Patients' awareness of adverse relation between Crohn's disease and their smoking: questionnaire survey

BMJ 1996; 313 doi: (Published 03 August 1996) Cite this as: BMJ 1996;313:265
  1. P L Shields, medical registrara,
  2. T S Low-Beer, consultant physiciana
  1. a Department of Medicine, Selly Oak Hospital, Birmingham B29 6JD
  1. Correspondence to: Dr Low-Beer.
  • Accepted 11 April 1996

Smoking is an independent risk factor for clinical, surgical, and endoscopic recurrence in Crohn's disease.1 In a 10 year follow up of 174 patients the recurrence rate was 70% in smokers and 41% in non-smokers.2 Passive smoking increases the risk of Crohn's disease in children3 and of having the more severe form. Ileocolonic and small bowel disease is more common in heavy smokers.4 On current evidence, encouraging patients to stop smoking ought to be an important part of the management of Crohn's disease, but there are few or no published data describing patients' knowledge of the association between smoking and their disease. We therefore investigated patients' and general practitioners' awareness of the link between smoking and Crohn's disease to identify the standard of education in this area.

Methods and results

A total of 102 patients (43 men) with Crohn's disease (mean age 42 (range 17-84) years) under the care of two gastroenterologists completed a questionnaire either in the outpatient clinic (n = 33) or by post (n = 69; 83% response rate). This asked whether they were a smoker or an ex-smoker; if they knew of any link between smoking and Crohn's disease; if anyone had informed them of the link and if so was it their general practitioner or hospital doctor; and if they had been advised to stop smoking. It also asked if they noticed any effect of smoking on the symptoms they associated with their disease.

Fifty one general practitioners were questioned about their knowledge of the link between smoking and Crohn's disease when they telephoned to refer patients to hospital urgently.

Forty per cent (41/102) patients smoked (28 women, 13 men); 19 were ex-smokers. Sixty four per cent (26) of the smokers were under 42; 35 smokers began before the onset of Crohn's disease.

Thirteen patients (11 smokers, 2 non-smokers) were aware of the adverse affects of smoking on their Crohn's disease. All 13 had been informed by their hospital doctor. No ex-smokers knew of the link, and all said they had given up cigarettes for reasons unrelated to their Crohn's disease. Fifteen of the 41 smokers had never been asked to stop smoking by their hospital doctor, and 27 had never been asked to stop by their general practitioner.

Only 5 of the current or ex-smokers felt that smoking had influenced symptoms they associated with their Crohn's disease. Of these, three felt that smoking improved symptoms and two that their symptoms worsened.

Two of the 51 general practitioners questioned knew of the adverse association between smoking and Crohn's disease.


This survey indicates that many general practitioners and their patients with Crohn's disease are unaware that the incidence and course of Crohn's disease are influenced by smoking. Furthermore, some gastroenterologists do not provide their patients with this information. This is compounded by fact that most smokers do not feel that smoking influences the symptoms they associate with their Crohn's disease.

In patients with asthma, chronic obstructive airways disease, and ischaemic heart disease, advice to stop smoking is regarded as important. Because Crohn's disease runs a chronic course with clinical relapses often requiring surgery, anything to improve the course of the disease, such as stopping smoking, should be strongly encouraged.

We should do more to educate both general practitioners and our patients about these facts. Patients will then be in a better position to make an informed decision to quit smoking and to have a positive effect on their disease.


  • Funding None.

  • Conflict of interest None.


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