Psychological stress, cancer incidence and mortality from non-malignant diseases

Abstract

Summary Psychological stress has been claimed to contribute to the onset of cancer and to increase mortality from a number of nonmalignant diseases. We investigated the effect of a genuine psychological stressor, i.e. cancer in a child, on the incidence of cancer and mortality from non-malignant diseases of 11 231 parents in a Danish nationwide population-based study. The children were identified from records in the Danish Cancer Registry for the period 1943-85; their parents were identified from population registers. Overall, 1665 parental malignancies were diagnosed from the date the cancer of the child was reported until 1992, compared with 1702 expected from national incidence rates, yielding standardized incidence ratios of 1.0 (95% confidence interval, 0.9-1.0) for all parents, 1.0 for mothers and 1.0 for fathers. No statistically significant deviation of the relative risk from unity was seen for any period of follow-up after the stressful event, and no excess risk was seen for any particular type of cancer. Moreover, a total of 2137 parental deaths were observed over the period 1974-92, compared with 2333 expected from national mortality rates, giving an overall standardized mortality ratio of 0.9 (range 0.9-1.0). No excess mortality was seen from causes associated with allergic illness, autoimmune conditions, chronic illness or changes in behaviour. Our data provide no support for the hypothesis of an association between psychological stress and the incidence of cancer or mortality from nonmalignant diseases. We conclude that the human organism is highly adaptable, even to extreme psychological stress.

Stressful life events and cancer risk

“…Positive associations between severe stressors (i.e., stressful life events) and cancer risk have frequently been reported from retrospective and casecontrol studies, whereas prospective studies with unbiased data sources for exposure assessment, such as administrative registers, have shown no association between stressors, like death of a spouse, divorce, death of a child or serious illness in a child, and the subsequent risk for cancer (Johansen and Olsen, 1997;Kvikstad et al, 1994).…”

“…The assumption of an association between stress and cancer occurrence is popular in the lay public (Baghurst et al, 1992) and among cancer patients (Stewart et al, 2001) and the topic has received intensive research attention in the past. Positive associations between severe stressors (i.e., stressful life events) and cancer risk have frequently been reported from retrospective and casecontrol studies, whereas prospective studies with unbiased data sources for exposure assessment, such as administrative registers, have shown no association between stressors, like death of a spouse, divorce, death of a child or serious illness in a child, and the subsequent risk for cancer (Johansen and Olsen, 1997;Kvikstad et al, 1994).We investigated the association between self-reported experience of stressful life events and the risk for cancer. As opposed to many previous prospective studies (Johansen and Olsen, 1997;Li et al, 2002;Dalton et al, 2004), all analyses were adjusted for a number of lifestyle factors known to be associated with cancer risk.…”

“…As opposed to many previous prospective studies (Johansen and Olsen, 1997;Li et al, 2002;Dalton et al, 2004), all analyses were adjusted for a number of lifestyle factors known to be associated with cancer risk.…”

Cancer incidence and survival following bereavement

“…26 The research advantages of examining parental bereavement resulting from war are manifold. First, there is a smaller probability of confounding by variables related to the loss or the environment than in studies of conjugal bereavement, 13,27 cancer in one's child, 14 or divorce. 9 Second, the status of the bereaved parent never ceases.…”

“…[2][3][4] First, studies on this topic are fraught with methodological problems-for example, biased samples, retrospective designs, small numbers of cases, and limited follow-up. Second, reviewers 2,[5][6][7] have concluded that most case-control [8][9][10] as well as cohort studies, [11][12][13][14] with few exceptions, 15 have shown little or no association.…”