Objective: To examine epidemiologically whether subjects with higher stress perception levels have higher leptin concentrations.
Research methods and procedures: In this cross-sectional study, the study population comprised 1062 male workers at local government offices in central Japan. Self-administered questionnaires were distributed in 1997. Awareness of stress was assessed by the question: "Do you have much stress in your life?" and participants were asked to select from four possible responses: "very much," "much," "ordinary," or "little." Blood samples were also collected after fasting 12 hours overnight to determine serum leptin concentrations.
Results: The mean (standard deviation) age and BMI were 50.2 (6.4) years and 23.3 (2.6) kg/m(2), respectively. Crude leptin concentrations according to stress categories were 2.86, 3.26, 3.32, and 3.54 ng/mL, respectively, and leptin concentrations adjusted for age, BMI, physical activity, drinking and smoking habits, overtime work, shift work, sleep duration, and availability of confidants were 2.96, 3.24, 3.34, and 3.43 ng/mL for "little," "ordinary," "much," and "very much," respectively (p = 0.03 by one-way analysis of covariance; p < 0.01 by test of linear trend). Significant associations were also observed among the level of perceived psychological stress and work-related stressors, variables related to sleep, and other psychological variables.
Discussion: This study showed that subjects who perceived psychological stress had high leptin levels, which provides epidemiological evidence that psychological stress may have the potential effect of increasing blood levels of the pleiotropic peptide, leptin.