Environment and Lifestyle: Their Influence on the Risk of RA.

Carine Salliot,Yann Nguyen,Raphaèle Seror,Marie-Christine Boutron-Ruault

doi:10.3390/jcm9103109

Abstract

Background: Rheumatoid arthritis (RA) is a complex disease in which environmental agents are thought to interact with genetic factors that lead to triggering of autoimmunity. Methods: We reviewed environmental, hormonal, and dietary factors that have been suggested to be associated with the risk of RA. Results: Smoking is the most robust factor associated with the risk of RA, with a clear gene–environment interaction. Among other inhalants, silica may increase the risk of RA in men. There is less evidence for pesticides, pollution, and other occupational inhalants. Regarding female hormonal exposures, there is some epidemiological evidence, although not consistent in the literature, to suggest a link between hormonal factors and the risk of RA. Regarding dietary factors, available evidence is conflicting. A high consumption of coffee seems to be associated with an increased risk of RA, whereas a moderate consumption of alcohol is inversely associated with the risk of RA, and there is less evidence regarding other food groups. Dietary pattern analyses (Mediterranean diet, the inflammatory potential of the diet, or diet quality) suggested a potential benefit of dietary modifications for individuals at high risk of RA. Conclusion: To date, smoking and silica exposure have been reproducibly demonstrated to trigger the emergence of RA. However, many other environmental factors have been studied, mostly with a case-control design. Results were conflicting and studies rarely considered potential gene–environment interactions. There is a need for large scale prospective studies and studies in predisposed individuals to better understand and prevent the disease and its course.

Highlights

The immune onset of rheumatoid arthritis (RA), so called “preclinical phase” of the disease, might occur several years before the first symptoms of Rheumatoid arthritis (RA), with the development of autoimmunity as evidenced by detectable anti-citrullinated peptide antibodies (ACPA) and rheumatoid factors (RF)
The involvement of environmental, dietary, reproductive, and lifestyle factors in the pathogenesis of RA is supported by numerous observations which include the following: two thirds of individuals who develop RA are women, suggesting the role of female hormones; the latitude gradient influences the incidence of RA and age at onset, and the socioeconomic status and educational levels are consistently associated with the risk of RA [2,3,4,5]
NHS, Nurses’ Health Study (USA); IWHS, Iowa Women’s Health Study; Epidemiologic Investigations of RA (EIRA), Swedish Epidemiological Investigation of RA; RR, relative risk; OR, odds ratio; HR, hazard ratio; 95% CI, 95% confidence interval; RF, rheumatoid factor; ACPA, anti-citrullinated peptide antibodies; OC, oral contraception; Post-Menopausal Hormonal Treatment (PMHT), post-menopausal hormonal treatment; SERM, selective oestrogen receptor modulator; aromatase inhibitors (AI), aromatase inhibitor; SE, shared epitope

Summary

Introduction

The immune onset of rheumatoid arthritis (RA), so called “preclinical phase” of the disease, might occur several years before the first symptoms of RA, with the development of autoimmunity as evidenced by detectable anti-citrullinated peptide antibodies (ACPA) and rheumatoid factors (RF). The involvement of environmental, dietary, reproductive, and lifestyle factors in the pathogenesis of RA is supported by numerous observations which include the following: two thirds of individuals who develop RA are women, suggesting the role of female hormones; the latitude gradient influences the incidence of RA and age at onset, and the socioeconomic status and educational levels are consistently associated with the risk of RA [2,3,4,5]. The aim of this study is to review the literature evidence on external and internal exposures (so called “exposome”) associated with the risk of RA and its phenotype, and their interaction with genetic risk factors. Methods: We reviewed environmental, hormonal, and dietary factors that have been suggested to be associated with the risk of RA. There is a need for large scale prospective studies and studies in predisposed individuals to better understand and prevent the disease and its course

Objectives

Methods

Findings

Conclusion