Summary Points/Introduction Environmentally Related Rheumatic Syndromes Problems With Interpreting the Literature About Potentially Environmental-Related Rheumatic Diseases   Environmental Factors That May Influence Rheumatic Diseases Conclusion References Editorial Board Contact Us Sign Up Archives

Volume 51, Number 10

The Role of Environmental Factors in Rheumatic Diseases

Daniel J. Wallace, MD
Michael H. Weisman, MD
Division of Rheumatology
Cedars-Sinai Medical Center/UCLA School of Medicine
Los Angeles, CA

Summary Points

• It is difficult to know if there is any causal relationship between environmental factors and rheumatic diseases because of the difficulty in obtaining sufficient numbers of patients and adequate controls and defining the exposure.

• There are some examples of environmental agents inducing rheumatic diseases, including contaminated rapeseed oil causing a scleroderma-like disease and contaminated L-tryptophan causing eosinophilic myalgia syndrome.

• Ultraviolet light may trigger lupus, and smoking may aggravate or worsen a number of rheumatic diseases.

Introduction

Rheumatic and autoimmune disorders stem from a combination of factors. The current accepted hypothesis is that in the presence of certain susceptibility genes, drugs, chemicals, and other agents in the environment are thought to play inciting roles. Over the last 30 years, progress has been made in defining the epidemiology of rheumatoid arthritis, systemic lupus erythematosus, scleroderma, inflammatory myopathy, the vasculitides, polymyalgia rheumatica, and the seronegative spondyloarthropathies. Investigators have been able to elucidate incidence, prevalence,  mortality rates, as well as age, sex, racial, and comorbid associations. Candidate genes or putative genetic associations have been identified for nearly all of these diseases.

Our understanding of the role of the environment has been less successful (1). In place of scientific evidence, unsubstantiated theories of the role of certain non-infectious environmental agents (eg, contaminated ground water causes lupus and scleroderma) has led to costly litigation and an industry that has been called “junk science” (2). The lack of substantiated work in this area has resulted in confusion among organizations that  advocate for patients with rheumatic diseases. In an Arthritis & Rheumatism editorial, Rose concluded that “establishing a cause-and-effect relationship between an agent and a disease…requires a valid statistical association between the putative agent and the disease, and a feasible biologic mechanism to account for the association” (3).