Supplementary Material for: Vitamin D and Albuminuria in Youth with and without Type 1 Diabetes

Background/Aims: In adults, lower vitamin D has been associated with increased albuminuria. This association has not been extensively studied in youth with or without type 1 diabetes. Methods: We examined the cross-sectional association between vitamin D and albuminuria (urine albumin to creatinine ratio ≥30 mg/g) in 8,789 participants of the National Health and Nutrition Survey 2001–2006 (NHANES), who were 6–19 years old. Further, we examined the association between vitamin D and albuminuria in 938 participants from the SEARCH Nutritional Ancillary Study (SNAS), a longitudinal cohort of youth with type 1 diabetes. Results: Of the NHANES participants, 5.3, 19.5, and 53.7% had vitamin D levels <30, 50 and 80 nmol/L, respectively. Albuminuria was present in 12.8% and was more common in younger children, females, non-Hispanic whites, non-obese children, and children with hypertension. After adjustments, there was no association between vitamin D and albuminuria. Among the SNAS participants with type 1 diabetes, we also found no association between baseline vitamin D and subsequent albuminuria in unadjusted or adjusted analyses. Conclusion: We did not find an association between serum vitamin D and albuminuria in either non-diabetic youth or those with type 1 diabetes. Further research is needed to more fully understand this relationship.