No abstract

The receipt of a screening test does not cause sustained anxiety and the existence of psychiatric morbidity is not a factor affecting a person's decision to accept or refuse a screening test for colorectal cancer.

Objective-To examine the relation between the use of aspirin and non-steroidal anti-inflammatory drugs and the presence of asymptomatic colorectal adenomas.Design-Case-control study of subjects participating in a randomised controlled trial of faecal occult blood screening for colorectal cancer. Data on analgesics and other drugs were obtained from a questionnaire which was mainly concerned with diet and was administered by an interviewer.Setting-Nottingham. Subjects-147 patients with positive results in faecal occult blood tests who were found to have colorectal adenomas (cases), 153 age and sex matched control subjects with negative results in such tests (negative controls), and 176 control subjects with positive results in the tests who were found not to have colorectal adenomas (positive controls).Main outcome measures-Relative risk of developing colorectal adenomas according to frequency and duration ofuse ofanalgesics.Results-Cases reported taking less aspirin and non-steroidal anti-inflammatory drugs than the negative controls, with the estimated relative risk for any use being 0 49 (95% confidence interval 0 3 to 0.8). The inverse association was less strong when cases were compared with the positive controls (0-66 (0 4 to 1.1)). The association was specific for aspirin and non-steroidal anti-inflammatory drugs there being no association with paracetamol or other drugs. Prescribed use of non-steroidal antiinflammatory drugs for longer than five years was associated with the lowest risk (0.21 (0.1 to 0 8)), although the numbers reporting prolonged prescribed use were small.Conclusions-These findings support the hypothesis that aspirin and non-steroidal antiinflammatory drug use protects against the development ofcolorectal neoplasia.

Summary Diets high in animal fat and protein and low in fibre and calcium are thought to be factors in the etiology of colorectal cancer. Intakes of these nutrients were determined in three groups participating in a randomised trial of faecal occult blood (FOB) screening. A diet history was obtained by interview from 147 patients with colorectal adenomas, 153 age and sex matched FOB-negative controls (a) and 176 FOB-positive controls without colorectal neoplasia (b). Unconditional logistic regression was used to estimate relative risks (RR) and 95% confidence limits (t) adjusted for age, sex and social class.After adjustment for total energy intake, no associations were found with total, saturated or monounsaturated fat, or calcium intake. For total fibre intake there were non-linear relationships with both control groups with the crude RR for highest quintiles of total fibre intake compared to the lowest being 0.6, although this pattern was no longer apparent after adjustment for energy intake with group (a). In comparison with group (b) cereal fibre intake showed a more consistent inverse relationship with adenoma prevalence with the RR for ascending quintiles of intake being 1.0, 0.7 (0.3-1.6), 0.5 (0.3-1.1), 0.7 (0.4-1.4) and 0.3 (0.1-0.6) (trend x2 = 8.80, p = 0.003). In comparison with group (a), the adjusted RR for the highest quintile of cereal fibre intake compared with the lowest was 0.6, but no clear trend was apparent. There was an unexpected positive relationship between adenomas and polyunsaturated fat intake with the RR for having an adenoma being 1.0, 2.8 (1.3-6.1), 1.6 (0.7-3.4), 3.5 (1.6-7.5) and 2.3 (1.1-5.0) for ascending quintiles of polyunsaturated fat intakes (trend x2 = 4.8, P = 0.03) in comparison with group (a) only.Our data, while providing no support for the role of dietary animal fat or protein, do support the protective role of dietary cereal fibre in the etiology of colorectal adenomas.High intakes of animal fat and protein (Wynder & Shigematsu, 1967;Drasar and Irving, 1973), and low intakes of fibre (Burkitt, 1971) and calcium (Newmark et al., 1984) have been postulated to increase the risk of colorectal cancer. However, the role of these nutrients has not been clarified in analytical epidemiological studies (Zaridze, 1983;Willett, 1989a (Paul & Southgate, 1978).In addition to the nutrients about which we had specific hypotheses, we considered total energy intake as an important potential confounder (Willett, 1989b, pp , the sources of protein and fibre, and the different types of fatty acid.We also asked subjects about the frequency of consumption of certain foods which might be markers of 'healthy Correspondence: J. Little,

The results suggest that there may be a higher proportion of slower growing tumours in subjects aged > or = 65 and that cancers occurring in the distal colon may have a longer mean sojourn time than cancers proximal to the sigmoid colon.