Effect of Sunlight Exposure on Vitamin D Status of Individuals Living in a Nursing Home and Their Own Homes

Introduction/background: The present study was carried out to determine prevalence of vitamin D deficiency and related factors in individuals living in nursing home and their own homes. Methodology: This cross-sectional study included 72 elderly people 60 yr and older. All subjects were given a questionnaire form evaluating their individual characteristics, eating habits which affected their vitamin D status, wearing habits, and their duration of sun exposure and a Standardized Mini Mental Test evaluating their cognitive levels. Serum 25(OH)D, calcium, parathyroid hormone, alkaline phosphatase and phosphorus levels, and bone mineral density measurements were also considered. Results: Vitamin D deficiency was observed in 47% of elderly people (nursing home: 64%, own home 31%, p = 0.05). Both 25(OH)D (14 +/- 8 vs 27 +/- 10, respectively, p < 0.001) and ultraviolet index value (0.63 +/- 0.3 vs 0.92 +/- 0.27, respectively, p < 0.001) were lower in people living in nursing home compared to ones living in their own homes. Parathyroid hormone level, on the other hand, was lower in people living in own homes. Vitamin D deficiency/insufficiency was more common in elderly people living in nursing home (100%) compared to those living in their own homes (64%) (p = 0.003). Osteopenia and osteoporosis incidence rates were also higher in elderly people living in nursing home (p = 0.001). No significant associations were found between vitamin D status and body mass index, smoking or dietary habits (p > 0.05). As levels of benefiting from ultraviolet index increased, significantly improvements were observed in 25(OH)D levels (p < 0.001). Conclusions: In elderly people living in nursing home, vitamin D deficiency was higher and benefitting from ultraviolet index was lower compared to elderly people living in their own homes. Vitamin D deficiency could be prevented in elderly people, especially ones living in nursing homes, through enough sun exposure with appropriate clothing.