Correlation between environmental factors and clinical and laboratory parameters of rheumatoid arthritis at different stages of its development

Rheumatoid arthritis (RA) is a multifactorial disease. Environmental toxins are among its suspected triggers. Objective. The aim of the study is to examine the correlation between environmental parameters and clinical and laboratory parameters in patients with RA and individuals with pre-RA. Materials and Methods. The study enrolled four groups of patients with early (early RA, n=349), established (established RA, n=529), and preclinical (pre-RA, n=333) stages of RA, as well as presumably healthy individuals with no family history of autoimmune and immuno-inflammatory diseases (control, n=203). The authors analyzed the correlation between clinical signs and laboratory parameters of RA with 10-year average environmental parameters in the administrative districts of the Republic of Tatarstan (RT) and heavy metal concentrations in soil samples from the residential areas of the study participants. Results. Environmental factors at maximum permissible concentrations (MPCs) influenced some key parameters in all groups, including the control one, particularly RF and ESR. Furthermore, environmental factors also affected serum Ig levels in the combined cohort of all subjects examined, and these parameters were inversely proportional to environmental toxicant levels. Undeniable evidence of the environmental factor impact on immunopathological processes at pre-RA stages is the identified pattern: unlike patients with pre-RA (stages III and VI) and those with early RA (stage V), patients with RA stage I (genetic) predominate in areas with lower population density and lower concentrations of certain air pollutants. Further evidence of the involvement of environmental factors in the immunopathogenesis of pre-RA and the disease itself is the identified correlation between clinical and laboratory parameters of RA in the pre-RA and early RA groups. Conclusion. Correlation between environmental factors and clinical/laboratory parameters was demonstrated in all study groups. The obtained data on the role of environmental factors in RA pathogenesis can be used to develop therapeutic intervention algorithms aimed at preventing or delaying the disease onset at its preclinical stage.