title: Sunlight exposure is important for preventing hip fractures in patients with Alzheimer's disease, Parkinson's disease, or stroke.
abstract: OBJECTIVE
  Hypovitaminosis D as a result of malnutrition or sunlight deprivation, increased bone resorption, low bone mineral density (BMD), or an increased risk of falls may contribute to an increased risk of hip fractures in patients with neurological diseases, including Alzheimer's disease, Parkinson's disease, and stroke. The purpose of this study was to clarify the efficacy of sunlight exposure for reducing the risk of hip fractures in patients with such neurological diseases.
  
  
  METHODS
  The English literature was searched using PubMed, and randomized controlled trials evaluating the efficacy of sunlight exposure for reducing the risk of hip fractures in patients with Alzheimer's disease, Parkinson's disease, and stroke were identified. The relative risk and the 95% confidence interval were calculated for individual randomized controlled trials, and a pooled data analysis (meta-analysis) was performed.
  
  
  RESULTS
  Three randomized controlled trials were identified. Sunlight exposure improved hypovitaminosis D and increased the BMD. The relative risk (95% confidence interval) of hip fractures was 0.22 (0.05, 1.01) for Alzheimer's disease, 0.27 (0.08, 0.96) for Parkinson's disease, and 0.17 (0.02, 1.36) for stroke. The relative risk (95% confidence interval) calculated for the pooled data analysis was 0.23 (0.10, 0.56) (P = 0.0012), suggesting a significant risk reduction rate of 77%.
  
  
  CONCLUSIONS
  The present meta-analysis added additional evidence indicating the efficacy of sunlight exposure for reducing the risk of hip fractures in patients with Alzheimer's disease, Parkinson's disease, and stroke.
authors.affiliation: Institute for Integrated Sports Medicine, Keio University School of Medicine, Tokyo, Japan. jiwamoto@a8.keio.jp
authors.forename: J
authors.initials: J
authors.lastname: Iwamoto
authors.forename: T
authors.initials: T
authors.lastname: Takeda
authors.forename: H
authors.initials: H
authors.lastname: Matsumoto
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology*; D015519:Bone Density / Q000502:physiology; D005260:Female; D006620:Hip Fractures / Q000453:epidemiology* / Q000517:prevention & control*; D006801:Humans; D008297:Male; D010024:Osteoporosis / Q000453:epidemiology / Q000517:prevention & control*; D010300:Parkinson Disease / Q000453:epidemiology*; D020521:Stroke / Q000453:epidemiology*; D013472:Sunlight; D014807:Vitamin D / Q000008:administration & dosage / Q000502:physiology
chemical_list: D014807:Vitamin D