Original Full Length ArticleQuantitative Ultrasound and bone's response to exercise: A meta analysis
Highlights
► We present a critical evaluation of current available evidence on QUS' response to bone loading exercises in 878 participants. ► QUS was sensitive to exercise induced changes in bone health. ► QUS may be considered for use in exercise-based interventions for preventing osteoporosis.
Introduction
With a projected worldwide increase in prevalence of osteoporosis due to an ageing population [1] and an increasing financial, social and psychological cost of treatment subsequent to fracture [2], [3], the indication for a paradigm shift from anti-osteoporotic drug treatment and or secondary prevention to non-pharmacologic primary prevention is strong [4] and yet evolving [5]. Exercise for maximising peak bone mass, minimising age-related bone loss via weight-bearing physical activity, and minimising fall and fracture risk through strength, flexibility and balance training sits at the central core of this demand.
The measurement of bone mineral density (BMD) with the aid of dual energy absorptiometry (DXA) is widely acknowledged as the gold standard for radiographic diagnosis of osteoporosis, the prediction of fractures, and monitoring of bone health status [6]. Recent bone densitometry guidelines do not support routine bone density screening for the entire population [7]. This restriction and the enduring debate over repeat DXA testing spells uncertainty over both clinical and non-clinical monitoring of responses to exercise intervention as a public health strategy for prevention and management of osteoporosis [7], [8]. The bulk of current evidence on the benefits of exercise for management of osteoporosis had been garnered from BMD measurements. Considering the argument on ethical issues and cost-effectiveness associated with repeat DXA testing, exposure to ionising radiation (especially to the immature skeleton) and the rapidly evolving aspects of exercise interventions that may enhance bone health, research on the role of QUS for monitoring the effect of exercise intervention on bone health is well situated.
The QUS has been valued for its high correlation with BMD measurements [9], [10]. Its portability, radiation-free, time-saving capability, and low-cost is purported to make it an attractive alternative to DXA [11], [12]. However, as opposed to DXA, the dearth of data from prospective controlled trials for both bone health enhancement and anti-osteoporotic treatment using Quantitative Ultrasound (QUS) as a benchmark for efficacy has limited the propensity to recommend the same for monitoring changes in treatment. Hence, the utility of QUS for assessment of response to exercise intervention for the purpose of enhancing bone health across the age spectrum has remained equivocal [13]. While there might have been published and unpublished literatures of strong evidence-based arguments pro and against the use of QUS for monitoring exercise-induced changes in bone mass, a systematic review and meta-analysis of controlled studies (across age groups) of exercise intervention and bone health using QUS as an efficacy criterion is yet to be undertaken. The purpose of this study was, therefore, to ascertain the sensitivity of QUS for detecting change in BUA due to exercise intervention.
Section snippets
Methods
A systematic review of published and unpublished literature on the role of QUS in monitoring and evaluating bone's response to exercise across age groups was conducted. The inclusion criteria are given in Table 1. Structured computer searches of MEDLINE/PubMed, EMBASE, Web of Science, SportDiscus, Cochrane controlled trials register, AMED, BNI, HMIC, PROQUEST and CINAHL were undertaken from their inception till December 2011 to locate relevant studies. Search terms, keywords and participant
Description of studies/study quality assessment
Twelve articles (2 cohorts and 10 controlled trials [CT]) involving 878 participants in total were included in this review. A summary of the review process is presented in Fig. 1 and a synopsis of data from the 12 studies is presented in Table 2. Out of the five studies [16], [17], [18], [19], [20] that reported randomisation of study participants into exercise intervention groups and control groups, only three [16], [18], [20] gave details of the randomisation process. The study of Arnett &
Discussion
The evidence presented by all the studies in this review attest to the sensitivity of the QUS to changes in bone mass as a result of varying exercise interventions. There is well supported research evidence to show that lifelong skeletal competence is hinged on achievement of peak bone mass by the second decade of life [33]. Promotion of physical activity to stimulate osteogenesis in young age has since been adopted as a public health osteoporosis prevention strategy [1]. QUS appears to be
Limitations
The results of this present study may be regarded with caution due to the paucity of evidence from large RCTs, and the heterogeneity in the type, frequency, amount and duration of mechanical loading in the exercise regimes of the primary studies that were reviewed. In order to mitigate the latter, subgroup analysis of QUS index according to age groups was explored in the meta-analysis (Fig. 2). A high probability of positive results publication bias was reflected by the funnel plot's asymmetry.
Conclusions
This meta-analysis augments the mounting evidence for the associations between exercise-induced changes in bone and QUS parameters. The weight of evidence for widespread utility of the QUS in research and public health settings is subject to the conduct of more large randomised controlled trials and an updated meta-analysis in future. Technological fine-tuning of QUS devices and an empirical explanation of its mechanisms also presents challenge for future research. The portability, time-saving
Conflict of Interest
No disclosures.
Disclosure of Interest
None.
Acknowledgments
We are grateful to the anonymous reviewers of this manuscript for their constructive criticisms.
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