Journal of chronic diseases最新文献

Statistical methods based on the Armitage-Doll mathematical model of the carcinogenic process are presented for analyzing epidemiologic case-control studies of cancer. These methods are proposed to provide inferences regarding the stage(s) in the cancer process at which the exposure of interest acts. An example of these methods is given which shows evidence that carcinogens in cigarette smoke appear to affect the transition rates for two separate stages in the development of lung cancer, and the relative magnitudes of these effects are estimated. The data for this analysis came from a European multi-center case-control study of lung cancer.

The results of the analysis show that: (1) the relative risk of lung cancer among continuing smokers compared to nonsmokers of the same age decreases as the age started smoking increases, while the rate of smoking stays fixed, a result which indicates a carcinogenic effect on an early stage in the process; and (2) the relative risk among ex-smokers compared to continuing smokers having the same duration and rate of smoking decreases with time since smoking stopped, a result which indicates a carcinogenic effect on a late stage in the process. Both results are shown to be best described by the hypothesis that cigarette smoking affects two stages. The estimated relative magnitudes of cigarettes' carcinogenic effects on the two stages indicate that the largest proportion of the total lifetime lung cancer risk among continuing smokers is due to its late stage effect, and that the proportion of risk due to causes other than smoking varies from 23% among men smoking 1–10 cigarettes per day to 6% among those smoking greater than 30 cigarettes per day. These findings imply that preventive measures directed toward inducing smokers to stop would have a potentially substantial payoff in reducing future lung cancer mortality.

Qunatitative estimation of doses of carcinogens delivered to physiologic targets facilities specification of organ-specific dose-response functions. Typically, exposure measurements, such as air or water concentrations of carcinogens, are used as dose surrogates in epidemiologic studies. An illustrative exception to this usual situation is the case of airborne alpha radiation-emitting radionuclides, for which organ-specific doses can be derived. A metabolic modeling approach for estimating doses delivered to the lung, gastrointestinal tract and bone is described for three classes of radionuclides: soluble uranium, insoluble uranium and plutonium. The dose models are defined in terms of biological retention patterns and organ-specific depositions affinities. Application of the metabolic modeling approach is illustrated with a hypothetical example of excess lung cancer risk projection in a cohort of persons exposed to plutonium. Also, a simple example is presented to demostrate how adherence to the metabolic model structure can avoid gross overestimation of doses in the case of multiple in vivo lung counting measurements taken in close temporal proximity following a large exposure intake.

The validity of identifying incident cases of non-fatal acute myocardial infarction (AMI) between 1971 and 1982 in Western Australia from routine hospital records was assessed in ages 25–64 years, according to the WHO criteria defined in 1970 and 1983. This was done by reviewing original data sources and by using the Perth Coronary Register of 1971 as an external reference.

Events with a coded discharge diagnosis of acute or subacute ischemic heart disease were found to be highly sensitive (97%) for cases of “definite” AMI (WHO 1983 criteria). The specificity of such events was lower (positive predictive value of about 70%) and validation of these events would be necessary for studies requiring high specificity. The sensitivity and specificity of these events for “definite” AMI seemed quite stable over time with similar values being observed in 1971 and 1978. Although the situation for “possible” AMI (non-fatal) is less clear, certainly many more records would need to be reviewed to validate this diagnosis.

Trends in age-specific and age-adjusted blood pressure and the prevalence of hypertension were obtained from the National Nutrition Survey of Japan, 1956–1980. The national trends in the age-adjusted blood pressure of people (30–69 years old) in Japan during the 1956–1980 period show an increasing pattern reaching a peak around 1964 followed by a descreasing pattern. To explore the possible factors which have contributed to the change in blood pressure levels, we analyzed the relationship between the blood pressure and several possible factors, including the rate of treatment for cardiovascular diseases (CVD) for men and women, annual salt and alcohol consumption per capita and body mass index (MB1) for men and women. Only alcohol consumption was considered in the analysis of men because women in Japan still tend to drink relatively little alcohol.

In simple descriptive analyses, the increasing trend in the treatment rates of CVD seemed to be related to the decrease in the blood pressure level and in the prevalence rate of hypertension for both men and women. The impact of treatment rate seemed to overcome the adverse influence of the increasing trends in BMI. Recent decrease in salt consumption may account in part for the later period of the decreasing trends in blood pressure level and the prevalence of hypertension. In multiple regression analysis using these time series data. CVD. BMI and alcohol consumption were significantly related to blood pressure level and the prevalence of hypertension, although salt was not significant in these analyses.

A cross-sectional study was conducted to identify predictors of tardive dyskinesia (TD) in a group of 180 psychiatric outpatients maintained on neuroleptic medications. The estimated prevalence of this involuntary movement disorder was 33% in the total study population. Using multiple logistic regression, we found that TD was independently related to five factors: being 55 yr of age and older; being male; using depot (injectable) neuroleptics; having 6 or more years of neuroleptic exposure; and having less than 6 months of psychiatric hospitalization. In addition, the effect of depot medication was much greater in white males than it was in other race-sex groups. We observed no other interaction effects between pairs of predictor variables, nor did we find significant independent effects of race, denture use, DSM III diagnosis, current neuroleptic dose and potency, percent time on neuroleptics, and recent use of antiparkinsonian drugs or lithium. This study is serving as a pilot investigation for a large prospective incidence study that has already begun among patients at risk of developing TD in the same source population.

This paper explores the problems of benefit measurement in the economic evaluation of heart transplant programmes. We present data from our evaluation of the U.K. heart transplant programmes on both survival and quality of life and we examine the relationship between the two. The quality of life measure used, the Nottingham Health Profile (NHP), is described and results presented. We attempt to aggregate this profile measure into a single index score and combine these data with life expectancy gains to produce estimates of Quality Adjusted Life Years (QALYs) gained for heart transplantation. In addition we examine the extent to which pre-transplant NHP scores can be used as predictors of post-transplant survival.

We used two methods to examine how lung cancer death rates vary with cumulative exposures to radiation and tobacco among U.S. uranium miners. We assumed that exposures act proportionately on age-specific death rates among nonsmokers who are unexposed to uranium. The two methods produced similar results when death rate ratios were taken to be the product of radiation and tobacco effects. The estimates were discrepant when death rate ratios were taken to be the sum of radiation and tobacco effects. Both methods indicated better fit for the multiplicative model, as judged by the maximized loglikelihood values. Death rates estimated in this way for white males in the absence of mining and smoking increased only weakly with age. This weak relation suggests that our models of death rates fit poorly. It may be that cumulative exposures are inappropriate measures of the effects of radiation and tobacco on lung cancer death rates.