| Mothers
but not fathers show increased cancer risk after the death of a child
The extreme stress caused by the death of a child appears to increase slightly mothers’ risks for smoking-related cancers compared with the risks for their male partners and for mothers who have not experienced the loss of a child, according to an article published online on October 31st and in the November 15th print issue of CANCER. No association was made between death and risk for breast cancer or other hormone-related malignancies. The possibility of risk through behavior change is something that mental-health professionals should consider in evaluating and treating parents, particularly women, who have lost a child. One hypothesis underlying a relation between stress and cancer risk is that stress impairs the ability of the immune system to detect and fight cancer in its early stages. In addition, chronic stress is known to enhance production of hormones that may stimulate tumor growth (an example, estrogen and estrogen-receptor positive breast cancer). Other scientists have hypothesized that stress leads to behaviors that are risk factors for cancers (an example, smoking and lung cancer). Many studies have been plagued by methodological shortcomings that leave open the question of stress as a risk factor for cancer. The current study is one of the largest and most complete studies to date to investigate the effect of an extreme stressor--- the death of a child--- with overall cancer incidence rate and with incidence rates of specific cancers in affected parents. Dr. Jiong Li and his Danish colleagues conducted a retrospective longitudinal study of Danish national registries: They evaluated 21,062 parents who lost a child from 1980 to 1996 and 293,745 controls, randomly selected parents who had not lost a child. Parents were followed for up to 18 years for the incidence of all cancers and then for specific cancers, including hormone-related cancers such as breast cancer, smoking-related cancers, alcohol-related cancers, virus/immune-related cancers, and lymphatic/ hematopoietic cancers. Data was analyzed to determine whether the loss of a child caused a significantly greater incidence of cancer than that found in parents who had did not experienced such an extreme similar psychological stress. The study found that there was no significant increased risk for cancer in parents who had lost a child compared with those who had not. Only bereaved mothers were at slightly increased overall risk for cancer than those mothers who had not experienced the loss of a child (relative risk = 1.18). Fathers who lost a child experienced no statistically greater incidence of overall cancer or cancer of any specific type. In general, the relative risk estimates were slightly higher for bereaved mothers than for fathers. Neither the age of death nor the unexpected loss of a child was associated with significantly increased risk of cancer. In derailed analysis, the only type of cancer with a significant link to psychological stress in mothers was smoking-related cancers (relative risk = 1.65) --- specifically, lung cancer. No additional significant risk was observed for breast cancer, hormone-related cancers, alcohol-related cancers, hematopoietic cancers, or virus/immune related cancers. This suggests, according to the authors, that bereaved mothers "may have more adverse risky behaviors." The authors conclude "our study is in
line with most of the previous studies, suggesting that an increased
overall risk of cancer attributed to stressful life events is small
if it exists at all." They add, "only bereaved mothers
as opposed to fathers experienced a slightly increased risk, which
does not support a general association" between psychological
stress and cancer causation. The data suggests that psychological
stress leads to behaviors that are associated with higher cancer
risk, such as smoking. |