5 sets of criteria for diagnosis of Behçet's disease are in use--a problem which has hindered interpretation of different studies and collaborative research. An international study group, which included at least one proponent of 4 of the sets, was formed to derive new, internationally agreed diagnostic criteria for Behçet's disease. Data on 914 patients with Behçet's disease, from 12 centres in 7 countries, were compared with controls from the same centres. The new set of diagnostic criteria--which requires the presence of oral ulceration plus any two of genital ulceration, typical defined eye lesions, typical defined skin lesions, or a positive pathergy test--was simpler to use and had an improved discriminatory performance than its predecessors.

To develop guidelines for ranking the urgency with which patients with angiographically proven coronary disease need revascularisation procedures, factors that a panel of cardiac specialists agreed were likely to affect urgency were incorporated into 438 fictitious case-histories. Each panelist then rated the cases on a 7-point scale based on maximum acceptable waiting time for surgery; 1 on the scale represented emergency surgery and 7 delays of up to 6 months. For only 1% of cases was there agreement on a single rating by at least 12/16 panelists. Results of this ranking exercise were used by the panel to draw up triage guidelines. The three main urgency determinants were severity and stability of symptoms of angina, coronary anatomy from angiographic studies, and results of non-invasive tests for risk of ischaemia. Together these three factors generally gave an urgency rating for any given case to within less than 0.25 scale points of the value predicted with all factors. A numerical scoring system was derived to permit rapid estimation of the panel's recommended ratings.

The international incidence of myeloid leukaemia, cancer of the kidney, melanoma, and certain childhood cancers all show significant correlation with radon exposure in the home. For myeloid leukaemia, analysis suggests that in the UK 6-12% of incidence may be attributed to radon. In Cornwall, where radon levels are higher, the range is 23-43%. For the world average radon exposure of 50 Bq.m-3, 13-25% of myeloid leukaemia at all ages may be caused by radon.

Factors that increase the risk of cancer during adult life may also increase the risk of cancer when they act in utero (eg, ionising radiation and diethylstilboestrol in human beings and chemicals in animals). The existing empirical data seem to be compatible with the hypothesis that increased concentrations of oestrogens in pregnancy increase the probability of future occurrence of breast cancer in daughters.

There are 14 unconfounded randomised trials of antihypertensive drugs (chiefly diuretics or beta-blockers): total 37,000 individuals, mean treatment duration 5 years, mean diastolic blood pressure (DBP) difference 5-6 mm Hg. In prospective observational studies, a long-term difference of 5-6 mm Hg in usual DBP is associated with about 35-40% less stroke and 20-25% less coronary heart disease (CHD). For those dying in the trials, the DBP difference had persisted only 2-3 years, yet an overview showed that vascular mortality was significantly reduced (2p less than 0.0002); non-vascular mortality appeared unchanged. Stroke was reduced by 42% SD 6 (95% confidence interval 35-50%; 289 vs 484 events, 2p less than 0.0001), suggesting that virtually all the epidemiologically expected stroke reduction appears rapidly. CHD was reduced by 14% SD 5 (95% CI 4-22%; 671 vs 771 events, 2p less than 0.01), suggesting that just over half the epidemiologically expected CHD reduction appears rapidly. Although this significant CHD reduction could well be worthwhile, its size remains indefinite for most circumstances (though beta-blockers after myocardial infarction are of substantial benefit). At present, therefore, a sufficiently high risk of stroke (perhaps because of age, blood pressure, or, in particular, history of cerebrovascular disease) may be the clearest indication for antihypertensive treatment.