Association between chronic inflammation status and serum testosterone and free testosterone in adult males

Chronic inflammation may contribute to biochemical hypogonadism, but evidence regarding composite inflammatory indicators is limited. This study examined the associations of the systemic inflammation response index (SIRI) and aggregate index of systemic inflammation (AISI) with serum testosterone and free testosterone (FT) in adult males. Data were obtained from NHANES 2011–2016 and 2021–2023, including 7,576 men for serum testosterone and 3,590 for FT. Multivariable regression, smoothing curves, threshold effect, and age-stratified analyses were conducted. Higher SIRI and AISI were significantly associated with lower serum testosterone and FT levels (P SIRI and AISI are independently associated with lower serum testosterone in men, while associations with FT appear age-dependent.