10 Things That Increase Cancer Risk

Some cancer risk factors are well established and well known, like smoking. Others aren’t well known at all. Here are 10 things that are linked to cancer, some of which may surprise you:

1. Shift work. For all those employees working vampire hours, it’s discouraging to hear that shift work has joined the list of items considered “probably carcinogenic to humans,” according to the International Agency for Research on Cancer (IARC). Studies show that women working the graveyard shift, like flight attendants and nurses, have a greater risk of developing breast cancer. Researchers are investigating how disruption of the circadian system, the body’s natural sleep-wake cycle, can affect melatonin production and possibly cause tumors to develop.

2. High-temperature cooking. If you like your steak grilled to a crisp, you might be putting yourself at risk for something more than just burnt taste buds. Studies cite a connection between high-temperature cooking (like grilling or frying) and colorectal cancer. The good news, however, is that this greater cancer risk only seems to come into play in people with a specific type of genetic make-up.

3. Hormones. When a woman goes through menopause, her body produces fewer hormones. These lowered levels of estrogen and progesterone can trigger uncomfortable and sometimes painful symptoms. Menopausal women, or women with ovary issues, can choose estrogen and/or progestin replacement therapies to pump female hormones back into their bodies. Unfortunately, these hormone therapies carry the risk of endometrial (uterine) cancer, breast cancer, and possibly ovarian cancer. Women should carefully discuss the pros and cons of using female hormone therapies with their doctors.

4. Infection. “[We] once thought [that infection] didn’t have much to do with cancer,” says Michael Thun, MD, vice president of epidemiology and surveillance research for the American Cancer Society. However, Dr. Thun notes, infection and viruses are now linked to many cancers. For example, researchers have found connections between the human papilloma virus and cervical and ovarian cancers; hepatitis viruses B and C and liver cancer; bacterial infections and stomach cancer; and the human immunodeficiency virus and lymphomas.

5. Mom and Dad’s genes. You can develop cancer based on abnormal genes passed through your family tree. It’s more common for cancer to spread through a family based on carcinogenic exposure or just plain coincidence, but genetic mutations do occur (between 5 and 10 percent of cancers are inherited). Usually, abnormal genes are at fault if the cancer is a rare type; the person has more than one type of cancer; the person get the cancer at a younger age than is usual for that cancer type; the cancer impacts a pair of organs (like both kidneys); and childhood cancer affects multiple siblings. Prostate, ovarian, breast, and colon cancers are examples of cancers that can be passed on.

6. Diesel engine exhaust. Trying to breathe while you’re stuck behind a huge semi truck spewing out soot can be pretty miserable. However, it can be downright dangerous if you work or live near these pollutants. People who continuously inhale diesel exhaust have a higher risk of developing lung cancer, as well as respiratory problems like asthma.

7. Cancer treatments. It seems a cruel twist of fate that some therapies designed to treat cancer have carcinogenic properties. For example, tamoxifen (Nolvadex) is a medication used to treat breast cancer; however, potential side effects of the drug include the development of endometrial and uterine cancers. Some people treated with radiation therapy later develop a form of leukemia. Depending on the treatment and individual case, doctors may advise that the benefits of cancer treatments outweigh the risk of side effects.

8. Anabolic steroids. Manmade male hormones called anabolic, or androgenic, steroids can be used to help men with hormone-related problems. More often, however, we hear about the illegal side of steroids — athletes using these products to help build muscle mass and improve performance. Athletes may be able to run farther and score more points, but these skills will mean nothing if they develop one of the possible side effects of long-term anabolic steroid use — liver cancer.

9. Hair salon chemicals and dyes. Exposure to specific hair dyes, chemicals, and pigments has been linked to certain cancers for hairdressers and barbers. The IARC classifies these salon products as “probably carcinogenic to humans.” But before we all go through a lifetime of bad hair days, it’s important to note that hair dyes made for personal use have yet to show the same carcinogenic results. Hairdressers and barbers who wear gloves limit their exposure to these products. In addition, some of these cancer-causing agents already have been eliminated from certain hair products.

10. Hazards to painters. Artists should pay attention to their doctors as well as their critics. Painters put themselves at a higher risk of developing lung and bladder cancers when working with certain mediums. Although researchers have yet to determine which agents trigger the increased risk, it’s safe to say that painters who work around hazardous chemicals and pigments, including carcinogenic materials like silica and asbestos, may inadvertently be harming themselves.

Thun emphasizes that although there are many carcinogens in the world, people can do their part and keep cancer at bay by taking action in five important arenas: Avoid tobacco, eat right and exercise regularly, go for recommended screenings, limit alcohol, and maintain a healthy weight.

“If we could apply everything we know now, we could probably prevent almost half of the world’s cases of cancer,” he says.