Researchers: Lena Novack¹, Iftach Sagy¹

Background: Climate change and air pollution may affect the onset and course of autoimmune rheumatic diseases. However, evidence regarding the effects of environmental exposures on disease incidence and flares remains inconsistent, and their potential impact on healthcare utilization is poorly characterized.

Objectives: To examine associations between environmental and climatic conditions and the incidence and flares of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), and to estimate the associated burden on healthcare services.

Method: This nationwide study used Clalit Health Services data from 2001–2024, linked with environmental data on temperature, humidity, and air pollution. The cohort included 30,876 patients with RA and 2,455 with SLE. Associations with disease incidence were evaluated using spatial Poisson regression, while short-term associations with flares were assessed using a case-crossover design and distributed lag models. Healthcare burden was evaluated using hospitalizations following RA flares and attributable fractions for environmental exposures.

Findings: PM10 exposure was associated with increased RA incidence. Short-term exposure to benzene, NO₂, SO₂, and PM2.5 was associated with RA flares. For SLE, temperature, humidity, and SO₂ were associated with disease incidence, while associations with flares were less consistent. During the study period, 45,117 hospitalizations occurred within 30 days following RA flares. Modelling suggested that a proportion of these hospitalizations was attributable to environmental exposures, particularly benzene and NO₂.

Conclusions: Environmental conditions, particularly air pollution, may contribute to the incidence and clinical course of autoimmune rheumatic diseases and impose an additional burden on healthcare services and costs.

Recommendations: Environmental information should be incorporated into healthcare planning and risk-alert systems for vulnerable populations. Reducing air-pollution exposure may potentially reduce disease-related morbidity, healthcare utilization, and associated healthcare costs.

Research end date: 08/2026