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Updated June 06, 2015.

Humans have been smoking since antiquity. As a social vehicle for interaction, its use originated in the Americas 5000 years ago. So for a good five millennia, no one had any problem with smoking. The "ignorance is bliss" attitude lasted until the late 1900's when smoking's ill health effects became apparent. Even then, the tobacco industry put up a big fight challenging that conclusion.

Worldwide, legislation has helped drastically reduce smoking rates.


The fact that smoking is bad for your health is not even much of a debate anymore. There is ample evidence that smoking causes cancer, lung disease, heart disease, etc. Cigarette smoke contains harmful chemicals including carbon dioxide, lead, and cadmium. Today, the average smoker dies 10 years younger, and 1 in 5 deaths in the US are related to cigarette smoking.

HOW SMOKING CAUSES KIDNEY DISEASE

Smoking's harmful effects on the kidneys are not as well understood by the average person as its effects on other organs. Here are some ways smoking hurts your kidneys:

Short-term effects

• Smoking increases nervous system activity which leads to increase in blood pressure.
• The above change leads to changes in kidneys' blood supply and reduction in the kidneys' filtration rate, or the GFR.
• This increase in blood pressure and reduction in kidneys' blood flow begin to harden the kidneys arterioles.

Long-term effects

Persistence of the above short-term changes because of continued smoking eventually leads to permanent changes in the kidneys' vasculature.

There is alteration in substances that are essential to maintain the kidneys' function including prostaglandins and nitric oxide.  As these effects take hold, the kidneys' cells begin to die and are progressively replaced by dead scar tissue.

WHAT DO THESE CHANGES MEAN FOR THE KIDNEY

On account of the above changes, smoking has been linked not just to the development of chronic kidney disease in an otherwise healthy person, it is also associated with faster decline in kidney function in people already diagnosed with chronic kidney disease. Initially, physicians used to think that smoking only hurt the kidneys indirectly due to its effect on raising blood pressure and causing hypertension.  However now we know that smoking is an independent risk factor for kidney disease, above and beyond its role in causing blood pressure elevation. Smoking's association with heart and vascular disease is also a risk factor which only exacerbates the decline.

As the kidney function continues to decline, smokers could eventually develop advanced stages of chronic kidney disease (CKD), which in the worst case could require dialysis or kidney transplantation. 

THE LINK WITH KIDNEY CANCER

As if the prospect of dialysis was not scary enough, long-term smoking also brings the risk of developing kidney cancer. Smoking increases risk of a type of kidney cancer called renal cell carcinoma (RCC). If you look at patients diagnosed with RCC, a good 30% are found to have a link with long term smoking. As per this study, there is even a clear relationship between the number of cigarettes smoked and RCC risk.  

Its not just the RCC risk that the smoker has to worry about. Heavy smokers are also more likely to develop aggressive and advanced form of kidney cancer, which is likely to have spread to other organs by the time of diagnosis. 

CONCLUSION

No matter how you look at it, smoking is bad for you. The average person is usually pretty well aware of its damaging effects on lungs and the heart. However, smoking significantly ups the risk of kidney disease as well, including kidney cancer. In the worst case scenario, the heavy smoker could develop advanced kidney failure to the point where they might require dialysis or transplantation.