1. ¹University of Wales College of Medicine, Cardiff, UK
2. ²Tinuviel Software, Warrington, UK
3. ³Carmarthenshire NHS Trust, Carmarthen, UK

Correspondence: Dr M L Burr, Centre for Applied Public Health Medicine, University of Wales College of Medicine, Temple of Peace and Health, Cathays Park, Cardiff CF10 3NW, UK. E-mail: michael.burr@bro-taf-ha.wales.nhs.uk

^*Guarantor: Dr ML Burr.

^†Contributors: MLB and AMF designed the study. PALA-W and AMF were responsible for the day-to-day running of the study. Clinical interviews were conducted by PB, MLB and PCE. AMF, PALA-W, TA and PCZ were responsible for the dietary information. NAAH provided the serum cholesterol measurements. PALA-W collated the data, FDJD conducted the analysis and MLB wrote the paper.

Received 6 July 2001; Revised 23 May 2002; Accepted 28 May 2002.

Abstract

Objective: To see whether mortality among men with angina can be reduced by dietary advice.

Design: A randomized controlled factorial trial.

Setting: Male patients of general practitioners in south Wales.

Subjects: A total of 3114 men under 70 y of age with angina.

Interventions: Subjects were randomly allocated to four groups: (1) advised to eat two portions of oily fish each week, or to take three fish oil capsules daily; (2) advised to eat more fruit, vegetables and oats; (3) given both the above types of advice; and (4) given no specific dietary advice. Mortality was ascertained after 3–9 y.

Results: Compliance was better with the fish advice than with the fruit advice. All-cause mortality was not reduced by either form of advice, and no other effects were attributable to fruit advice. Risk of cardiac death was higher among subjects advised to take oily fish than among those not so advised; the adjusted hazard ratio was 1.26 (95% confidence interval 1.00, 1.58; P=0.047), and even greater for sudden cardiac death (1.54; 95% CI 1.06, 2.23; P=0.025). The excess risk was largely located among the subgroup given fish oil capsules. There was no evidence that it was due to interactions with medication.

Conclusion: Advice to eat more fruit was poorly complied with and had no detectable effect on mortality. Men advised to eat oily fish, and particularly those supplied with fish oil capsules, had a higher risk of cardiac death. This result is unexplained; it may arise from risk compensation or some other effect on patients' or doctors' behaviour.

Sponsorship: British Heart Foundation, Seven Seas Limited, Novex Pharma Limited, The Fish Foundation.