Objectives This study aims to examine the relationship between low vitamin D levels and lateral epicondylitis (LE). Patients and methods Between January 2016 and January 2018, a total of 40 patients (17 males, 23 females; mean age: 38.6±10.7 years; range, 18 to 59 years) diagnosed with LE were included as the study group, while 66 patients (33 males, 33 females; mean age: 33.6±12.5 years; range, 18 to 58 years) who did not have any elbow complaints and met the study criteria were included as the control group. Both groups were compared in terms of vitamin D levels, of which levels of >30 ng/mL were considered normal, levels between 20-30 ng/mL were accepted as vitamin D insufficiency, and levels <20 ng/mL were categorized as vitamin D deficiency. Results Vitamin D levels of the LE group were significantly lower than the control group (p<0.001). The mean vitamin D level was 16.47±8.22 (range, 8.32 to 39.55) ng/mL in the LE group, and 23.64±8.4 (range, 11.6 to 49) ng/mL in the control group. While 31 of the patients (77.5%) diagnosed with LE had vitamin D deficiency, four (10%) had vitamin D insufficiency, and five (12.5%) had normal vitamin D levels. In the control group, 29 (43.9%) patients had vitamin D deficiency, 20 (30.3%) had vitamin D insufficiency, and 17 (25.8%) had normal vitamin D levels. Conclusion Although the etiology of LE has not been fully understood yet, vitamin D levels were significantly lower in LE patients in our study. This finding supports that low vitamin D may be one of the factors in the etiology of LE.

IntroductionThe anabolic effects of vitamin D on bone tissue have been demonstrated in experimental studies. The aim of this study was to evaluate the relationship between greater tuberosity primary bone marrow edema (GTPBMO) and vitamin D levels.Materials and MethodsThirty‐nine patients (22 females and 17 males; mean age 49.02 ± 13.08 years) with isolated GTPBMO between March 2016 and March 2018 were included in the study. Sixty patients (34 females and 26 males; mean age 43.45 ± 12.61 years) who did not have any shoulder complaints and fulfilled the study criteria were selected as the control group. Both groups were compared in terms of vitamin D levels.ResultsThe mean vitamin D level was 13.43 ± 9.02 ng/mL in the GTPBMO group. In contrast, mean vitamin D level was 21.54 ± 8.03 ng/mL in the control group (p < 0.001). In the GTPBMO group, vitamin D deficiency was detected in 31 (79.5%) patients, vitamin D insufficiency was detected in 5 (12.8%) patients, and vitamin D levels were normal in 3 (7.7%) patients. In the control group, vitamin D deficiency was detected in 29 (48.3%) patients, vitamin D insufficiency was detected in 16 (26.7%) patients, and vitamin D levels were normal in 15 (25%) patients.ConclusionThe etiology of GTPBMO has not yet been fully understood, but the results obtained in this study show that vitamin D levels were significantly lower in patients with GTPBMO. The findings suggest that low vitamin D levels may be one of the contributing factors in the etiology of GTPBMO.