Association of dietary vitamin E intake with current stone formation: A NHANES analysis 2017 - 2020.

Introduction: Free radical-mediated oxidative renal tubular injury secondary to hyperoxaluria is a proposed mechanism in the formation of calcium oxalate stones. Vitamin E, an important physiologic antioxidant, has been shown in rat models to prevent calcium oxalate crystal deposition. Our objective was to determine if low dietary vitamin E intake was associated with a higher incidence of stones.

Materials And Methods: We analyzed data from the 2017 to 2020 National Health and Nutrition Examination Survey, a nationally representative sample (n = 7,707). A multivariable logistic regression model was used to assess the association between elevated dietary vitamin E intake (≥ 15 mg/day) and nephrolithiasis controlling for key demographic variables: water and nutrient intake (sodium, calcium, vitamin C), and diabetes mellitus.

Results: The incidence of nephrolithiasis was 1.66% (1.38% - 1.95%). In patients consuming < 15 mg/day vitamin E, the incidence was 1.8% compared to 0.8% in patients with vitamin E intake ≥ 15 mg/day (p = 0.024). In adjusted models, participants with low vitamin E intake had a significantly higher odds of reporting stone passage (aOR = 2.83, 95% CI (1.07 - 7.5)).

Conclusion: We found that low vitamin E intake is associated with a > 2.5× greater odds of stone passage. These data are consistent with animal models suggesting that vitamin E may play an important protective role in the pathogenesis of calcium oxalate stone formation. This is the first study assessing the relationship between vitamin E intake and nephrolithiasis in humans. Future investigation of vitamin E supplementation in stone formers may help further determine if vitamin E is useful in the management of calcium oxalate stones.