ISSN:1044-3983    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1044-3983    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Background.There has been some concern that exposure to electromagnetic fields may cause birth defects. We studied risks of birth defects by residential exposure to 50-Hz magnetic fields from power lines.Methods.We estimated the distance between residence and power lines for 161,844 Norwegian residences, and their corresponding magnetic fields in the period 1980 to 1997. Risks of 24 categories of birth defects were compared across exposure levels, adjusting for social and demographic variables.Results.Among those living near power lines, the greatest reductions in risk were for cardiac defects (odds ratio = 0.5; 95% confidence interval = 0.3–0.9) and respiratory defects (0.4; 0.2–0.9). The largest increase in risk was for esophageal defects (2.5; 1.0–5.9). Other associations were weaker and had wide confidence intervals.Conclusions.There was little evidence that residence near power lines affected the risk of birth defects. The observed decreased risks of cardiac and respiratory defects and the increased risk of esophageal defects should be interpreted with caution given the number of endpoints, the imprecision in the calculations of the distance from the residence to the power line, and the limited information on pregnant women's change of residence.

ISSN:1044-3983    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Background.Interest in the incidence of varicella (chickenpox) has increased since the discovery of an effective vaccine, but calculations to date have incorrectedly ignored the question of susceptibility.Methods.We studied the occurrence of varicella in Italy on the basis of 33,343 children (age 0–14 years) cared for by 35 pediatricians between 1 October 1997 and 30 September 1998. The life-table technique was used to calculate the number of susceptible children. On this basis, we estimated the corrected age-specific and cumulative incidence.Results.We identified 1749 cases among the estimated 21,783 susceptible children, for a crude incidence of 8.0% (95% confidence interval [CI] = 7.7–8.4). The rate age-standardized to the Italian population 0–14 years old was 6.8 (CI = 6.5–7.2). The incidence was more than 16% among children age 3–4 years and more than 4% for those age 1–10 years. Comparison of the usual method and our corrected method showed that the uncorrected method underestimates the crude annual incidence (5.2%vs8.0%), shifts the peak incidence to earlier ages, and underestimates cumulative incidence (at age 14, 49%vs67%).Conclusions.The use of our corrected method provides more valid estimates of the incidence of varicella than the ones that are currently available. Corrected estimates should be preferred to uncorrected ones in models to study the cost-effectiveness of universal vaccination against varicella.

ISSN:1044-3983    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Background.Clinical studies suggest that depression may be accompanied by an activation of the inflammatory response system. We investigated the relation of cytokine interleukin-6 and the acute phase proteins &agr;1-antichymotrypsin and C-reactive protein with depression in a population-based study.Methods.We screened for depressive symptoms 3884 adults at age 60 and older living in a district of Rotterdam, and performed a psychiatric work-up on those who were screened positive. All subjects had blood drawn. We compared levels of inflammation markers adjusted for smoking, stroke, functional disability and cognitive score for 263 cases with depressive symptoms (including 106 subjects with depressive disorders) and 461 randomly selected reference subjects.Results.Age- and gender-adjusted analyses suggested associations of &agr;1-antichymotrypsin and C-reactive protein with depressive disorders, but these associations disappeared after adjustment for additional confounding factors. Even after adjustment, increased levels of interleukin-6 were related to depressive disorders (odds ratio per standard deviation increase in interleukin-6 = 1.47; 95% confidence interval = 1.15–1.89). Further analyses demonstrated that this relation was mainly attributable to the subjects with high interleukin-6 concentrations, suggesting a threshold effect.Conclusions.Interleukin-6 levels were strongly increased in some subjects with depressive disorders, possibly indicating a specific immunologic process. However, the associations of acute phase proteins with depression in this population-based study could be explained by confounding.

ISSN:1044-3983    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

A comparison of expected number of deaths with the observed is a widely used method with an extensive history. Epidemiologists often study the mortality rate from a particular cancer in an initially healthy population. Using cause-specific mortality rates from a reference population will overestimate the expected number of deaths because it does not take into account the fact that the study cohort is initially cancer free. It is more accurate to calculate the expected number of deaths by explicitly considering the probability of getting cancer in a given year and the probability of dying from it before the end of the follow-up.

ISSN:1044-3983    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1044-3983    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1044-3983    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1044-3983    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:1044-3983    

出版商:OVID    

年代:2003

数据来源: OVID