Oral Presentation Skin Cancer 2024

Determining the effect of vitamin D supplementation on health outcomes: the D-Health Trial (#39)

Mary Waterhouse 1 , Hai Pham 2 , Bridie Thompson 3 , Sabbir Rahman 4 , Catherine Baxter 1 , Briony Duarte Romero 1 , Donald McLeod 5 , Bruce Armstrong 6 , Peter Ebeling 7 , Dallas English 8 , Gunter Hartel 1 , Michael Kimlin 9 , Rachel O’Connell 10 , Jolieke van der Pols 9 , Alison Venn 11 , Penelope Webb 1 , David Whiteman 1 , Rachel Neale 1
  1. QIMR Berghofer Medical Research Institute, Brisbane
  2. The University of Queensland, Brisbane
  3. Queensland Health, Brisbane
  4. Australian Digital Health Agency, Brisbane
  5. Department of Endocrinology and Diabetes, Royal Brisbane and Women’s Hospital, Brisbane
  6. School of Public Health, University of Sydney, Sydney
  7. Department of Medicine, School of Clinical Sciences, Monash University, Melbourne
  8. Melbourne School of Population and Global Health, University of Melbourne, Melbournce
  9. Queensland University of Technology, Brisbane
  10. NHMRC Clinical Trials Centre, University of Sydney, Sydney
  11. Menzies Institute for Medical Research, University of Tasmania, Hobart

Background

Sun exposure is the main modifiable risk factor for skin cancer. However, exposure to ultraviolet radiation is necessary for cutaneous production of vitamin D. Understanding the effect of vitamin D on health is important for developing guidelines that balance the risks and benefits of sun exposure.

Methods

The D-Health Trial was a population-based, double-blind, randomised, placebo-controlled trial of oral vitamin D3 supplementation (60,000 international units per month) for up to 5 years, conducted in 21,315 Australians aged 60-84 years. Outcomes were ascertained primarly via linkage with administration datasets, and/or self-report.

Results

Compared with the placebo group, the vitamin D group had lower rates of major cardiovascular events (hazard ratio [HR] 0.91, 95% CI 0.81 to 1.01), myocardial infarction (HR 0.81, 95% CI 0.67 to 0.98), extended hospitalisations for infection (incidence rate ratio [IRR] 0.80, 95% CI 0.65 to 0.99), repeat antibiotic prescription episodes (IRR 0.96, 95% CI 0.93 to 1.00) and, from ~3.5 years after randomisation, fractures (HR at 5 years 0.83, 95% CI 0.69 to 0.99). Supplementation also reduced the length and severity of acute respiratory tract infection. In people predicted to have insufficient vitamin D at baseline, vitamin D supplementation reduced the risk of antidepressant use (HR 0.88, 95% CI 0.75 to 1.02) and antibiotic use (IRR 0.93, 95% CI 0.87 to 0.99).

Conclusions

These findings add to a body of evidence that vitamin D has a clinically relevant effect on the immune system, and indicate that mitigating vitamin D deficiency is necessary for optimal health.