(HealthDay)—The average prevalence of leukemia in grandparents is higher than the general population, a Danish-led study finds.

This wasn’t because they were more likely to get their leukemia, the study concluded.

“People with leukemia in their grandparents respond better to drugs than others,” said senior author Jan Moverudera, of Aarhus University in southern Denmark.

The average leukemia rate in grandparents among younger people affected was 8.4 per 1,000 person-years, compared with 7.8 per 1,000 person-years in people who were over 65 years old.

The study involved 51 grandparents, mostly of second and third-generation Swedish descent, and their grandchildren. All of the 118 grandchildren aged 19 to 62 who didn’t get their first blood cancer were in the study sample. Of those, 134 were patients who were diagnosed with leukemia and 21 with lymphoma, a cancer that creates a clot in the bloodstream.

The average age of the first cousin affected in each family cohort was 18 years old. The incidence rates for children was very similar when compared with age at husband and wife, with no granddaughters and no grandchildren diagnosed with leukemia.

In the grandchildren whose family was granted partial or full exemption from the exclusion, the incidence rates of leukemia were tenfold higher compared to those who were not granted partial or full exemptions.

Among all the grandchildren with VUS, the average leukemia rate was 55.6 per 1,000 person-years compared with 48.1 per 1,000 in the general population.

The study wasn’t a controlled experiment that would clearly prove whether or how this family’s leukemia rate might directly impact new treatments for the disease, which most often affects children of mothers and siblings.

Still, the findings underscore the need for adults of all generations to address this underlying health problem, said Sunil Dave, a researcher at the University of South Australia in Brisbane who wasn’t involved in the study.

“The target population is the adult who have the greatest capacity,” Dave said by email. “This is the age group that would benefit the most from programs that encourage discussion and personalization of treatments and testing, follow up with promising results and generates the most hope for effective therapies.”

The young, or first-born, child of parents can expect to have an average lifespan of just over 10 years, according to the U.S. National Institutes of Health.

Those who became ill with leukemia or lymphoma can manage them well for three to six years, according to the National Institutes of Health.