Objective: Low total testosterone levels (TT) have been associated with increased morbidity and mortality. However, the prevalence and incidence of testosterone deficiency (TD) in association with its risk has not been assessed systematically to date.
Methods: Data from the prospective population-based Study of Health in Pomerania were used. From the 2117 men aged 20-79 years at baseline, 1490 men with complete TT data were analysed. Crude and age-specific prevalence and incidence rates of TD were estimated by TT levels below the age-specific 10th percentile. Analysis of covariance and Poisson regression models were used to assess the association of socio-demographic characteristics, health-related lifestyle, as well as somatometric, medical and laboratory measures with risk of incident TD.
Results: TD baseline prevalence was 10.4% (N = 155) and incidence 11.7 per 1000 person-years. TT levels showed a significant age-related decline with an unadjusted rate of 0.05 nmol/l per year. Obesity, metabolic syndrome, diabetes and dyslipidaemia were identified as risk factors of incident TD. Subpopulations of men without the revealed risk factors at both examinations maintained constant TT levels over time.
Conclusions: Besides aging alone, lifestyle and different comorbidities were associated with TT level decline, suggesting that the age-related TT decline may be at least partly prevented through the management of potentially modifiable risk factors and health related behaviour.