Could your job increase your risk of cancer? Nearly 40% of Americans will be diagnosed with cancer at some point in their lives, according to the National Cancer Institute.

While most people are aware of the major risk factors involved with the disease, not many have stopped to think about whether or not their job could be making them sick — until now. Reader's Digest released a report listing several jobs that can increase your risk of cancer. We look at seven of those:

1. Flight attendant — Experts are finding mounting evidence that links the job of a flight attendant to an increased risk of cancer. This could be because at high altitudes, cabin crew are exposed to more ionizing radiation, which could lead to several types of cancer that affect the colon, breast, stomach, and liver.

2. Welder — Exposure to welding fumes, radiation, and asbestos can potentially cause various health problems in welders that include lung cancer, kidney cancer, and melanoma of the eye. Paul Blanc, professor of medicine at the University of California–San Francisco noted that exposure could also result in "damage to the lungs, causing scarring, and damage to other internal organs, including the liver and kidneys."

3. Desk jobs — Researchers are now suggesting that sitting too much behind a desk could be linked to cancer. In fact, people who spend most of their time seated have a 24% higher risk of colon cancer and a 32% higher risk of endometrial cancer, studies have found. Time in the gym is not enough to counteract the damage of sitting all day and experts advise getting up and moving around often during the course of the day.

4. Manicurist — Nail technicians are exposed to toxic fumes and chemicals each and every day, which are inhaled or absorbed through the skin. These toxins can raise the risk of cancer while causing serious harm to the respiratory and reproductive systems.

5. Farmer — Forget rustic, outdoor living — agricultural workers exposed to pesticides have a much higher chance of developing various types of cancer that affects the stomach, prostate, skin, and brain, studies have found. Exposure to other factors such as engine exhaust, solvents, and fertilizers add further risk to clinical illness.

6. Firefighters — These rescue workers are putting their lives on the line in more than one way. In addition to the obvious dangers of the job, exposure to toxins released by burning plastic, building materials, and other substances can greatly increase their risk of developing several types of cancer, including testicular cancer and mesothelioma.

7. Car mechanics — Each day auto mechanics are exposed to a number of toxic chemicals and carcinogens that can increase their risk of developing various cancer types that affect the kidney, bladder, lung, bladder, esophageal, and stomach.

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