Exploration of cytokines relating to masked obesity in Japanese women

Background Masked obesity (MO) has been associated with chronic inflammation; however, its immunological profile has not been extensively studied. Objective This exploratory study aimed to investigate immunological profile in MO by examining serum cytokine levels and clinical characteristics in individuals with reduced muscle mass and increased fat. Methods Body composition was assessed in 432 female employees of The University of Osaka (aged 30-59 years) using InBody270 during health examinations. Participants with skeletal muscle mass index (SMI) ≥ 5.7 kg/m² and percent body fat (PBF) < 30% were classified as the healthy (H) group, while those with SMI < 5.7 kg/m² and PBF ≥ 30% were classified as the MO group. Serum cytokine concentrations were measured in randomly selected participants, 34 from the H group and 24 from the MO group. Results Compared to the H group, the MO group had significantly higher triglyceride (p < 0.0001), low-density lipoprotein cholesterol (p = 0.0047), and insulin (p = 0.0008) levels, and significantly lower grip strength (p < 0.0001). Interleukin-17 C levels (unadj. p = 0.017, q = 0.33), colony-stimulating factor-1 (unadj. p = 0.051, q = 0.33) and lymphotoxin-alpha (unadj. p = 0.053, q = 0.33) levels tended to be lower, and interleukin-6 (unadj. p = 0.049, q = 0.33), C-C motif chemokine ligand (CCL) 8 (unadj. p = 0.064, q = 0.33) and CCL2 (unadj. p = 0.066, q = 0.33) levels tended to be higher in the MO group than in the H group. Conclusion This exploratory study demonstrates that MO might be associated with circulating levels of some cytokines, suggesting that these cytokines could be potential biomarkers for MO.