Exercise as it relates to Disease/Exercise, an inexpensive way of preventing osteoporosis in later life?

This is a critical analysis on the original journal article "Effects of high-impact exercise on bone mineral density: a randomized controlled trial in premenopausal women" - Aki Vainionpää, Juhani Leppäluoto, Raija Korpelainen, Timo Jämsä (2005)

What is the background to this research?
Osteoporosis may be one of the most undiagnosed conditions in the Western world, with 10% of Australians reported of having the disease according to the Australian Bureau of Statistics in 2015. Osteoporosis has no overt symptoms, therefore the condition is often undiagnosed until a fracture occurs. Osteoporosis is defined as a condition that causes bones to become weak and fragile, in so making the risk of fracture more prevalent. Pre-menopausal women may be at the greatest risk with 1 in 3 women over the age of 50 likely to experience osteoporosis in their remaining life.

A vast amount of research has suggested that exercise enhances the bone development pathways thus improving overall bone density. Further reading specifies that high-impact exercise, in particular, was most effective in increasing BMD. Regular exercise during adolescence may contribute to the reduced risk of fractures if a fall were to occur later in life

Where is the research from?
All contributors to this study are staff from the University of Oulu, Finland. The four authors pooling their expertise from a range of departments including Medical Rehabilitation and Biomedicine. Aki Vainionpää and Juhani Leppäluoto both have research involved with menopausal women and the role exercise plays with that population. Raija Korpelainen and Timo Jämsä are both particularly invested in the research of fracture mechanics and the role of bone mineral density in at-risk populations and are both currently tied in with projects involving these matters.

What kind of research was this?
This study was unique at the time in that it was assumed to be the first randomized controlled trial performed on a population-based cohort, to the knowledge of the authors.

What did the research involve?
The study set out to determine the effects of high-impact exercise on BMD at several common stress sites in premenopausal women. A population of 120, criteria appropriate women, were randomized into either an exercise group (n=60, age=38.1±1.7) or a control group (n=60, age=38.5±1.6 ).

Participants submitted a self-reported questionnaire regarding their history of exercise exposure and an assortment of female-specific information. Body fat and lean mass percentages were measured using bioimpedance equipment (BodyStat 1500) which is often the first choice for reliable and accurate body composition measurements.

Exercise Protocol
The exercise regimen consisted of a home program plus a supervised, progressive, high-impact session. Both programs were analyzed and modified bimonthly while non-exercise participants were advised to maintain their current physical activity. There was vague reporting on whether non-exercisers complied with this advice, perhaps more frequent check-ups would have been beneficial.

Limitations
It is widely suggested that self-reported physical activity (or any self-reported data) is often an unreliable way to gather information. It may have been more beneficial for this study to conduct more thorough questionnaires than self-reports, even if that lengthened the process. This study reported a drop out rate of 33%. Several other studies reported a similar drop out rate amongst exercise related studies (~38%), therefore this drop out rate is not unusual for this type of study.

Analysis of Data
Mean with standard deviation (SD) or confidence interval of 95%(CI) was used to report findings. Independent t-test and x-square tests were used to assess the differences between study subjects and those women who did not participate in the study.

What were the basic results?
Significant gain in BMD occurred at the femoral neck, intertrochantric and total femoral sites. In the lumbar area, a change was significant in the L1 BMD both compared to control groups and within the exercise group (2.2%), although there were no exercise-induced effects in other vertebrae.

Implications of high-impact exercise suggested by this report are consistent with results of similar studies.

What conclusions can we take from this research?
The study has suggested that high-impact exercise has a significant effect on BMD in the lower extremities of premenopausal women, yet seems to only affect BMD in the upper region of the lumbar spine. This sort of physical intervention may be an effective and cheap benefactor for the prevention of osteoporosis. This correlates with more recent data, which suggests progressive, high-impact exercise compiled with sufficient nutrition will prevent osteoporosis to at least some degree.

Practical advice
It is imperative to highlight that exercise must be appropriately prescribed only after pre-screening has been undertaken. It is also vital to note that exercise prescriptions, although not mentioned in this particular study, must be complemented by an adequate diet including calcium and vitamin D to reap full musculoskeletal health benefits. Additionally, consistent supervision is required for individuals at high risk of low trauma fracture and those who have not participated in high-intensity exercise prior to prescription.

Further Readings

 * High-impact exercise vs. Stretching →A two-year program of aerobics and weight training enhances bone mineral density of young women.
 * 18 months of high-impact training →Randomised controlled trial of effect of high-impact exercise on selected risk factors for osteoporotic fractures.
 * Does high-impact effect Post -menopausal equally? →Pre‐ and Postmenopausal Women Have Different Bone Mineral Density Responses to the Same High‐Impact Exercise