By Karla Gale
NEW YORK (Reuters Health) – In patients with type 1 diabetes mellitus, improved glucose control and smoking cessation almost immediately begin to reduce the risk of developing microalbuminuria, according to investigators in Boston.
Dr. Andrzej S. Krolewski at the Joslin Diabetes Center and associates identified 943 patients who had normoalbuminuria over a 2-year baseline period. During the ensuing 4 years, microalbuminuria developed in 109 subjects, according to the investigators' report in the December issue of Diabetes.
The researchers' analysis showed that the incidence rate of microalbuminuria changes "almost imperceptibly" as glycosylated hemoglobin levels (HbA1c) increase up to 8%. Beyond that, the risk rises steeply.
However, Dr. Krolewski told Reuters Health, "We do not see a cumulative effect of hyperglycemia. If somebody had poor glycemic control in the past and then improved, the risk [of renal complications] would quickly decline."
Current smoking is also significantly associated with the risk of onset of microalbuminuria. In fact, the epidemiologist stated, "Smoking is the most important risk factor for microalbuminuria." In the study, the effect of concurrent hyperglycemia and smoking on the risk of persistent microalbuminuria was greater than the sum of their separate effects.
As with normalizing blood glucose levels, quitting smoking significantly decreases the chance of developing kidney complications within about 6 months, Dr. Krolewski noted. "This is different from other diseases associated with smoking," he said. "For example, past smokers have to wait about 10 years before their risk of cancer is significantly reduced."
These findings could provide greater motivation for patients with diabetes to improve their lifestyle, Dr. Krolewski said. "If someone has poor glycemic control and smokes and hasn't yet developed kidney complications, that person should quit smoking and improve their glucose control. Then it doesn't matter what happened in the past."