Background: Vitamin D is essential for bone strength. In our previous study of urban, elderly, males, the prevalence of
vitamin D insufficiency was 48%, and they had a lower level of bone turnover marker than normal, young adult, Thai males.
Objective: To A) ascertain the prevalence of vitamin D insufficiency, B) to determine the bone turnover marker level in rural elderly males, and C) to compare urban and rural males with these parameters.
Results: The prevalence of vitamin D insufficiency among rural elderly males was 13.6%, while the level of bone turnover
markers (β-CTx, and PINP) were in the normal Thai reference range. It was also found that rural elderly males had a
significantly higher level of the calcidiol, iPTH, β-CTx, and PINP than their urban counterparts.
Conclusion: The prevalence of vitamin D insufficiency among rural elderly males was significantly lower than among urban
males and rural males had a higher level of calcidiol, iPTH and bone turnover marker. The hypothesis was that differences
in rural vs. urban lifestyle accounted for the discrepancy; possibly because elderly rural males performed strenuous outdoor labor while most urbanites stayed at home and/or had sedentary jobs.

Keywords: Vitamin D insufficiency, Prevalence, Rural elderly males, Calcidiol