Occupational Respiratory Disorders Zafar Fatmi Associate Professor & Head Division of Environmental Health Sciences Department of Community Health Sciences Aga Khan University February, 2014

Contribution of Occupation in lung disorders is difficult to determine NOTE: 60-90% similar chemicals

Contribution of Occupation for Respiratory Disorders Clinical and pathologic expression are indistinguishable Effects occur after a latent interval following exposure Individual susceptibility are substantially different – genetic differences in metabolism, age, gender or size, co-exposures to substances, co-morbids, complex behavioral factors

PM 10/2.5 Bronchial irritation Reduced mucocilliary clearance Wheezing, asthma Respiratory infections COPD and exacerbation Industrial Pollutants and Respiratory Health (Criteria Pollutants +188 Air Toxics - known)

Particulate Matter Coarse particles: TSP – Include wind blown dust as well as bacteria, pollens and mold spores. PM 10 are inhalable particles (include some bacteria and viruses) Fine particles (PM 2.5 ): tiny particles or droplets in the air mainly from combustion (Industrial, vehicle and Tobacco smoke)

Lungs has the largest surface area (equal to land area of a small house) (90m 2 ). More than the SKIN Lungs has the largest surface area (equal to land area of a small house) (90m 2 ). More than the SKIN 6 liters per minute air 6 liters per minute air Why lungs are exposed more in Occupational setting?

Two broad categories Diseases that are not occupation-specific, but are aggravated at work, such as occupational asthma; and Diseases related to a specific occupation, such as asbestosis, coal worker’s pneumoconiosis (black lung), and farmer’s lung.

Occupational Referral Clinic-Outpatient General Diagnosis Categories

Respiratory Disorders Diagnosis Categories

COPD/OLD American Thoracic Society (ATS) recently estimated the contribution of occupational exposure to the overall population burden of COPD to be at least 15%.

Types of Occupational Asthma (OA) Sensitizer-induced OA (immune-mediated) ~50% - gradual exposure – Poultry, Baker, Printing, Carpenter, Pharmaceutical etc. Irritant-induced OA (non-immune) ~50% - Single, high level of exposure – irritant gases, fumes, and smoke (Reactive airway dysfunction) Aggravation of asthma ~<1% – Cigarette smoke, Fumes from cleaning agents, Dusts, Paint, Cold air, Exercise

Exposure assessment

Findings from textile workers study in Karachi Nafees AA et. al, Cross-sectional survey among 372 textile workers conducted at 15 textile mills in Karachi and its outskirts

Table 3 Frequency distribution of chronic/severe symptoms and illnesses among textile workers (n=372), Karachi, Pakistan, 2010 SymptomFrequencyPercentage (95% CI) Cough* ( ) Phlegm* ( ) Wheeze± ( ) Shortness of breath#78 21 ( ) Chest tightness§ ( ) Illness Byssinosis ǂ ( ) Asthma ‡154 (2-6) *cough or phlegm for more than 2 years ± wheeze for more than 2 years #Question asked: do you have to walk slower than people of your age on the level because of breathlessness? ( grade 2 dyspnea) §Question asked: does your chest feel tight and/or your breathing becomes difficult occasionally apart from cold? ǂ based on Schilling’s criteria ‡Question asked: has a doctor ever told you that you have asthma?

Table 4 Distribution of byssinosis according to the sections of textile mill (n=372) Section of textile mill nNumber of workers with byssinosis Percentage Spinning % Weaving19884 % Distribution of grades of byssinosis (n=39)

Causality in population studies, and when dealing with an individual patient in a clinic. Epidemiologic causality:Key Clinical Questions for Occupational disease TemporalityWhen in relation to exposure do / did the symptoms start? ReversibilityDo the symptoms improved when not exposed e.g. on holiday? Exposure-response Are the symptoms worse when undertaking tasks/ in areas with high exposures? Strength of association Do other workers / patients suffer from similar symptoms associated with the same exposures? Specificity What other exposures / causal factors could be responsible for the same symptoms? (Smoking perhaps?)

Thank You! Zafar Fatmi Protect Your Lungs