How does cigarette smoking affect kidney health?

How Cigarette Smoking Affects Kidney Health

Cigarette smoking is an established, modifiable risk factor for both the development and progression of chronic kidney disease (CKD), and all patients with kidney disease or at risk for kidney disease should be strongly advised to quit smoking immediately and commit to lifelong abstinence. 1

Direct Effects on Kidney Function

Smoking accelerates kidney disease progression across all causes of CKD, including diabetic nephropathy, IgA glomerulonephritis, and polycystic kidney disease. 2, 3, 4

• Tobacco use increases proteinuria and accelerates the decline in glomerular filtration rate in both the general population and those with established kidney disease 2, 3
• In diabetic patients, smoking nearly doubles the rate of progression to end-stage renal failure and increases the risk of developing nephropathy in both type 1 and type 2 diabetes 4
• The adverse effects are dose-dependent and time-dependent, meaning heavier and longer smoking causes greater kidney damage 2

Cardiovascular Risk Amplification

Patients with CKD who smoke face compounded cardiovascular risk, as CKD itself dramatically increases cardiovascular event rates, and smoking further multiplies this already elevated baseline risk. 1

• Current smokers with non-dialysis CKD (NDD-CKD) have significantly higher rates of cardiovascular events compared to never smokers, and this relationship persists even in subgroups with prior cardiovascular disease or diabetes 1
• Smoking is associated with all-cause mortality in hemodialysis patients, though the relationship with cardiovascular events specifically in dialysis populations shows conflicting results 1

Kidney Cancer Risk

Tobacco smoking is one of the most established modifiable risk factors for renal cell cancer, which accounts for 80-85% of kidney cancers. 1

• The best advice to reduce kidney cancer risk is to maintain a healthy weight and avoid tobacco use entirely 1

Benefits of Smoking Cessation

Smoking cessation attenuates the increased risk of kidney damage and slows CKD progression, with former smokers demonstrating lower cardiovascular event rates than current smokers. 1, 2

• Studies show that former smokers have lower cardiovascular event risk compared to current smokers with CKD 1
• The benefits of cessation are time-dependent, with risk reduction occurring progressively after quitting 2

Mechanisms of Kidney Damage

The pathogenesis involves multiple mechanisms, with intermittent blood pressure increases during smoking playing a major role, though the complete pathophysiology remains incompletely understood. 4

• Smoking causes acute hemodynamic changes including blood pressure elevation that directly damages kidney tissue 4
• Additional mechanisms beyond blood pressure effects are likely operative but require further investigation 4

Kidney Transplant Outcomes

Smoking worsens survival in kidney transplant recipients and shortens graft survival. 2

• Tobacco exposure negatively impacts both patient survival and allograft function after kidney transplantation 2

Clinical Recommendations

All patients with CKD or at risk for CKD should be strongly counseled to avoid tobacco products entirely, with referral to smoking cessation programs where available. 1, 5

• The 2024 KDIGO guidelines emphasize that patients with CKD should not use tobacco products as part of comprehensive lifestyle modification 1, 5
• Healthcare providers should recommend tobacco cessation given the known health and economic benefits, even though few studies have specifically examined cessation benefits in the CKD population 1
• Referral to smoking cessation programs should be offered where indicated and available 1, 5

Special Considerations for Living Kidney Donors

Potential living kidney donors who smoke should be advised to quit at least 4 weeks prior to donation to reduce perioperative complications and commit to lifelong abstinence to prevent long-term complications. 1

• Heavy smokers with health issues attributable to smoking are unlikely to be acceptable donors 1
• For moderate or light smokers, strong counseling and smoking cessation before donation is reasonable 1

Emerging Concerns: E-Cigarettes

E-cigarette use should also be discouraged, as emerging evidence suggests vaping may cause kidney damage including albuminuria and reduced eGFR, though long-term data remain limited. 6

• Cross-sectional studies suggest associations between vaping and kidney damage in adolescents and young adults 6
• Animal experiments indicate e-cigarette constituents may lead to structural and functional kidney damage 6
• Nephrologists should actively address both conventional cigarette smoking and e-cigarette use in their patients 6

Common Pitfalls to Avoid

• Do not underestimate smoking as a kidney risk factor simply because randomized controlled trials are lacking—the observational evidence is compelling and consistent across multiple populations 2, 3, 4
• Do not assume the cardiovascular risks of smoking are less relevant in advanced CKD or dialysis patients—mortality risk remains elevated even if cardiovascular event associations are inconsistent in some dialysis studies 1
• Do not fail to invest effort in motivating patients to quit—nephrologists must prioritize smoking cessation counseling as an essential component of CKD management 3