Sex-Specific Associations between Serum IL-16 Levels and Sarcopenia in Older Adults.

Epidemiological studies of older adults have suggested a differential sex-specific prevalence of sarcopenia, which is a condition characterized by a progressive loss of skeletal muscle mass and function. Recently, we collected serum samples from 80 fully evaluated older adults and identified CXCL12α as a sex-independent serum marker of sarcopenia. Here, we used this serum collection to find potential sex-specific serum markers via the simultaneous quantification of 34 inflammatory cytokines/chemokines. The appendicular skeletal muscle index (ASMI) was used as a decisive criterion for diagnosing sarcopenia. A Pearson correlation analysis revealed a negative correlation between ASMI and serum IL-16 in females only ( = 0.021). Moreover, women with sarcopenia exhibited significantly higher IL-16 ( = 0.025) serum levels than women in a control group. In contrast, males with sarcopenia had lower IL-16 ( = 0.013) levels than males in a control group. The further use of Fisher's exact test identified obesity ( = 0.027) and high serum levels of IL-16 ( = 0.029) as significant risk factors for sarcopenia in females. In male older adults, however, malnutrition ( = 0.028) and low serum levels of IL-16 ( = 0.031) were the most significant risk factors for sarcopenia. The differential sex-specific associations of IL-16 in older adults may contribute to the development of more precise regression models for future research and elucidate the role of IL-16 in the progression of sarcopenic obesity.