Familial predisposition to breast cancer in a British population: implications for prevention.

The aims of this study were to estimate the familial relative risk of breast cancer according to the age of the at risk individual and the age at which the relative was affected, and to estimate the proportion of the general population in several breast cancer risk categories because of a family history and, thus estimate the potential to reduce the overall breast cancer burden using interventions targeted at women at increased risk because of family history. Familial relative risks were computed by comparing breast cancer incidence in relatives of 2809 breast cancer cases from a population based case series with that expected from general population incidence rates. The proportion of the general population in different categories of risk according to family history was estimated from the relative risk of breast cancer for that category and the proportion of cases in that category. 389 (13.8%) cases had at least 1 first degree relative with breast cancer. The relative risk of breast cancer in sisters of index cases was 1.90 (95% confidence interval (CI) 1.63-2.36) and that in mothers 1.73 (1.52-1. 97). The risk to mothers of cases diagnosed under 50 years of age tended to decrease in older mothers, but no age effect was seen for mothers of cases diagnosed >/=50 years of age. There was no evidence that relative risk to sisters declined with age. For women with 2 affected first degree relatives the relative risk was 2.85 (2.12-3. 76). From these data, we estimate that in the general population 6. 8% of women under the age of 50 years and 9.7% of women aged 50-65 years have at least 1 first degree relative affected with breast cancer. Two per cent of women under 50 years have a family history which confers an increased risk of at least 2.5-fold. An intervention targeted at this group that reduced breast cancer morbidity by 20% would reduce the total burden of breast cancer in this age group by 1.1% at most. A family history of breast cancer is quite common in the general population, but preventive interventions targeted at women at high risk of breast cancer because of family history will have limited impact on breast cancer morbidity as a whole.

No association between a polymorphism in the steroid metabolism gene CYP17 and risk of breast cancer.

A recent study showed an association between a single base substitution, T-->C, in the promotor region of the CYP17 gene, the risk of breast cancer and age at menarche in Asian, African-American and Latino women from California and Hawaii. The C allele was associated with increased risk of breast cancer, significantly so for patients presenting with advanced disease, whereas the TT genotype was associated with later age at menarche in control subjects. We attempted to confirm these findings in a large case-control study in East Anglia, England (835 cases and 591 control subjects). We found no evidence of an increased risk of breast cancer [odds ratio (OR) 1.10, confidence interval (CI) 0.89-1.37] or advanced breast cancer (OR 0.88, CI 0.38-2.01) in C allele carriers, nor any association between age at menarche and genotype. We conclude that these alleles do not significantly alter breast cancer risk in the English population.

Adolescent milk, dairy product and fruit consumption and testicular cancer.

There is an association between dairy product consumption and the incidence of testicular cancer in different countries. To test the hypothesis that milk and dairy products are risk factors, a case-control study was performed in East Anglia, UK. All the cases were men with testicular cancer and for each of the 200 cases there were four controls, two cancer controls and two population controls. The response rate of those eligible subjects who received a questionnaire was: cases 73%, cancer controls 65% and population controls 57%. All responding subjects completed a dietary questionnaire including questions on current and adolescent milk, dairy product and fruit and vegetable consumption. The answers were corroborated when possible by the subjects' mothers using a separate questionnaire. Cases consumed significantly more milk in adolescence than population controls, but this difference did not apply to other dairy products or fruit. The consumption of milk by cancer controls was intermediate between cases and population controls. Cancer controls with non-epithelial cancers had a milk consumption similar to cases, whereas subjects with epithelial cancers had a consumption similar to population controls. In a multivariate analysis the odds ratio between cases and population controls for the association of undescended testis and testicular cancer was 7.19 (95% CI 2.36-21.9) and for each extra quarter pint of milk consumed it was 1.39 (95% CI 1.19-1.63).

Rates of admission to hospital for asthma.

OBJECTIVE: To describe trends in hospital admission rates for asthma in England and Wales (1976-85), the East Anglian region (from 1976 to 1991-2), and Wales (1980-90). DESIGN: Descriptive study. SETTING: Hospitals in England and Wales; hospitals in the East Anglian Regional Health Authority; hospitals in Wales. MAIN OUTCOME MEASURES: Hospital admissions for asthma as principal diagnosis in England and Wales (Hospital In-patient Enquiry, 1976-85), for the East Anglian region (Hospital In-patient Enquiry, 1976-7; Hospital Activity Analysis, 1978-86; Regional Information System, 1987-8 to 1991-2), and for Wales (Hospital Activity Analysis, 1980-90). RESULTS: Rates for England and Wales as a whole showed a steady upward trend throughout the period examined. Rates in East Anglia, though they were similar to the national trends in the early years, showed a peak in 1985 (for males and females) with some indication of a decline in rates thereafter. Rates for Wales showed an upward trend until 1988 (for both males and females) after which they showed a decline. CONCLUSIONS: Interpretation of the East Anglian trends is made more difficult by the change in England in 1987 of the system for the collection of hospital admission data. The fact that the rates for the East Anglian region seem to decline before this change and other considerations suggest that the observed trends, although partly reflecting the disruption of the coding during the changeover in systems, may not be entirely artefactual. The possible roles of diagnostic transfer and changes in the delivery of care, asthma treatment, admission and readmission policies, and the severity and prevalence of asthma in changing admission rates are considered. The changing trends in admission rates for East Anglia and Wales reflect recently published trends for mortality from asthma in England.