Protection from the environment in childhood, but not in adulthood, increases the likelihood of young adult Hodgkin lymphoma, according to a study of 656 servicemen with Hodgkin lymphoma diagnosed between ages 17 to 32 while on active duty. Researchers found:

• Risk increased independently with small sibship (OR, 2.3), low birth order (OR, 1.9), and an interval of at least 5 years between birth and that of a previous or subsequent sibling (OR, 2.1).

• Other factors independently and significantly associated with elevated risk of Hodgkin lymphoma were: tallness, high body mass index, more education (but not higher income) in the county of birth, BB or AB blood type, and past infectious mononucleosis (but a deficit of other childhood viral infections).

• Early fatherhood conveyed high risk (OR, 2.6) especially with a high-risk sibling configuration.

Citation: Mack TM, Norman JE, Rappaport E, Cozen W. Childhood determination of Hodgkin lymphoma among U.S. servicemen. [Published online ahead of print August 31, 2015]. Cancer Epidemiol Biomarkers Prev. doi: 10.1158/1055-9965.EPI-15-0145.