Enrolled in our study were 16 seriously handicapped persons (9 males and 7 females) institutionalized in our medical center. They were 20 to 58 years of age (mean 35 yrs). In the previous study, we found they had no evidence, serological or clinical, of osteomalacia but were verified as having significantly low bone mineral density (BMD) at the calcaneus and lumbar vertebrae. Serum levels of 25-OH-vitamin D were low and positively correlated with the lumbar vertebral BMD. Thus we postulated that low BMD was at least partly due to the lack of ultraviolet exposure. In the present study, the lumbar vertebral BMD of the above subjects were measured before and after increasing their exposure to sunlight. We found that mean lumbar BMD increased signigicantly from 770 mg/cm² to 786 mg/cm² (P<0.05, Wilcoxon, paired test). The Z-score also increased significantlyfrom 78 ± 13% to 80 ± 12%(P<0.05, Wilcoxon, paired test).
These findings suggest low BMD could be corrected to some extent by increasing sunlight exposure of institutionalized persons. Former members of farming communities who are retired, handicapped, or otherwise limited to indoor activity, can also recover their BMD and prevent osteoporosis by an increased daily exposure to sunlight.

Objectives: Although a few studies have investigated the relationship between kidney and oral function (number of remaining teeth), their results remain inconclusive. Therefore, this study aimed to investigate the relationship between kidney function and oral health in community-dwelling healthy elderlies and examine the factors associated with kidney function. Materials and Methods: We used cross-sectional data from the Shimane prefecture cohort recruited by the Center for Community-Based Health Research and Education in 2019. We collected clinical data on dental status, background factors and kidney function (estimated glomerular filtration rate [eGFR], mL/min/1.73 m2 and creatinine levels, mg/dL). Results: The study enrolled 481 participants, whose mean age was 66.7±7.4 years, and 223 (46.4%) participants were men. Multivariate analysis revealed significant correlations between eGFR (B=0.17, P=0.04), creatinine (B=–0.54, P<0.01), and the number of remaining teeth. The number of remaining teeth was associated with creatinine and eGFR, which are indicators of kidney function. Conclusion This study suggests that preserving the teeth may prevent decline in kidney function. Dental professionals should provide instructions and professional care to reduce the risk of systemic diseases such as kidney dysfunction.