Sauna use among dads linked to tumors in children

Would-be fathers who expose themselves to excessive heat in the weeks before they conceive children may place their future offspring at unnecessary risk of brain cancer, new research suggests. The study provides inconclusive data on whether maternal exposure to heat during early pregnancy similarly affects cancer risk.

Past studies have shown that in female animals, exposure to elevated temperature during pregnancy can cause fetuses to die or develop abnormally. Also, human sperm, which take about 10 weeks to develop, are acutely sensitive to temperature.

Researchers at Children’s Hospital of Philadelphia and St. Jude Children’s Research Hospital in Memphis, Tenn., studied 318 children who by the age of 6 years had developed either of two related forms of brain cancer. For comparison, the team studied 318 children of similar age and background who were free of cancer.

The investigators interviewed the children’s parents to determine whether they had used saunas or electric blankets or had other exposures to heat, such as bathing in hot tubs, during the months leading up to conception or during the first trimester of pregnancy.

Fathers of children with the two types of brain cancer were 3.4 times as likely as other dads to have used a sauna and 2.1 times as likely to have had exposure to at least one heat source during the 3 months prior to conception. Greta R. Bunin and her collaborators report those findings in the Aug. 1 American Journal of Epidemiology.

Exposure to heat sources, including saunas, was not significantly elevated among the mothers of children with the brain cancers, but the study couldn’t rule out the possibility of a harmful influence from heat during early pregnancy.