Exercise as it relates to Disease/How much physical activity should osteoporotic men get?

Background
Falls and osteoporotic fractures are common among older adults: about 30% of individuals fall at least once per year with 40% of these falls leading to injury [1]. Osteoporosis is a disease characterized by low bone mass and the deterioration of bone tissue, leading to enhanced bone fragility resulting in an increased fracture risk [2]. Physical activity has been associated with the decrease of osteoporotic fractures. Clinical trials of exercise programs and falls suggest that exercise may reduce the risk of fall, especially those focusing of balance exercises [1].

Research
This study was published online in the Journal of the American Geriatrics Society. This study was conducted by Cauley, J. A., Harrison, S. L., Cawthon, P. M., Ensrud, K. E., Danielson, M. E., Orwoll, E., & Mackey, D. C.

Research type
This research was a longitudinal cohort study designed to determine risk factors for osteoporosis, fractures and falls in six US clinical centers Birmingham, Minneapolis, Palo Alto, Monongahela Valley near Pittsburgh, Portland, and or San Diego.

Research protocol
In 2000-2002 this study was conducted on a group of 5994 men who enrolled in the Osteoporotic Fractures in Men Study (MrOS). The cohort of men were primarily recruited through mass mailings targeted to age-eligible men. All men were > age 65, able to walk independently and also did not report any bilateral hip replacements, of this 35% of men were age 65-69 and 11% aged 80 or older at baseline. All the men were instructed to wear the multi-sensor SenseWear Pro Armband (SWA) (Body Media, Inc; Pittsburgh, PA) at all times [1], including while sleeping, for a 7 day period and to remove it only momentary for bathing and/or water activities. Written informed consent was obtained from each participant to ensure they understood and agreed to what was going to happen, once this information was gather it was sent away and the protocol was approved by the institutional review boards at each institution.

Results of the study
Primary outcomes of this study showed that the increased in physical activity or increased energy expenditure (EE) were associated with lower rates of fractures and falls, while men with high levels of sedentary behaviour had much higher risks of falls and fractures. The men that were recorded to have the lowest active EE had a 43% higher risk of falling therefore increasing the chances of fractures occurring, compared to men with higher EE were about 33% less likely to fall. Another major outcome related to physical activity showed that men participating in less than 33 minutes of moderate activity per day were associated with a 70% increased risk of fracture compared to most active men.

Interpretation of study
The interpretation of the study along with the results indicate that the increase in energy expenditure along with the reduction of sedentary behaviour both help to reduce osteoporotic fractures associated with falls among the male population [1]. The results gathered suggest that fall prevention strategies aimed at reducing the occurrence of falls also needs to consider the age of the patient. Among the young-old, must be careful to select appropriate physical activities that do not expose individuals to an increased risk of falling. Whereas for the old-old interventions aimed at increasing EE or time spent participating in physical activities >30min each day may help reduce the risk of falling.

Conclusion
The conclusion that should be taken away from this study is that physical activity and the increased EE are both seen to improve the occurrence of osteoporotic fracture. This is because the incident of falls is reduced, therefore eliminating the chances of osteoporotic fractures happening in the first place. It’s extremely important that sedentary behaviour is limited to as little as possible and physical activity levels achieved are as high as possible to help benefit the individual.

Practical Implications
This study shows that among the total cohort, the men with the lowest levels of active EE and physical activity were at a 70-80% increased risk of fracture. It is suggested that active EE of 200Kcal/day or 30 minutes of moderate intensity activities every day may reduce the risk of osteoporotic fractures [3]. Other research suggest that mechanical loading through physical activity is another potentially important factor in the preservation of bone mass in the elderly [4]. This is important to understand because bone mineral density (BMD) is related to osteoporosis, if the BMD is low this increases the risk of osteoporotic fractures [5].

Limitations of the study
The primary limitation of this study is because it’s an observational study, the problem is the inability to balance variables across activity groups. Health status is the most important with the association between physical activity and fractures, The healthier the individual the more motivated they are to be active and also the healthier the induvial the more capable they are at participating in the study [1].