Smoking and kidney health: A hazardous connection

Cigarette smoking is well known to be a major cause of many health issues, such as cardiovascular disease (cardiovascular), respiratory disease(lungs), and cancer. Yet, one aspect of health that is not usually discussed when the topic of smoking comes up is its effect on the kidneys.

The kidneys are vital organs that filter waste products from blood, control blood pressure(BP), balance fluids, and keep the body in overall homeostasis.
smoking is bad for kidneys and is one of the main causes of CKD and progression of CKD and also it makes patients who already have a kidney problem do worse.
29% of Indians, (age 15+ years) in India use tobacco, and out of them the most common thing to smoke is tobacco.
11 to 12 per cent of Indian population suffers from CKD, most of these don't even know that they have a kidney component.
Before comprehending the effects of harm through smoking, there is a need to identify the vital role that the kidneys play. On average, each day, the kidneys filter around 180 lts of blood to clear waste and excess compounds via urine. They are also responsible for regulating electrolytes, secreting hormones such as erythropoietin (that stimulates the manufacture of red blood cells) and assisting with maintaining blood pressure using the renin-angiotensin-aldosterone mechanism. Thus, any injury to the kidneys would have extensive impact throughout the rest of the body.

How smoking hones the kidneys
1. Hindered blood flow and oxygenation:
Smoking makes way for nicotine and other toxins that constrict arteries in the body. This creates compromised blood flow and oxygen to the kidneys that weakens their capacity to operate as effectively. This long-term oxygen deficit, with the passing of time, may create scar tissue and injuries to the kidneys' tissues.
2. Higher blood pressure:
Smoking is a cause of high blood pressure, a leading risk factor for kidney disease. Nicotine activates the nervous system and leads to the release of catecholamines, which increase blood pressure and heart rate. Chronic hypertension injures the small blood vessels in the kidneys, impairing their filtering capacity and leading to CKD.
3. Proteinuria (Protein in Urine):
Smokers have a higher risk of developing proteinuria, an earlier indicator of kidney damage. Proteinuria itself is not just an indicator of kidney damage but also a pathogenic factor.
4. Oxidative stress and inflammation:
Cigarette smoke consists of thousands of harmful chemicals, most of which produce oxidative stress and inflammation. These phenomena hasten the aging of kidney tissues and worsen pre-existing kidney ailments
5. Diabetic kidney disease risk:
Smoking is particularly dangerous in people with diabetes. Diabetic kidney disease, is a frequent complication of diabetes. Smoking makes sugar control worse and increases the adverse effects of elevated sugar on kidney tissues.

Chronic kidney disease and smoking
Chronic kidney disease is a long-term condition characterized by a gradual loss of kidney function. It affects millions worldwide and can lead to end-stage kidney disease (ESKD), requiring dialysis or transplantation. Smoking not only increases the risk of developing CKD but also accelerates its progression. Studies have found that smokers with CKD are more likely to experience faster declines in glomerular filtration rate (GFR) and higher mortality rates compared to non-smokers.

Kidney transplant results and smoking
For end-stage kidney disease patients, transplantation is the best quality of life and long-term result. Smoking drastically undermines transplant success, though. Smokers have a greater chance of delayed graft function, rejection, and infection after transplanting, smoking heightens the risk of cancer following transplantation,
Several transplant centers currently mandate that patients stop smoking prior to being listed as eligible for kidney transplantation.

Secondhand smoke and kidney health
Secondhand smoke is also dangerous to kidney health. people who share living space with smokers can develop high blood pressure and compromised renal function in the long run, even if they themselves do not smoke.

The benefits of quitting smoking
The silver lining is that stopping smoking can greatly enhance kidney function and overall health. Ex-smokers experience a slow decrease in their risk of CKD over time. Blood pressure normalizes, inflammation reduces, and kidney function can improve or worsen more slowly. In patients with pre-existing kidney disease, smoking cessation is an essential part of treatment.
Healthcare professionals tend to feel that pairing behavioral therapy with pharmacologic agents, including prescription medications and nicotine patches, is the best way to ensure successful smoking cessation in their patients. Providing education on the dangers of smoking and how it specifically affects the kidneys can also encourage patients to work toward quitting.

Although the relationship between smoking and cancer and heart disease is known, the destructive nature of smoking on kidney health is no less grave and in need of concern. Smoking accelerates kidney deterioration, enhances susceptibility to chronic kidney disease, and complicates prognosis in patients who have underlying disease. It further lowers the efficacy of kidney transplant. Since kidneys play a very crucial part in keeping a person healthy overall, taking care of them by refraining from tobacco use is necessary. Not smoking, or not smoking at all, is among the strongest actions a person can do to keep their kidney function and their overall quality of life in top condition.

Dr. Anoop M Gowda, Consultant Nephrologist & Transplant Physician, Apollo Hospitals, Sheshadripuram, Bengaluru