- L H Soderstrom: Department of Medicine, Division of Biostatistics and Epidemiology, Medical University of South Carolina, Charleston, SC 29425, USA.
AIMS: To evaluate the association between Vitamin D insufficiency and peripheral neuropathy in a nationally representative sample of adults with diagnosed diabetes.
METHODS: Vitamin D concentrations, medical examination variables and questionnaire results from the 2001-2004 National Health and Nutrition Examination Survey were analysed for adults ≥ 40 years old with diagnosed diabetes (unweighted n = 591, weighted n = 8.82 million). neuropathy was defined as self report of peripheral neuropathy symptoms of painful sensation, tingling, numbness or loss of feeling in hands or feet. Additionally, Semmes-Weinstein monofilament test results were used as an indicator of neuropathy. Insufficient Vitamin D was characterized as < 30 ng/ml.
RESULTS: In the weighted population, 81% of adults with diabetes had Vitamin D insufficiency. Vitamin D insufficiency was more common among Hispanics (92%) and non-Hispanic black people (98%) than among non-Hispanic white people (76%). Within the 3 months preceding the questionnaire, 50% reported experiencing pain or numbness (paresthesia) in their hands or feet; 37% reported pain or tingling in hands or feet; and 38% reported numbness or loss of feeling in hands or feet. Eight per cent had 4-6 insensate areas on their feet as determined by the Semmes-Weinstein monofilament test. Logistic regressions demonstrate Vitamin D insufficiency is associated with the adjusted composite paresthesia measure (odds ratio 2.12; 95% CI 1.17-3.85) and the adjusted numbness measure (odds ratio 2.04; 95% CI 1.18-3.52).
CONCLUSIONS: Vitamin D insufficiency is associated with self-reported peripheral neuropathy symptoms even after adjusting for demographic factors, obesity, co-morbidities, use of medications for neuropathy and diabetes duration and control.