Preventing or Reducing the Risk of Leukemia

There are a number of risk factors for leukemia that can't be modified, such as your age or your sex. And while there aren't any proven methods for the outright prevention of leukemia, there are ways you may be able to reduce the odds of your developing the disease. Having an awareness of exposures such as to benzene and pesticides, avoiding unnecessary medical radiation, not smoking, exercising, and eating a healthy diet may all help. Testing your home for radon and maintaining a healthy weight may also have an impact.

Knowledge of substances in our environment that might raise leukemia risk (carcinogens) is limited. Still, practicing caution in relation to what is known or even suspected is worthwhile, particularly in the event that certain exposures are later confirmed to be cancer-causing.

Benzene

Perhaps the best known and most documented exposure linked with leukemia is benzene. Benzene is a chemical found in many products such as paints, wood stains and varnishes, solvents, resins, some glues, some plastics, some cleaning products, automotive products, driveway sealer, pesticides, weed killers, detergents, and unleaded gasoline. It is a byproduct of the combustion of coal and petroleum, and is present in motor vehicle exhaust. It is also present in tobacco smoke. People may be exposed occupationally, in jobs that manufacture or use these products, or at home, such as when updating a room.

In addition to risks for adults, exposure of young children or during pregnancy has been associated with childhood leukemia. If a product contains benzene, there may be a label indicating a carcinogen is present, but it's important to practice caution even if a warning label isn't obvious. On-the-job, employers are required to provide Material Safety Data Sheets to employees, which outline information about any products they will be using.

Avoidance is the best form of prevention, but this is not always possible. Make sure to read labels and follow precautions. Refrain from using these products when children are present.

Formaldehyde

Formaldehyde has also been associated with an increased risk of leukemia. On-the-job, it is common in medical laboratories and embalming fluid. At home, formaldehyde is found in pressed wood products (such as particle board), some air fresheners, upholstery, wallpaper, and permanent press clothing.

There are guidelines on the maximum amount of formaldehyde emissions allowed from pressed wood products, such as those in U.S. Department of House and Urban Development (HUD) homes, but individual awareness is needed to minimize your exposure. It appears that exterior grade pressed wood products emit less formaldehyde.

Pesticides

Home and garden pesticides have been found to be associated with leukemia in children exposed in utero, young children exposed in the home, and adults exposed at home or on the job. Some studies have found the risk in children exposed to home pesticides to be as high as 7 times that of non-exposed children. Home pesticide exposures of concern may include:

• Gardening chemicals (for houseplants and garden plants)
• Chemicals applied by professional pest services
• Some fertilizers
• Weed killers (fungicides and herbicides): This is the reason yard services place signs on the grass recommending that pets not walk on the grass for a period of time.
• Some insecticides
• Some shampoos used to treat head lice
• Flea killers for pets (including flea collars and flea bombs)

To reduce exposures, the Environmental Protection Agency, among others, recommends using integrated pest management principles when faced with the need to eliminate pests in the homes:

• Practice caution when using gardening chemicals.
• Pulling weeds or killing them with boiling water are alternatives for pesky weeds in your landscape.
• Pet products, such as flea killers, should be kept away from children. While some products, such as flea "bombs" recommend leaving the home for a period of time, this should be a very minimum, especially for young children.

Pesticide residue on foods has not been determined to raise the risk of leukemia, though those who opt for organic foods may cite this as the reason. For those who wish to avoid pesticide residue as much as possible while on a budget, the majority of pesticide exposure from foods comes from only 12 foods known as the "Dirty Dozen".

Radon

Radon in our homes is a well-known carcinogen and is considered the second leading cause of lung cancer in the United States. Research suggests it may play a role in leukemia as well. Radon is a normal breakdown product of uranium found in rocks and soil beneath homes, and has been found in homes in all 50 states and around the world. The gas is odorless and colorless, and the only way to know if your home is safe is to do radon testing.

The exact relationship between leukemia and radon is uncertain. We've known for some time that the incidence of chronic lymphocytic leukemia (CLL) in the United States isn't random, and the disease is much more common in some regions, such as the northern and central states. A 2016 study found that these regions with a high incidence of CLL are also the regions that have the highest level of radon in homes on average. While this is only a correlation and doesn't mean that radon is the cause, the association of radon with lung cancer has scientists wondering if the mechanism with leukemia is the same.

Radon test kits are available at most hardware stores and cost only around $10. If your level is abnormal, the Environmental Protection Agency has great advice on what the different numbers mean and when you may need radon mitigation.

Smart Choices

With any chemicals at home or on-the-job, read labels. If a substance calls for good ventilation, heed the instructions. Some products should only be used when wearing a respirator (a regular mask may do nothing). Wearing gloves is also a must; skin is not a solid barrier. A general rule is that if you wouldn't eat something, you should think twice about touching it without gloves.

You can even reduce your exposure to some chemicals by adding houseplants to your home, which have been proven to improve air quality. The National Aeronautics and Space Administration (NASA) did research to determine which houseplants are most beneficial in absorbing indoor air carcinogens.

The best houseplants for removing benzene include chrysanthemums, Gerbera daisies, peace lilies, and spider plants.

For formaldehyde, the best choices appear to be Boston ferns, chrysanthemums, English ivy, golden pathos, Janet Craig dracaena, palms (many types, including parlor palm), philodendron, peace lilies, rubber plants, and spider plants.

Other good houseplants include ficus, Chinese evergreen, marginata, and warnecki.

For reducing carcinogens in indoor air, the magic number appears to be around 15 plants in 6-inch containers (or the equivalent) for every 2000 square feet of living space. It's important to keep in mind that some plants can be poisonous to children or pets, cause allergies in some people, or result in mold production.

There are a remarkable array of diagnostic tests and treatment options for various medical issues today. While helpful for their intended purposes, some may also raise the risk of leukemia.

Diagnostic Medical Radiation

Imaging studies such as X-rays and CT scans use ionizing radiation to help doctors diagnose disease. The risk of leukemia related to these studies was first noted not long after X-rays were introduced and has been revisited in recent years, especially with regard to imaging studies for children.

The risk of cancer due to medical radiation varies significantly with the particular studies that are done. When talking about radiation exposure, doctors use the term millisievert (mSV) or milligray (mGy). It's not known exactly what level of exposure can lead to leukemia, but estimates have been made based on the risk found with atomic bomb exposures. It's thought that 10 mSV of exposure increases the risk of dying from cancer by 1 in 2000. The average American is exposed to around 3.0 mSv of natural radiation each year, with the amount somewhat higher at higher elevations.

The average yearly exposure to medical radiation has been increasing. In 1982, the average American was exposed to 0.5 mSV of medical radiation yearly. In 2006, the average exposure was 3.0 mSV per year, and 2018, 6.2 mSV per year. (With occupational exposure, the exposure limit is 50 mSV per year or 100 mSV over five years.) The average radiation exposure with some imaging studies are as follows:

• Chest X-ray (2 view): 0.10 mSV
• X-ray of an extremity (arm or leg): 0.001 mSV
• Chest CT scan: 8.0 mSV
• Abdominal CT scan: 10.0 mSv
• Head CT scan: 2.0 mSV
• Mammogram: 0.4 mSV
• Dental X-rays (4 view bite wing): 0.005 mSV
• Dental X-rays (panoramic): 0.007 mSV
• Lower GI series: 8 mSv
• PET/CT: 25 mSV

Exposure to medical radiation is of greater concern with children than with older adults, both due to susceptibility to radiation and a longer period of time over which cancer could develop.

Weighing Risks and Benefits

Oftentimes, the tests above will be needed, and the risk of missing a diagnosis (such as appendicitis) would outweigh the potential risk of the radiation exposure. That said, it's important to ask questions if one of these tests (especially tests such as an abdominal CT in a child) are recommended:

• Is this procedure medically necessary?
• Would waiting to see if a condition resolves on its own be detrimental? Could the test be put off for a few days, after which time it might not be needed?
• Is there another test that could be done that doesn't involve the same level of exposure? For example, a regular X-ray instead of a CT scan?
• Is there a test that could be used that doesn't involve radiation? MRI scans and ultrasound examinations do not expose people to ionizing radiation, for example.
• Could a procedure substitute for an imaging study? For example, could an upper or lower GI endoscopy (which do not involve radiation exposure) be done instead of barium X-ray studies?

With children, it's also very important to ask if the amount of radiation used can be adjusted for a child's size as this is not always done, especially in non-pediatric and community hospitals.

Radioactive Iodine Therapy

Radioactive iodine therapy (RAI) is a treatment that can be used for hyperthyroidism or thyroid cancer, where it is usually used as an adjuvant therapy after surgery to get rid of any cancer cells that may have remained behind. In a 2017 study, the risk of developing acute myelogenous leukemia (AML) was found to be almost 80 percent higher in those who received RAI than those who did. The risk of chronic myelogenous leukemia (CML) was yet higher, with those who received RAI 3.44 times more likely to develop CML than those who had surgery for thyroid cancer alone.

The increased risk of leukemia does not mean that everyone should avoid RAI. Rather, the risk should be considered when looking at the other risks and benefits of treatment options. Those who are considering RAI may want to opt for getting a second opinion, possibly at one of the larger National Cancer Institute-designated cancer centers.

Those who have had RAI should be aware of the symptoms of leukemia, and may wish to talk to their doctors about whether regular blood tests are needed.

Radiation Therapy and Chemotherapy

Radiation therapy for cancer can increase the risk of developing AML, with a peak risk occurring five to nine years after treatment. Likewise, some chemotherapy drugs increase the risk of leukemia beginning, with peak risk occurring five to 10 years after treatment. Most of the time, the benefits of treatment will far outweigh risks, but it can be helpful to talk to your doctor about this when weighing potential treatment options.

We hear a lot about healthy habits when it comes to other cancers, but less so with regard to leukemia, especially childhood leukemia. That said, and especially for adult leukemias, healthy habits may reduce your risk.

Eat a Healthy (Mediterranean-Style) Diet

A 2018 European study found that eating a traditional Western diet may increase the risk of CLL. In this study, the risk of CLL was compared between those who consumed a Western diet, Prudent diet, and Mediterranean diet. Those who ate a Western diet were 63 percent more likely to develop CLL than those who consumed the Prudent or Mediterranean diets.

Foods included in a typical Western diet include high-fat dairy products, processed meats, refined grains, sweets, convenience foods, and high-calorie beverages. In contrast, the Prudent diet stresses low-fat dairy products, vegetables and fruits, whole grains, and juice. Foods common in the Mediterranean diet include fish, beans (legumes), boiled potatoes, olives, fruits, and olive oil.

When choosing foods, it's helpful to note that a Mediterranean diet is associated with better health in many ways relative to a traditional Western-style diet.

Minimize Sucralose

The possible association of the artificial sweetener sucralose and cancer has raised some concern since its approval in 1999. At the current time, Sucralose is found in thousands of products worldwide, such as Splenda. Despite a multitude of reassuring studies prior to its approval, a 2016 Italian study on mice found that mice who were exposed to sucralose throughout their lives, beginning in-utero, had a significantly increased risk of leukemia. It's important to note that this was an animal study, so results cannot be automatically applied to humans.

Whether or not sucralose is associated with leukemia, there is evidence for caution. Sucralose has been found to reduce the number of "good bacteria" in the gut, and the ratio of good vs. bad bacteria in the intestines is now being linked with a number of health conditions, including lymphoma. Concerns about all types of artificial sweeteners, in fact, have been raised. Minimizing the use of any these options is likely wise as part of an overall healthy diet.

Exercise

We've known for a long time that exercise can reduce the risk of some solid tumors, but it's only recently that its potential role in reducing the risk of leukemia has been evaluated. A 2016 study looking at 1.4 million people found that more physical activity (leisure activity) was strongly associated with a lower risk of developing myeloid leukemias (AML and CML). The 20 percent reduction was not because people who were more active were less likely to be overweight or obese.

Not all studies have linked a lack of exercise with leukemia, but since it's thought that the majority of people in the United States get too little exercise, adding physical activity to a cancer prevention lifestyle may be helpful.

Don't Smoke

Smoking is a strong risk factor for the development of AML, thought to be responsible for around 20 percent of these cancers. In addition, parental smoking during pregnancy and even secondhand smoke exposure during pregnancy appears to increase the risk of childhood leukemia in offspring. Tobacco smoke contains many toxic chemicals, including benzene and formaldehyde. When these chemical are inhaled into the lungs, they can easily travel to the bloodstream, and from there, throughout the body.

Practice Safe Sex and Don't Share Needles

The human T-cell leukemia virus 1 (HTLV-1) is a type of virus that infects T lymphocytes (a type of white blood cell) and can significantly raise the risk of leukemia. Roughly 10 to 20 million people are infected with these viruses worldwide, and around 1 percent to 4 percent of people exposed will develop leukemia. HTLV-1 is uncommon in the United States, but is found in many areas of the world such as the Caribbean, central and west Africa, the Middle East, and other regions. It is spread through sexual contact, by sharing syringes or needles used to inject drugs, through blood transfusions, and from mother to child at birth or through breastfeeding.

Maintain a Healthy Weight

A number of studies have suggested that being overweight or obese is associated with an increased risk of AML. A 2011 review of studies, however, looked at all of the major types of leukemia. It was found that obesity (a BMI of 30 or over), but not being overweight (BMI of 25 to 29), was associated with an overall risk of adult-onset leukemia that was 17 percent higher than than that of people of normal weight. Broken down, the risk was increased 38 percent for AML, 62 percent for acute lymphocytic leukemia (ALL), 27 percent for CML, and 17 percent for CLL.

Since childhood leukemia has been increasing in California, it's thought that the reason is something in the environment. A 2016 study in California was done to find out more.

Babies born to mothers exposed to benzene and pesticides during their pregnancies demonstrated an elevated risk of leukemia. Smoking during pregnancy was also noted as a risk factor.

While alcohol intake does not appear to be linked with the major types of leukemia, there is some evidence that there is an increased risk of leukemia in children whose mothers consumed alcohol during gestation, only adding to the reasons to avoid drinking while pregnant.

It's not simply what to avoid that's important for pregnant women, however. A 2014 study found that babies born to mothers who used supplements of prenatal vitamins and folic acid had a lower risk of both AML and ALL.