Vitamin D Deficiency Linked to Increased Pain After Breast Cancer Surgery

A recent study indicates that breast cancer patients with insufficient vitamin D levels may endure heightened pain following surgery and require increased opioid medication for relief.

Conducted at Fayoum University Hospital in Egypt from September 2024 to April 2025, the research tracked 184 women scheduled for unilateral modified radical mastectomy. Half of these patients exhibited vitamin D deficiency, defined as levels below 30 nmol/L, while the remaining half had adequate vitamin D concentrations.

Both groups were comparable in demographics, with average ages of 44 and 42 years for the deficient and sufficient groups, respectively. Standard hospital protocols for pain management were applied, including fentanyl administration during surgery and intravenous paracetamol every eight hours postoperatively. Patients could self-administer tramadol via a control device with a 50mg hourly limit.

Vitamin D’s Influence on Postoperative Pain and Opioid Use

Researchers assessed pain intensity immediately after surgery and at intervals of 6, 12, 18, and 24 hours. Those with vitamin D deficiency were three times more likely to report moderate to severe pain within the first 24 hours compared to patients with sufficient vitamin D. Notably, no patient in either group experienced severe pain rated 7 or above on a 0–10 scale; differences were confined to moderate pain levels between 4 and 6.

During surgery, the vitamin D-deficient group received on average 8 micrograms more fentanyl, a difference described as modest. Post-surgery, however, these patients used 112mg more tramadol on average than those with adequate vitamin D levels.

Additional Findings and Study Limitations

Side effects associated with opioid use, such as nausea and vomiting, were more prevalent among vitamin D-deficient patients. Vomiting occurred exclusively in this group, though the difference lacked statistical significance.

The study's observational design and single-center setting limit causal conclusions regarding vitamin D deficiency and increased pain. The researchers did not measure inflammatory markers or collect data on patients’ anxiety, depression, cancer stage, prior treatments, or sleep disturbances before surgery.

Despite these limitations, the authors stated, “Vitamin D deficiency is associated with a higher occurrence of moderate to severe postoperative pain and increased opioid consumption in patients undergoing unilateral modified radical mastectomy.” They suggested that “preoperative vitamin D supplementation in breast cancer patients with vitamin D levels below 30 nmol/L may have a role in modulating postoperative pain.”