Related Experiment Video
Updated: Aug 31, 2025

Measuring Carbon Content in Airway Macrophages Exposed to Carbon-Containing Particulate Matters
Published on: July 12, 2024
Associations between conjunctivitis and ambient PM2.5 and physical activity: A nationwide prospective cohort study
Ge Chen1, Yinglin Wu1, Zhengmin Min Qian2
1Department of Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, PR China.
Background:
Currently, there is no evidence of fine particulate matter pollution (PM2.5) altering the relationship between physical activity (PA) and the risk of conjunctivitis.
Methods:
Based on the UK Biobank study, we included 308,507 participants aged 40-69 years at baseline (2006 to 2010) and prospectively followed up for conjunctivitis diagnosis till 2020. Annual concentrations of PM2.5 in 2010 were estimated for each participant using Land Use Regression models. PA levels during work and leisure time were reported via the International Physical Activity Questionnaire at baseline. We used Cox proportional hazards models to examine the associations of PM2.5 and PA with incident conjunctivitis, as well as their interaction at both multiplicative and additive scales.
Results:
During the 11.6 years of follow up, we identified 4002 incident conjunctivitis cases. High-PA (≥3000 metabolic equivalent of task [MET]-mins/week) was associated with lower risk of conjunctivitis (hazard ratio [HR]: 0.79, 95% confidence interval [CI]: 0.73-0.86) compared to low-PA (0 to <600 MET-mins/week), while every 1 microg/m3 increment in PM2.5 was associated with a 16% higher risk of conjunctivitis (HR = 1.16, 95% CI: 1.09-1.23). We did not observe statistically significant interactions between PM2.5 and PA on their associations with conjunctivitis.
Conclusion:
Habitual PA and PM2.5 exposure were oppositely related to incident conjunctivitis. The benefits of PA remain in people irrespective of exposure to air pollution.
More Related Videos
10:11Fundus Photography as a Convenient Tool to Study Microvascular Responses to Cardiovascular Disease Risk Factors in Epidemiological Studies
Published on: October 22, 2014
09:33Visualizing Field Data Collection Procedures of Exposure and Biomarker Assessments for the Household Air Pollution Intervention Network Trial in India
Published on: December 23, 2022
Related Concept Videos
Asthma-II: Pathophysiology and Classification
Additionally, environmental and genetic factors play crucial roles in determining an individual's susceptibility to asthma and the severity of their condition.
Critical processes in asthma pathophysiology include:
Asthma-I: Introduction
Asthma-III: Symptoms and Complications
Classification of Asthma
Chronic Obstructive Pulmonary Disease-II: Pathophysiology
Chronic Inflammation
Asthma: Pathogenesis and Management
Asthma is classified as allergic and non-allergic. Allergens such as dust mites, pollen, and pet dander trigger allergic asthma, while factors like cold air, intense emotions, or exercise can induce non-allergic asthma.
COPD: Pathogenesis and Clinical Features
The primary cause for the onset of COPD is cigarette smoking and exposure to air pollution. These hazardous factors initiate a chain reaction within the lungs, resulting in chronic inflammation, damage to the airways, and a...