This study was conducted to describe a 10-year trend of the supplement from 2000 to 2009 and to evaluate age, gender and racial disparities using a national level health data.

Cross-sectional observational study.

Data collected from patient visit records to stand-alone US ambulatory care clinics. Visits made by men and women who were 40 years of age and older were included (n=175,830).

Overall prevalence of recorded calcium and vitamin D use for osteoporosis prevention and treatment, and annual visit rates were estimated by age, gender, race, insurance types, physician specialties, geographical regions, and metropolitan status using chi square test. Multivariate logistic regression was conducted to determine potential predictive factors for calcium and vitamin D supplements.

An increase in yearly trend of calcium and vitamin D supplements was observed. The increase was proportional to patients' age (p<0.05) and female gender was a strong predictor of calcium and vitamin D supplement (p<0.0001).Visits made by blacks were significantly less likely to be associated with the supplement (p<0.05). Visits associated with self-pay and Medicaid was less likely to be recorded with vitamin D (p<0.05) but not calcium supplements. Osteoporosis diagnosis was an independent predictor of calcium and vitamin D records (p<0.0001).

In spite of the observed increases in the trend of visits associated with calcium and vitamin D supplements, variability in the access to the medications was observed. More focused strategies targeting elderly, men, or black population are needed to maintain and improve adequate calcium and vitamin D supplements.