Et studie viste, at testosteronniveauet hos mænd i USA er faldet uafhængigt af alder over flere årtier. Faldet kan ikke forklares fuldt ud af livsstilsfaktorer som rygning og overvægt. Dette tyder på, at miljømæssige eller sundhedsmæssige faktorer, der endnu ikke er identificeret, kan spille en rolle.
Titel på undersøgelse:
A Population-Level Decline in Serum Testosterone Levels in American Men.
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Hele abstrakt på originalsprog:
This prospective cohort study investigates population-level changes in serum testosterone (T) concentrations in 1,532 randomly selected men aged 45-79 from greater Boston, Massachusetts, across three waves: baseline (T1: 1987-1999), T2 (1995-1997), and T3 (2002-2004), yielding 2,769 observations. The study aimed to quantify declines in total and bioavailable T and assess whether secular changes in factors like relative weight explain these trends. Results reveal a significant age-independent decline in T, exceeding typical cross-sectional age-related decreases, which persists despite accounting for health and lifestyle factors such as obesity and smoking. Conducted as an observational study, it suggests a substantial, unrecognized population-level drop in T among American men in recent decades, potentially linked to birth cohort differences or unmeasured health and environmental influences. These findings highlight a broader temporal trend in endocrine function beyond chronological aging.