RESUMO
OBJECTIVE: To evaluate the influence of chronic stress (CS) on urine composition of calcium oxalate (CaOx) stone patients and controls. METHODS: This case-control study enrolled 128 patients during a period of 20 months. The cases were CaOx stone formers with a recent stone episode. Controls were matched by sex and age. Dimensions of CS were evaluated in cases and controls by validated self-report questionnaires measuring stressful life events, perceived stress, anxiety, depression, burnout, and satisfaction with life. Blood and urine samples were collected to determine cortisol levels and urinary composition. RESULTS: More relations between CS dimensions and blood and urine parameters were observed in cases than in controls. In cases, the blood cortisol level was related positively with the number of stressful life events (P = .03), intensity of these events (P = .04), and anxiety (P = .04). In addition, urinary magnesium (P = .03) and pyrophosphate (P = .05) levels were positively related with satisfaction with life and burnout, respectively. In contrast, urinary magnesium levels were negatively related with perceived stress (P = .01), anxiety (P = .016), and depression (P = .03). In controls, the number of stressful life events and the intensity of stressful life events was related positively with magnesium (P = .06, P = .02) levels and negatively with blood cortisol levels (P = .03, P = .004). CONCLUSION: Based on the variation between cases and controls in relations between CS dimensions and biochemical parameters, we hypothesize that CS may trigger a differential biological response in CaOx stone formers and controls, which in turn may promote or protect against CaOx stone formation.