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Biomedical subjects

J Kaldor

Publications and source records attributed to J Kaldor.

At least 73 records · Page 4Linked to original sources
PubMed1992

Colon cancer in Argentina. II: Risk from fibre, fat and nutrients.

A case-control study has been conducted to investigate the relationship between total energy intake, fibre and nutrients and colon cancer in Argentina. Cases are 110 newly diagnosed patients from 10 hospitals between 1985 and 1986. Two neighbourhood controls per case were matched on age, sex and place of residence. The intake of calories, fibre and nutrients was estimated from the information collected on food consumption during the 5-year period up to 6 months prior to interview of subjects, based on a pilot study and standard portion sizes in Argentina. In conditional regression models, dietary fibre is highly protective (odds ratio (OR) = 0.07 per 19.02 g/day; 95% confidence interval (CI): 0.02 to 0.25) and total energy intake increases risk (RR = 1.82 per 1000 kcal/day; 95% CI: 1.20 to 2.77), each with adjustment for the other. Analysis of caloric components (fat, protein and carbohydrates) reveals that carbohydrates are the most important factor driving the total energy effect. Other nutrients make little apparent contribution to risk.

Adult↗
PubMed1992

Underreporting of AIDS, New South Wales, 1988-1989.

OBJECTIVE: To determine the completeness of medical practitioner reporting of patients with acquired immunodeficiency syndrome (AIDS) in New South Wales and the reasons for underreporting. DESIGN: We compared the number of patients with AIDS reported to the National AIDS Register by medical practitioners from 1 July 1988 to 23 November 1989 with numbers detected from the National Zidovudine Register, AIDS specialist medical practitioner records, death certificates and the Sydney AIDS Prospective Study database. We asked the AIDS specialist medical practitioners to suggest why some patients may not be reported. MAIN OUTCOME MEASURE: The number of persons known to have AIDS and the source from which they were detected. RESULTS: We found 457 recorded cases of AIDS in which the diagnosis was made during the study period. Of these 457 cases, 373 (81.6%) had been reported by medical practitioners and 84 had not. Of these 84 cases, 40 were detected from the National Zidovudine Register, 24 from the records of AIDS specialist medical practitioners, 18 from death certificates and two from the Sydney AIDS Prospective Study. Reporting rates among hospitals ranged from 38.5% to 95.7%. We estimated that the true number of persons diagnosed with AIDS in New South Wales over the study period was 476. The main reasons given by the doctors for not reporting persons with AIDS were difficulties with reporting procedures and the complicated AIDS case definition, concerns about maintaining patient confidentiality and inadequate Health Department feedback on AIDS surveillance data. CONCLUSIONS: At least 18.4% of the AIDS cases we detected were not reported by medical practitioners in New South Wales. More accurate information on the incidence of AIDS could be obtained if the Health Department regularly contacted AIDS specialist medical practitioners for unreported cases, simplified the reporting process, stressed the confidentiality provisions for AIDS reporting and provided feedback to reporting medical practitioners.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Effect of the revised CDC case definition of AIDS on the number of AIDS cases in the Sydney AIDS Prospective Study.

We sought to evaluate the potential impact of a proposed revision in the case definition of acquired immunodeficiency syndrome (AIDS) (from a clinical case definition to one also including subjects with HIV infection who have an absolute number of peripheral CD4+ cells of less than 200 x 10(6)/L) among 512 HIV-seropositive homosexual/bisexual who were reviewed between 1984 and 1991. According to the current case definition, 151 (30%) of 512 at-risk subjects developed AIDS between 1984 and August 1, 1991. Of the 361 at-risk subjects who were not classified as AIDS by the current definition, 47 (13%; 95% CI 9-17%) were classified as AIDS according to the revised definition. The median time to development of AIDS according to the revised definition was 288 weeks and that according to the current definition was 338 weeks. Data on clinical status were available for 34 of the new cases at the time of their diagnosis according to the proposed case definition: 16 (47%) of these were asymptomatic, 10 (29%) had persistent generalised lymphadenopathy and eight had minor infectious diseases. Of the 151 cases diagnosed according to the current definition, 78 (52%) had an antecedent CD4+ cell count that met the criteria for AIDS under the revised definition a median of 59 weeks before their diagnosis according to the current definition. These data indicate an appreciable increase in the number of cases of AIDS in this cohort when the revised case definition was applied. These findings have important implications for the surveillance, and for the clinical monitoring and treatment, of patients with HIV disease in Australia.

Acquired Immunodeficiency Syndrome↗
PubMed1992

The role of epidemiological observation in elucidating the mechanisms of carcinogenesis.

Epidemiological observations concerning a number of carcinogenic agents have been used to make inferences about the biological mechanisms of carcinogenesis. These inferences have generally been based on comparisons of epidemiological data with the predictions of various mathematical models of the process of carcinogenesis. Particular interest has focused on the relationships between cancer occurrence and level of exposure, age at exposure and time since cessation of exposure, and the combined effect of two carcinogenic agents. Analyses of epidemiological data in relation to mathematical cancer models have led to conclusions about mechanisms of action, but the validity of these conclusions is necessarily limited by the nature of epidemiological data and the unverifiability of assumptions underlying the models. A more fruitful application of the epidemiological perspective in elucidating the mechanisms of carcinogenesis may be through collaborative studies involving the recently developed techniques of molecular biology and related areas.

Carcinogens↗
PubMed1991

Nutritional factors in colorectal cancer risk: a case-control study in Majorca.

The relationship between energy intake, selected nutrients and colorectal cancer was investigated in the population of Majorca, a Spanish island in the Mediterranean basin. A population-based case-control study using food frequency questionnaires was conducted during the period 1984-1988 and included 286 cases of colorectal cancer, 295 population controls and 203 hospital controls. Food composition tables and ad-hoc estimates of portion sizes were used to derive intake estimates of 29 nutrients and of total calories. Relative risks were calculated for quartiles of consumption of each specific nutrient after adjustment for total calorie intake. Colorectal cancer was found associated with dietary intake of total calories (RRs = 1.0, 1.6, 1.6, 2.6) and cholesterol (RRs = 1.0, 0.9, 1.7, 1.7) and a protective effect was associated with the intake of fibre from legumes (pulses) and folic acid. The associations and the trends were statistically significant. Among the main energy-supplying nutrients, after adjustment for calories from other sources, increased risks were found for protein (RRs = 1.0, 1.1, 1.7, 2.5), notably animal protein, and carbohydrates (RRs = 1.0, 1.5, 1.4, 2.2), whereas no effects were found for increased consumption of lipids or saturated fats.

Case-Control Studies↗
PubMed1991

Human immunodeficiency virus antibodies in sera of Australian blood donors: 1985-1990.

OBJECTIVE: To describe the results of human immunodeficiency virus type 1 (HIV-1) antibody testing of blood donations in Australia. DESIGN: Blood transfusion services tabulated the number of HIV-1 antibody tests carried out on blood donations and the number of donations found to be positive, from 1985 to 1990. SETTING: All blood transfusion services in Australia. PARTICIPANTS: All donors of blood in Australia from 1 May 1985 to 31 December 1990. OUTCOME MEASURES: The proportion of blood donations found to have HIV-1 antibody, according to State or Territory, year of donation and, when available, age, sex and donation status (repeat or first-time) of the donor. RESULTS: To the end of December 1990, 5,367,970 donations had been tested for HIV-1 antibody, and 46 were found to have the antibody, giving an overall prevalence rate of 0.86 per 100,000 donations. The highest rate was recorded in New South Wales, followed by Western Australia, and four of eight Australian States and Territories reported no donors with HIV-1 antibody. There has been no clear trend with time, but the rate is about 20% higher for 1989-1990 than for 1985-1986. Of donors found to have HIV-1 antibody, 67% were male and 33% female, and 41% reported no known or potential exposure to HIV-1 other than heterosexual contact. Among blood donors in two major Australian cities, the overall prevalence of HIV antibody was higher in those who were male, younger, and first-time donors. There has been a recent increase in the number of blood donors with HIV-1 antibody who were women reporting heterosexual contact as their only potential exposure. CONCLUSION: The rate of HIV-1 antibody in Australian blood donations remains very low and shows no clear temporal trend, but specific donor characteristics define higher rates of antibody prevalence.

Adult↗
PubMed1991

The association between alcohol and breast cancer risk: evidence from the combined analysis of six dietary case-control studies.

Data from 1,575 cases and 1,974 controls enrolled in 6 previously conducted case-control studies of diet and breast cancer have been analysed with respect to alcohol intake. There appears to be an absence of any association between consumption of up to 40 g of alcohol per day and risk of breast cancer, and a highly statistically significant and consistent elevated risk of breast cancer for drinkers of 40 g or more of alcohol per day, for whom the relative risk, as compared with that of non-drinkers, is 1.69 (95% confidence interval 1.19 to 2.40). This association is not due to confounding by a number of diet-related factors, including total calories, fat, fibre and vitamin C.

Adult↗
PubMed1991

Helicobacter pylori serology using specimens collected on filter paper.

A simple method for the collection of blood specimens on filter paper for serology of Helicobacter pylori was devised. Blood was freshly applied to small Whatman 3 mm filter paper and allowed to dry. Serological activity, as measured by reactivity to H pylori antigens (AMRAD, Australia), was retained after storage for one month at both room temperature and at 4 degrees C. This technique eliminates formal venepuncture, separation of sera, and arduous packaging of specimens to be sent to the laboratory.

Antibodies, Bacterial↗
PubMed1990

Cancer in Jewish migrants to Israel.

Data on the incidence of 15 cancers in the Jewish population of Israel from the period 1961-1981 have been studied with emphasis on the risk of disease in relation to birthplace, calendar time, and duration of residence in Israel. The results show wide variations in incidence by birthplace, from less than 2-fold for pancreatic cancer to a 40-fold difference for oesophageal cancer in females; the reasons for these are often little understood. The potential importance of environmental agents in aetiology for different migrant groups is discussed in relation to the size and rapidity of changes in risk related to the duration of residence in Israel.

Africa, Northern↗
PubMed1990

A population-based case-control study of colorectal cancer in Majorca. I. Dietary factors.

A population-based case-control study was conducted between July 1984 and February 1988 in the Spanish island of Majorca; 286 incident colorectal cancer cases, 295 population controls and 203 hospital controls were interviewed using a food frequency questionnaire. In a multivariate analysis, an increased risk of colon cancer was found for high consumption of fresh meats (RR = 2.87) while a high consumption of cruciferous vegetables afforded protection (RR = 0.48). For rectal cancer an increased risk was associated with dairy products (RR = 3.08) while a protection was afforded by consumption of cruciferae (RR = 0.50). For colorectal cancer, the cereal food group also showed an increase in risk (RR = 1.92). When cases were compared to hospital controls, the effects of cruciferae in colon and rectum and those of dairy products in rectal cancer remained. The magnitude of the RR estimates was decreased for most comparisons, although in general terms the direction of the associations was the same. In addition, univariate analyses of food groups also suggested significant increases in risk of colorectal cancer for increasing consumption of cereals, potatoes, pastry, eggs and number of meals per day. An indication was found of a reduction in risk for consumers of coffee. An analysis based on risk scores was also conducted and a 4-fold increase in the risk of colorectal cancer and a highly significant statistical trend was found for high consumption of fresh meat, dairy products and cereals combined with low consumption of cruciferae.

Age Factors↗
PubMed1990

Log-linear models for cancer risk among migrants.

Epidemiological studies of migrants have played an important role in separating the environmental and genetic components of cancer aetiology. The statistical analyses of these studies have typically involved calculating age- and sex-adjusted rates by country of birth. We describe methods which permit the effect of duration of residence in the host country to be estimated after adjusting for other temporal effects such as age, and period or cohort. The methods, which are based on log-linear modelling, can also be applied in a case-control manner if appropriate denominator populations are unavailable. Examples are given in which the more traditional methods of analysis may have yielded misleading results.

Adolescent↗
PubMed1990

Second cancer following chemotherapy and radiotherapy. An epidemiological perspective.

Both ionizing radiation and alkylating chemicals are used to treat cancer, and both are themselves carcinogenic. Epidemiological methods of study have provided a substantial amount of information on the long-term risks of the two types of treatment. Radiotherapy appears to increase the risk of a wide range of cancers, but the size of the increase is not substantial. Chemotherapy, in contrast, produces a very large increase in the risk of acute leukaemia, and does not generally appear to produce other types of cancer. Leukaemias following both treatment modalities appear rapidly, while the risk of solid tumours induced by radiotherapy is not manifested until a decade or more has elapsed. There does not seem to be synergy between the two types of therapy in their carcinogenic action. Continued use of the epidemiological approach is essential in risk-benefit evaluation of cancer therapy.

Antineoplastic Agents↗
PubMed1989

Role of advanced statistical techniques in cancer mapping.

Maps are spatial representations of a single-dimensional quantity. When cancer is mapped by geographic region, it is necessary to choose what this quantity is to be. Some cancer atlases have chosen a measure of effect, such as incidence, mortality, or relative risk. These are certainly the quantities which interest us most, but when the number of cases in a given region is small, their estimates can be very imprecise, and unreliable. The usual alternative is to map the statistical significance of departure from the overall map average. This has the advantage of de-emphasizing areas with low precision, but it can conversely highlight areas with high populations, even if they differ only minutely from the overall mean. Attempts to combine the two quantities on one map, for example by starring significant areas with relative risks above a certain level, are clumsy, and detract from the simplicity of the map. The empirical Bayes approach provides an alternative. Rather than plotting rates or risks which are individually estimated, the goal is to plot quantities which are estimated in such a way that those which are imprecise are improved by estimates from other appropriate areas. In the simplest case, this is equivalent to plotting for each map region the weighted average of the estimate for the region and the mean of the whole map, with more weight given to the regional estimate if it is based on a large population, and lower weight given if it is based on a small population. More sophisticated models are also described, and the methods are illustrated by the example of lip cancer in Scotland.

Adult↗
PubMed1989

Cancer mortality in a northern Italian cohort of rubber workers.

An analysis of the mortality of a cohort of 6629 workers employed from 1906 to 1981 in a rubber tyre factory in northern Italy (978 deaths and over 133,000 man-years at risk) showed that the all cause mortality ratio was slightly lower than expected (0.91). Overall cancer mortality was close to expected (275 v 259.4) but there were significant excess rates for two cancer sites: pleura (9 observed v 0.8 expected, which may be due to the use of fibre containing talc) and bladder (16 observed v 8.8 expected). Death rates were not raised for other sites previously associated with employment in the rubber industry, such as cancers of the lung and brain, leukaemias, or lymphomas. The substantially reduced relative risk of pleural cancer among workers first employed after 1940 (RR = 0.05 compared with before 1940) probably reflected improvements in working conditions over more recent periods. For cancer of the bladder, the relative risk was also lower for workers first engaged after 1940. Thus no appreciable risk for any disease was apparent for workers employed over the past four decades. Analysis for each of the 27 job categories showed a substantial excess for cancer of the pleura in the mechanical maintenance workers (4 observed v 0.17 expected); an excess of cancer of the lung (21 v 13.48) was also present in this job category.

Adult↗
PubMed1988

Serotyping of Streptococcus pneumoniae by latex agglutination.

A simple method is presented for serotyping Streptococcus pneumoniae which uses easily prepared sensitized polystyrene latex particles. The technique is simple, fast and reliable and can detect pneumococcal antigens in body fluids.

Antigens, Bacterial↗