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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

The effect of physical exercise on bone density in middle-aged and older men: a systematic review

KA Bolam, JG van Uffelen, and DR Taaffe.

Review published: 2013.

CRD summary

This review concluded that regular resistance training and impact-loading activities were safe and may be effective as a preventative strategy against osteoporosis in middle-aged and older men despite the lack of conclusive results from most of the included studies. It was not clear that the conclusions were justified due to the limited amount of moderate quality data.

Authors' objectives

To systematically review the effects of weight-bearing and resistance-based exercise on the hip and lumbar spine bone mineral density of middle-aged and older men.

Searching

PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), PEDro and SPORTDiscus were searched to August 2012. Search terms were reported. Study design limitations were placed on the PubMed search. No language restrictions were applied. Only full-text articles were considered for inclusion.

Study selection

Randomised controlled trials (RCTs) or controlled trials with a population of men aged 45 years or older where the impact of resistance training, impact loading or weight-bearing aerobic exercise was assessed were eligible for inclusion. The primary outcome was bone mineral density measured using dual X-ray absorptiometry (g/cm²) in the lumbar spine, Ward's triangle or the hip and associated areas.

Study participants were primarily middle-aged and older men (50 to 79 years) who were not drawn from clinical populations; one study included heart transplant patients receiving glucocorticoids. Interventions included walking, resistance training, walking plus resistance training, resistance training plus impact-loading activities and resistance training plus Tai Chi. Most programmes prescribed three sessions per week (range two to five per week). Intensities varied considerably. Half of the programmes were supervised. Control conditions varied from being told to exercise as they pleased through to being told to walk for 30 minutes per day (this information was poorly reported by the original studies). Trial duration and follow-up ranged from three to 48 months.

Three reviewers independently assessed articles for inclusion. Any disagreements were discussed to consensus.

Assessment of study quality

Methodological quality was assessed using a validated scale (Delphi Checklist) by two reviewers working independently. Seven of the original nine items were considered (blinding of trainers and participants was not considered relevant). Each item was rated as yes/no/unclear and a percentage summary score was calculated.

Data extraction

Intervention programmes were classified as weight-bearing aerobic, strength training, impact-loading exercise or a combination according to an exercise physiologist.

Data were extracted by two reviewers working independently.

Methods of synthesis

Trial results were presented in tables and a narrative synthesis; between-group differences were reported where possible.

Results of the review

Nine articles on eight original interventions (649 participants, range 11 to 147) were included; six were RCTs and the others were controlled trials. Methodological quality scores ranged from 29% to 100% and three of the eight studies scored better than 50%. Two RCTs did not conceal randomisation; common methodological flaws included lack of reporting of point estimates, lack of blinding the outcome assessor and lack of an intention-to-treat analysis.

Bone mass density was significantly increased in most of the resistance training interventions. Only one trial (90 participants) reported a significant difference in favour of exercise compared with the control for bone mass density of the femoral neck. Although not statistically significant, exercise groups in seven out of the eight trials lost less bone mass density than the control groups.

Drop-out rates and attendance were reported in four of the eight trials. Where reported the average rate of drop-out was 3.3% (6.8% for exercise and 2.1% for control groups).

Two studies reported on adverse events and withdrawals. No serious or adverse events were reported but one study reported exacerbations of existing injuries in seven participants and three inguinal hernias were documented. Reasons for withdrawal from the other study were diverse and it was unclear whether they were related to the programme.

Authors' conclusions

Regular resistance training and impact-loading activities were most effective and should be considered as a strategy to prevent osteoporosis in middle-aged and older men. The interventions were considered likely to be safe. High quality RCTs were needed to confirm the optimal exercise prescription.

CRD commentary

The review addressed a clear question and covered a range of databases using a reasonable search strategy. Lack of attention to unpublished studies may have missed some relevant data. The review processes were clearly reported and conducted according to best practice for minimising reviewer error and bias.

The included studies were quality assessed and details were provided. As the authors noted, the quality assessment highlighted several flaws in the few small studies that were included. The narrative synthesis was brief and provided relatively little detail on the results; data tables were provided. It was not clear why a statistical synthesis was not considered.

The authors' conclusions suggested the interventions were safe (although only two trials reported any adverse event data) and may be effective as a preventative strategy against osteoporosis in middle-aged and older men (despite the lack of conclusive results from most of the included studies). It was not clear that the conclusions were justified on the basis of the limited amount of moderate quality data.

Implications of the review for practice and research

Practice: The authors recommended that regular resistance training and impact-loading activities should be considered as a strategy to prevent osteoporosis in middle-aged and older men.

Research: The authors stated that high quality RCTs were needed to establish an optimal exercise prescription for the prevention of osteoporosis in middle-aged and older men.

Funding

Not reported.

Bibliographic details

Bolam KA, van Uffelen JG, Taaffe DR. The effect of physical exercise on bone density in middle-aged and older men: a systematic review. Osteoporosis International 2013; 24(11): 2749-2762. [PubMed: 23552825]

PubMedID

23552825

Indexing Status

Subject indexing assigned by CRD

MeSH

Bone Density; Exercise; Humans; Aged; Male; Adult

AccessionNumber

12013019246

Date bibliographic record published

22/04/2013

Date abstract record published

22/05/2013

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 23552825

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