Objectives: To investigate the relationship between gonadal function, insulin and psychosocial stress in middle-aged men.
Design: A population-based, cross-sectional, observational study.
Setting: Glostrup Hospital, Copenhagen, Denmark.
Subjects: Four hundred and thirty-nine males, all aged 51 years.
Main variables: Body-mass index (BMI), waist-to-hip ratio (WHR), insulin, C-peptide, free testosterone, luteinizing hormone (LH), lipids, fibrinogen, lung function tests (FVC, FEV1, PEF), blood pressure, a self-administered questionnaire with questions on psychosocial variables, lifestyle and self-rated health.
Results: Free testosterone correlated inversely (P < 0.05) with weight, BMI, WHR, and fibrinogen, and positively with FEV1. An independent correlation between free testosterone and insulin (P < or = 0.03), but not with C-peptide, was seen after controlling for BMI and WHR. Subjects with low levels of free testosterone, or those in the lowest quintile of the distribution of the hypogonadal index (HI: free testosterone/LH), showed a cluster of negative psychosocial variables, and psychological as well as health-related problems. Furthermore, hypogonadal men had lower (P < 0.05) levels of FEV1, peak flow and FVC, but higher (P < 0.01) levels of fibrinogen and higher pulse pressure than men with normal gonadal function. This gradient of variables, relative to HI, was not seen for possible confounders like BMI, WHR, and tobacco or alcohol consumption.
Conclusion: Psychosocial stress may be associated with a process of premature ageing in middle-aged males, corresponding to a hypogonadal state as well as to indirect signs of increased insulin resistance.