New Research Uncovers Link Between Low Vitamin D and Increased Pain

Low vitamin D levels may be linked to more pain and greater opioid use after breast cancer surgery, according to a study published in Regional Anesthesia & Pain Medicine.

Researchers studied 184 breast cancer patients undergoing unilateral modified radical mastectomy in Egypt. Half had vitamin D deficiency, defined as levels below 30 nmol/L, while the others had levels above this threshold.

Vitamin D is important for bone health and may also influence pain processing and inflammation. Researchers examined whether low levels were linked to recovery.

All patients received standard pain treatment. They received fentanyl during surgery and intravenous paracetamol afterwards. Patients could also control additional tramadol through a patient-controlled pain relief system.

The results showed that patients with vitamin D deficiency were three times more likely to experience moderate to severe pain during the first 24 hours after surgery. The difference was due to moderate pain; none reported severe pain.

Patients with low vitamin D also received about 8 micrograms more fentanyl during surgery and used substantially more tramadol afterwards, averaging 112 mg compared with the vitamin D-sufficient group. Nausea was also more common among patients with deficiency.

Researchers suggest that vitamin D supplementation before surgery could potentially help patients with low levels, but the study does not prove that deficiency causes greater pain or opioid use.

Because this was an observational, single-hospital study, other factors may have influenced the results. Researchers did not measure inflammation and lacked information about anxiety, depression, cancer stage, treatment and sleep problems.

The findings may be relevant because vitamin D deficiency is common among people with breast cancer, but supplementation should not be considered proven to prevent postoperative pain based on this study alone.

Larger studies are needed to determine whether correcting vitamin D deficiency before breast cancer surgery can actually reduce postoperative pain and opioid requirements.

REFERENCE: Mahdy Ahmed Abdelhady, et al.; Association between preoperative vitamin D level and postoperative pain in patients undergoing breast cancer surgery: a prospective observational study. Regional Anesthesia, 2026; rapm-2025-107495 DOI: 10.1136/rapm-2025-107495