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At least 19 recordsLinked to original sources
PubMedDate not supplied

Epidemiological measures in planning: observations from Sweden.

This article reviews how epidemiological measures can be used in health planning. Theoretical considerations are discussed together with empirical data from Sweden. Formulation of targets, priority settings, resource allocation and monitoring systems are some ways in which epidemiological data can improve health planning. One important lesson for planning is that problems related to health, inequalities in health, and access to care, must be made visible to politicians, health personnel and the public. Further, there is a need to complement a national health policy with a decentralized planning system that takes local conditions and needs into consideration.

Data Collection↗
PubMed1987

Relations among standard epidemiologic measures in a population.

Recent developments in population mathematics apply to measurement issues in epidemiology. In particular, they demonstrate explicitly the relations that prevail among incidence, prevalence, case-fatality, mortality, and duration of illness in a population at a moment in time, rather than in a cohort of persons followed through time (or in a population artificially assumed to be stationary). They indicate explicitly how certain common indicators such as the ratio of deaths to new cases should be interpreted. They also suggest possible new strategies for estimating certain measures, but these would require some reorientation of current approaches to measurement.

Epidemiologic Methods↗
PubMed1993

The effects of joint misclassification of exposure and disease on epidemiologic measures of association.

This paper addresses the effects of simultaneous misclassification of both exposure and disease on epidemiologic measures of association. If misclassification of a dichotomous exposure is independent of a dichotomous disease status and vice versa (non-differential misclassification), and misclassification of exposure is independent of misclassification of disease, then the bias is always toward the null. In practice, however, errors in exposure and disease ascertainment may often be correlated. In this case, the observed exposure-disease association may be strongly biased in any direction even with non-differential misclassification. As an important corollary, the assertion commonly made in the discussion of epidemiologic study results that the observed measures of association can only be biased toward the null due to presumedly non-differential misclassification has to be viewed as inadequate unless the assertion that exposure and disease misclassification are independent is also justified. Inferences regarding the degree and direction of bias due to misclassification of exposure and disease should consider plausible degrees of correlation in classification errors in addition to the overall misclassification rates. Whenever possible, sensitivity analyses should be performed to provide a quantitative basis for such inferences.

Bias↗
PubMedDate not supplied

Epidemiological measurement of bronchial responsiveness in polyurethane workers.

A shortened protocol was developed for the epidemiological measurement of bronchial responsiveness to methacholine without compromising sensitivity, power, precision or safety, and without distorting the numerical value of the PD20.FEV1 (the cumulative dose from a doubling incremental sequence which provokes a 20% decrement in FEV1). It was used in a survey of 254 polyurethane workers (83% of the eligible workforce) exposed occupationally to toluene diisocyanate. The mean duration of each test proved to be 38 min, it was well tolerated and 64 workers (25%) proved to be reactors. PD20.FEV1 appeared to be distributed unimodally. It was significantly correlated with questionnaire records of shortness of breath, chest tightness, and wheeze; and with pre-shift FEV1 and FEF25-75. Even the reactors requiring the highest dose of 640 cumulative inhalation units (1 unit = one 8.9 microliters inhalation of methacholine 1 mg.ml-1) to generate a PD20 measurement reported significantly more wheeze than the non-reactors. This indicates that the test had clinical meaning throughout its dose range of 0.3-640 units. No correlation was found between PD20 and individual changes in ventilatory function across the working shift, but mean shift changes were negligible and not statistically significant. PD20 was also found to be unrelated to age, sex, race, smoking, cough and atopy.

Asthma↗
PubMed2004

Model-based estimation of relative risks and other epidemiologic measures in studies of common outcomes and in case-control studies.

Some recent articles have discussed biased methods for estimating risk ratios from adjusted odds ratios when the outcome is common, and the problem of setting confidence limits for risk ratios. These articles have overlooked the extensive literature on valid estimation of risks, risk ratios, and risk differences from logistic and other models, including methods that remain valid when the outcome is common, and methods for risk and rate estimation from case-control studies. The present article describes how most of these methods can be subsumed under a general formulation that also encompasses traditional standardization methods and methods for projecting the impact of partially successful interventions. Approximate variance formulas for the resulting estimates allow interval estimation; these intervals can be closely approximated by rapid simulation procedures that require only standard software functions.

Case-Control Studies↗
PubMed2005

Epidemiological measurement of children's and adolescents' exposure to community violence: working with the current state of the science.

A number of measures have been used in epidemiological studies of children's exposure to community violence, yet the quality of these instruments is not uniformly good. This paper undertakes a systematic review of the most commonly used (or most promising) self-report or interview-administered instruments, with regard to their conceptual bases and psychometric properties. Based on the review, recommendations are made for working with the current state of the science in order to move the field forward. A key recommendation is for sounder conceptualization of work in the field and greater transparency in the reporting of research, in order to facilitate the comparability of studies.

Adolescent↗
PubMed1991

Comparative research in social epidemiology: measurement issues.

The aim of comparative research in social epidemiology is to determine how risk factors for disease may vary within and between sociocultural and ethnic groups and in relation to outcomes. This aim assumes that measurement equivalence within and between social groups can be established, an assumption usually left untested. A model is presented here for deriving cross-culturally valid measures that are also intraculturally sensitive. Measurements so derived can then be used to compare cross-cultural and intracultural effects in a single analytic model. This approach is illustrated by pooling data on social stressors, social supports, and blood pressure from three studies.

Adult↗
PubMed1995

Epidemiological measures of participation in community health promotion projects.

BACKGROUND: The paper is concerned with the use of epidemiological methods to measure the rates at which different strata of a defined population participate in community health promotion projects. The specific aim was to estimate the incidence rates of participation in projects sponsored by the Western Australian Health Promotion Foundation (Healthway), separately for sociodemographic and health-related behavioural subgroups. METHODS: Data were drawn from Healthway sponsorship projects in 1992. Each sport, arts and racing project was associated with promotion of a health message and creation of a health promoting environment. The study used a two-stage sampling design. Thirteen of 57 large sponsorship projects and 30 of 129 small projects were selected. In the second stage, respondents were randomly surveyed from among project participants. A total of 4060 respondents aged > or = 10 years was sampled from the 43 selected projects. Population-based incident participants were estimated and were related to person-years at risk. RESULTS: The total participation rate was 4.01 per person-year. The rate was very high at ages 10-14 years and thereafter declined with increasing age. Compared with the least socially disadvantaged 25% of population, the participation rate fell by around one-third in the medium and high disadvantage groups, but exceeded the baseline by a ratio of 1.85 (95% confidence interval: 1.57-2.18) in the most disadvantaged 10% of population. The effect was most pronounced at ages 10-19 years. Participation was higher in those who smoked, drank alcohol unsafely, reported sunburn and reported low consumption of fruit and vegetables. However, participation was reduced in people who were sedentary. CONCLUSIONS: Epidemiological methods can be used to evaluate the distribution of participation of a population in community health promotion projects. The Western Australian Health Promotion Foundation has been successful in reaching disadvantaged youth.

Adolescent↗
PubMedDate not supplied

Basic occupational epidemiologic measures.

This chapter focuses on the "response" side of the exposure-response relationship and summarizes some of the measures of effect that are commonly used in occupational epidemiologic research. The author covers some basic statistical standardization procedures that are used to help compare these measures among groups that differ with respect to age or other factors.

Case-Control Studies↗
PubMedDate not supplied

[What epidemiological measures are useful in the evaluation of tuberculous disease?].

Among the epidemiological barometers useful in evaluating tuberculosis, the Annual Infection Risk is the one which has been shown to be the most useful. This rate can be calculated indirectly (by way of Tables) or directly (by testing the same group of individuals twice over a one-year period). The most ideal method for making these calculations, by consecutively having the same population of 6 year-olds at intervals over a one-year period, is presented. The results indicate a statistically significant difference (P less than 0.001) between the two methods, an indirect AIR of 0.079 to 0.118 being obtained, as related to a Case Rate of 0.44. The fact that said difference is probably due to the impact of the BCG vaccination, which leads to pressure phenomena, and finally, whilst we are not free of said vaccination, this index should be calculated indirectly, based on tuberculosis infection prevalence rates.

Child↗
PubMed2005

[Variability of epidemiological measures in mild cognitive impairment and dementia].

Variability in occurrence estimates is one of the basic features of the epidemiology of dementia and mild cognitive impairment (MCI). This review will cover two levels of variability that affect epidemiological research on dementia and MCI: the conceptual and the operational level. More specifically, it is highlighted how the lack of a precise definition of MCI leads to a greater variability in the occurrence estimates of this condition, when compared to dementia. Variability will decrease only when more precise criteria and aims of the concept "MCI" will be specified.

Aged↗
PubMed2004

Motherhood meets epidemiology: measuring risk factors for breast-feeding cessation.

OBJECTIVE: To examine statistical models that have been used to predict the cessation of breast-feeding. SETTING: In nutritional epidemiology, a knowledge of risk factors that lead to breast-feeding cessation is essential to promote optimal infant health by increasing or sustaining breast-feeding rates. However, a number of methodological issues complicate the measurement of such risk factors. It is important when building multivariate models that variables entered into the model are not intervening variables, factors on the causal pathway or surrogate outcomes. Inclusion of these types of variable can lead to inaccurate models and biased results. A factor often cited to predict breast-feeding is 'intention to breast-feed' prior to the birth of the infant, although this factor is directly on the causal decision-making pathway. Another factor often cited is the age of introduction of formula feeding, which is actually part of the outcome variable because formula feeding defines the difference between full, complementary and no breast-feeding. Rather than include these as risk factors in multivariate models, factors removed from the causal pathway such as influences of educational practices, including advice to complementary feed, and beliefs and attitudes of families and health-care practitioners should be measured. CONCLUSIONS: The accurate quantification of modifiable risk factors is essential for designing public health education campaigns that are effective in sustaining or increasing breast-feeding duration.

Adult↗
PubMed1997

Exposure assessment in occupational epidemiology: measuring present exposures with an example of a study of occupational asthma.

The aim of the present paper is to present a comprehensive review of the issues involved in exposure assessment for occupational epidemiology studies and to provide an example. Exposure assessment for occupational epidemiology studies is becoming more quantitatively refined. This paper discusses important issues that need to be taken into account for exposure assessment, with particular reference to occupational asthma. It discusses issues such as survey design, data collection, the effect of measurement error and data interpretation. It presents recently developed methodology to evaluate exposure variability and its effect on the attenuation of risk estimates. It also presents methodology to control for such variability. It uses examples from a recent cohort study of flour millers and bakers. This example shows various characteristics of exposure and demonstrates that various measures of exposure, such as peak and full-shift exposure measurements, are regularly correlated, which has consequences for the analyses of exposure-response relationships. This paper stresses the importance of the recognition and evaluation of exposure variability and its effect on risk estimates and shows that with different exposure grouping schemes, different health risk estimates can be obtained. Quantitative exposure assessment is generally difficult, time-consuming and expensive and many issues need to be taken into account, but it can be rewarding and has become an absolute necessity for many occupational epidemiology studies. Evaluation of components of exposure variance is absolutely necessary. Exposure variability could lead to serious attenuation of risk estimates.

Asthma↗
PubMed1996

A technique for measuring epidemiologically useful features of birthweight distributions.

Birthweight distributions have been conceptualized as a predominant Gaussian distribution contaminated in the tails by an unspecified 'residual' distribution. Acknowledging this idea, we propose a technique for measuring certain features of birthweight distributions useful to epidemiologists: the mean and variance of the predominant distribution; the proportions of births in the low- and high-birthweight residual distributions, and the boundaries of support for these residual distributions. Our technique, based on an underlying multinomial sampling distribution, involves estimating parameters in a mixture model for the multinomial bin probabilities after having chosen the support of the residual distribution with a model selection criterion. A modest simulation study and experience with a few actual datasets indicate that use of a Bayesian information criterion (BIC) as model selection criterion is superior to use of Akaike's information criterion (AIC) in this application.

Analysis of Variance↗