Background Vitamin D (VD) influences bone quality and is important in maintaining bone densityl; however, there are few reports clarifying how VD status changes over time and what factors may affect the prognosis of VD status.
Objectives To clarify the natural course of subjects with VD insufficiency, factors associated with the prognosis of VD where compared between subjects with VD insufficiency and the general population.
Methods The Research on Osteoarthritis/Osteoporosis Against Disability study (ROAD), a large-scale population-based cohort study, was performed between 2005 and 2007. Serum 25D levels were measured in 1683 participants. The change of VD status in 1346 individuals (79.6%), who completed a follow-up survey 3 years later, was evaluated. The VD insufficiency group was comprised of 717 individuals (53.3%). Factors associated with VD insufficiency prognosis after 3 years were determined using multinominal logistic regression analysis after adjustment for potential risk factors.
Results After 3 years, of the 717 subjects with VD insufficiency at baseline, 387 (54.0%) maintained insufficiency, 281 (39.2%) improved to normal VD status, and 49 (6.8%) exhibited worsening of VD status. Multinominal logistic regression analysis indicated that higher serum levels of 25D (p<0.001) and lower intact parathyroid hormone levels (p<0.007), increased alcohol consumption (p=0.017), and lower total daily energy intake were significantly associated with worsening of VD status (p=0.001).
Conclusions VD insufficiency status altered over a 3-year period with improvement in 40% of patients, and worsening in 7%. The present study revealed that high serum 25D and low serum intact parathyroid hormone at baseline, low alcohol consumption, and higher daily energy intake are factors associated with improved VD status overtime.
Disclosure of Interest None declared