Your child may have a higher risk of cancer if you keep your house too clean, study says

Two children with acute lymphocytic leukemia play in the hospital. A study published in the journal Nature Reviews Cancer found that children in "overly clean" houses are more likely to develop ALL, the most common type of cancer in kids.
Two children with acute lymphocytic leukemia play in the hospital. A study published in the journal Nature Reviews Cancer found that children in "overly clean" houses are more likely to develop ALL, the most common type of cancer in kids. National Cancer Institute

There's a way to reduce your child's risk of getting cancer, a new study says, and it also gives you an excuse to clean your house less.

A study published in the journal Nature Reviews Cancer found that, among other things, keeping a house too spotless and clean can increase a child's risk for developing acute lymphoblastic leukemia (ALL). The research comes from Mel Greaves, a professor and biologist from the The Institute of Cancer Research, London.

Greaves analyzed about three decades' worth of data to reach his conclusion, according to a news release from The Institute of Cancer Research.

His study suggests that a child's risk for the cancer starts with a genetic mutation in the womb, which about 1 percent of people develop. Among those with the mutation, having an overly clean house in the first year of life increases the risk of developing ALL, which is the most common type of childhood cancer.

ALL accounts for about one-fifth of all cancers among Americans under the age of 20, according to the Centers for Disease Control and Prevention. The National Cancer Institute says that 85 percent of children with ALL are expected to survive at least five years after diagnosis.

Greaves, who has spent 40 years studying leukemia, said his findings might answer lingering questions about the disease.

"It has always struck me that something big was missing, a gap in our knowledge – why or how otherwise healthy children develop leukemia and whether this cancer is preventable," he said in a news release. “This body of research is a culmination of decades of work, and at last provides a credible explanation for how the major type of childhood leukemia develops.”

The study's findings also gives a potential answer to why children in more affluent countries come down with the cancer — because kids in those places are more likely to grow up in a sterile environment that leaves their immune systems weakened. Greaves called it a "paradox of progress in modern societies."

As noted by BBC, Greaves used a variety of different cases to come to the conclusion that children who lack exposure to certain microbes and bacteria are more susceptible to developing leukemia. Children with older siblings in daycare had a lower rate of getting the cancer, the study found, while kids who were born vaginally — and exposed to more microbes — had a lower rate of developing leukemia when compared with those who came into the world through the more sterile option of a C-section.

The study also found that breastfeeding reduced a kid's chance of coming down with the childhood cancer, possibly because it introduces a child to more microbes.

But don't feel bad if you have taken extra precaution to keep your child's surroundings clean in the past, Greaves told the Independent. Moving forward, the scientist does suggest loosening up a bit and allowing your child to get some more contact with their peers during their first year of life.

“Be less fussy about common or trivial infections," he said, "and encourage social contact in the first year of life with as many children as possible. And actually, contact with older children is probably a good thing."

He also emphasized that it's not the fault of parents if their child develops cancer. Part of the risk factor is determined by genetics, he said in a news release, and evidence suggests that only the risk factor for ALL, and not other cancers like infant leukemia, can be reduced with exposure to microbes at a young age.

So what can you do to keep your kid healthy, aside from planning more play dates with older children and dialing back on the cleaning? Greaves told BBC that he believes a yogurt cocktail filled with certain microbes could provide children with protection.

But more research is needed to determine whether such a cocktail could work — and whether Greaves' findings are valid at all.

Alasdair Rankin, director of research at Bloodwise, a blood cancer charity, said there's isn't any proof that ALL can be completely prevented with a change in the child's environment.

"While developing a strong immune system early in life may slightly further reduce risk, there is nothing that can be currently done to definitively prevent childhood leukemia," he told the Independent. “As noted by this study, other factors influence its development – including pure chance.”

Chris Bunce, who studies cancer at the University of Birmingham, said the study carries extra weight because Greaves is “one of the superstars amongst modern cancer biologists."

Greaves said he hopes his study can save the lives of more children in the future.

The study "busts some persistent myths about the causes of leukemia, such as the damaging but unsubstantiated claims that the disease is commonly caused by exposure to electro-magnetic waves or pollution," he said. “I hope this research will have a real impact on the lives of children. The most important implication is that most cases of childhood leukemia are likely to be preventable."