Global Asbestos Congress 2000

PROTOCOL - third draft

Reducing Asbestos-related Lung Cancer on Wirral

Background

Combined exposure to toxic agents and tobacco smoke in the environment, particularly in workplaces, amplifies the severity of adverse effects beyond what could be expected from smoking or the toxic hazard alone (WHO factsheet No. 158, 1998). Asbestos has a range of harmful effects, mainly on respiratory health, including asbestosis (lung and pleural fibrosis), lung cancer, pleural mesothelioma, cancer in other parts of the body, and obstructive airways disease in smokers. Smokers who have been exposed to asbestos have a 10-40 times greater risk of developing these diseases compared to a non-smoking asbestos worker, and a 90-fold greater risk compared to a non-smoker not occupationally exposed to asbestos (WHO factsheet No.158, 1998).

What is the size of the problem locally?

The population of Wirral may be expected to have had a relatively high historic exposure to asbestos, due to its shipbuilding industry, but we would expect this to be unevenly distributed across Wirral. Current data for lung cancer mortality shows that three wards on the Mersey side of the peninsula experience the highest death rates. These are also the most economically deprived wards. Therefore we have designated the high mortality area as a putative "high exposure" area , and selected one practice from there, and designated the west Wirral low lung cancer mortality wards as a putative "low exposure" area.

Precise figures on the population likely to be exposed are not available, but estimates can be derived based on relevant information which is to hand. Liverpool Occupational Health Project (LOHP) conducted interviews with full occupational history with patients waiting to see their GP (for unrelated conditions) in selected practices in Liverpool over a number of years. From April to October 1992 they surveyed 2601 people specifically about previous asbestos exposure; about one in eight men reported asbestos exposure at some time in their working life, of whom a third were still smoking (LOHP - Annual Report).

As mesothelioma is so closely related to asbestos exposure, mesothelioma can be taken as an index of past exposure to asbestos in the population. From a study of cohorts of men born from the end of the 19th century onwards, it appears that men born in the 1940s are worst affected by the "asbestos epidemic" - and asbestos-related mortality can be expected to continue to rise until sometime between 2010 and 2020. Analysis of occupation on death certificates shows that building workers, especially plumbers and gas fitters, carpenters and electricians are numerically the largest high-risk group (Peto et al, 1995).

Wirral's shipbuilding industry would be a major source of exposure for those working up to the mid-1970s when tighter control came into force.

What can be done to reduce lung cancer?

A review of surveillance and intervention studies on respiratory cancers in asbestosexposed workers has recently been published (Merler et al, 1997). Studies were either national or regional surveillance programmes (4), programmes based in factories or industrial sectors (8) or chemoprevention (beta-carotene and retinol) studies (3). The studies had different aims and outcomes.

A cross-sectional cohort study in Telemark, Norway, where 21,319 men were followed up over 8 years, found that those (asbestos exposed men) who abstained from tobacco for greater than 12 years reduced their lung cancer risk by two thirds (Waage et al, 1993).

To date I have found no study based in a primary care setting, i.e. getting practice staff to ask "screening" questions to establish previous exposure to asbestos, in order to target this high risk group with a smoking cessation intervention. Further literature search is underway. An Aberdeen based study is underway to look at the effect of computer generated letters from practice-held information on smoking (Lennox, National Research Register), but this will be limited by the lack of both occupational and smoking data in most general practices.

Newell and Vogel (1988) presented a helpful summary of personal risk factors in cancer over a decade ago:
(1) individuals at risk are often unaware of their risk
(2) physicians may not know those factors associated with the highest cancer risk
(3) methods to reduce risk have been under-applied because of lack of knowledge, lack of funds, or lack of motivation among both patients and physicians.
These points are still very relevant in the UK in the year 2000.

The challenge is to come up with an intervention which is simple, which primary care staff will have the resources to deal with, and yet will reach the very high risk group (men born in the 1940s) in time to help them reduce their personal cancer risk . The present study is seen as providing necessary background for the planning of a more definitive study or programme for which major R&D funding will be sought.

The present study (Phase 1) combines elements of both research and audit - the findings which are generalisable and help inform a more definitive strategy and further study can be considered research. The findings which will be fed back into patients' records at the practice, and hopefully assist future patient management can be considered audit. As it is difficult to separate the two, the study is being treated as a whole, and submitted for ethical consideration in its entirety.

Phase 2 will entail an intervention being developed targeting those current smokers who have been exposed to asbestos and express a desire to quit smoking. This will involve working closely with the practice nurses in the 2 practices, and doing qualitative research (observation and patient interviews).
This will be researched separately by Chris Harwood, as part of a Masters degree, and the protocol once refined will be submitted for ethical review.

Aim: To reduce the risk of lung cancer (and other related morbidity) in people who have been exposed to asbestos and are still smoking tobacco.

Objectives:

  1. To establish the prevalence of current smoking and previous asbestos exposure in two practice populations, one is a supposed high-exposure area (Tranmere) and one in a low exposure area (Heswall).
  2. To test the validity of the questionnaire developed.
  3. To assess the impact of the survey, and perhaps heightened awareness of the issues, on patients and staff at the practices.

Methods

Prevalence study

We are working collaboratively with two general practices, one in a supposed highexposure area (Tranmere) and one in a low exposure area (Heswall). They have adult populations of 4396 and 3636 respectively.

In order to determine prevalence of both smoking and asbestos exposure, we will survey all adults (aged 18 and over) in the two practices. No existing tool was quite fit to purpose, so a new one has had to be devised (See Appendix 1). It has been designed to be as brief and simple to complete as possible, with smoking questions on one side, and occupational history on the reverse.

Piloting the questionnaire and cover letter

A pilot study will be conducted on approximately 30 people, who are waiting to be seen at a similar practice in Tranmere (Dr Oates') - to test for understandability, acceptability, readability of the questionnaire and cover letter. One or two of the researchers will be present in the waiting room, and ask patients to look at questionnaire and cover letter and comment on how acceptable and understandable they find them. Minor modifications to wording and layout will then be made if necessary.

Sending out the questionnaire

A letter-headed cover letter from the patient's own practice will accompany the (amended) questionnaire. This will bear a printed signature from one of the GPs. (See Appendix 2)

All questionnaires will be numbered with the patients' existing NHS number. This is necessary to allow linking back to patients own records so that they can be amended with the up-to-date smoking and occupational data. A master record of patient identifying details (name, address, date of birth, NHS number) will be downloaded from practice computer systems (using Miquest) to an Excel spreadsheet, to be held in Wirral Health Authority.

It is our intention to prepare all the letters and questionnaires for mailing, and then mail out all 8032 in one batch. This is to make the logging period for response shorter, and to concentrate any extra activity generated by the study into as short a period as possible for the benefit of practice staff.

Reminders

An extensive body of research shows that using reminders increases response rate significantly from this type of community survey. Those patients who have not responded within 3 weeks will be sent a reminder postcard through the post, asking them to please return the questionnaire within the next 2 weeks, or to ring for a replacement to be sent out to them if the questionnaire has been discarded.

Logging impact on services

Practice staff at the two practices will be briefed about the study, so that they will be aware should any patients contact them. Contacts should be directed to:

  1. at Victoria Park practice, to Sue Gethin, practice nurse
  2. at Silverdale practice, to Sister Margaret Clarke, practice nurse

who can answer patients' questions, advise them about the specific options open to them with regard to smoking cessation.

Briefing for practice staff will be at two levels. All staff (including receptionists) will be informed that a study is underway, and its basic purpose. As many sessions as necessary will be arranged to catch all staff. They will be advised to refer any specific patient queries to the named contact, and to log any contacts from patients regarding these issues over the subsequent four weeks on a specific log sheet for all enquiries to reception staff.

More in-depth briefing - supplemented by reference literature and how to get further expert advice, and where to refer patients for specialist advice has been drafted. This will be sent for review to a chest physican with a specialist interest in occupational disease, a solicitor who deals with asbestos claims, and a local support group who are aware of benefits for victims of asbestos. This briefing will be aimed at the GPs and practice nurses, and will take the form of a lunchtime presentation, supplemented with a document summarising the main points and providing contact details for further information.

The two practice nurses will keep log sheets of patient contact pertaining to the study, and receptionists also asked to log any patient queries. All GPs in the two practices will also be asked to log any patient queries and outcomes stemming from the letter and questionnaire over the next four weeks.

Data input

Returned questionnaires will be processed by Health Authority staff. Date of response will be recorded, and patient responses entered on the Excel spreadsheet set up for this purpose, in the appropriate patient specific fields. Although it was intended to download to practice computer systems, it seems that the GP systems involved cannot receive this type of input. If this is the case, we will liaise with staff from the Medical Audit Advisory Group, and the two practices about how they could input the individual data for practice records.

Testing the validity of the questionnaire

As the questionnaire is a new instrument, we do not know how effective it is at picking up asbestos exposure in a community sample. There is no definitive "gold standard" against which to assess the instrument, but we intend to use the experience of the Liverpool Occupational Health Partnership to slightly amend the basic interview they evolved over seven years of interviewing patients waiting in surgery waiting rooms. We plan to conduct these similar semi-structured, face-to-face interviews with a randomly selected sub sample of approximately 100 patients who returned questionnaires, and agreed to be contacted again (question No. 8 of our questionnaire). The interview schedule and separate information sheet and consent form for this subsample will be submitted as a protocol amendment once refined.

Analysis

Patient data

Results will be analysed to provide:

  1. response rate
  2. prevalence of current smoking:
    1. smoking exposure (how long X how many)
    2. % wishing to give up
    3. % of those wishing to give up who have had previous attempts to quit
    4. addiction levels?
  3. prevalence of asbestos exposure
    1. patient reported exposure
    2. occupational history suggestive of exposure (?graded)

The frequencies above will also be displayed broken down by gender, age group and practice.

Cross-tabulations will be calculated to identify various sub-groups - especially those who want to quit and have been exposed to asbestos (i.e. our high-risk group).

Service data

The logs of enquiries related to or stemming from the letter and questionnaire from the named practice contact, GPs and receptionists will be collated. SUPPORT data for the relevant period for the two practices (perhaps also)

Audit data

We could compare the data from the survey with existing practice data on smoking.

Costs

Most of the costs of undertaking this study are being met by existing staff of Wirral Health Authority, Wirral Medical Audit Advisory Group and the two practices. The consumable costs are being met through the Health Authority's clinical audit budget.

Additional R&D costs (as opposed to extra service costs) to practices may be reimbursable through the R&D in primary care network funds (i.e. spending time at steering group meetings, but not counseling patients who may be caused anxiety by the questionnaire).

Practices to estimate how much additional practice nurse time will be spent on project, and submit to the network.

Consumables

Post-paid return envelopes (8500 - may need to get a print run of 10,000) Practice letter-headed paper - Tranmere practice 5000 @ £x per thousand Heswall practice 4000 @ £x per thousand

Large envelopes for survey 8500 Copying the questionnaire (1 sheet A4, double-sided, coloured paper) 8500 Reminder post cards to be printed.

Time scale

July 2000 Final draft protocol submitted to Ethics Committee Pilot questionnaire and cover letter in Dr Oates' surgery. Briefing circulated for expert opinion.
August 2000 Ordering stationery, printing of letters, questionnaires Compiling initial database, and using this to print address labels Briefing sessions (as many as necessary to catch all staff) Recruit/second assistant. Training in SPSS arranged.
Sept 2000 Questionnaires dispatched Responses logged
Oct 2000 Services continue logging relevant contacts Data input. Finalise validity interview structure and submit to LREC.
Oct-Feb 2001 Data input completed, data cleaned, and analysis performed. Prevalence report drafted. Data transfer to practice systems completed
Jan - Mar 2001 Conduct validity interviews.
May 2001 Planning of the study of the impact of the high risk message Final report of this study circulated.

References

Merler E, Buiatti E, Vainio H, 1997 Surveillance and intervention studies on respiratory cancers in asbestos-exposed workers, Scand J Work Environ Health; 23:83- 92

Newell GR & Vogel VG, 1988 Personal Risk Factors. What Do They Mean?, Cancer 62:1695-1701

Peto J, Hodgson JT, Matthews FE, Jones JR, 1995 Continuing increase in mesothelioma mortality in Britain, The Lancet Vol 345:535-539

Waage HP, Vatten LJ, Opedal E, Hilt B, 1993 Smoking Intervention in Subjects at Risk of Asbestos-Related Lung Cancer, American Journal of Industrial Medicine 31:705-712

WHO factsheet No.158, 1998 - www.who.int/inf-fs/en/fact158.html


Appendix 1

Draft questions for the prevalence study in two practices

  1. Do you currently smoke at least one cigarette, cigar or pipe a day?
    • No, I have never been a smoker
    • No, I do not smoke now, I gave up in ________(write year)
    • (please go to question 6, overleaf)
    • Yes, I smoke cigarettes (please go to question 2)
    • Yes, I smoke cigars
    • Yes, I smoke a pipe

  2. How long have you smoked in total? _______________(write in years)

  3. How many cigarettes a day do you usually smoke? ______

  4. Do you want to give up smoking?
    • No
    • Yes

  5. Have you tried to quit smoking before?
    • No
    • Yes

      • if yes, how many times _____________
      • and what was the longest time you managed to stay off the cigarettes (or cigars or pipe)?
        ________________________(please write days, months or years)

  6. To your knowledge, have you ever worked with asbestos, or been exposed to the dust or fibres from asbestos?
    • No
    • Yes

  7. Have you ever worked in the following industries?

    If so please show roughly how long by ticking all the appropriate boxes in the grid below:

    Industry / trade Less than 1 year 1 -10 years 10 years +
    metal plate or shipbuilding      
    vehicle manufacture      
    plumbing/ gas fitting      
    carpentry      
    electrics or electrical plant      
    upholstery      
    construction work      
    boiler operation      
    chemical engineering      
    docks      
    machine and tool operation      

    and finally,

  8. Would you be prepared to be contacted again to ask more in-depth questions about your work history?
    • No
    • Yes

(Your participation in any research is entirely voluntary and will in no way affect the care you receive).

Thank you very much. Now place your completed questionnaire in the post-paid return envelope and post it. (to be printed on coloured paper, double sided)

Appendix 2

Cover letter

(to be printed on appropriate practice letter-headed paper)

Dear Patient,

This practice is trying to reduce cancer in our patients. You are probably aware that smoking is the biggest risk factor for lung cancer and many other health problems. Workplace exposure to certain harmful chemicals can also increase the risk of cancer caused by smoking.

The good news is that this risk can be reduced by quitting smoking. Help is at hand both in the practice, and at the new specialist smoking cessation service "SUPPORT".

To help us update our information on occupation and smoking, would you please fill in the enclosed questionnaire, and return it to us in the pre-paid envelope.

The information you provide will be used to help the Health Authority plan campaigns to reduce cancer on the Wirral. All information which is collected about you will be kept strictly confidential, and that which leaves the practice will have your name and address removed so that you cannot be recognised from it. The survey results will be published in a report available from Wirral Health Authority from May 2001. Your own data will be summarised in your medical records.

If you want to discuss any of the issues raised by this questionnaire, the practice nurse _____________________ would be happy to speak to you…contact details?

If you do not wish to be contacted about this matter again, please return the blank questionnaire in the post-paid envelope enclosed. This will in no way affect the care you receive from the practice.

Yours sincerely

Dr Murray Freeman (for the Victoria Park Practice) - confirmed
? Dr Tom Hennessey (for the Silverdale Practice - to be confirmed with practice doctors)