Parent Age May Affect Child's Cancer Risk, Study Finds

The age at which couples are having babies has been rising in recent years, and that may lead to an increased risk of their children developing pediatric cancer, according to a recent study conducted by researchers at the University of Denmark and University of California, Los Angeles (UCLA).

“We knew that parental age was a risk factor for childhood cancer,” said Julia Heck, associate professor at the UCLA School of Public Health said in an interview with CURE. “In most cases, older parents confer greater risk, but in some instances very young (teenage) parents may also have offspring with higher cancer rates. We wanted to explore this relationship in our population-based study in Denmark.”

The study examined 5,856 cancer cases of Danish children who were diagnosed before the age of 16, according to the Danish Cancer Registry. Parental age was gathered from the Central Population Registry and was stratified into groups by the researchers: under 25 years old; 25 to 29; 30 to 34; 35 to 39; 40 to 45; and 45 years of age and older.

Heck said that she was not particularly surprised at the results.

There was an increase in leukemia diagnoses— especially acute lymphoblastic leukemia (ALL) — among children whose parents were older than 35. An association was also noted for Hodgkin lymphoma risk and parents between the age of 30 and 34, and for non-Hodgkin lymphoma for parents over the age of 35.

“Older parental age was a risk factor for various childhood cancers in Danish children,” the authors wrote. “Further investigation of the biological and social factors that may be contributing to these associations is warranted.”

Heck mentioned that this correlation may be due to an increase in chromosomal mutations in older people.

“The usual explanation is that there are increasing chromosomal aberrations with older parental ages. Increasing de novo mutations (new mutations, not ones the parents have in their DNA but rather a new mutation that happens in sperm or egg cells) are linked with older age in parents,” she said. “Similarly, there is the greater risk of Down Syndrome in the children of older mothers; fathers are studied less often but there are reports of increases in the risk of birth defects related to single gene mutations, as well as neurodevelopmental disorders.”

The study particularly emphasized the correlation between maternal age and childhood cancer risk, because while there was a slight increase in leukemia and NHL for the children of older men, that increase was eliminated after the statistics were adjusted for maternal age.

But there are other steps that soon-to-be parents can take that may promote the health of their baby, Heck explained. These include limiting alcohol intake, not smoking and limiting exposure to chemicals as much as possible.

Further studies in childhood cancer, in general, are also warranted, Heck mentioned.

“Childhood cancer risk factors are understudied are in general, just because the diseases are rare, so it's hard from a scientific standpoint to gather together a large enough number of cases to study the causes,” she said. “It's a challenge inherent to the study of any rare disease. So, we are lucky that we can access national data to get a true sense of the distribution of cancers in Denmark.”