[Reliability and accuracy of reported causes of death from cancer. I. Reliability of all cancer reported in the State of Rio de Janeiro, Brazil] / Confiabilidade e validade dos atestados de óbito por neoplasias. I. Confiabilidade da codificação para o conjunto das neoplasias no Estado do Rio de Janeiro.

Mortality records are often used in epidemiological studies, particularly in cancer studies. This paper aims to evaluate reliability and accuracy of cancer mortality data in Rio de Janeiro, Brazil. A systematic random sample of 394 death certificates was obtained from a total of 12615 cancer deaths. This sample was recoded by an independent codifier. A kappa coefficient of 0.89 (95% C.I. 0.86-0.92) was obtained to the third digit, which increases to 0.95 (95% C.I. 0.94-0.96) when restricted to the mortality list used in international publications. The positive predictive value was 95.7% for this sample. These results reveal a high standard reliability of cancer mortality records in the State of Rio de Janeiro making them suitable for use in epidemiological research.

[Reliability and accuracy of reported causes of death from cancer. II. Accuracy of stomach cancer reported in the municipality of Rio de Janeiro County, Brazil] / Confiabilidade e validade dos atestados de óbito por neoplasias. II. Validação do câncer de estômago como causa básica dos atestados de óbito no Município do Rio de Janeiro.

Quality of data is a central concern in epidemiological studies, particularly when using secondary data. This study aims to carry out on reliability and accuracy of stomach cancer mortality data in the city of Rio de Janeiro. A simple random sample of 97 death certificates was obtained from a total of 645 stomach cancer deaths in 1990, and was used for validation. A questionnaire specifically designed to obtain clinical and laboratory data was completed for each case. Two physicians read this questionnaire and completed the new death certificates, allowing analysis of the instrument's reliability. A total of 86 cases were studied as a consequence of 11 losses (11.3%). Reliability analysis of questionnaires revealed 90.7% agreement according to stomach cancer diagnosis (kappa = 0.73). Accuracy was calculated by positive predictive value: 90.7%. Eight cases were discharged after clinical and laboratory revision. The study concludes that mortality data by stomach cancer in the city of Rio de Janeiro are very reliable, and that their level of accuracy is adequate for use in epidemiological studies.

Stomach cancer incidence in Brazil: an ecologic study with selected risk factors.

Contrary to many industrialized countries in which a sharp decline in stomach cancer incidence has been observed, Brazil still shows intermediate to high incidence rates. An ecologic analysis was performed to explore variables possibly associated with the development of stomach cancer. Cluster analysis, principal component analysis, and factor analysis were carried out with population data, including the following: stomach cancer incidence rates in the early 1990s obtained from population-based cancer registries in Porto Alegre, Campinas, Fortaleza, Belém, and Goiânia; and data from a Brazilian national survey on family expenditures (several diet consumption items and availability of home refrigerators) carried out in 1974-75. The results suggested that past availability of a home refrigerator, i.e. food preservation, may have played an important role in currently observed differences in stomach cancer incidence among the various populations studied in Brazil. Differences in living standards among populations in these cities also appear to have played an important role in the observed incidence differences.