Efficacy of high dose Vitamin D supplementation in improving serum 25(OH)D among migrant and non migrant population: a retrospective study.

BACKGROUND: Higher dose of vitamin D supplementation 50000 IU is required for those whose serum 25(OH)D levels are 50 nmol/L and below. The increment in serum 25(OH)D though not significantly affected by race, sex or age it is negatively correlated to the baseline 25(OH)D concentration. This study investigated whether the mean increase in serum 25(OH)D will be higher among participants with lower baseline 25(OH)D levels and whether the duration of supplementation has an influence on the serum 25(OH)D achieved. METHODS: A clinical audit of patients' medical records from a community health centre in Melbourne for the period 01.01.2010 to 31-12.2012 was undertaken. Paired sample t test was used to determine difference in pre and post dose serum 25(OH)D. Simple and multiple linear regressions were used to examine the association between the difference in pre and post dose serum 25(OH)D and duration of supplementation and baseline serum 25(OH)D, adjusting for socio-demographic factors. RESULTS: A total of 205 patients were included in the study. Mean difference in serum 25(OH)D was highest 52.8 nmol/L (95 % CI: 46.63-58.92) among those whose serum 25(OH)D was below 25 nmol/L at baseline. Baseline 25(OH)D alone accounted for 13.7 % of variance in the effect size (F(2, 202) = 16.0. p < 0.001), with the effect size significantly higher among participants with a baseline 25(OH)D level of 25-49 nmol/L (ß = 11.93, 95 % CI: 0.48, 23.40, p < 0.05). Mean serum 25(OH)D difference was highest, 47.53 nmol/L (95 % CI: 40.95-54.11) when measured within 3 months of supplementation. Duration of supplementation explained 2.9 % of the variance in the effect size (F (1, 203) = 6.11, p < 0.05) and there was an inverse relationship between the length of supplementation and mean pre and post supplementation serum 25(OH)D difference (ß = -1.45, 95 % CI: -2.62, -0.29, p = 0.014). CONCLUSION: Following 50000 IU vitamin D3 for 12 months mean serum 25(OH)D increase was highest among those whose baseline serum 25(OH)D was lower. Migrants especially dark-skinned are at a high risk for vitamin D deficiency in Australia. High dose vitamin D3 50000 IU (cholecalciferol) is effective in achieving sufficient serum 25(OH)D among these populations who tend to have lower baseline serum 25(OH)D.

Vitamin D testing patterns among general practitioners in a major Victorian primary health care service.

OBJECTIVE: To examine 25(OH)D testing patterns and frequency among general practitioners in a major community health service. METHOD: A clinical audit of patient records at a community health centre in Melbourne was undertaken. Patients aged 18 years and above were included. Univariate and multivariate logistic regression was used to examine the association between vitamin D testing and socio-demographic characteristics while Poisson regression was used for the frequency of testing. RESULTS: There were 1,217 patients tested for serum 25(OH)D. The community health centre was served by 12 general practitioners and an infectious disease specialist. The odds of vitamin D testing showed a positive, albeit weak, association with age (OR 1.01, 95%CI 1.00-1.02, p<0.05), were higher among females than males (OR 1.42, 95%CI 1.18-1.70, p<0.05) and higher among migrants compared to non-migrants (OR 2.57, 95%CI 2.14-3.09, p<0.05). The frequency of testing was also higher among females than males (IRR 1.17, 95%CI 1.07-1.28, p<0.05) and higher among migrants than non-migrants (IRR 1.19, 95%CI 1.08-1.31, p<0.05). CONCLUSION: Advancing age, being female and being a migrant were associated with an increased likelihood of vitamin D testing. IMPLICATIONS: Development of evidence-based policies and guidelines are needed to manage over-testing of vitamin D in Australia. Studies that include health services from different areas are required to understand vitamin D testing patterns among the general practitioners.