Lifestyle and cancer: effect of parental divorce.

According to previous studies, divorced individuals have increased risks of cancers related to alcohol and tobacco consumption and sexual habits, but the increases are balanced with decreased risks of many common cancers. In the present study, cancer risks were analyzed for 0-70-year-old offspring of divorced parents, on the basis the Swedish Family-Cancer Database with cancer data from the years 1958 to 2002. We calculated standardized incidence ratios for cancer among offspring of divorced parents (19,000 cancer patients) and compared them with offspring of stably married parents (121,000 cancer patients). Standardized incidence ratios were adjusted for many factors, including socio-economic status. Offspring of divorced parents were divided into groups depending on whether their mothers, fathers or both had had children with different partners. Offspring of divorced parents had an increased risk of upper aerodigestive tract, esophageal, anal, pancreatic, lung and cervical cancers. Decreased risks were noted for Hodgkin's disease and bone cancer. For Hodgkin's disease, the data suggest protective effects through early exposure to childhood pathogens but for bone cancer mechanisms remain to be established. The overall cancer risk for offspring of divorced parents was at or above unity. The results show that offspring of divorced parents have increased cancer risks at tobacco-related, alcohol-related and sex-related sites, in analogy to their parent, but they lack decreased risks at common sites, experienced by their parents. Divorce is becoming increasingly common in many countries and any deviant cancer patterns among offspring of divorced parents will have an impact on the population risk.