50% of women had at least one clinic visit for injury, including 14% of men and 25% of women who lost more than 5 days of training due to injury. Recruits who reported smoking at least one cigarette in the month prior to beginning basic training (which was conducted in a smoke-free environment) had significantly higher injury rates during training than those who did not report smoking (40% versus 29% for men, and 56% versus 46% for women). The relationship with smoking history was present most strongly for overuse injuries (32% versus 24% in men and 51% versus 40% in women). Multiple logistic regression analyses controlling for all other factors consistently showed adjusted odds ratios of about 1.5 for injury rate in those with a history of smoking compared to those without.

CONCLUSIONS

The association of history of cigarette smoking with injury occurrence was consistent throughout the analyses, with very little confounding by other factors. The detrimental effects of smoking on injuries appears to persist at least several weeks after cessation of smoking.

Premenopausal smoking and bone density in 2015 perimenopausal women

The importance of cigarette smoking in relation to bone mass remains uncertain, especially in younger women. In a recent meta-analysis including 10 studies in premenopausal women no effect was seen in this age group. We used baseline data from a large national cohort study (Danish Osteoporosis Prevention Study [DOPS]) to study the cumulated effect of pre- and perimenopausal smoking on bone mineral density (BMD) measured shortly after the cessation of cyclic bleedings. Baseline observations on 2015 recently menopausal women were available. Eight hundred thirty-two women were current smokers and 285 were exsmokers. Significant negative associations of cigarette smoking coded as current, ex-, or never smoking were seen on bone mass in the lumbar spine (P = 0.012), femoral neck (P<0.001), and total body (P<0.001). Quantitatively, the differences between current smokers and never smokers were limited to 1.6, 2.9, and 1.9%, respectively. A statistical interaction was found between smoking and fat mass, indicating that women in the highest tertile of fat mass were unaffected by cigarette smoking. Serum vitamin D levels and osteocalcin were inversely related to the number of cigarettes smoked per day (r = 0.11 and P<0.001; r = 0.17 and P = 0.04), respectively. Bone alkaline phosphatase (BALP) and urinary hydroxyproline (U-OHP) were unaffected by current smoking. The average cumulated effect of premenopausal smoking on bone is small but biologically significant. Reduced body mass in smokers explains part of the negative effect on the skeleton and a complex interaction between smoking and fat mass on the skeleton is indicated. Serum levels of 25-hydroxyvitamin D (25-OHD) and osteocalcin are lower in smokers, which may effect rate of bone loss.

Tobacco smoking and risk of hip fracture in men and women

BACKGROUND

Previous findings suggest that tobacco smoking increases the risk of hip fracture in women. A similar adverse effect of smoking is suspected to be present in men, but bone mineral density studies have raised the concern that men may be more sensitive to the deleterious effect of smoking on bone than women. In this study we prospectively determined the influence of current, previous, and cumulative smoking history on risk of hip fracture in men and women and addressed the issue of possible gender difference in the susceptibility to tobacco smoking.

METHODS

Pooled data from three population studies conducted in Copenhagen with detailed information on smoking habit. A total of 13,393 women and 17,379 men, initially examined between 1964 and 1992, were followed until 1997 for first admission due to hip fracture. The relative risks (RR) of hip fracture associated with smoking were estimated by means of multiplicative Poisson regression models.

RESULTS

During follow-up, 722 hip fractures were identified in women, and 447 in men. After adjustment for potential confounders, including body mass index, female current smokers had an RR of hip fracture of 1.36 (95% CI: 1.12-1.65) and male smokers 1.59 (95% CI: 1.04-2.43) relative to never smokers. In both sexes, the RR of hip fracture gradually increased by current and accumulated tobacco consumption. The RR were consistently higher in men than in women, but the test for interaction between sex and tobacco smoking was insignificant. After 5 years, male ex-smokers had an adjusted RR of 0.73 (95% CI: 0.55-0.98) relative to current smokers, while no significant decrease in risk was observed in female ex-smokers (RR = 0.91; 95% CI: 0.72-1.17)). Approximately 19% of all hip fractures in the present study population were attributable to tobacco smoking.

CONCLUSION

Tobacco smoking is an independent risk factor for hip fracture in men and women, and there appears to be no gender differences in smoking related risk. Smoking cessation reduces the risk of hip fracture in men after 5 years, while the deleterious effect of smoking seems to be more long-lasting in female ex-smokers.

Risk factors for low bone mineral density among a large group of Norwegian women with fractures

The objectives of this study were to determine factors related to fractures and bone mineral density (BMD) in a large group of Norwegian women. In a cross-sectional study, 3803 women aged 50-75, all with a history of fractures, were included in the study. BMD was measured with Dual energy X-ray absorptiometry at both hip (neck) and spine (L1-L4), while information on other factors thought to influence BMD were obtained through a questionnaire. In multivariate analysis, the strongest positive predictor of both hip and spine BMD was current body weight, while weight loss since the age of 25 and number of years since menopause were the strongest inverse predictors. In addition, use of cortisone and maternal history of fractures were associated with lower BMD, as was loss of height since the age of 25. Physical activity was positively correlated with BMD. These results show the complexity of factors involved in the etiology of osteoporosis, with several factors acting in synergism. This points to the need for multifactorial prevention strategies, which most effectively need to be instituted at an early age, before peak bone mass is achieved.

Assessment of the aging man

Knowledge of the aging process and the care of older patients has been increasing at a rapid pace. It is important to recognize and separate disease from the physiologic aging process. It is important to do appropriate comprehensive assessments in aging men, so that problems may be identified early and interventions instituted at the right time to delay physical decline, maintain independent living, and ultimately improve the quality of life of this part of the population.

A cross-sectional study of smoking and bone mineral density in premenopausal parous women: effect of body mass index, breastfeeding, and sports participation

The objective of this cross-sectional study was to describe the relationship between cigarette smoking, effect modifiers, and bone density in premenopausal parous women. We studied a sample of 276 women (mean age 33 years) from Southern Tasmania. The study factors were cigarette smoking, body mass index (BMI), sports participation, and breastfeeding history. Bone mineral density was measured utilizing an Hologic QDR 2000 densitometer and converted to Z scores using the group mean and variance. There were 118 current smokers and 158 nonsmokers. Smokers had lower bone mass at all sites (femoral neck, -0.32 SD, 95% confidence interval [CI] -0.60 to -0. 04; lumbar spine, -0.49 SD, 95% CI -0.76 to -0.22; total body, -0.40 SD, 95% CI -0.66 to -0.14). Stratifying by BMI revealed that this association was only present, but greater in magnitude, for those with a BMI <25 kg/m2. Smokers who had breastfed at least one child had an additional deficit in bone mass (femoral neck, -0.48 SD, 95% CI -0.89 to -0.07; lumbar spine, -0.39 SD, 95% CI -0.80 to 0.02; total body, -0.37 SD, 95% CI -0.77 to 0.06) while smokers who took part in competitive sport had significant increments in bone mass (femoral neck, 0.74 SD, 95% CI 0.31 to 1.17; lumbar spine, 0.48 SD, 95% CI 0.03 to 0.93; total body, 0.42 SD, 95% CI 0.00 to 0.84). Neither of these two associations were present in nonsmokers. In conclusion, current smoking was associated with substantial deficits in bone mass in our sample of women, particularly those with a BMI <25 kg/m2. In addition, smoking may prevent the usual postweaning recovery phase of bone after breastfeeding while sports participation may offset the negative effect of smoking on bone mass. These observations need to be confirmed in longitudinal studies but they imply that past studies of smoking in this age group may have missed important associations as they did not consider possible effect modifiers.

Mental distress and risk of hip fracture. Do broken hearts lead to broken bones?

OBJECTIVE

Mental distress may entail increased risk of hip fracture, but it is uncertain whether the effect consists solely of an indirect effect through use of medication, or whether it is also mediated through other mechanism. The purpose of this study was to examine the association between mental distress and risk of hip fracture in women, adjusted for medication (that is, use of tranquillisers/sedatives or hypnotics).

DESIGN

A three year follow up of hip fracture was conducted on 18,612 women, consisting of 92.5% of all women aged 50 years or older in a Norwegian county. Three hundred and twenty nine suffered a hip fracture. A mental distress index was based on questions about life dissatisfaction, nervousness, loneliness, sleep disorders, troubled and uneasy feelings, depression and impairment attributable to psychological complaints. Relative risk with 95% confidence intervals (CI) of hip fracture with respect to mental distress were controlled for medication, age, body mass index (BMI), smoking, physical inactivity, and physical illness by means of Cox regression.

RESULTS

The 10% of women with the highest mental distress had more than twofold increased risk of hip fracture compared with the 10% of women with the lowest mental distress, after adjustment for age and medication. The relative risk was 1.95 (95% CI 1.2, 3.3) after additional control for BMI, smoking, physical inactivity, and physical illness. The relative risk of hip fracture for daily users of medication compared with never users was 2.1 (95% CI 1.6, 2.9). After adjusting for mental distress it was 1.5 (95% CI 1.0, 2.2).

CONCLUSIONS

Risk of hip fracture was positively related to mental distress, also after adjustment for medication use. The effect of tranquillisers/sedatives or hypnotics on hip fracture risk may be overestimated in studies with no adjustments for mental distress.

Smoking, smoking cessation, and risk of hip fracture in women

PURPOSE

To examine the effects of cigarette smoking and smoking cessation on the risk of hip fracture in women.

PATIENTS AND METHODS

We studied 116,229 female nurses, 34 to 59 years of age at baseline in 1980, who were followed for up to 12 years. Smoking habits and the occurrence of incident hip fractures (n = 377) due to low or moderate trauma were self-reported on biennial mailed questionnaires.

RESULTS

Compared with women who had never smoked, the age-adjusted relative risk (RR) of hip fracture among current smokers was 1.3 (95% confidence interval [CI] 1.0 to 1.7). The risk of hip fracture increased linearly (P = 0.09) with greater cigarette consumption (RR = 1.6, 95% CI 1.1 to 2.3 for 25 or more cigarettes per day). These associations were somewhat reduced by adjusting for other risk factors for osteoporosis (menopausal status, use of postmenopausal estrogen, physical activity, and intakes of calcium, alcohol, and caffeine): RR = 1.2, 95% CI 0.8 to 1.3 for all current smokers; RR = 1.4, 95% CI 0.9 to 2.1 for 25 or more cigarettes per day. Relative risks were further reduced when body mass index was added to the model. There was no apparent benefit from quitting smoking until 10 years after cessation. After 10 years, former smokers had a reduced risk of hip fracture (adjusted RR = 0.7, 95% CI 0.5 to 0.9) compared with current smokers.

CONCLUSION

Smokers are at increased risk of hip fracture and their risk rises with greater cigarette consumption. Risk declines among former smokers, but the benefit is not observed until 10 years after cessation. Both the increased risk among current smokers and the decline in risk after smoking cessation are in part accounted for by differences in body weight.

Smoking increases bone loss and decreases intestinal calcium absorption

Cigarette use is a risk factor for increased bone mineral density (BMD) loss but the mechanisms are not well understood. The relationship of smoking to rates of BMD change at the femoral neck, spine, and total body, and to intestinal calcium absorption were examined in 402 elderly men and women (32 smokers, 370 nonsmokers) who participated in a 3-year placebo-controlled study of calcium and vitamin D supplementation. Subjects in the supplemented group took 500 mg/day of elemental calcium and 700 IU/day of cholecalciferol. Two-hour calcium absorption fraction was determined three times, at 18, 30, and 36 months, with a single isotope method utilizing 45Ca in a subset of 333 subjects. Annualized rates of BMD loss (adjusted for baseline BMD, weight, age, gender, supplementation status, and dietary calcium intake) were higher in smokers than nonsmokers at the femoral neck (-0.714 +/- 0.285 %/year vs. +0.038 +/- 0.084 %/year, p < 0.02), and total body (-0.360 +/- 0.101 %/year vs. -0. 152 +/- 0.030 %/year, p < 0.05). No significant difference was observed at the spine (+0.260 +/- 0.252 %/year in smokers vs. +0.593 +/- 0.074 %/year in nonsmokers, p = 0.21). The mean (+/- SEM) calcium absorption fraction was lower in smokers (12.9 +/- 0.8%, n = 23) than nonsmokers (14.6 +/- 0.2%, n = 310, p < 0.05) after adjustment for gender, age, supplementation status, and dietary calcium and vitamin D intakes. Smokers of at least 20 cigarettes per day (n = 15) had the lowest mean absorption fraction (12.1 +/- 1.1%). With calcium and vitamin D supplementation, the proportionate increase in urinary calcium/creatinine excretion was lower in smokers (44 +/- 12%) than nonsmokers (79 +/- 9%, p < 0.05). These results suggest that smoking accelerates bone loss from the femoral neck and total body in the elderly and that less efficient calcium absorption may be one contributing factor.

Ex-smokers and risk of hip fracture

OBJECTIVES

The purpose of this study was to examine the reversibility of the effect of smoking on hip fracture incidence rates.

METHODS

A 3-year follow-up cohort study was conducted involving 35,767 adults 50 years of age or older. Of these individuals, 421 suffered a hip fracture.

RESULTS

Among participants less than 75 years of age, the relative risk (RR) of hip fracture was elevated for ex-smokers, even for those who had quit smoking more than 5 years previously (men: RR = 4.4, 95% confidence interval [CI] = 1.2, 15.3; women: RR = 1.3, 95% CI = 0.6, 3.0), but was not as high as that for current smokers (men: RR = 5.0, 95% CI = 1.5, 16.9; women: RR = 1.9, 95% CI = 1.2, 3.1).

CONCLUSIONS

The effect of smoking on risk of hip fracture was not reversed completely 5 years after smoking cessation.

The Tromsø Study: physical activity and the incidence of fractures in a middle-aged population

We have studied the relation of occupational and recreational physical activity to fractures at different locations. All men born between 1925 and 1959 and all women born between 1930 and 1959 in the city of Tromsø were invited to participate in surveys in 1979-1980 and 1986-1987 (The Tromsø Study). Of 16,676 invited persons, 12,270 (73.6%) attended both surveys. All nonvertebral fractures (n = 1435) sustained from 1988 to 1995 were registered in the only hospital in the area. Average age in the middle of the follow-up period (December 31, 1991) was 47.3 years among men and 4501 years among women, ranging from 32 to 66 years. Fracture incidence increased with age at all locations among women, but it decreased with or was independent of age among men. Low-energetic fractures constituted 74.4% of all fractures among women and 55.2% among men. When stratifying by fracture location, the most physically active persons among those 45 years or older suffered fewer fractures in the weight-bearing skeleton (relative risk [RR] 0.6, confidence interval [CI] 0.4-0.9, age-adjusted), but not in the non-weight-bearing skeleton (RR 1.0, CI 0.7-1.2, age-adjusted) compared with sedentary persons. The relative-risk of a low-energetic fracture in the weight-bearing skeleton among the most physically active middle-aged was 0.3 (CI 0.1-0.7) among men and 0.9 (CI 0.4-1.8) among women compared with the sedentary when adjusted for age, body mass index, body height, tobacco smoking, and alcohol and milk consumption. It seems that the beneficial effect on the skeleton of weight-bearing activity is reflected also in the incidence of fractures at different sites.

Risk factors for hip fracture in white men: the NHANES I Epidemiologic Follow-up Study

This prospective population-based study assessed predictors of hip fracture risk in white men. Participants were members of the Epidemiologic Follow-up Study cohort of the First National Health and Nutrition Examination Survey, a nationally representative sample of noninstitutionalized civilians who were followed for a maximum of 22 years. A cohort of 2879 white men (2249 in the nutrition and weight-loss subsample, 1437 in the bone density subsample) aged 45-74 years at baseline (1971-1975) were observed through 1992. Ninety-four percent of the original cohort were successfully traced. Hospital records and death certificates were used to identify a total of 71 hip fracture cases (61 in the nutrition and weight-loss subsample, 26 in the bone-density subsample). Among the factors evaluated were age at baseline, previous fractures other than hip, body mass index, smoking status, alcohol consumption, nonrecreational physical activity, weight loss from maximum, calcium intake, number of calories, protein consumption, chronic disease prevalence, and phalangeal bone density. The risk adjusted relative risk (RR) of hip fracture was significantly associated with presence of one or more chronic conditions (RR = 1.91, 95% confidence interval [CI] = 1.19-3.06), weight loss from maximum > or = 10% (RR = 2.27, 95% CI 1.13-4.59), and 1 SD change in phalangeal bone density (RR = 1.73, 95% CI 1.11-2.68). No other variables were significantly related to hip fracture risk. Although based on a small number of cases, this is one of the first prospective studies to relate weight loss and bone density to hip fracture risk in men.