Background: Low concentrations of vitamin D are considered one of the risk factors for hip fracture and are associated with worse outcomes. The purpose of this retrospective study was to compare vitamin D deficient group and vitamin D sufficient group and assess the association preoperative vitamin D deficiency and postoperative walking ability after hip fracture surgery. Methods: Between January 2014 and January 2020, 1,029 elderly patients with hip fracture (243 in men and 785 in women) were measured preoperative serum 25-hydroxy-vitamin D3 levels. Among 1,029 elderly patients, 702 patients were classified as Vitamin D deficient group (<20 ng/mL). Outcome parameters for functional recovery were the length of the hospital stay and KOVAL score, and those for complications were delirium, pneumonia, and thromboembolism. Results: The mean length of the hospital stay in the vitamin D deficient group was significantly longer than in the vitamin D sufficient group (27.7±17.8 vs. 2.9±11.8 days; odds ratio [OR], 1.03; 95% confidence interval [CI], 1.02-1.05; P=0.001). The mean postoperative KOVAL score in the deficient group was significantly higher than in the sufficient group (4.0±2.1 vs. 3.1±1.9 days; OR, 1.21; 95% CI, 1.11-1.32; P=0.001). Vitamin D deficiency was significantly associated with a higher risk of delirium and pneumonia in deficiency group. Conclusions Preoperative vitamin D deficiency in hip fractures patients was associated with prolonged duration of hospital stay and decrease of postoperative ambulatory status, and may increase the risk of delirium and pneumonia. Therefore, it is necessary to evaluate the preoperative vitamin D level and recommend vitamin D supplementation in elderly patients with a high probability of hip fracture.

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Lung cancer is a leading cause of cancer-related death in the world. Smoking is definitely the most important risk factor for lung cancer. Radon (222Rn) is a natural gas produced from radium (226Ra) in the decay series of uranium (238U). Radon exposure is the second most common cause of lung cancer and the first risk factor for lung cancer in never-smokers. Case–control studies have provided epidemiological evidence of the causative relationship between indoor radon exposure and lung cancer. Twenty-four case–control study papers were found by our search strategy from the PubMed database. Among them, seven studies showed that indoor radon has a statistically significant association with lung cancer. The studies performed in radon-prone areas showed a more positive association between radon and lung cancer. Reviewed papers had inconsistent results on the dose–response relationship between indoor radon and lung cancer risk. Further refined case–control studies will be required to evaluate the relationship between radon and lung cancer. Sufficient study sample size, proper interview methods, valid and precise indoor radon measurement, wide range of indoor radon, and appropriate control of confounders such as smoking status should be considered in further case–control studies.
Lung Neoplasms* ; Lung* ; Natural Gas ; Radium ; Radon* ; Risk Factors* ; Sample Size ; Smoke ; Smoking ; Uranium