Prevention of (occupational) disease. - Institute of Population

Prevention of (occupational) disease.

MBChB, Phase I, Year 1, Semester 230th April 2009, 11.00 a.m.

Roscoe Bldg, Lect. Theatre A

Raymond AgiusProfessor of Occupational & Environmental Medicine,

& Consultant in Occupational Medicine*

*Medical specialty dealing with the effects of work on health,and of health on work.

The effects of work on health can be positive or negative. In this session we are dealing with the latter.

www.medicine.manchester.ac.uk/oeh/undergraduate/onlineresources/

Learning Objectives:

• Understand the relevance of work to health and disease. (Knowledge)

special reference to recognition & prevention of disease

• Take an occupational history … (Skill)

• Appreciate the different perspective required by the Occupational Health approach (Attitude)

Structure of Presentation:

Introduction.

Body:1. Burden of Occupational Disease in the UK.2. Recognising Occupational Disease & its causes

- Taking an Occupational History3. Preventing Disease related to work.Conclusion.

Structure of Presentation:

Introduction.

Body:1. Burden of Occupational Disease in the UK.2. Recognising Occupational Disease & its causes

- Taking an Occupational History3. Preventing Disease related to work.Conclusion.

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

People who believed that they were suffering from an illness caused or made worse by their current

or past work.

?

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7*

Total ~ 2 Million

(2,200,000. Confidence Interval: 2,131,000 to 2,269,000)Rate: 5110 per 100,000 ever employed

*Self-reported work-related illness in 2006/2007: Results from the Labour Force Survey. Jones et al; HSE

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

Musculoskeletal:

?

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

Musculoskeletal~ 1.0 Million

(1,144,000 Confidence Interval: 1,094,000 to 1,193,000)Rate per 100,000 ever employed = 2650

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

Stress, depression or anxiety:

?

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

Stress depression / anxiety: 530,000

(Confidence Interval: 496,000 to 565,000)Rate per 100,000 ever employed = 1230

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

Breathing and lung problems:

?

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

Breathing and Lung problems: 142,000

(Confidence Interval: 125,000 to 159,000)Rate per 100,000 ever employed = 330

Diseases caused by asbestos include:

Asbestosis (a form of lung fibrosis)

Bronchial cancer

Mesothelioma ( cancer of the pleura)

[still responsible for thousands of deaths per year from exposures of 3-4 decades ago]

Pneumoconioses are diseases caused by dust,

e.g. silicosis caused by silica

Occupational asthma is the commonest occupational lung disease arising from current exposures

Examples of agents causing asthma:

Number of Estimated Cases of Asthma Attributed to Glutaraldehyde Exposure Reported to SWORD

(1989-2008)

84

27

46

1712

5 37 5

2 1 0 1

18 1613

612

5 37 5

2 1 0 10

20

40

60

80

100

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

num

ber o

f cas

es

Estimated casesActual cases

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

Hearing problems:

?

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

Hearing problems: 75,000

(Confidence Interval: 63,000 to 87,000)Rate per 100,000 ever employed = 170

Audiogram showing Noise Induced Hearing Loss

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

Heart disease/attack, other circulatory system:

?

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

Heart disease/attack, other circulatory system: 60,000

(Confidence Interval: 49,000 to 71,000)Rate per 100,000 ever employed = 140

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

Skin problems:

?

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7

Skin problems: 29,000

(Confidence Interval: 21,000 to 36,000)Rate per 100,000 ever employed = 67

Eczema / dermatitis

The commonest occupational skin disease

Occupational skin disease - Most frequently reported industries

Estimated cases of all skin disease reported by dermatologists in 2008 (‘Epiderm’: University of Manchester)

345

284

267

229

0 50 100 150 200 250 300 350 400

Health and social care(213)

Hairdressing andbeauty (86)

Public administration& defence (58)

Construction (75)

Estimated cases

Incidence rates of all skin disease reported to EPIDERM (2008) by most frequently reported industries per 100,000 employed per year

compared with population denominator from the Labour Force Survey 2007 data

9.77

114.08

12.84

9.79

0 20 40 60 80 100 120

Health and social care

Hairdressing andbeauty

Public administration& defence

Construction

incidence rate

But other occupational skin disease too …

•Case:

fair skinnedoutdoor exposure

3years flat mole1 month pink raiseditchy, bleeding

Melanoma (malignant)

•Case

Vet

tending cattle

Orf

Estimated prevalence of self-reported work-related illness in Great Britain in 2006/7 –

order of illness types

Estimated prevalence (thousands) Rate per 100,000 ever employedDiagnostic category

Central Lower CI Upper CI Central Lower CI Upper CI

Musculoskeletal 1144 1094 1193 2650 2540 2770

Stress, depression / anxiety

530 496 565 1230 1150 1310

Breathing / lung problems

142 125 159 330 290 370

Other complaints 147 129 165 340 300 380

Hearing problems 75 63 87 170 150 200

Circulatory system 60 49 71 140 110 160

Infectious disease 72 32 52 98 75 120

Skin problems 55 21 36 67 49 85

0% 25% 50% 75% 100%

All cases

Health & social care

Construction

Public admin & defence

Retail

Education

Catering

Other business

Food Manufacture

Metal manufacture

Financial

Land transport

Agriculture

Hair & beauty

Musculoskeletal Mental ill health Skin Respiratory Audiological Other

Industries reported by diagnostic category by GPs (THOR-GP 2006-07)

Structure of Presentation:

Introduction.

Body:1. Burden of Occupational Disease in the UK.2. Recognising Occupational Disease & its

causes - Taking an Occupational History3. Preventing Disease related to work.Conclusion.

The Occupational History.Bernardino Ramazzini:

“What is your job?…Tell me about it”

Work can be: • The ‘unique’ cause of a disease, or• A contributory factor amongst others, or• It can make a disease worse

Determining Cause

The Occupational History

What pattern of enquiry would you follow to determine whether there was a causal relationship between a particular exposure and a worker’s health concerns?

NB: For this purpose, and at this stage DO NOT address specific exposures nor specific symptoms/signs.

Enquiry:When in relation to exposure do / did the symptoms start?

Temporality

Enquiry:Do the symptoms improve when no longer exposed?

Reversibility

Enquiry:Are the symptoms especially worse when undertaking high exposure tasks or in areas with high exposures?

Exposure-response

Enquiry:Do other workers / patients suffer from similar symptoms associated with the same exposures?

Strength of association

Enquiry:What other exposures / causal factors could be responsible for the same symptoms?

Specificity

Enquiry:Are there other reports of the same symptoms associated with or caused by the same exposure?

Consistency

Enquiry:Have similar agents/ chemicals of similar structure been implicated in the same ill health.

H2N NH2

P-Phenylenediamine

HN NH

Piperazine

CH3

NCO

NCO

2,4-Toluene diisocyanate

N

CONH-NH2

Isonicotinic acid hydrazide

HydralazineNH-NH2

N

N

CH3CH2NH2Ethylamine

NH2

Aniline

NH

Piperidine

H2NCH2CH2NH2Ethylenediamine

H2NCN:NCNH2Azodicarbonamide

O ONot-asthmagens vs Asthmagens

Enquiry:Have similar agents/ chemicals of similar structure been implicated in the same ill health.

Analogy

Enquiry:Do the symptoms 'add up' in terms of what is known about the mechanisms of disease?

Biological plausibility

Austin Bradford Hill’s ‘criteria’ for causal association•Temporality•Reversibility•Exposure-response•Strength of Association•Specificity•Consistency•Analogy•Biological Plausibility

Clinical (individual) approach Epidemiologic (group) approach

Individuals Groups of people

Symptomatic/ill/worried Ill or at risk

Aims for Diagnosis Aims for Causal relationships

Individual risk factors Contributory factors Or workplace hazards Exposure-response relationships

Treatment / local control Population intervention

Education Attitudes in society

Review Evaluation of intervention

Structure of Presentation:

Introduction.

Body:1. Burden of Occupational Disease in the UK.2. Recognising Occupational Disease & its causes

- Taking an Occupational History3. Preventing Disease related to work.Conclusion.

Steps to prevent occupational disease:

1. Eliminate the hazard or 2. Substitute it by something ‘safer’.

Cases of occupational asthma attributed to latex: 1991-2008(SWORD: Surveillance of Work related & Occupational Respiratory Disease

– The University of Manchester)

31

4

10

16

20

5148

17

30

1012

16

42 2 3

0

31

4

10

16

9

18

1517

810

12

5 42 2 3

00

10

20

30

40

50

60

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

num

ber o

f cas

es

EstimatedActual

Steps to prevent occupational disease:

3. Contain / segregate the hazard or 4. Draw the hazard awayor5. Wear personal protection(last resort since it does not work as well as expected, and can be awkward to wear or be a hazard in itself)

Some examples in the health service

Manufacturing Industry

6. Most important steps to prevent work related ill health (can apply to all jobs):

Improve the organisation of work, and work practices, addressing issues such as:

- Proper communication between employers and employees - Workload (overload or underload)- Matching workers’ skills to the jobs- Having clear lines of accountability and responsibilities- Appropriate work patterns e.g. shiftwork- Job security- Ensuring a ‘happy’ workplace and worker – free from bullying etc- ‘Safe’ working practices- Training and educating workers

… but not like this!

However absence of work is also associated with increased ill-health!

“Employment is nature’s physician and is essential for human happiness”

Galen, ca 180 AD

Structure of Presentation:

Introduction.

Body:1. Burden of Occupational Disease in the UK.2. Recognising Occupational Disease & its causes

- Taking an Occupational History3. Preventing Disease related to work.Conclusion.

• There remains a large burden of work related ill health in the UK.

• Appropriate history taking is essential to recognise this.

• A hierarchy of control can prevent it:– Elimination or substitution of hazards– Enclosure/Segregation so as to reduce exposure– Local exhaust and/or dilution ventilation if relevant– Appropriate education, work organisation and practice– Personal protection

• (But most work is probably good for you)

Thank you.