A major goal of epidemiology is to discover the causes of disease in populations. The aim of this study was to develop a method for establishing research priorities within this very broad area of scientific inquiry.
While the approach is applicable to many diseases, cancer was used here, in part because of its importance to both individuals and governments. Measures of disease were estimated from data in the Ontario Cancer Registry, and combined to yield a single assessment of impact for each cancer site. Measures of exposure prevalence were identified from recent population health surveys. Cross-classification by disease and exposure rankings yielded a matrix of scores of "relative importance" for each cancer-exposure combination. Onto this matrix was overlaid: 1) estimates of statistical power for examining each association; 2) biological plausibility of each association; and 3) strength of the epidemiological evidence supporting each association.
The disease-exposure matrix, viewed in light of statistical power, biological plausibility, and current epidemiological evidence, yielded, in the examples shown, some potentially interesting yet understudied associations (e.g., non-Hodgkin lymphoma (NHL) and certain aspects of dietary intake).
The associations identified within the research hierarchy suggest not only new avenues for etiologic research, but also priorities for research focus.
Comment In: Ann Epidemiol. 1999 Jan;9(1):17-89915604
The respiratory health of 230 female and 1,734 male farming students (FS) and 407 male rural controls was analyzed. A significantly increased prevalence of cough (6.9%) was reported among the male FS compared to the controls (2.5%). Measured FEV1 and FVC did not differ between the male FS and the controls, as opposed to significantly higher values among the female FS compared to a random sample of urban females stratified for height. Skin prick test (SPT) to house dust and storage mites was significantly more prevalent among the controls (18.7%) compared to the male FS (12.8%) and the female FS (11.9%). The size of the house dust mite weal and the number of positive skin prick reactions were significantly associated with bronchial hyperreactivity. The difference in lung function among the female FS and the lower prevalence of skin reaction among the male FS and female FS probably reflects a healthy workers selection.
Among patients with bronchial asthma, there are predominantly females who live in an industrial area. In this area, patients with severe bronchial asthma are 2.4 times more and those with a severe exacerbation are twice more. Bronchial asthma may serve as a marker of the poor environment.
BACKGROUND: The susceptibility to develop hay fever is putatively the result both of genetic and environmental causes. We estimated the significance and magnitude of genetic and environmental contributions to hay fever among young adult twins. METHODS: From the birth cohorts 1953-82 of The Danish Twin Registry 11,750 twin pairs were identified through a nationwide questionnaire survey. Subjects were regarded hay fever cases when responding affirmatively to the question 'Do you have, or have you ever had hay fever?' Latent factor models of genetic and environmental effects were fitted to the observed data using maximum likelihood methods. RESULTS: The overall cumulative prevalence of hay fever was 12.6%. Identical twins were significantly more likely to be concordant for hay fever than were fraternal twins (P
Norway is among the countries with the highest prevalence of type 1-diabetes, and the incidence is increasing. Both environmental- and genetic factors contribute to development of the disease; but no environmental risk factor for type 1-diabetes has been identified, and it is therefore difficult to prevent the disease. In the prospective research study MIDIA (Norwegian acronym for Environmental triggers of type 1-diabetes) 100,000 new-borns will be tested for a gene combination that approximately 2.1% of the children have. Each of the 2,100 children with this combination have a 6-10% risk for childhood diabetes. They will be followed for up for 15 years with regular stool samples, questionnaires and blood samples with the aim of finding causes of diabetes. Detection of autoantibodies towards beta cells in the pancreas indicates an ongoing disease process and will be used as the first end-point. The aim of this article is to inform Norwegian doctors about the study, and to discuss scientific and ethical aspects of the project.
We evaluated the allergy status of 134 immigrants from Asia, Africa, the Middle East and South America, who were referred to our clinic during the past 10 years. Fifty Swedish patients were used for comparison. When the atopy state was not taken into account, no significant difference was found between the two groups with respect to total IgE levels. However, IgE levels of non-atopic immigrants were significantly higher than the IgE levels of non-atopic Swedes. While there was no significant difference in IgE levels between atopic and non-atopic immigrants, this difference was significant in Swedish patients. In general, IgE levels of immigrants showed a decline with time and reached approximately the same levels as for the Swedish patients in 10.5 years. In the immigrant group atopic women had a considerably lower IgE level than the atopic men. Among the atopics there were no differences between sexes. In Swedes and immigrants pollen was the most common group of allergens. The spectrum of allergy in the immigrant group changed with time in Sweden, and gradually became more similar to the Swedish spectrum. Skin and/or RAST positivity to birch increased from 16% within 2.5 years to 53% after more than 10.5 years in Sweden. Our data indicate that environmental factors rather than hereditary differences determine the IgE state. Within a few years the immunologic status of immigrants adapts to the new environment.
BACKGROUND: Self-reported annoyance from electrical equipment has been in evidence since the mid-1980s, and the first reports of illness from everyday chemicals arose in the 1960s. However, the extent of the problem has not yet been fully established. AIMS: The aim of this study was to estimate the prevalence of annoyance related to electrical and chemical factors in a Swedish general population, and to assess possible relationships with subjective health and daily functioning. METHODS: In total, 13,604 subjects, representative of the population of Scania, Sweden, answered a survey containing five questions regarding annoyance from five environmental factors: fluorescent tube lighting, visual display units, other electrical equipment, air that smells of chemicals, and other smells. The survey also obtained data on self-reported health (SRH-7), mental well-being [General Health Questionnaire (GHQ)-12], work situation and daily functioning. RESULTS: Almost one-third of the respondents reported annoyance from at least one environmental factor. Annoyance was more frequent among women, subjects of working age and immigrants. Subjects who reported environmental annoyance scored higher on GHQ-12 and lower on SRH-7, indicating impaired subjective physical and mental well-being. They were also more likely to report deteriorated daily functioning. CONCLUSIONS: Annoyance related to electrical and/or chemical factors was common in a Swedish population. Subjects reporting environmental annoyance rated their overall health significantly poorer than the general population. The association with subjective health and functional capacity increased with severity of annoyance, which suggests that there is some connection between environmental annoyance, well-being and functional capacity.
Studies of the prevalence of asthma among migrating populations may help in identifying environmental risk factors.
We analyzed data from Vancouver, Canada, and from Guangzhou, Beijing and Hong Kong, China, collected during phase 3 of the International Study of Asthma and Allergies in Childhood. We subdivided the Vancouver adolescents according to whether they were Chinese immigrants to Canada, Canadian-born Chinese or Canadian-born non-Chinese. We compared the prevalence of asthma and wheezing among Chinese adolescents born in Canada, Chinese adolescents who had immigrated to Canada and Chinese adolescents living in China.
Of 7794 Chinese adolescents who met the inclusion criteria, 3058 were from Guangzhou, 2824 were from Beijing, and 1912 were from Hong Kong. Of 2235 adolescents in Vancouver, Canada, 475 were Chinese immigrants, 617 were Canadian-born Chinese, and 1143 were Canadian-born non-Chinese. The prevalence of current wheezing among boys ranged from 5.9% in Guangzhou to 11.2% in Canadian-born Chinese adolescents. For girls, the range was 4.3% in Guangzhou to 9.8% in Canadian-born Chinese adolescents. The prevalence of ever having had asthma ranged from 6.6% to 16.6% for boys and from 2.9% to 15.0% for girls. Prevalence gradients persisted after adjustment for other environmental variables (odds ratios for ever having had asthma among Canadian-born Chinese compared with native Chinese in Guangzhou: 2.72 [95% confidence interval 1.75-4.23] for boys and 5.50 [95% confidence interval 3.21-9.44] for girls; p