Smoking – A Renal Risk Factor

Abstract

One of the most important tasks of clinical and experimental nephrology is to identify the risk factors of progression of renal failure. A major renal risk factor which has not been sufficiently acknowledged despite increasing evidence is cigarette smoking. Diabetologists were the first to recognize the adverse effects of smoking on the kidney: both in type 1 and in type 2 diabetes smoking (i) increases the risk of development of nephropathy and (ii) nearly doubles the rate of progression to end-stage renal failure. Until recently it was not known whether smoking also increases the risk to progress to end-stage renal failure in patients with primary renal disease. A retrospective multicenter European case-control study showed that smoking is an independent risk factor for end-stage renal failure in patients with inflammatory and noninflammatory renal disease, i.e. IgA glomerulonephritis and polycystic kidney disease. The pathogenesis of the smoking-related renal damage is largely unknown. The intermittent increase in blood pressure during smoking seems to play a major role in causing renal damage, but further potential pathomechanisms are presumably also operative. Smoking as a renal risk factor is of great interest to diabetologists as well as nephrologists, but unfortunately so far this information has had little impact on patient management. The present article reviews the current knowledge about the renal risks of smoking and discusses the potential mechanisms of smoking-mediated renal injury.

Predictors of diabetic nephropathy

“…Statistical analysis showed that smoking is associated with significantly elevated risk of DN (OR=2.24, CI 95% 1.27-3.96, P= 0.005) [23], with the greatest risk of CKD development among heavy smokers (>30 pack years) as reflected with OR=2.6 (95% CI=1.53-4.41, p < 0.0001) [23]. These results are in line with earlier clinical studies suggesting smoking as a major exacerbating factor for DN progression in both type 1 [24][25][26] and type 2 diabetics [27,28]. However, this study is suggesting association rather than causation.…”

Smoking and the Kidney

“…Several potential mechanisms of smoking-induced renal damage have been discussed (76), but the precise nature of the nephrotoxic effect of smoking is not well understood. The postulated smoking-induced pathomechanisms causing renal damage are summarized in Table 2.…”

“…The nicotine-induced increase in BP and heart rate via sympathetic activation and vasopressin release appears to be a major mechanism contributing to the adverse renal effects of smoking (for review see (76)). Nicotine directly stimulates catecholamine release from peripheral sympathetic nerve endings and the adrenal medulla.…”

Effects of Smoking on Systemic and Intrarenal Hemodynamics

“…Large epidemiologic studies had found that smokers are not more frequently hypertensive than nonsmokers (5). These studies, however, did not perform ambulatory BP measurement, which besides that smokers weigh less than their more obese nonsmoking counterparts explains these false-negative results (6). More recent studies using ambulatory BP measurement clearly document that smokers have higher BP than nonsmokers, i.e.…”