Risk Factors for Osteoporosis and Hip Fractures

Association between age and risk of osteoporotic fracture

The study shows that of the factors considered here, the main determinant of risk of major osteoporosis and hip fracture are age, weight and BMI. The first question in this study sought to determine the association between age and risk of osteoporotic fracture. The mean age for 100 subjects in this study is 62.57. The result of this study show a significant increase in the risk of major osteoporosis and risk of hip fracture in regards to age. Bone mineral density is known to decrease rapidly as we get older. This finding is in agreement with Loh, Shong, Lan, Lo, & Woon (2008) findings which showed that age is significantly associated with low BMD. This happened because with advancing age, there will be prominent lost of trabecular and cortical bone mass (Francis, 2001). Approximately 35-50% of trabecular bone in women and 15-45% among men are lost while 25-30% of cortical bone in women and 5-15% in men are lost due to the advancing age (Francis, 2001) The loss of bone mass will eventually lead to osteoporosis and this can be the major cause of osteoporotic fracture. According to Keng Yin Loh, King Hock Shong, Soo Nie Lan, Lo, and Shu Yuen Woon (2008) age-related osteoporotic fracture can be explained by the fact that prevalence of osteoporosis is higher among older adult above 50 years old. Another possible explanation regarding age-related bone loss include reduce osteoblast activity, increase osteoclast activity, or a lack of physical activity among elderly (Metcalfe, 2008). In this study, the percentage of subjects participating in physical activity is low that is 24% only. This shows that with the advancing age, the participation in physical activity had decrease. Without exercising, there is lack of mechanical stress put on the bone and the rate of bone mineralization reduced thus increase the chances of elderly people to get osteoporotic fracture.

Association between weight/BMI with risk of osteoporotic fracture

Another important finding was that there is significant difference of negative correlation between weight and BMI with risk of major osteoporosis and risk of osteoporotic fracture. However, the relationship between weight and risk of osteoporotic fracture was stronger than between BMI and risk of osteoporotic fracture. The findings of the current study are consistent with those of Unnanuntana, Gladnick, Donnelly and Lane (2010) of who found low body weight can contribute to osteoporotic fracture. People with low body weight are known to have low BMD. This is because as people get older, calcium and mineral contents in bones declines causing the elderly become low weight, less dense and prone to get fractured (Fawzy et al., 2011). The correlation between BMD and BMI was highly positive in clinical study among UAE population done by Fawzy et al., (2011). This finding supports previous research into this brain area which links BMD and BMI. Keng Yin Loh, King Hock Shong, Soo Nie Lan, Lo and Shu Yuen Woon (2008) reported a significant difference between lower body weight and risk of osteoporotic fracture. Thinner person was said to have low BMD. Salamat, Salamat, Abedi and Janghorbani (2013) in their journals explained the mechanism on how obesity gives positive effect on BMD status. One of the reason is that obesity helps to improve bone mass in men because of the conversion of androgen to estrogen (Salamat et al., 2013). gObesity causes physiological changes in humans due to the modification of circulating sex steroid hormone such as androgens and estrogens (Mammi et al., 2012). Testosterone is the major circulating androgen in men which is synthesized from cholesterol (Sinnesael, Boonen, Claessens, Gielen, & Vanderschueren, 2011). Testosterone can be converted into estrogen via P 450 aromatase enzyme and it can be found in adipose tissue and bone (Merlotti, Gennari, Stolakis, & Nuti, 2011). This can best explains why study done by (Mammi et al. (2012) reported a high level of plasma estrogens in obese men. According to Sinnesael et al. (2011) conversion of androgen into estrogen can help to increase bone density especially on the cortical bone among men thus can reduce risk of osteoporotic fracture. This view is supported by Merlotti et al. (2011) who agreed that conversion of androgen into estrogen play a vital role in improving bone mass density either in young men or elderly.

On the other hand, people with more weight can put more mechanical stress on bone. Compared to low body weight people, they have less mechanical stress exerted on bone. The positive effect of mechanical loading on bone conveyed by increased body weight can help to stimulates bone formation (Cao, 2011). This is because proliferation and differentiation of osteoblast and osteocytes increased with the increased of body weight (Cao, 2011). This finding corroborates the ideas of Shapses & Riedt, (2006) who suggested that obesity gives higher bone mass by means of weight-bearing effect of excess soft tissue on the skeleton.

Association between balance and risk of osteoporotic fracture

Contrary to expectations, this study did not find a significant difference between functional reach and risk of hip fracture. There is no correlation between balance and risk of osteoporotic fracture. This is related to the result of de Abreu et al. (2009) who reported that there is no differences between body balance of osteoporotic women and non-osteoporotic women when measured with Berg Balance Scale and Time-Up and Go Test. It is difficult to explain this result but it might be related to a low demand task required to performed these tests yet it is not efficient to predict the risk of fall and functional impairment in elderly people (de Abreu et al., 2009). Furthermore, we choose to study older adult who have functional independent and free from pathologies. The subject in our study included a large sample on older adult aged 50-59 years old and 60-69 years old compared to elderly of 70-79 and 80-89 years old. This can be a reason why their balances are also good. This finding supports previous research into this brain area which links age and related test performance in community-dwelling elderly people. People with a good functional independent need a more realistic choice of clinical tests in the examination of elderly patient (Steffen, Hacker, & Mollinger, 2002). In addition, the present findings seem to be consistent with other research which foundthe relationship between balance, age and estimated fall risks. In a study among community-dwelling older adults done by Smee, Anson, Waddington, & Berry, (2012) elderly aged 65 years old are being categorized to have a Low-Mild falls risk because they have better balance as compared to the older-old group. Therefore, a younger-old group is said to have a low fall risk that lead to a low risk of osteoporotic fracture.

Strength and Weakness of the study

The strength referred to as advantages of this study. In return, this study can be a good study to be reviewed and as references for related future study. Meanwhile, weakness corresponds to any lacking possessed that may interfere the findings or result.

Strength

1. The sample size was larger compared to previous study thus giving a more precise calculation.
2. The forward reach test is easy, inexpensive and convenient to be applied to community-dwelling elderly with a good test-retest reliability and concurrent validity.

Weakness

1. This study only predicts future hip fracture without calculated the risk of vertebral fracture and proximal humeral fracture.
2. This study only focuses on independently mobile community-dwelling older adult. The lack of more elderly aged 65 and above including those with poor proprioceptive control, vision and vestibular input may limit the generalisability of this study related to postural control.

References

Cao, J. J. (2011). Effects of obesity on bone metabolism. Journal of Orthopaedic Surgery and Research, 6(1), 30. doi:10.1186/1749-799X-6-30

De Abreu, D. C. C., Trevisan, D. C., Reis, J. G., da Costa, G. D. C., Gomes, M. M., & Matos, M. S. (2009). Body balance evaluation in osteoporotic elderly women. Archives of Osteoporosis, 4(1-2), 25–29. doi:10.1007/s11657-009-0023-y

Fawzy, T., Muttappallymyalil, J., Sreedharan, J., Ahmed, A., Alshamsi, S. O. S., Al Ali, M. S. S. H. B. B., & Al Balsooshi, K. A. (2011). Association between Body Mass Index and Bone Mineral Density in Patients Referred for Dual-Energy X-Ray Absorptiometry Scan in Ajman, UAE. Journal of Osteoporosis, 2011, 876309. doi:10.4061/2011/876309

Francis, R. M. (2001). Falls and fractures. British Geriatrics Society, 30(4), 25–28. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/24519586

Loh, K. Y., Shong, K. H., Lan, S. N., Lo, W.-Y., & Woon, S. Y. (2008). Risk factors for fragility fracture in Seremban district, Malaysia: a comparison of patients with fragility fracture in the orthopedic ward versus those in the outpatient department. Asia-Pacific Journal of Public Health / Asia-Pacific Academic Consortium for Public Health, 20(3), 251–7. doi:10.1177/1010539508317130

Mammi, C., Calanchini, M., Antelmi, A., Cinti, F., Rosano, G. M. C., Lenzi, A., … Fabbri, A. (2012). Androgens and adipose tissue in males: a complex and reciprocal interplay. International Journal of Endocrinology, 2012, 789653. doi:10.1155/2012/789653

Merlotti, D., Gennari, L., Stolakis, K., & Nuti, R. (2011). Aromatase activity and bone loss in men. Journal of Osteoporosis, 2011, 230671. doi:10.4061/2011/230671

Metcalfe, D. (2008). The pathophysiology of osteoporotic hip fracture. McGill Journal of Medicine : MJM : An International Forum for the Advancement of Medical Sciences by Students, 11(1), 51–7. Retrieved from http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2322920&tool=pmcentrez&rendertype=abstract

Salamat, M. R., Salamat, A. H., Abedi, I., & Janghorbani, M. (2013). Relationship between Weight, Body Mass Index, and Bone Mineral Density in Men Referred for Dual-Energy X-Ray Absorptiometry Scan in Isfahan, Iran. Journal of Osteoporosis, 2013, 205963. doi:10.1155/2013/205963

Shapses, S. A., & Riedt, C. S. (2006). Bone, Body Weight and Weight Reduction : What Are the Concerns? The Journal of Nutrition, 136(6), 1453–1456. Retrieved from http://jn.nutrition.org/content/136/6/1453.full

Sinnesael, M., Boonen, S., Claessens, F., Gielen, E., & Vanderschueren, D. (2011). Testosterone and the male skeleton: a dual mode of action. Journal of Osteoporosis, 2011, 240328. doi:10.4061/2011/240328

Smee, D. J., Anson, J. M., Waddington, G. S., & Berry, H. L. (2012). Association between Physical Functionality and Falls Risk in Community-Living Older Adults. Current Gerontology and Geriatrics Research, 2012, 864516. doi:10.1155/2012/864516

Steffen, T. M., Hacker, T. A., & Mollinger, L. (2002). Research Report Age- and Gender-Related Test Performance in Community-Dwelling Elderly People : Six-Minute Walk Test , Berg Balance Scale , Timed Up & Go Test , and Gait Speeds. Journal of American Pysical Therapy Association and de Fysiotherapeut, 82, 128–137. Retrieved from http://ptjournal.apta.org

Unnanuntana, A., Gladnick, B. P., Donnelly, E., & Lane, J. M. (2010). The assessment of fracture risk. The Journal of Bone and Joint Surgery. American Volume, 92(3), 743–53. doi:10.2106/JBJS.I.00919