The Relationships among Vitamin D Level, Balance, Muscle Strength, and Quality of Life in Postmenopausal Patients with Osteoporosis

[Purpose] The aim of this study was to examine the relationships among vitamin D levels, balance, falls, muscular strength, and quality of life in patients with postmenopausal osteoporosis. [Subjects and Methods] Forty-six patients diagnosed with postmenopausal osteoporosis and forty-six healthy controls were included in the study. Bone mineral density was determined by DEXA, and functional balance was evaluated the Timed Up and Go (TUG) test, Chair Raising (CRT) test, Berg Balance Scale (BBS). The muscular strengths were evaluated manually. The lumbosacral region range of motion (ROM) was measured by goniometry. The QUALEFFO-41 questionnaire was used for evaluating the quality of life. [Results] No statistically significant differences in muscular strength, balance, and fall values were found between the two groups. Statistically significant differences were noted between the QUALEFFO C, E, F and G scores and the QUALEFFO total scores of the QUALEFFO-41. Dividing the patient group into two groups revealed that patients with 25(OH)D levels < 15 ng/ml had significantly higher TUG and CRT test scores compared with patients with levels ≥ 15 ng/ml. Also, binary logistic regression analysis revealed that QUALEFFO total scores were found to be the independent factors for osteoporosis. [Conclusion] In this study, we found that vitamin D is necessary to maintain back extensor muscle strength, lumbar ROM, and balance. Our results show that bone mineral density, vitamin D level, balance, lumbar ROM, and the specified muscular strengths are factors that affect the quality of life.