Lower vitamin D levels are found in patients with painful diabetic peripheral neuropathy (DPN) compared to those with painless DPN, patients with diabetes without any neuropathy, and healthy people.

The findings have major clinical significance because painful DPN is distressing and disabling.

25% of DPN patients have pain and most are undiagnosed and suffer in silence because they believe it is just part of the aging process," he explained. The small proof-of-principle study was a borne out of anecdotal findings that vitamin D supplements or injections given to patients with painful DPN improved their pain.

The article was published online August 13 in Diabetic Medicine.