Body mass index is associated with interleukin-1, adiponectin, oxidative stress and ioduria levels in healthy adults.

Background: iodine contributes to maintain the balance of the reduced and oxidized species and is also required for thyroid hormones synthesis as triiodothyronine (T3), which regulates energy metabolism in adults. Increased body mass index (BMI) is associated with inflammatory markers, oxidative stress, and abnormalities in adipocytokines secretions that are associated with obesity and chronic disease.

Objective: the aim of the study is to investigate the association between ioduria, oxidative stress, total antioxidant status, adiponectin and interleukin-1 (IL-1) with BMI in healthy adults.

Methods: a cross-sectional study was performed in 114 healthy adult volunteers, aged 25-44 years, divided according to their BMI in three groups: normal weight (BMI < 25), overweight (BMI ≤ 25 to < 30), obesity (BMI ≥ 30). Adiponectin and IL-1 were measured by immune-enzymatic assays; oxidative stress, by determination of malondialdehyde (MDA); and total antioxidant status (TAS) and ioduria were measured by colorimetric assays. Statistical association was done by Spearman's test.

Results: overweight and obese subjects have higher serum levels of MDA, TAS and IL-1 vs normal weight subjects. Moreover, overweight and obese subjects have lower levels of iodine and adiponectin vs normal weight subjects. MDA was positively related only with obese subjects (r = 0.787, p = 0.008) and TAS with overweight (r = 0.398, p = 0.049) and obese subjects (r = 0.448, p = 0.030). In contrast, a reverse correlation with ioduria was found in obese subjects (r = 0.463, p = 0.001). Adiponectin was negatively related only in obese subjects (r = -0.477, p = 0.001), while, IL-1 was positively related with the increase of BMI (overweight r = 0.287, p = 0.050; and obesity r = 0.515, p = 0.006).

Conclusion: alteration in IL-1, adiponectin and oxidative stress levels were found to be related to overweight and obesity; also, iodine levels decreased when BMI increased, contributing to loss of redox equilibrium. All this data may play an important role in etiopathogenesis of chronic disease related to the increase of BMI.