Life events, cortisol and levels of prostate specific antigen: a story of synergism.
ABSTRACT 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.
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.
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.
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.