Quit smoking; 2.2 X more likely if vitamin D level > 20 ng
The relationship between smoking cessation and vitamin D
Irish Journal of Medical Science 2026 Feb 28. doi: 10.1007/s11845-026-04290-6
Turkey
Background Smoking addiction is the most important reversible risk factor affecting many organs, including the heart, lungs, and central nervous system. Smoking cessation alone should not be the sole focus of smoking addiction, and comorbidities should be considered.
Aims In our study, the relationship between successful smoking cessation and vitamin D levels was analyzed.
Methods This was a retrospective cohort study. Our study included patients who visited the smoking cessation outpatient clinic. All patients were started on the same dosage of cytisine active ingredient at the same time. After one month of treatment, smoking cessation success and vitamin D levels were compared. In addition, demographic data, the amount and duration of smoking, and smoking cessation success after treatment were recorded.
Results Our study included 327 patients and the smoking cessation rate after treatment was 58.7%. A statistically significant correlation was found between vitamin D level and smoking cessation success. We found that patients with higher vitamin D levels had a higher smoking cessation success rate
Conclusion Many studies have reported a relationship between addiction and vitamin D level. Vitamin D supplementation has been used in many addiction treatments, and positive results have been obtained with this treatment. In our study, we found that patients with low vitamin D levels had low smoking cessation success rates. In our study, we found a relationship between high vitamin D levels and smoking cessation success and suggested that vitamin D supplementation should be initiated in patients with low vitamin D levels to increase the smoking cessation rate.
Claude AI - 2.2 more likely to quit if > 20 ng
The study doesn't explicitly calculate a risk ratio or odds ratio for the comparison. What it does report is the raw data from which you can derive one:
- Vitamin D ≥20 ng/mL (110 patients): 78 quit (70.9%)
- Vitamin D <20 ng/mL (217 patients): 114 quit (192 total quitters minus 78 = 114, so about 52.5%)
They simply state a statistically significant correlation (p<0.05) between having vitamin D ≥20 ng/mL and smoking cessation success, but they never compute a relative risk, odds ratio, or hazard ratio to quantify the magnitude of that association.
From the numbers, you can calculate that patients with adequate vitamin D were roughly 1.35× more likely to quit than those who were deficient (70.9% vs. 52.5%), or equivalently, the deficient group had about a 35% lower relative success rate. The odds ratio works out to approximately 2.2 (favoring the ≥20 ng/mL group).
It's a notable gap in the paper — a formal adjusted odds ratio accounting for confounders like smoking duration (which was also significant) would have strengthened their findings considerably.