Atteinte oculaire et environnement : clinique et physiopathologie

Short-term association of in-vehicle ultrafine particles and black carbon concentrations with respiratory health in Parisian taxi drivers

INTRODUCTION

Professional drivers are exposed inside their vehicles to high levels of air pollutants due to the considerable time they spend close to motor vehicle emissions. Little is known about ultrafine particles (UFP) or black carbon (BC) adverse respiratory health effects compared to the regulated pollutants.

OBJECTIVES

We aimed to study the short-term associations between UFP and BC concentrations inside vehicles and (1) the onset of mucosal irritation and (2) the acute changes in lung function of Parisian taxi drivers during a working day.

METHODS

An epidemiological study was carried out on 50 taxi drivers in Paris. UFP and BC were measured inside their vehicles with DiSCmini® and microAeth®, respectively. On the same day, the frequency and the severity of nose, eye, and throat irritations were self-reported by each participant and a spirometry test was performed before and after the work shift. Multivariate analysis was used to evaluate the associations between in-taxis UFP and BC concentrations and mucosal irritation and lung function, after adjustment for potential confounders.

RESULTS

In-taxis UFP concentrations ranged from 17.9 to 37.9 × 10³ particles/cm³ and BC concentrations from 2.2 to 3.9 μg/m3, during a mean of 9 ± 2 working hours. Significant dose-response relationships were observed between in-taxis UFP concentrations and both nasal irritation and lung function. The increase of in-taxis UFP (for an interquartile range of 20 × 10³ particles/cm³) was associated to an increase in nasal irritation (adjusted OR = 6.27 [95% CI: 1.02 to 38.62]) and to a reduction in forced expiratory flow at 25-75% by -7.44% [95% CI: -12.63 to -2.24], forced expiratory volume in one second by -4.46% [95% CI: -6.99 to -1.93] and forced vital capacity by -3.31% [95% CI: -5.82 to -0.80]. Such associations were not found with BC. Incident throat and eye irritations were not related to in-vehicle particles exposure; however, they were associated with outdoor air quality (estimated by the Atmo index) and in-vehicle humidity, respectively.

CONCLUSION

To our knowledge, our study is the first to show a significant association, within a short-period of time, between in and vehicle UFP exposure and acute respiratory effects in professional drivers.

The Differential Diagnosis of Dry Eyes, Dry Mouth, and Parotidomegaly: A Comprehensive Review

Primary Sjögren's syndrome (pSS) is a frequent autoimmune systemic disease, clinically characterized by eyes and mouth dryness in all patients, salivary gland swelling or extraglandular systemic manifestations in half of the patients, and development of lymphoma in 5 to 10 % of the patients. However, patients presenting with sicca symptoms or salivary gland swelling may have a variety of conditions that may require very different investigations, treatments, or follow-up. Eye and/or mouth dryness is a frequent complaint in clinical setting, and its frequency increases with age. When evaluating a patient with suspected pSS, the first step is to rule out its differential diagnoses, before looking for positive arguments for the disease. Knowledge of normal and abnormal lachrymal and salivary gland physiology allows the clinician to prescribe the most adapted procedures for evaluating their function and structure. New tests have been developed in recent years for evaluating these patients, notably new ocular surface staining scores or salivary gland ultrasonography. We describe the different diagnoses performed in our monocentric cohort of 240 patients with suspected pSS. The most frequent diagnoses are pSS, other systemic autoimmune diseases, idiopathic sicca syndrome and drug-induced sicca syndrome. However, other diseases are important to rule out due to their specific management, such as sarcoidosis, granulomatosis with polyangeitis, IgG4-related disease, chronic hepatitis C virus or human immunodeficiency virus infections, graft-versus-host disease, and head and neck radiation therapy. At the light of these data, we propose a core of minimal investigations to be performed when evaluating a patient with suspected pSS.