Completeness of cancer registration in Denmark 1943-1966 and efficacy of record linkage procedures

The completeness of registration in the national, population based cancer registry in Denmark was evaluated for the first 23 years (1943-1966) of operation. The registry was linked to a complementary data file on 5674 Danish invasive cervical cancer patients enrolled in an international, clinical follow-up study on the basis of identifying information including name, month and year of birth and date of cervical cancer diagnosis. The cancer register had a deficit of 2.2% (95% confidence interval, 1.8-2.6) cervical cancer patients; this figure is low compared to those of other cancer registers. Some 80% of the identified cases were retrieved by computerized matching alone, and an additional 15% were identified by combining computerized and visual matching procedures. Scrutiny of non-retrieved case records revealed that major errors in the identifiers of the cohort used for linkage were responsible for inability to identify an additional 1.7%. The presents study underlines the importance of meticulously recorded, high quality key identifiers in registers, and linkage of cohorts to establish the presence or absence of disease.     

Trends in the incidence of cancer of the corpus uteri in Denmark, 1943-1980

The occurrence of cancer of the corpus uteri in Denmark is examined by the use of data from the Danish Cancer Registry. The study population consists of 14,149 cases diagnosed with cancer of the corpus uteri between 1943 and 1980. Since 1943, the incidence has been steadily increasing. The trend in the incidence rates varies in different age groups, and examination of birth cohorts shows higher rates after the age of 50 for more recent generations. The trend is evaluated in relationship to changes in diagnostic practices and to changes in prevalence of risk factors. Of the latter, estrogen use is considered a plausible explanation for the increasing incidence in women aged 55-64 years Correction of the age-specific incidence rates for hysterectomy reveals a pattern very similar to that of breast cancer.     

Demographic factors and cancer mortality. A mathematical model for cancer mortality in Denmark 1943-78

Deaths from cancer in Denmark from 1943-1978 were extracted from the Danish National Death Register at the Danish Institute for Clinical Epidemiology. This paper illustrates the relationship between demographic factors and mortality from a large group of cancers, which increases progressively from young adult life into old age. One-year age-specific mortality rates between 30 and 79 years of age were computed for 14 different cancer sites among both males and females, in five ten-year birth cohorts and for the capital and provinces. The number of deaths at a particular age were found to follow a Poisson distribution and the mortality rate could be expressed by the function lx = bxk, where lx is the mortality rate at age x, and b and k are parameters to be estimated. With this model a straight line is obtained, when mortality and age are plotted on a double logarithmic scale. The maximum likelihood estimates of b and k were found iteratively for each of the 280 combinations of sex--cancer site--residence--cohort. For fixed sex and cancer site the relationship between age, residence and cohort was examined. It appeared that k was independent of residence. For 10 of the male cancers and 12 of the female cancers, k was found to be independent of cohort and in the last 6 cases k was found to be a linear function of cohort. For 12 out of 14 cancer sites among males the ratio of mortality in the capital to mortality in the provinces was significantly greater than one.(ABSTRACT TRUNCATED AT 250 WORDS)     

Incidence of Mesothelioma in Glasgow 1981-1984

Considerable public concern exists about the effects of exposureto asbestos both at the workplace and in the general environment.In addition, the recording of mesothelioma in health registersis questionable both in terms of accuracy and completeness.This paper compares nine different sources of data for mesotheliomain an attempt to establish the true incidence of the diseasein the geographical area of the Greater Glasgow Health Boardbetween 1981 and 1984. Although 113 cases were identified, nosingle source identified more than 86 per cent of this total,thus presenting a case for a special mesothelioma register.A questionnaire-based study of the occupational exposures andresidential histories of the cases was also carried out. Itconfirmed the findings of similar studies in that mesotheliomaoccurs predominantly in those exposed by reason of their occupation.No relationship with place of residence was apparent independentof occupation. Requests for reprints should he addressed to: Dr C. R. Gillis, West of Scotland Cancer Surveillance Unit, Ruchill Hospital, Glasgow G20 9NB, UK     

Incidence of childhood cancer in Ho Chi Minh City, Vietnam, 1995-97

Incidence rates of childhood cancer for the city of Ho Chi Minh are presented for the first time. For the 3-year period 1995-97, a total of 302 cancer cases were registered in children under 15 years of age, with a male to female ratio of 1.1. The overall crude rate was 78.8 and the age-standardised incidence rate was 88.4 per million person-years, which was low in comparison with other countries in eastern Asia and with the predominantly white population of Australia. Leukaemia (principally acute lymphocytic), brain tumours and lymphomas were the most common childhood neoplasms, which is consistent with the pattern observed in other registries of the region. The rate of retinoblastoma was higher than in the other regional registries. On the other hand, no cases of hepatocellular carcinoma were registered.     

Incidence of childhood cancer in Thailand 1988–1991

Summary. Incidence rates of cancers of childhood in Thailand are presented for the first time, and compared with results from cancer registries in Asia, Europe and the USA. As elsewhere in the world, leukaemia (principally acute lymphocytic), brain tumours and lymphomas comprise two-thirds of all childhood neoplasms. Carcinomas are rare, but the principal sites (liver, nasopharynx, thyroid and salivary gland) are extremely unusual elsewhere. Several features of the cancer partem correspond to that in other Asian populations (China, Japan, Philippines), in particular the low incidence of Hodgkin's disease, Wilms' tumour and Ewing's sarcoma. Conversely, Burkitf s lymphoma is more common than elsewhere, although this may represent increasing awareness of this diagnosis amongst clinicians in recent years.     

Incidence of cancer in persons with occupational exposure to electromagnetic fields in Denmark.

Several studies suggest that work in electrical occupations is associated with an increased risk of cancer, mainly leukaemia and brain tumours. These studies may, however, not be representative if there is a publication bias where mainly positive results are reported. To study an unselected population the incidence of cancer was followed up over a 17 year period (1970-87) in a cohort of 2.8 million Danes aged 20-64 years in 1970. Each person was classified by his or her industry and occupation in 1970. Before tabulation of the data on incidence of cancer, each industry-occupation group was coded for potential exposure to magnetic fields above the threshold 0.3 microT. Some 154,000 men were considered intermittently exposed and 18,000 continuously exposed. The numbers for women were 79,000 and 4000 respectively. Intermittent exposure was not associated with an increased risk of leukaemia, brain tumours, or melanoma. Men with continuous exposure, however, had an excess risk of leukaemia (observed (obs) 39, expected (exp) 23.80, obs/exp 1.64, 95% CI 1.20-2.24) with equal contributions from acute and other leukaemias. These men had no excess risk of brain tumours or melanoma. A risk for breast cancer was suggested in exposed men but not in women. The risk for leukaemia in continuously exposed men was mainly in electricians in installation works and iron foundry workers. Besides electromagnetic fields other exposures should be considered as possible aetiological agents.     

Incidence of cancer and mortality among employees in the asbestos cement industry in Denmark

In a cohort study of the incidence of cancer and mortality among 7996 men and 584 women employed in the Danish asbestos cement industry between 1928 and 1984 over 99% were traced. Chrysotile asbestos was the only fibre type used until 1946, when amosite and (in 1952) crocidolite were also introduced. Chrysotile constituted 89%, amosite 10%, and crocidolite 1% of the asbestos used. During the first 25 years of manufacture the exposure levels were high, especially in areas where the asbestos was handled dry. Measurements from 1948 indicate that the fibre levels may have ranged from 100 to 1600 times over the present Danish threshold limit value of 0.5 fibre/ml. In 1973 more than 41% of personal samples were higher than 2 f/ml. About 76% of the workforce left the factory within five years of starting employment. A total of 1346 deaths and 612 cases of cancer were observed in the cohort between 1943 and 1984. Among employed men the overall mortality (O/E 1.18; 95% CI 1.12-1.25), cancer mortality (O/E 1.32; 95% CI 1.19-1.46), and overall incidence of cancer (O/E 1.22; 95% CI 1.12-1.32) were significantly increased compared with all Danish men. This was not so among employed women. For men, significant excess risks were found for cancer of the lung (O/E 1.80; 95% CI 1.54-2.10), pleura (O/E 5.46; 95% CI 2.62-10.05), mediastinum (O/E 5.00; 95% CI 1.01-14.61), stomach (O/E 1.43; 95% CI 1.03-1.93), and other male genital organs (O/E 3.03; 95% CI 1.11-6.60). The mortality was significantly increased for men for non-malignant pulmonary diseases (O/E 1.63; 95% CI 1.33-1.98). Among the group of asbestos cement workers with first employment 1928-40 an excess risk of laryngeal cancer was found (O/E 5.50;95% CI 1.77-12.82). A total of 12 cases of pleural and one of peritoneal mesotheliomas was observed when the original notification forms were reviewed for all patients with cancer in the cohort.     

Incidence of lung cancer by histological type among asbestos cement workers in Denmark.

OBJECTIVE--A significant twofold increased risk of lung cancer was found among 8000 men employed in the Danish asbestos cement industry between 1928 and 1984. The histological pattern of 104 lung cancer cases was studied with the aim of evaluating a relation between specific morphological types, duration of employment, and time since first employment. METHODS--Age, sex, and calendar time specific incidence of morphological subtypes of lung cancer (adenocarcinoma, squamous cell carcinoma, anaplastic carcinoma, and unspecified malignant tumour) for all Danish men were computed from 1943 to 1984, from data routinely collected by the Danish Cancer Registry. Person-years of observation were counted from 15 years after the date of first employment until date of diagnosis of cancer, death, emigration, or the end of follow up on 31 December 1984. Expected numbers of cases were computed by applying person-years at risk to the appropriate incidence rates. Observed numbers were distributed accordingly and the relative risk calculated. RESULTS--The relative risk for adenocarcinoma was 3.31 (observed (O) 24, expected (E) 7.26), for squamous cell carcinoma 1.67 (O, 37, E, 22.12), for anaplastic carcinoma 1.58 (O, 23, E, 14.53), and for unspecified malignant tumour 1.57 (O, 18, E, 11.46). An increased risk by duration of employment and time since first employment was most pronounced for adenocarcinoma. CONCLUSION--The link between adenocarcinoma and asbestos was confirmed in this, the first study of risk of lung cancer by histological category based on incident cancer cases for a whole population during a 50 year period.     

Incidence and cost of rotavirus hospitalizations in Denmark

In anticipation of licensure and introduction of rotavirus vaccine into the western market, we used modeling of national hospital registry data to determine the incidence and direct medical costs of annual rotavirus-associated admissions over >11 years in Denmark. Diarrhea-associated hospitalizations coded as nonspecified viral or presumed infectious have demonstrated a marked winter peak similar to that of rotavirus-associated hospitalizations, which suggests that the registered rotavirus-coded admissions are grossly underestimated. We therefore obtained more realistic estimates by 2 different models, which indicated 2.4 and 2.5 (for children <5 years of age) and 4.9 and 5.3 (for children <2 years of age) rotavirus-associated admissions per 1,000 children per year, respectively. These admissions amount to associated direct medical costs of US $1.7-1.8 million per year. Using 2 simple models to analyze readily available hospital discharge data resulted in more consistent and reliable estimates.     

Incidence of cancer and mortality among employees in the asbestos cement industry in Denmark.

In a cohort study of the incidence of cancer and mortality among 7996 men and 584 women employed in the Danish asbestos cement industry between 1928 and 1984 over 99% were traced. Chrysotile asbestos was the only fibre type used until 1946, when amosite and (in 1952) crocidolite were also introduced. Chrysotile constituted 89%, amosite 10%, and crocidolite 1% of the asbestos used. During the first 25 years of manufacture the exposure levels were high, especially in areas where the asbestos was handled dry. Measurements from 1948 indicate that the fibre levels may have ranged from 100 to 1600 times over the present Danish threshold limit value of 0.5 fibre/ml. In 1973 more than 41% of personal samples were higher than 2 f/ml. About 76% of the workforce left the factory within five years of starting employment. A total of 1346 deaths and 612 cases of cancer were observed in the cohort between 1943 and 1984. Among employed men the overall mortality (O/E 1.18; 95% CI 1.12-1.25), cancer mortality (O/E 1.32; 95% CI 1.19-1.46), and overall incidence of cancer (O/E 1.22; 95% CI 1.12-1.32) were significantly increased compared with all Danish men. This was not so among employed women. For men, significant excess risks were found for cancer of the lung (O/E 1.80; 95% CI 1.54-2.10), pleura (O/E 5.46; 95% CI 2.62-10.05), mediastinum (O/E 5.00; 95% CI 1.01-14.61), stomach (O/E 1.43; 95% CI 1.03-1.93), and other male genital organs (O/E 3.03; 95% CI 1.11-6.60). The mortality was significantly increased for men for non-malignant pulmonary diseases (O/E 1.63; 95% CI 1.33-1.98). Among the group of asbestos cement workers with first employment 1928-40 an excess risk of laryngeal cancer was found (O/E 5.50;95% CI 1.77-12.82). A total of 12 cases of pleural and one of peritoneal mesotheliomas was observed when the original notification forms were reviewed for all patients with cancer in the cohort.     

Incidence of cancer in Martinique 1981-1982

A systematic registration of morbidity from cancers was started in 1981 and 1982 in the french department of Martinique. In the course of two years 1081 new cases of cancers were recorded for a population of 320 000. The survey gives information on topography, differences for sex and ages. The morbidity survey allows comparison with the incidence rate of cancers in other departments of France or other countries.     

1984～1993年全国慢性职业中毒发病情况报告

作者总结了我国１９８４～１９９３年化学毒物所致慢性职业中毒的报告发病情况及其分布特点与规律。１０年共报告２８９０１中毒病例。铅、苯和三硝基甲苯是３种主要的化学毒物，其中以铅中毒为首位，占总中毒例数的４７．５％。辽宁、湖南、江苏三个省的中毒病例居多。７５．４％的病例发生于机械、化工、冶金、轻工和有色金属等工业部门。１０年中报告的发病例数呈减少趋势，并进行了原因分析。作者提出，当前职业病报告数据质量主要依附于职业病防治工作的正常开展。     

Incidence and characteristics of childhood suppurative meningitis in Hungary in 1983-87

Data of 1208 infants and children hospitalized for purulent meningitis were analysed. The incidence of the disease was closely age related: morbidity calculated for 100,000 children was found 97.5 under one year of age; 15.6 in 1 to 5 and 2.2 in 6 to 14 years of age. Incidence of newborn meningitis cases was 3.7 per 10,000 live-borns. The disease was caused by N. meningitidis in 278 (23%), H. influenzae in 171 (14%), S. pneumoniae in 157 (13%), E. coli in 74 (6%), B-group streptococcus in 61 (5%), other bacteria (altogether 17 species) in 107 (9%) cases, while in 360 cases (30%) the etiology remained unknown. Overall case fatality was 19.6 per cent. When compared to international data mortality was especially high among the newborns (53%) and in meningitis cases due to S. pneumoniae (29%), E. coli (48%), B-group streptococcus (37%) and "other bacteria" (41%). Neurologic sequelae were found in 17 per cent of the patients at discharge however, in newborns it was 54 per cent. Since the antibacterial therapy was appropriate in all cases, authors try to reveal the possible causes of the relatively high mortality and make recommendations for reducing it.     

Trends in cancer mortality in Switzerland, 1951-1984

Trends in overall age-standardized, truncated (35-64 years) and age-specific (40 to 49) cancer death certification rates in Switzerland from 1951 to 1984 were analysed. There was a substantial rise in lung cancer mortality in males, with an over 100% increase in overall rates. Thus, in the early 1980's, lung cancer alone accounted for 26% of all cancer deaths in Swiss males. However, male lung cancer rates tended to level off in subsequent cohorts starting from younger middle age in the late 1960's. In females, lung cancer mortality was approximately ten times lower than in males, but rates had been consistently rising since the late 1960's in all age groups. Declines were observed for several neoplasms of the digestive tract: besides stomach (overall decline 68% in males, 77% in females), trends were markedly downwards also for oesophageal cancer in males (-57%), and there was some moderate fall for intestinal sites in both sexes and gallbladder in females. Several trends for other common neoplasms were similar to those observed in other developed countries, such as the declines for (cervix) uteri, the general stability for breast cancer, or the increases in pancreatic cancer and (melanoma) of the skin. A peculiar feature of Swiss data, besides the marked decline in oesophageal cancer in males, was the consistent downward trend in thyroid cancer for both sexes. Thus, overall age-standardized total cancer mortality over the last three decades was moderately upwards in Swiss males, but consistently downwards in females. Male trends were more reassuring in middle age, chiefly in consequence of the flattening in lung cancer rises. Possible interpretations of these trends in terms of aetiological hypotheses (i.e., changes in alcohol drinking and improvements in diet for oesophageal cancer, or reduced prevalence of iodine deficiency for thyroid neoplasms) are discussed.     

Incidence of cancer in Navarra. 1988-92

AIM. An exposition is given of the data on the incidence of malign tumours in Navarra in the five year period 1988-92, by age and sex groups. MATERIAL AND METHODS. The collection of data of the 1988-92 five year period was carried out in an active form in the information sources. The procedures for collection, control of duplicates and processing of previous years were maintained. Both the indicators of quality and the calculations of the different rates were obtained following the recommendations proposed by the International Agency of Cancer Research (IARC). RESULTS. Between 1988 and 1992 11,608 incident cases of malign tumours were registered in Navarra. 58% were found in men. Excluding other skin cancer, the rate adjusted to the world population was of 274.1 per 100,000 for men and 182.9 per 100,000 for women. The localisations where the adjusted rates were higher for men excluding other skin cancer were lung, prostate and bladder, and for women the localisations were breast, uterine corpus and colon. Amongst men an increasing tendency was noted of cancer of the colon and bladder, and of breast cancer amongst women. The decrease of stomach cancer in both sexes was notable. CONCLUSIONS. Navarra is situated at an intermediate level of incidence with respect to other European countries. In relation to other registers was of note the high rate of larynx cancer in men and the low rate of cervical cancer in women.