SUMMARYObjecti e : To identify risk factors for infectious intestinal disease (IID) due to rotavirus group A in children aged under 16 years. Methods : Case-control study of cases of IID with rotavirus infection presenting to general practitioners (GPs) or occurring in community cohorts, and matched controls. Results : There were 139 matched pairs. In children under 16 years the following risk factors were significantly associated with rotavirus IID : living in rented council housing (adjusted OR l 3n78, P l 0n022), accommodation with more than five rooms (OR l 0n72, P l 0n002), contact with someone ill with IID (OR l 3n45, P 0n001). Some foods were associated with decreased risk. In infants, bottle feeding with or without breast feeding was associated with increased risk (OR l 9n06, P 0n05). Conclusions : Contact with persons with IID, living in rented council housing and accommodation with fewer rooms, were significant risk factors for sporadic rotavirus IID in children whereas breast feeding is protective in infants.

No abstract

SummaryRaised levels of factor VII coagulant activity (VIIC) have been reported to increase the incidence of CHD. Preliminary evidence from observational and experimental studies suggests that dietary fat intake is positively associated with VIIC. We explored this further in 4,246 men aged 45–69, who were found to be free of major CHD when screened for a primary prevention trial of antithrombotic medication. All men were asked about their consumption of fatty foods and changes in consumption in the last month.In the 9% of men who reported avoidance of fatty foods in the month before interview, age adjusted VIIC was 7.8% of standard (95% CI 5.1–10.6%) lower than in the remainder. Serum cholesterol and body mass index (BMI) were also significantly lower. The extent to which fat consumed in the past month had deviated from usual intake was significantly and positively related with VIIC, serum cholesterol and BMI. Thus, the VIIC difference between those eating much less fatty food than usual and those eating much more than usual was 11% of standard, with those eating their usual amount having an intermediate level.This study adds to the evidence that dietary fat intake influences VIIC and coagulability. The effect is rapid, so that much of the benefit of dietary fat reduction on thrombogenic risk in CHD is likely to occur within a short time. Thus, the results reinforce the value of a low fat diet, even in individuals with advanced atheroma, in whom dietary intervention has sometimes been considered unlikely to be effective.

There are often reasons to suppose that there is dependence between the time to event and time to censoring, or dependent censoring, for survival data, particularly when considering medical data. This is because the decision to treat or not is often made according to prognosis, usually with the most ill patients being prioritised. Due to identifiability issues, sensitivity analyses are often used to assess whether independent censoring can lead to misleading results. In this paper, a sensitivity analysis method for piecewise exponential survival models is presented. This method assesses the sensitivity of the results of standard survival models to small amounts of dependence between the time to failure and time to censoring variables. It uses the same assumption about the dependence between the time to failure and time to censoring as previous sensitivity analyses for both standard parametric survival models and the Cox model. However, the method presented in this paper allows the use of more flexible models for the marginal distributions whilst remaining computationally simple. A simulation study is used to assess the accuracy of the sensitivity analysis method and identify the situations in which it is suitable to use this method. The study found that the sensitivity analysis performs well in many situations, but not when the data have a high proportion of censoring.