Skeletal Effects of Smoking

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.

Lower Bone Mineral Density at the Hip and Lumbar Spine in People with Psychosis Versus Controls: a Comprehensive Review and Skeletal Site-Specific Meta-analysis

It remains unclear if differences in bone mineral density (BMD) exist at different skeletal sites between people with schizophrenia and age- and sex-matched healthy controls (HCs). Major databases were searched from inception until February 2016 for studies measuring BMD using dual-energy X-ray absorptiometry (DXA) at any skeletal site in individuals with schizophrenia. Ten studies investigating 827 people with schizophrenia (55.4 % female, 33.8 ± 9.7 years) and 1379 HCs (58.7 % female, 34.7 ± 9.1 years) were included. People with schizophrenia had significantly reduced BMD at the lumbar spine (standardised mean difference adjusted for publication bias (SMD) = -0.950 (95 % CI = -1.23 to -0.66, fail-safe number = 825) and hip (SMD = -0.534, 95 % CI = -0.876 to -0.192, fail-safe number = 186). A higher proportion of hyperprolactinaemia (β = -0.0102, p < 0.0001) and smokers (β = -0.0099, p = 0.02) moderated a larger reduced BMD at the lumbar spine. Further research is required to investigate if low bone mass and fractures can be prevented in people with schizophrenia.