| 1. |
- Adami, HO, et al.
(author)
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Epidemiology, medicine and public health
- 1999
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In: International journal of epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 28:5, s. S1005-S1008
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Journal article (peer-reviewed)
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| 2. |
- Ahlborg, Gunnar, 1948, et al.
(author)
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Shift work, nitrous oxide exposure and subfertility among Swedish midwives
- 1996
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In: International Journal of Epidemiology. - 0300-5771. ; 25:4, s. 783-90
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Journal article (peer-reviewed)abstract
- BACKGROUND: Shift work and nitrous oxide exposure have both been suspected of having adverse influence on the reproductive performance of health workers. Time to pregnancy has been suggested as a sensitive measure of fecundity in occupationally exposed groups. We investigated the effects of shift work and nitrous oxide exposure on the fertility of Swedish midwives. METHODS: A questionnaire was mailed to all members of the Swedish Midwives Association who were born 1940 or thereafter, 3985 in all. Eighty-four per cent responded. Detailed information on the number of menstrual cycles required to achieve pregnancy and the working conditions during that period were obtained concerning the most recent, planned pregnancy occurring after 1983. The per cycle probability of becoming pregnant was calculated for each exposure category, and the relation to the unexposed was expressed as fecundability ratios. RESULTS: Midwives who worked two-shift, three-shift rotas, or only nights had reduced fertility compared to those working in the day time. The fecundability ratios were 0.78 (95% confidence interval [CI]: 0.65-0.94), 0.77 (95% CI: 0.60-0.98), and 0.82 (95% CI: 0.64-1.03), respectively, after adjustment for covariates. No effect of nitrous oxide exposure was noted except in the small group reporting that they assisted at more than 30 deliveries per month when nitrous oxide was used (fecundability ratio = 0.64; 95% CI: 0.44-0.95). CONCLUSION: Shift work and frequent, high occupational exposure to nitrous oxide may have a negative influence on the ability of women to become pregnant.
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| 6. |
- Cutts, F T, et al.
(author)
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Child and Maternal Mortality during a Period of Conflict in Beira City, Mozambique
- 1996
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In: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 25:2, s. 349-356
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Journal article (peer-reviewed)abstract
- Background Child mortality rates have been declining in most developing countries. We studied child and maternal mortality and risk factors for child mortality in Beira city in July 1993, after a decade of conflict in Mozambique. Methods A community-based cluster sample survey of 4609 women of childbearing age was conducted. Indirect techniques were used to estimate child mortality (‘children ever born’ method and Preceding Birth Techniques [PBT]), and maternal mortality sisterhood method). Deaths among the most recent born child, born since July 1990, were classified as cases (n = 106), and two controls, matched by age and cluster, were selected per case. Results Indirect estimates of the probability of dying from birth to age 5 (deaths before age 5 years, 5q0 per 1000) decreased from 246 in 1977/8 to 212 in 1988/9. The PBT estimate for 1990/91 was 154 (95% confidence interval(CI): 124–184), but recent deaths may have been underreported. Lack of beds in the household (odds ratio[OR] = 2.0, 95% CI: 1.1–3.8), absence of the father (OR = 2.4, 95% CI: 1.2–4.8), low paternal educational level (OR = 2.1, 95% CI: 0.8–5.4), young maternal age (OR = 2.0, 95% CI: 1.0–3.7), self-reported maternal illness (OR = 2.4, 95% CI: 1.2–4.9), and home delivery of the child (OR = 2.3, 95% CI: 1.2–4.5) were associated with increased mortality, but the sensitivity of risk factors was low. Estimated maternal mortality was 410/100 000 live births with a reference date of 1982. Conclusions Child mortality decreased slowly over the 1980s in Beira despite poor living conditions caused by the indirect effects of the war. Coverage of health services increased over this period. The appropriateness of a risk approach to maternal-child-health care needs further evaluation.
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| 8. |
- Diderichsen, F, et al.
(author)
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Trends in occupational mortality among middle-aged men in Sweden 1961-1990.
- 1997
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In: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 26:4, s. 782-7
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Journal article (peer-reviewed)abstract
- BACKGROUND: Many European countries have in recent decades reported growing socioeconomic differentials in mortality. While these trends have usually paralleled high unemployment and increasing income disparities, Sweden had low unemployment and narrowing income differences. This study describes trends, 1961-1990, in total and cardiovascular mortality among men, 45-69 years of age, in major occupational classes in Sweden. METHODS: From census data four cohorts were created from those enumerated in 1960, 1970, 1980 and 1985. Through record linkage with the Swedish cause of death registry the mortality in each cohort was followed for 5-10 years. Age-standardized mortality trends 1961-1990 were calculated for occupational groups, categorized according to sector of the economy. RESULTS: The increase in mortality among middle-aged men in Sweden 1965-1980 was mainly a result of increasing cardiovascular mortality among industrial workers and farmers. In the 1980s the trend for these groups changed into a last decrease in mortality similar to that for non-manual occupations for the whole period. Consequently the rate ratio for industrial workers in comparison with men having a professional/managerial type of occupation increased from 0.98 to 1.43. The slowest decrease is now found among unqualified occupations in services and transportation. CONCLUSIONS: While Sweden, during the period studied, had narrowing income differentials and low unemployment this result points to the importance of working conditions in understanding trends and distribution of male adult mortality.
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| 9. |
- Elmståhl, Sölve, et al.
(author)
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Bias in diet assessment methods - Consequences of collinearity and measurement errors on power and observed relative risks
- 1997
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In: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 26:5, s. 1071-1079
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Journal article (peer-reviewed)abstract
- Background. If several risk factors for disease are considered in a regression model and these factors are affected by measurement errors, the observed relative risk will be attenuated. In nutritional epidemiology, several nutrient variables show strong correlation, described as collinearity. The observed relative risk will then depend not only on the validity of the chosen diet assessment method but also on collinearity between variables in the model. Methods. The validity of different diet assessment methods are compared. The correlation coefficients between common nutrients and foods are given using data from the Malmo Food Study. Intake of nutrients and foods were assessed with a modified diet history method, combining a 2-week food record for beverages and lunch/dinner meals and a food frequency questionnaire for other foods. The study population comprised 165 men and women aged 50-65 years. A multivariate logistic regression model is used to illustrate the effect of collinearity on observed relative risk (RRo). Results. A moderate to high correlation between risk factors will substantially influence RRo even when using diet assessment methods with high validity. Methods with low validity might even give inverse RRo. Conclusion. It is stressed that caution must be exercised and only a selected number of variables should be included in the model, especially when they are highly intercorrelated, since RRo might be severely biased.
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| 10. |
- Forsberg, Bertil, et al.
(author)
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Childhood asthma in four regions in Scandinavia : risk factors and avoidance effects
- 1997
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In: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 26:3, s. 610-619
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Journal article (peer-reviewed)abstract
- BACKGROUND: The high and increasing prevalence of childhood asthma is a major public health issue. Various risk factors have been proposed in local studies with different designs.METHODS: We have made a questionnaire study of the prevalence of childhood asthma, potential risk factors and their relations in four regions in Scandinavia (Umeå and Malmö in Sweden, Kuopio in eastern Finland and Oslo, Norway). One urban and one less urbanized area were selected in each region, and a study group of 15962 children aged 6-12 years was recruited.RESULTS: The prevalence of symptoms suggestive of asthma varied considerably between different areas (dry cough 8-19%, asthma attacks 4-8%, physician-diagnosed asthma 4-9%), as did the potential risk factors. Urban residency was generally not a risk factor. However, dry cough was common in the most traffic polluted area. Exposure to some of the risk factors. such as smoking indoors and moisture stains or moulds at home during the first 2 years of life, resulted in an increased risk. However, current exposure was associated with odds ratios less than one.CONCLUSIONS: Our findings were probably due to a combination of early impact and later avoidance of these risk factors. The effects of some risk factors were found to differ significantly between regions. No overall pattern between air pollution and asthma was seen, but air pollution differed less than expected between the areas.
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