Predictors of obstructive lung disease Predictors of obstructive lung disease among seafood processing workers among seafood processing workers

along the West Coast of the along the West Coast of the Western Cape ProvinceWestern Cape Province

Adams S1, Jeebhay MF1, Lopata AL2, Bateman ED3, Smuts M4, Baatjies R1,Robins TG5

1 Occupational and Environmental Health Research Unit, School of Public Health, UCT 2 Division of Immunology, IIDMM, NHLS, Groote Schuur Hospital, UCT3UCT Lung Institute, UCT 4Medical Research Council, South Africa5 Department of Environmental Health Sciences, University of Michigan, U.S.A

Funded by: MRC, NIOSH R01 Grant No. F002304

Literature reviewLiterature reviewDemographic Household Survey: SA prevalence of asthma diagnosis Demographic Household Survey: SA prevalence of asthma diagnosis was 2.7% was 2.7% (men) and 3.1% (women) with PAF for occupational exposure 13.6%.(men) and 3.1% (women) with PAF for occupational exposure 13.6%.Ehrlich et al,Thorax 2004Ehrlich et al,Thorax 2004

Risk factors for NSBH in SA adults are female sex and occupationRisk factors for NSBH in SA adults are female sex and occupational exposure to al exposure to a job causing wheeze a job causing wheeze Van Schalkwyk et al, ERS,2005Van Schalkwyk et al, ERS,2005

Role of dietary polyunsaturated fatty acids in obstructive lung Role of dietary polyunsaturated fatty acids in obstructive lung disease uncertain disease uncertain but some protection for NSBH and exercisebut some protection for NSBH and exercise--induced bronchospasminduced bronchospasmMickleborough TD, Journal of Asthma 2005Mickleborough TD, Journal of Asthma 2005

Patterns of sensitization impact on clinical expression of asthmPatterns of sensitization impact on clinical expression of asthmaaBousquet J et al,Bousquet J et al, Allergy 2006Allergy 2006

Burden of obstructive lung disease is considerable and COPD projected to become the 3rd leading cause of death by 2020. Viegi et al , Respiration 2001

Occupational exposure accounts for a large proportion of symptoms and functional impairment consistent with COPD (15%).ATS review, 2001

ObjectivesObjectives

�� To determine the prevalence of asthma and COPD To determine the prevalence of asthma and COPD in a in a population of seafood processing workers on the West Coast of population of seafood processing workers on the West Coast of the Western Cape Province.the Western Cape Province.

�� To describe the host and environmental determinants To describe the host and environmental determinants associated with obstructive lung disease (asthma and COPD)associated with obstructive lung disease (asthma and COPD)

�� To conduct a detailed analysis of To conduct a detailed analysis of IgEIgE reactivity profiles (SPT) reactivity profiles (SPT) and their relationship with asthma outcomesand their relationship with asthma outcomes

�� To examine the relationship between serum fatty acid profiles To examine the relationship between serum fatty acid profiles and the relationship with asthma outcomes and the relationship with asthma outcomes

Fish canningFish canning Fishmeal productionFishmeal production

Common fish processing activities in factories

MethodologyMethodologyStudy design and populationStudy design and population�� CrossCross--sectional study of two factory population groups (N=643)sectional study of two factory population groups (N=643)�� Comprised 76% adults resident in this fishing village Comprised 76% adults resident in this fishing village

InstrumentsInstruments�� QuestionnaireQuestionnaire-- modified ECHRS modified ECHRS �� Skin prick test to common aeroallergens Skin prick test to common aeroallergens �� Spirometry Spirometry �� Methacholine challenge test (tidal breathing method) according tMethacholine challenge test (tidal breathing method) according to o

ATS guidelines ATS guidelines �� Serum omegaSerum omega--3 and omega3 and omega--6 6

Results

Occupational factorsOccupational factors

Outcome definitions for asthmaOutcome definitions for asthma

1. Atopy:1. Atopy: A positive SPT with a wheal read 15 A positive SPT with a wheal read 15 minutes after testing that had a diameter (mean minutes after testing that had a diameter (mean of two perpendicular measures) of of two perpendicular measures) of ≥≥ 3 mm more 3 mm more than the negative control to any allergenthan the negative control to any allergen

2. Asthma symptoms:2. Asthma symptoms: yes to any of: yes to any of: ““Have you Have you had an attack of asthma in the last 12 months?had an attack of asthma in the last 12 months?””, , ““Have you been woken by an attack of shortness Have you been woken by an attack of shortness of breath in the last 12 months?of breath in the last 12 months?””, , ““Have you Have you been woken up with a feeling of tightness in your been woken up with a feeling of tightness in your chest any time in the last 12 months?chest any time in the last 12 months?””

3. Current asthma:3. Current asthma: SelfSelf--reported wheeze in the reported wheeze in the past 12 months and the presence of NSBHpast 12 months and the presence of NSBH

Outcome definitions for asthmaOutcome definitions for asthma

4. Doctor4. Doctor--diagnosed asthma:diagnosed asthma: yes to both questions: yes to both questions: ““Have you ever had asthma?Have you ever had asthma?”” and and ““Was this Was this confirmed by a doctor?confirmed by a doctor?””

5. Non5. Non--specific bronchial hyperresponsiveness:specific bronchial hyperresponsiveness:A positive methacholine challenge test with a PC20 A positive methacholine challenge test with a PC20 ≤≤ 8 mg/ml causing a drop in FEV1 of 20% or more 8 mg/ml causing a drop in FEV1 of 20% or more or an increase in FEV1 of or an increase in FEV1 of ≥≥12 % after 10 minutes 12 % after 10 minutes of bronchodilator administration on baseline of bronchodilator administration on baseline spirometry, was considered indicative of the spirometry, was considered indicative of the presence of NSBH.presence of NSBH.

Demographic, medical and occupational factors Demographic, medical and occupational factors and asthma outcomesand asthma outcomes

Sensitization to common aeroallergens (N=626)Sensitization to common aeroallergens (N=626)

2 5 %

1 5 %1 4 %

9 %

5 %

4 %

3 %

2 %

H D MC o c k r o a c h R y e g r a s sB e r m u d a g r a s sD o gM o u ld m ix C a tA s p e r g i l lu s

Patterns of allergic sensitization and asthmaPatterns of allergic sensitization and asthma

Polyunsaturated fatty acids and asthmaPolyunsaturated fatty acids and asthma

Definitions for COPDDefinitions for COPD--related outcomesrelated outcomes

1. Chronic bronchitis symptoms:1. Chronic bronchitis symptoms: Reporting a Reporting a chronic productive cough for 3 months in 2 or chronic productive cough for 3 months in 2 or more consecutive yearsmore consecutive years

2. Airway obstruction:2. Airway obstruction:FEV1 / FVC < 70% FEV1 / FVC < 70%

3.3. Fixed airway obstruction:Fixed airway obstruction:FEV1 / FVC < 70% and absence of NSBHFEV1 / FVC < 70% and absence of NSBH

4. COPD:4. COPD: FEV1 / FVC < 70% and postFEV1 / FVC < 70% and post--bronchodilator FEV1 < 80% predictedbronchodilator FEV1 < 80% predicted

Demographic factors and COPDDemographic factors and COPD

Medical and occupational factors and COPD Medical and occupational factors and COPD outcomesoutcomes

ConclusionConclusion

Prevalence of asthma 5% - 26% and of COPD 3-5%

Pre-existing respiratory disease is important as a risk factor for asthma and COPD in working adults

Work is an important risk factor for obstructive lung disease particularly peak exposures and work-related ocular-nasal and chest symptoms

Sensitization to indoor allergens is an important risk factor for asthma

The potentially protective role of dietary fats (n-3) in asthma needs further investigation

Thank YouThank You