Background: The incidence of colorectal cancer increases with vitamin D deficiency as shown in recently published studies. In addition, prospective investigations have indicated that low vitamin D levels may be associated with increased mortality of colorectal cancer, especially in stage III and IV cases. However, the exact incidence of vitamin D deficiency and the relation between vitamin D deficiency and osteopenia/osteporosis is still not known. The aim of this study is to identify severity of vitamin D deficiency and absolute risk factors of osteopenia/osteoporosis in colorectal cancer survivors.
Materials and methods: A total of 113 colorectal cancer survivors treated with surgery and/or chemotherapy ± radiotherapy were recruited from medical oncology outpatient clinics during routine follow-up visits in 2012-2013. Bone mineral densitometry (BMD) was performed, and serum 25-OH vitamin D levels were also checked on the same day of the questionnaire. The patients was divided into 2 groups, group A with normal BMD and group B with osteopenia/osteoporosis.
Results: The median age of the study population was 58 (40-76). Thirty (30.0%) were female, whereas 79 (70.0%) were male. The median follow-up was 48 months (14-120 months). Vitamin D deficiency was found in 109 (96.5%); mild deficiency (20-30 ng/ml) in 19 (16.8%), moderate deficiency (10-20 ng/ml) in 54 (47.8%) and severe deficiency (<10 ng/ml) in 36 (31.9%). Osteopenia was evident in 58 (51.4%) patients whereas osteoporosis was noted in 17 (15.0%) . Normal BMD was observed in 38 (33.6%). No apparent effects of type of surgery, presence of stoma, chemotherapy, radiotherapy and TNM stage were found regarding the risk of osteopenia and osteoporosis. Also, the severity of the vitamin D deficiency had no effect in the risk of osteopenia and osteporosis (p=0.93). In female patients, osteopenia/osteoporosis were observed in 79.5% patients as compared to 60.7% of male patients (p=0.04).
Conclusions: In our study, vitamin D deficiency and osteopenia/osteoporosis was observed in 96.5% and 66.4% of colorectal cancer survivors, respectively. There is no defined absolute risk factor of osteopenia and osteoporosis in colorectal cancer survivors. To our knowledge, in the literature, our study is the first to evaluate all the risk factors of osteopenia and osteoporosis in colorectal cancer survivors.