1.Prevention of Osteoporosis by Sunbath-Bone Mineral Density of Institutionalized Subjects after Sunlight Exposure.
Kazuko WATANABE ; Miki SUGA ; Keiko NAGANO ; Eiichi KITANO ; Satsuki NAKAO ; Kazuhiro IWAO ; Junichi SHIDA ; Keisuke MATSUO ; Takayuki SATAKE ; Takeshi KIRIYAMA ; Sumiaki OKAMOTO
Journal of the Japanese Association of Rural Medicine 1999;47(5):708-712
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.