Cancer and Other Risks of Hookah Smoking

The popularity of hookah smoking, in which a fruit-flavored tobacco product is inhaled through a glass pipe, is raising concerns about harmful effects such as cancer and other medical conditions. Hookah smoke contains many of the same carcinogens present in tobacco smoke. There is some indication, in fact, that hookah smoke may be even more dangerous, depending on factors such as how much smoke is inhaled and how deeply.

Hookah smoking is especially popular among teens and young adults, most of whom appear to be unaware that what they're inhaling is as potentially dangerous as cigarette smoke.

According to a 2014 study, 18% of high school seniors claimed to have smoked a hookah in the previous 12 months. Other research shows the rate of hookah smoking is around 30%, with most students generally unaware of the potential risk of disease. Among young adults, studies have found that up to 60% don't consider hookah smoking to have the dangers associated with cigarette smoking, and some don't even consider it "smoking."

Toxins and Carcinogens

According to the Centers for Disease Control and Infection (CDC), hookah smoke is at least as toxic as cigarette smoke: A 2015 review of studies looking at the potential toxins in hookah smoke found that it contains 27 known or suspected carcinogens.

Several of these were found to be in higher concentrations in hookah smoke than in cigarette smoke, including carbon monoxide (from the charcoal that is used to heat the water in a hookah pipie), which can contribute to heart disease; benzene; and high molecular weight polycyclic aromatic hydrocarbons (PAHs) for which levels are higher in hookah smoke than cigarette smoke. Other toxins found in both cigarette and hookah smoke include arsenic, cobalt, chromium, and lead.

Greater Amount of Inhaled Smoke

One reason hookah smoke may be more toxic than cigarette smoke is that more smoke is inhaled. In a typical "session" of water-pipe smoking (roughly an hour), 200 puffs are inhaled versus the 20 puffs ordinarily inhaled in smoking a single cigarette. This translates into a typical hookah session resulting in the inhalation of 90,000 milliliters (ml) of smoke as compared to the 500 to 600 ml of smoke inhaled with a cigarette.

Depth of Inhalation

People tend to inhale hookah smoke more deeply into the lungs than they do cigarette smoke. Although it hasn't been established that this is significant, it may help to look at changes in lung cancer rates after the addition of filters to cigarettes. Before cigarettes had filters, the smoke was not inhaled as deeply and was more likely to cause a type of lung cancer known as squamous cell carcinoma. This type of lung cancer occurs most often in the large airways entering the lungs (the bronchi) and due to this location, tends to be discovered at an earlier stage of the disease (because it leads to symptoms such as coughing, coughing up blood, wheezing, and frequent infections due to airway obstruction).

With the addition of filters to cigarettes, lung adenocarcinoma became more common. This type of lung cancer often occurs in the periphery of the lungs, and due to this location, is often found in the later stages of the disease.

Addiction

It is the nicotine in cigarettes that leads to addiction and nicotine is present in hookah smoke just as it is in cigarette smoke. Despite advertising to the contrary, hookah smoke does contain tar as well. It is the process of burning (with cigarettes) or heating (with hookah) which creates tar. In fact, hookah smoking may result in higher exposure to tar as it is smoked for a longer period of time and requires a stronger drag.

Risk of Cancer

Hookah smokers may be at risk for the same cancers caused by cigarette smoking, including:

• Lung cancer: Several of the same lung-cancer-causing carcinogens present in cigarette smoke are also found in hookah smoke. In a study in India, hookah smokers were over four times more likely to develop lung cancer than non-hookah smokers.
• Head and neck cancer
• Esophageal cancer
• Oral cancer: Tobacco irritates the tissues in the mouth and throat, and as seen with people who chew tobacco, causes inflammation which can lead to cancer.
• Stomach cancer (gastric cancer): Recent studies have shown an association between hookah smoking and stomach cancer, as well as precancerous lesions in the stomach of regular hookah users.
• Bladder cancer: In the United States, 50% of bladder cancers in men are caused by cigarette smoking.
• Pancreatic cancer: Studies have noted that hookah users have an increased risk of developing pancreatic cancer. Hookah smoking also increases the risk of gum disease which is a significant risk factor for pancreatic cancer.
• Leukemia: Benzene, a carcinogen associated with acute myelogenous leukemia (AML) and other blood-related cancers. Researchers evaluated 105 hookah smokers and 103 non-hookah smokers who were exposed to hookah smoke measuring the breakdown products of benzene before and after exposure. Hookah smokers had a level 4.2 times higher after smoking in a hookah bar and 1.9 times higher after a home event.

Other Health Conditions Related to Hookah Smoking

Just as with cigarette smoking, there are many other health conditions related to hookah smoking that go beyond cancer.

Hookah and Obesity

Although cigarette smoking is sometimes associated with weight loss, the opposite appears to be true with hookah smoking. A 2019 meta-analysis of studies looking at the association between obesity and hookah smoking revealed that hookah smoking is associated with a higher risk of obesity regardless of age or gender.

Exposure to Infections

Whereas cigarettes are usually smoked alone by an individual, a hookah pipe is usually shared by several individuals, as they "pass around" the pipe at a hookah lounge or home event. Bacteria or viruses present in the mouths of fellow hookah smokers may be "shared," including microbes like the oral herpes virus.

Other diseases and conditions that may result from hookah smoking are emphysema, chronic obstructive pulmonary disease (COPD), heart disease, osteoporosis, pregnancy complications, premature birth, and infertility.

Secondhand Hookah Smoke Risk

There has been little research looking at the effect of secondhand hookah smoke on non-smokers. Environmental tobacco smoke (ETS) or secondhand smoke refers to a combination of mainstream smoke, sidestream smoke, and smoke exhaled by smokers.

Since many of the toxins and carcinogens present in cigarette smoke are present in hookah smoke, it seems logical that the secondhand smoke from a hookah would be as potentially dangerous as that from a cigarette. That said, the secondhand smoke from a hookah may be different from inhaled secondhand smoke from a cigarette, with much of the exposure being made up of smoke exhaled by the smoker. Whether this is good or bad is another question.

Studies have found that levels of benzene increase in people exposed to hookah smoke. There also is research to show that levels of a lung carcinogen called NNK (4-[methylnitrosamino]-1-[3-pyridyl]-1-butanone) is found in higher levels in the bedrooms of children exposed to weekly or monthly hookah smoking.

The bottom line is that despite the seemingly innocuous practice of hookah smoking and the fruity flavor of the tobacco product, a hookah habit may be as hazardous to one's health—and the health of loved ones, especially children and young adults—as cigarette smoking.