Issue 133 Item 9 Vitamin E Unlikely to Reduce Microvascular Complications in Dia

Vitamin E supplementation has no demonstrable effect on major cardiovascular outcomes, microvascular complications or glycemic control in diabetics at high risk for cardiac events. That’s according to results of the Heart Outcomes Prevention Evaluation (HOPE) trial and the Microalbuminuria Cardiovascular Renal Outcomes (MICRO-HOPE) substudy.

Results of the original HOPE study, published in 2000 in The New England Journal of Medicine, showed no cardiovascular benefit to vitamin E in individuals at high risk for MI, stroke or other CV-related death.

In the MICRO-HOPE substudy researchers looked at the effects of vitamin E therapy on CV events and microvascular outcomes in 3654 middle-aged and elderly diabetics in the HOPE trial. The results of MICRO-HOPE are published in the November issue of Diabetes Care.

Dr. Eva Lonn of McMaster University in Hamilton, Ontario, Canada said that, MICRO-HOPE is "the largest study of vitamin E on microvascular complications of diabetes ever published."

Briefly, Dr. Lonn and colleagues randomized diabetics to daily administration of 400 IU vitamin E and 10 mg ramipril, or their respective placebos, and followed them for an average of 4.5 years.

In addition to the neutral effect of vitamin E on macrovascular outcomes, the current study found "no effect on diabetic nephropathy and other microvascular complications, [such as] the need for laser therapy for diabetic retinopathy," she said. Vitamin E also had no marked effect on glycemic control.

"The use of antioxidant vitamins was advocated as potentially particularly beneficial in people with diabetes, as these people have higher oxidative stress related to hyperglycemia," Dr. Lonn said.

"Unfortunately, based on the results of our study, vitamin E cannot be recommended in the prevention of vascular disease or microvascular complication…in people with diabetes," she added. "The use of proven effective preventive therapies such as lipid lowering, blood pressure control and glycemic control needs to be pursued." Diabetes Care 2002;25:1919-1927.