Association between Cytokines, 25-Hydroxyvitamin D, and Physical Activity: Evidence from a  cross sectional Brazilian Population

Background: Vitamin D is of vital importance for bone health and also regulates inflammatory cytokines, which contribute to immune signaling and defenses. It is possible that physical activity could influence serum 25(OH)D levels, and it has been suggested that exercise can increase serum 25(OH)D concentration. The aim of this study was to investigate the association between inflammatory biomarkers and 25(OH)D concentration in a sample of Brazilian adults, taking into account the influence of physical activity on this association. Methods: This is a cross-sectional population-based study, conducted with 712 adults aged 20 to 59 years living in the urban area of Viçosa, Minas Gerais, Brazil. Sociodemographic, anthropometric, behavioral and biochemical variables were collected. Multiple linear regression models (crude and adjusted) were used to determine associations between 25(OH)D concentration and inflammatory biomarkers, with statistical significance analyzed at 5%. Results: In the multiple linear regression models, it can be observed that for each unit increase in the concentration of 25(OH)D, there was an average decrease in the inflammatory biomarkers. Physical activity level was considered an effect modifier of the association between serum 25(OH)D levels and some cytokines, and participants whose PAL was greater than 150 minutes tended to have lower levels of IL-6, IL-10, TNF-α and IL-12p70 when plasma 25(OH)D concentration was increased. Conclusions: Higher 25(OH)D concentrations were associated with lower levels of inflammatory biomarkers in Brazilian adults. Furthermore, physical activity served as a significant effect modifier of this association, enhancing the reduction of pro-inflammatory cytokines. These results underscore the importance of maintaining adequate 25(OH)D levels in conjunction with an active lifestyle to modulate inflammation and promote overall health.