Age, smoking, obesity and sedentary lifestyles are well known causes for many types of cancer. Recent research, though, has uncovered some everyday things you probably had no idea pose a cancer threat.
1. Automobile Exhaust
In the modern world, nearly everyone is exposed to diesel exhaust, a complex mixture of soot and gases that fill roadways of cities, farms, waterways, mines and other places. The World Health Organization (WHO) now says petroleum -- mainly diesel -- fumes definitely causes cancer in humans by changing the DNA inside cells.
Diesel exhaust is also believed to play a role in other health problems, such as eye irritation, headache, asthma and other lung and heart disease, and possibly immune system problems.
In 2012 the WHO reclassified diesel exhaust to the same health risk category as asbestos, arsenic and mustard gas.
The U.S. Environmental Protection Agency doesn’t go that far. It considers diesel exhaust a likely, rather than known, human carcinogen.
An analysis published in February 2014 in Environmental Health Perspectives, a journal funded by the National Institutes of Health, reviewed three studies on miners and truck drivers and estimated that 6 percent of lung cancer deaths annually were due to workplace and environmental diesel exhaust exposure.
2. Birth Control
Some newer versions of the drugs used to prevent pregnancy -- particularly those with high doses of estrogen, some types of progestin and certain dosing schedules -- appeared to boost the risk of breast cancer 50 percent or more, according to a review of 20 years of health system electronic pharmacy records.
Researchers at the Fred Hutchinson Cancer Research Center found birth control pills manufactured in the last year that contain high-dose estrogen (50 micrograms or more) boosted breast cancer risk nearly threefold. Those that contained moderate-dose estrogen (30-35 micrograms) increased the chances about 1.6 times.
Other risky culprits were pills that contained a type of progestin called ethynodiol diacetate, and triphasic pills that deliver drugs in multiple doses or phases containing norethindrone.
In contrast, pills that delivered low-dose estrogen (20 micrograms) didn’t increase the risk, the study showed.
3. Microwave Popcorn
You may have heard the myth that microwave popcorn flavorings contains chemicals proven to cause lung cancer. You can relax, we're definitely not claiming that. Microwave popcorn bags, on the other hand, may pose a minor concern.
It seems the bags use a nonstick coating on the inside that decomposes when heated and then cooled. The compound perfluorooctanoic acid is produced. It’s associated with increased risk of liver and prostate cancer.
Some good evidence exists. One 1993 study found that factory workers exposed to the chemical had increased cancer mortality. it is still inconclusive, though, as to whether or not microwave popcorn bags pose any risk.
Many cosmetics, antiperspirants, sunscreens, shampoos and personal lubricants today contain parabens. These are preservatives that protect the products from molds, bacteria and fungi contamination, extending the shelf-life.
Concern over parabens rose when researchers discovered they produce estrogen-like properties that mimic the natural female hormones that may cause cancer of the reproductive organs to grow.
While the jury is still out on parabens, there seems to be two camps forming. One camp thinks that low doses of parabens, such as those found in cosmetic products, pose no serious risk, even if used long term. The other believes that any evidence that a substance may be linked to cancer, regardless of the dose, should be cause enough for it to be banned from use.
Most scientists and regulatory agencies fall in the first camp, but several cosmetic companies have now voluntarily stopped using parabens in their products. If you want to go paraben-free, look for products without parabens which start with the words methyl, ethyl, propyl or butyl.
5. Night-Shift Work
There is mounting evidence that if you work the night shift, you are also raising your risk for certain types of cancer, including breast cancer. Several studies have found long-term night-shift workers (30 year or more) have higher rates of cancer, but researchers still don’t know why.
One theory involves exposure to light. Such exposure is known to reduce the production of melatonin. So night-shift workers going from a day environment to an artificial light environment at night would have lower levels of this hormone.
Another theory is that night work interrupts the natural circadian cycle, the body’s molecular clock that regulates sleep, metabolism, the immune system, temperature and other physiological and biochemical processes. This also lowers melatonin production.
Researchers say the melatonin-sleep-cancer link is far more complicated than once thought. It may not be when you sleep or how long, but rather how well you sleep that matters most.
Also, certain races tend to have higher natural melatonin levels than others, so genetics may be a significant factor. The one thing researchers do agree on is that getting enough restful sleep is critical to good health.
“A third of us are sleeping less than 6 hours a night, 1½ hours less than we were 100 years ago. But human sleep needs haven’t changed in that time,” says Nathaniel Watson, co-director of the University of Washington Medicine Sleep Center.
6. Gel Manicures
Who doesn’t love a nail polish that lasts? In recent years, gel manicures have gained a loyal following precisely for that reason, but concern over the UV light used to cure the polish has raised concern.
A pair of studies has suggested that the lights may be to blame for skin cancer developing on the backs of some patrons’ hands, but more studies are needed.
Some experts say the cancer risk for someone getting a gel manicure once in a while is small. But they also warn that the UV light is harmful to unprotected eyes and will speed up photoaging on the hands. In other words, your nails look fantastic, but your hands will eventually look like baseball gloves.
7. Risky Sex
In the United States, about 19 million new sexually transmitted infections are thought to occur each year during vaginal, anal or oral sex or during genital touching. Several strains of the human papillomavirus (HPV), a common STI, are linked to some mouth and throat cancers, almost all cervical cancers, and some anal cancers.
Doctors report more of these cancers, once considered rare in young people, are now showing up in higher numbers.
Aside from abstinence, experts suggest that not smoking, correctly using condoms during sex, and limiting the number of sexual partners will reduce your risk.
While condom use is highly recommended, the U.S. Centers for Disease Control and Prevention warns, “HPV infection can occur in both male and female genital areas that are covered or protected by a latex condom, as well as in areas that are not covered.”
It is unknown whether condoms prevent HPV infections, the CDC says, however, “condom use has been associated with a lower rate of cervical cancer.”
Diesel Engine Exhaust. IARC press release.12 June 2012
Vermeulen R, Silverman DT, Garshick E, Vlaanderen J, Portengen L, Steenland K. 2014. Exposure-response estimates for diesel engine exhaust and lung cancer mortality based on data from three occupational cohorts. Environ Health Perspect 122:172–177;
Some birth-control pills may raise breast cancer risk 50 percent. Fred Hutch News Service.1 Aug. 2014
Long-term Night Shift Work Linked to Breast Cancer. Medical News Today. 3 Jul 2014.
Circadian disruption, shift work and the risk of cancer. Cancer Causes Control. 2006 May;17(4):539-45
CDC. What Can I do to reduce my risk for cervical cancer? Accessed 19 Sept. 2014.
What contaminants are you eating?
Seven Common Foods That May Be Harmful. Dana-Farber/Brigmham and Women’s Cancer Center. Accessed 19 Sept. 2014.
Reviewed September 22, 2014
by Michele Blacksberg RN
Edited by Jody Smith