Smoking increases the risk of renal dysfunction in men with diabetes type 2

Smoking is associated with a low glomerular filtration rate in type 2 diabetic men, according to an Italian study published in "Diabetes Care".

If the association between smoking and renal dysfunction has been clearly established in type 1 diabetes, "studies in type 2 diabetes were conducted on small samples, so do not do we have data conclusive, "explained Dr. Salvatore De Cosmo Institute Casa Relief of Suffering in San Giovanni Rotondo (Italy), and colleagues.

The Italian team measured the glomerular filtration rate of two groups of men with diabetes type 2: 158 participants who smoked at least one cigarette per day for more than a year and 158 others who had never smoked. For their study, the authors considered the estimated glomerular filtration rate (eGFR) as weak when it was below 60 ml/min/1, 73 sqm.

Their analysis allowed them to rank the most important predictors of a low GFR, which were comparable in smokers and nonsmokers. Hypertension (odds ratio or OR = 3.26) ahead of albuminuria (OR = 3.15), metabolic syndrome (OR = 2.79), smoking (OR = 1.97) and length of diabetes (OR = 1.03).

The proportion of patients with a low eGFR was significantly higher in smokers (20.9% vs. 12%). The risk to smokers thus appeared 2.2 times higher after adjusting for various risk factors (duration of diabetes, albuminuria, dyslipidemia and glycated hemoglobin or HbA1c).

According to Italian researchers, who are based on the results of more extensive calculations to establish these findings, the deleterious effects of smoking on renal function would be related to the fact that accelerates the development of a low GFR. However, they result as "modest" metabolic syndrome (whose occurrence is favored by smoking and affects itself renal function).

THE RISK OF THIS ALSO hyperfiltration

In the subgroup of patients with an eGFR greater than or equal to 60 ml/min/1, 73m ², the proportion of participants with hyperfiltration (GFR> 120 ml/min/1, 73m ²) also proved superior (15 2% vs. 5.7%).

"The increase in blood pressure and heart rate induced by nicotine via a sympathetic action and the release of vasopressin, probably explains the higher hyperfiltration in our smoking rate," say the authors.

Finally, a test in two subgroups of smokers (46 patients) and non-smokers (54 patients), Italian researchers showed higher values of free radicals in smokers (560 vs 442.7) sign of a greater oxidative stress in these patients. This element could play a role in the induction of inflammation and endothelial dysfunction, but also be involved in increasing the risk of developing a low GFR.

"Until prospective studies that clarify the links [causal] between smoking and kidney damage in diabetic patients, it is recommended to increase aid to smoking cessation in patients with type 2", conclude the authors.