Researchers in Qatar looked at nearly 24,000 patients who had surgery to see if vitamin D levels affected their risk of getting infections at the surgical site afterward. They found that patients with low vitamin D before surgery were more likely to develop infections compared to those with normal vitamin D levels. Since vitamin D helps your immune system fight off germs, this finding suggests that checking and improving vitamin D levels before surgery might be a simple way to help prevent these infections, which can be serious and costly to treat.

The Quick Take

  • What they studied: Whether having low vitamin D before surgery increases the chances of getting an infection at the surgery site
  • Who participated: Nearly 24,000 adult patients who had surgery in Qatar between 2021 and 2023. About 55% were women, the average age was 45 years old, and about 16% had low vitamin D levels
  • Key finding: Patients with low vitamin D had infection rates of 2.7%, compared to 1.8-1.9% in those with normal vitamin D levels—meaning low vitamin D roughly doubled the infection risk
  • What it means for you: If you’re planning surgery, getting your vitamin D checked beforehand might help reduce your infection risk. However, this study shows a connection but doesn’t prove vitamin D supplements will definitely prevent infections, so talk to your doctor about your individual situation

The Research Details

This was a retrospective chart review, which means researchers looked back at medical records from patients who had already had surgery. They examined records from a large hospital system in Qatar between 2021 and 2023. They specifically looked for patients who had their vitamin D levels measured within three months before surgery and then tracked whether those patients developed infections after surgery.

The researchers organized patients into three groups based on their vitamin D levels: deficient (very low), insufficient (somewhat low), and sufficient (normal). They then used statistical analysis to compare infection rates between these groups while accounting for other factors that might affect infection risk, like age, gender, and type of surgery.

This type of study is useful for finding patterns in large groups of people, but it can’t prove that low vitamin D directly causes infections—only that the two seem connected.

This research approach is important because it looks at real-world data from thousands of actual patients rather than a small controlled experiment. This makes the findings more relevant to everyday medical practice. The large sample size (nearly 24,000 patients) gives the results more credibility. However, because researchers were looking backward at existing records rather than randomly assigning people to different vitamin D levels, we can’t be completely certain that vitamin D deficiency itself causes the infections or if other factors might be involved.

Strengths: The study included a very large number of patients from a real hospital system, which makes the findings more reliable and applicable to real life. The researchers used proper statistical methods to account for other factors that might affect infection risk. Limitations: This was a retrospective study, so researchers couldn’t control all the variables like they could in a controlled experiment. The study only included patients from Qatar, so results might not apply equally to other populations. The study doesn’t prove cause-and-effect, only that low vitamin D and infections are connected.

What the Results Show

Out of 24,097 patients studied, 3,818 (about 16%) had vitamin D deficiency before surgery. The key finding was that infection rates differed significantly between groups: patients with low vitamin D had a 2.7% infection rate, while those with insufficient vitamin D had 1.8%, and those with normal vitamin D had 1.9%.

This means that patients with low vitamin D were roughly 1.4 to 1.5 times more likely to develop surgical site infections compared to those with normal vitamin D levels. The difference was statistically significant, meaning it’s unlikely to have happened by chance.

The study also noted that about 55.8% of Qatar’s population has vitamin D deficiency, which is much higher than in many other parts of the world. This makes the findings particularly relevant for the Middle Eastern region, where vitamin D deficiency is extremely common due to factors like sun exposure patterns and dietary habits.

The study found that vitamin D deficiency was quite common in the surgical population studied—affecting about 16% of patients who had vitamin D levels measured. The researchers noted that vitamin D plays an important role in immune function and the body’s ability to fight off bacteria and other germs. This biological mechanism helps explain why low vitamin D might increase infection risk. The findings suggest that about 60% of surgical site infections might be preventable by addressing modifiable factors like vitamin D levels, along with other infection prevention strategies.

This is the first study to directly examine the link between vitamin D deficiency and surgical site infections in Qatar’s population, even though vitamin D deficiency is very common there. Previous research in other parts of the world has suggested that vitamin D plays a role in immune function and infection prevention, but this study provides specific evidence from a large Middle Eastern population. The findings align with what scientists already know about vitamin D’s role in immunity, making the results more believable.

The study looked backward at existing medical records rather than following patients forward, which limits what we can conclude. We can’t be sure that low vitamin D directly causes infections—other unmeasured factors could be involved. The study only included patients from one hospital system in Qatar, so results might not apply to other countries or populations with different genetics, diets, or sun exposure. Not all surgical patients may have had vitamin D levels measured, which could bias the results. The study didn’t look at whether patients received vitamin D supplements or other treatments that might have affected their vitamin D levels.

The Bottom Line

If you’re planning surgery, ask your doctor to check your vitamin D level beforehand (moderate confidence). If your level is low, discuss with your doctor whether vitamin D supplementation before surgery makes sense for you (moderate confidence). This is especially important if you live in the Middle East or other regions where vitamin D deficiency is common. However, this should be one part of a comprehensive infection prevention plan that includes proper wound care, sterile surgical techniques, and other proven prevention strategies.

This finding is most relevant for people planning elective (non-emergency) surgery who have time to address vitamin D levels beforehand. It’s particularly important for people living in regions with high rates of vitamin D deficiency, like the Middle East. People with known vitamin D deficiency or risk factors for deficiency (limited sun exposure, certain diets, darker skin in sunny climates) should especially consider getting tested. This may be less relevant for emergency surgeries where there’s no time to address vitamin D levels beforehand.

If you’re found to have low vitamin D before surgery, it typically takes 4-12 weeks of supplementation to significantly raise vitamin D levels, depending on how low they are and the supplement dose. Ideally, you’d want to optimize vitamin D levels several weeks before planned surgery. If surgery is sooner, discuss with your doctor whether supplementation is still worthwhile or if other infection prevention measures should be emphasized.

Want to Apply This Research?

  • If you’re planning surgery, track your vitamin D levels monthly for 3 months before the procedure. Record the date, your vitamin D level (in ng/mL or nmol/L), any supplements you’re taking, and sun exposure. This helps you and your doctor monitor progress toward optimal levels.
  • If your vitamin D is low, use the app to set a daily reminder to take your vitamin D supplement at the same time each day. Log your supplement intake and any dietary sources of vitamin D (fatty fish, fortified milk, egg yolks). Track outdoor time in sunlight, aiming for 10-30 minutes of midday sun exposure several times per week if possible.
  • Set up monthly check-ins in the app to record your vitamin D test results as you get them. Create a pre-surgery checklist that includes vitamin D optimization as one item. After surgery, use the app to monitor your surgical site for any signs of infection (redness, warmth, discharge, increased pain) and report concerning changes to your healthcare provider immediately.

This research shows a connection between low vitamin D and surgical site infections but does not prove that vitamin D deficiency directly causes infections. This information is for educational purposes and should not replace professional medical advice. Before surgery, consult with your surgeon and primary care doctor about your vitamin D levels and whether supplementation is appropriate for you. Do not start, stop, or change any supplements without discussing it with your healthcare provider first. If you develop signs of infection after surgery (fever, redness, warmth, drainage, or increased pain at the surgical site), contact your healthcare provider immediately.