Life events, cortisol and levels of prostate specific antigen: A story of synergism

Background: Previous studies have tested the relationship between stressful life events (LE) and cancer onset, but inconsistent results have been found. One possibility is that the LE-cancer relation may depend on other biological factors pertinent to stress and cancer. Methods: This study examined the relationship between LE and prostate specific antigen (PSA) levels, a tumor marker, and whether cortisol mediates or moderates a LE-PSA relationship. During a voluntary screening for prostate cancer risk, 139 men (mean age = 57.3 years) were assessed with the Holmes and Rahe questionnaire about their LE during the past 1-5 years, and their PSA and serum cortisol levels were measured. Results: LE and cortisol alone were unrelated to PSA. However, statistically controlling for age, body mass index and the ratio of triglycerides to HDL cholesterol, we found evidence for a synergistic interaction between LE and cortisol. Among men with low cortisol, number of LE were inversely and significantly correlated with PSA (r = -0.265, p < 0.05), while in men with high cortisol, number of LE were positively and significantly correlated with PSA (r = 0.344, p < 0.01). These results more consistently stemmed from the effects of uncontrollable LE. Similar results were found, using a clinically significant PSA cut-off. Conclusions: These results suggest considering the joint effects of psychosocial and biological factors in relation to possible cancer risk, where the hypothalamic pituitary adrenal axis may moderate stress-cancer risk associations. (C) 2010 Elsevier Ltd. All rights reserved.