Smoking: a factor promoting onset and progression of diabetic nephropathy.

Although smoking was identified two decades ago as a factor promoting the onset and progression of nephropathy in Type 1 and then in Type 2 diabetes, its role has been largely neglected. More recently, it has been shown that smoking adversely affects renal haemodynamics and protein excretion even in subjects without renal disease. In addition, it impairs the prognosis for renal function in patients with non-diabetic renal disease. Recent studies have suggested the involvement of sympathetic activation, increased endothelin production, and impaired endothelial cell-dependent vasodilatation in the genesis of smoking-induced renal function impairement. Cessation of smoking apparently slows progression to renal failure, but the decision to stop smoking is difficult because of the high addictive potential of the habit. The challenge remains for diabetologists and nephrologists to motivate patients to stop smoking.