Preschool attendance appears to lower the risk of Hodgkin’s disease in young adults, according to a report in Cancer Epidemiology, Biomarkers & Prevention.

Increased contact with other children lowers the risk of childhood allergies, the authors explain, which may also protect against Hodgkin’s disease, a type of lymphoma, or cancer of the lymph system, that primarily affects children and young adults.

Dr. Ellen T. Chang from Harvard School of Public Health, Boston, and colleagues evaluated the relationship between Hodgkin’s disease risk and childhood social environment in a population-based study involving 565 subjects with Hodgkin’s disease and 679 subjects without cancer who served as a comparison.

In contrast to earlier studies, the authors report, Hodgkin’s disease risk among young adults was not associated with parental education, number of siblings, housing density, and history of infectious mononucleosis.

Hodgkin’s disease risk among older adults (55 to 79 years) was associated with lower measures of childhood socioeconomic status.

However, the risk of Hodgkin’s disease among young adults who attended nursery school or day care was 13 percent lower than that among young adults who did not. The risk was 36 percent lower for those who attended preschool for at least one year. These associations did not hold for the risk of Hodgkin’s disease among older adults.

Interestingly, the investigators found evidence that there was no difference in preschool attendance in Hodgkin’s disease patients who tested positive and those who tested negative for Epstein-Barr virus, which is thought to play a role in this and other cancers.

“The risk of Hodgkin’s disease among young adults appears to be positively associated with delayed infection during childhood,” Chang, now at Karolinska Institute, Stockholm, told Reuters Health, “but Hodgkin’s disease among older adults may not be.”

“Having attended nursery school, which tends to favor earlier exposure to childhood infections, now appears to be more important than other determinants of childhood social environment (such as number of siblings or mother’s education level) in influencing the risk of young-adult Hodgkin’s disease,” Chang said.

“Although our research does not address how to treat Hodgkin’s disease, we do offer some insight into what may cause the disease, much of which still remains unknown,” Chang added. “Other investigators are currently examining possible risk factors including diet, occupation, and genes.”

SOURCE: Cancer Epidemiology, Biomarkers and Prevention, August 2004.