ISSN:1044-3983    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:1044-3983    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

We used multistep register linkage to measure the occurrence of cancer in offspring of male members of the Oslo unions of printers. A file of their children was established through linkage with the Central Population Register. Children born 1950-1987 (N = 12,440) were traced for cancer during 1965–1987 in the Cancer Registry of Norway (193,406 person years). We found 33 cases of cancer. The standardized incidence ratio was near expected for person-years after age 14 (25 cases observed) but lower than expected for person-years in the age group 0-14 years (eight cases observed, standardized incidence ratio 0.58, 95% confidence interval 0.25-1.14). This negative association was stronger when more precise criteria for time of exposure were applied, especially for children 0–14 years with fathers in categories exposed to lead 1 year before the child's birth. Methodologic problems with this approach are nondifferential exposure misclassification and the need for large data sets. The method could serve as an alternative to the case-control design in reproductive epidemiology. (Epidemiology 1992;3:60–10)

ISSN:1044-3983    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Most published calculations of mortality risk, especially those for lung cancer associated with smoking, are based almost exclusively on the underlying cause as recorded on death certificates. Such risk calculations implicitly assume that the conditional probability of recording lung cancer as the underlying cause of death, given that it really is the underlying cause, is the same for all exposure groups. If these probabilities are not equal for all exposure groups, we call the resulting bias a cause of death attribution bias.We analyzed the 1986 National Mortality Followback Survey, a sample of 18,733 U.S. death certificates, and the 1954–1962 Dorn study, a follow-up study of approximately 250,000 holders of U.S. Veterans Life Insurance. Both data sets include information on the smoking habits of decedents and on the underlying and contributing causes of their deaths. We found that lung cancer as an underlying cause is recorded with a much smaller relative frequency if the decedent is known to be a never-smoker and with a much larger relative frequency when the decedent is known to be a smoker. On the other hand, lung cancer as a contributing cause is recorded with a much larger frequency if the decedent is known to be a never-smoker and with a much smaller frequency when the decedent is known to be a smoker. The reverse is true for cancers other than of the lung. There is no similar pattern related to smoking for other causes of death (specifically for myocardial infarction, other chronic ischemic heart disease, diabetes, or cerebrovascular disease). This pattern provides evidence of a possible bias because knowledge of a decedent's smoking status appears to influence the designation of lung cancer or some other cancer as the underlying cause or a contributing cause of death. This bias is especially strong when the choice of possible underlying causes of death is limited to one of a number of cancers. Insofar as calculations of lung cancer risk utilize exclusively recorded underlying causes, the observed attribution bias must result in an overestimate of the lung cancer mortality rate for smokers. (Epidemiology 1992;3:11–16)

ISSN:1044-3983    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Recent advances in laboratory techniques for measuring the pregnancy hormone human chorionic gonadotropin have allowed detection of occult very early pregnancy losses based on assaying urine. We used data from the Early Pregnancy Study carried out in North Carolina to develop a simplified collection protocol for reducing costs and improving compliance in similar studies conducted in less-selected populations of women. Collection of specimens only during menses would have caused some decrease in sensitivity but would nevertheless have allowed detection of at least 75% of the losses detected in the North Carolina study. Reduced-collection protocols would also result in some loss in specificity. Simulations suggest that moderate losses in sensitivity and specificity, as would result from reduced-collection protocols, produce only moderate loss of power for detecting associations between risk factors and early pregnancy loss. A “fertility bias” exists, however, which can produce seriously misleading results when specificity is less than perfect. We therefore recommend use of a baseline group of sterile women, so that criteria for “pregnancy” can achieve specificity close to 1.0. (Epidemiology 1992;3:17–22)

ISSN:1044-3983    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

We assembled data from numerous studies to examine whether active smoking and occupational exposure to arsenic act synergistically (more than additively) to increase the risk of lung cancer. Although several smaller studies lacked the power to reject simple additive relations, the joint effect from both exposures consistently exceeded the sum of the separate effects by about 70 to 130%. The only study not showing a greater than additive effect appeared to have inadequate data to address this question. We calculated the excess fractions for the synergism; these showed that a minimum of between 30% and 54% of lung cancer cases among those with both exposures could not be attributed to either one or the other exposure alone. Previous authors addressing the synergism between arsenic exposure and smoking have evaluated deviations from a multiplicative model, which is inappropriate for this purpose. Reports of no interaction or “negative” interaction have therefore been misleading. Taken as a whole, the evidence is compelling that arsenic and smoking act in a synergistic manner to produce lung cancer. Substantial reductions in the lung cancer burden of smokers occupationally exposed to arsenic could be achieved by reductions in either exposure. The mechanism for the synergism is unclear. (Epidemiology 1992;3:23–31)

ISSN:1044-3983    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

We studied reproductive outcomes in a cohort of 7,450 pregnancies identified through three Kaiser-Permanente facilities in the San Francisco Bay Area, in relation to exposure to the pesticide malathion, applied aerially to control an infestation by the Mediterranean fruit fly. We included in the cohort all women over age 17 who were registered at these facilities and who were confirmed as pregnant during the spraying period. Residence histories throughout the pregnancy were obtained by mailed questionnaire or telephone interview from 933 women with adverse outcomes and a sample of 1,000 women with normal outcomes, and were converted to geographical coordinates. We linked the coordinates for malathion spraying corridors with the residence coordinates to create individual exposure indices for each week of pregnancy. The statistical analysis compared each of the adverse pregnancy outcome groups against an appropriate control group using logistic regression or survival time regression approaches. After adjustment for various confounders, no important association was found between malathion exposure and spontaneous abortion, intrauterine growth retardation, stillbirth, or most categories of congenital anomalies. Gastrointestinal anomalies were related to second trimester exposure (odds ratio = 2.6), based on 13 cases and not specific to any particular International Classification of Diseases code. (Epidemiology 1992;3:32–39)

ISSN:1044-3983    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

Blood pressure measurement in childhood can be considered as a screening test for future blood pressure levels. Evaluating this test involves calculating sensitivities, specificities, and predictive values for a blood pressure measurement at an initial time for predicting underlying true blood pressure at a subsequent time. We demonstrate the use of childhood blood pressure tracking correlations that are corrected for within-person variability to calculate unbiased estimates of these test characteristics. In a cohort of 333 schoolchildren, we measured blood pressure on multiple visits in each of 4 successive years. Using these data for within-person variances and corrected tracking correlations, and U.S. population data for means and total variances, we tabulated positive predictive values, sensitivities, and specificities for the case of predicting a 9-year-old male's true systolic blood pressure 3 years later. For example, if a 9-year-old's average blood pressure from 4 visits is 115 mmHg, the probability of his true blood pressure being >116 mmHg (90th percentile) at age 12 is 0.50. With longer follow-up, the use of predictive values, sensitivities, and specificities that incorporate corrected correlations should allow determination of the accuracy of predicting adult blood pressure from childhood values, and therefore the usefulness of screening children for those at high risk of developing hypertension. (Epidemiology 1992;3:40-46)

ISSN:1044-3983    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

We conducted a population-based case-control study of inflammatory bowel disease and dietary habits in Stockholm during 1984–1987. We obtained retrospective information about food intake 5 years previously by a postal questionnaire for 152 cases with Crohn's disease, 145 cases with ulcerative colitis, and 305 controls. The relative risk of Crohn's disease was increased for subjects who had a high (55 gm or more per day) intake of sucrose (relative risk = 2.6, 95% confidence interval = 1.4–5.0) and was decreased for subjects who had a high (15 gm or more per day) intake of fiber (relative risk = 0.5, 95% confidence interval=0.3–0.9). The most striking finding was an increased relative risk of both Crohn's disease and ulcerative colitis associated with consumption of fast foods: the relative risk associated with consumption of fast foods at least two times a week was estimated at 3.4 (95% confidence interval = 1.3–9.3) for Crohn's disease and 3.9 (95% confidence interval=1.4–10.6) for ulcerative colitis. Although coffee seemed to provide a protective effect for both diseases, there are reasons to consider this finding an artifact. (Epidemiology 1992;3:47–52)

ISSN:1044-3983    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

This analysis assesses the relation between a history of migraine and the risk of preeclampsia or gestational hypertension. Cases (172 women with preeclampsia and 254 with gestational hypertension) and controls (505) were primiparae with no history of hypertension before pregnancy. Information on migraine attacks in the year before pregnancy was obtained after delivery. Migraine was reported by 16% of preeclamptic women, 12% of women with gestational hypertension, and 8% of the controls. Adjusted odds ratios (95% confidence interval) of preeclampsia and gestational hypertension were 2.44 (1.42–4.20) and 1.70 (1.02–2.85), respectively. We conclude that women who have a recent history of migraine may be at higher risk of pregnancy-induced hypertension. (Epidemiology 1992;3:53–56)

ISSN:1044-3983    

出版商:OVID    

年代:1992

数据来源: OVID