Modification Effects of Changes in Job Demands on Associations Between Changes in Testosterone Levels and Andropause Symptoms: 2-Year Follow-up Study in Male Middle-Aged Japanese Workers

Abstract

Purpose: The purpose of this longitudinal study was to ascertain if changes in job demands modify associations between changes in testosterone levels and andropause symptoms in male Japanese workers.

Method: A baseline survey including job demands and the Aging Males' Symptoms scale, lifestyle factors, and blood levels of testosterone was conducted in 2007. Among 192 men (mean age ± SD 52.2 ± 7.6 years) who completed all relevant questionnaires and provided blood at baseline, 104 men (50.9 ± 7.2 years) were followed up in 2009. Changes of variables in 2 years were calculated (data of follow-up minus those of baseline).

Results: Testosterone levels were increased significantly, whereas job demands and somatic symptoms were reduced significantly, at follow-up. Changes in testosterone levels were negatively associated with changes in total andropause symptoms, psychological symptoms, and sexual symptoms (standardized β = -0.27, -0.24, and, -0.29, p < 0.05, respectively), after adjustment for confounders. Changes in job demands were positively associated with changes in somatic symptoms (standardized β = 0.21, p < 0.05). Significant interactions of changes in testosterone levels and job demands were noted for changes in psychological symptoms (standardized β = 0.26, p < 0.05). For men with a 1-SD reduction in job demands, negative associations between changes in testosterone levels and psychological symptoms were intensified, but not for men with a 1-SD increase in job demands.

Conclusion: Andropause symptoms may be affected by changes in testosterone levels and job demands. Change in job demands may modify associations between changes in testosterone levels and andropause symptoms.

Keywords: Andropause symptoms; Japanese workers; Job stress; Longitudinal study; Testosterone.