Does low vitamin D before diagnosis increase the risk of getting thyroid cancer?
Vitamin D is important for immune function and cell growth. Some research suggests that low vitamin D levels before a thyroid cancer diagnosis may increase the risk of developing the disease. A large study found that people with vitamin D deficiency had a higher chance of being diagnosed with thyroid cancer over a 10-year period 3. However, the evidence is not yet conclusive, and more research is needed.
What the research says
A 2024 retrospective cohort study using the TriNetX database examined the link between pre-diagnostic vitamin D deficiency (VDD) and thyroid cancer risk over 10 years. The study found that VDD was associated with a higher risk of incident thyroid cancer 3. This supports findings from earlier studies that suggested a connection between low vitamin D and thyroid cancer 78. For example, a case-control study reported that serum vitamin D levels were borderline significantly lower in patients with papillary thyroid cancer compared to controls 7. Another study found that preoperative serum levels of 1,25-dihydroxyvitamin D3 were significantly lower in papillary thyroid cancer patients than in those with benign nodules 8. However, these earlier studies were smaller and could not prove cause and effect. The large cohort study provides stronger evidence, but it is still observational, meaning it cannot prove that low vitamin D causes thyroid cancer 3.
What to ask your doctor
- Should I have my vitamin D levels checked as part of routine screening?
- If my vitamin D is low, what are the recommended ways to raise it safely?
- Does having low vitamin D affect my thyroid cancer risk or treatment plan?
- Are there other risk factors for thyroid cancer I should be aware of?
- How often should I monitor my vitamin D levels if I am at risk?
This question is drawn from common patient questions about this topic and answered using cited medical research. We do not provide individualized advice.