Journal of chronic diseases最新文献

The forced expiratory volume in one second (FEV₁) is routinely used in epidemiologic studies of lung function to assess the presence and severity of obstructive airways disease. Normative prediction equations developed using data from healthy, asymptomatic individuals may then be used both in a clinical setting and to adjust comparisons among risk subgroups for known demographic differences. Unfortunately no concensus has yet developed as to how best to model lung function data. This paper addresses this issue in a systematic manner using data derived from two cohorts followed over a period of 9–11 years. We compare a variety of cross-sectional and longitudinal models for FEV₁, show how they may be expressed as members of a larger class of general linear models, and discuss goodness-of-fit procedures for comparing them. We found little objective evidence for discriminating among these models; only those fit to FEV₁/ht³ performed poorly. We argue on subjective grounds for the use of models based on FEV₁, as a function of age, height and their interactions.

This paper reviews the sources of apparent time trends in effect. Apparent changes in effect may arise from changes in covariate distributions, background rates, exposure distribution, measurement quality, or selection factors. As with time trends in rates, time trends in effect must have at least one of these sources, since time itself has no effect. If background incidence is changing, however, time trends in effect become dependent on choice of effect measure, and interpretation must take this into account. Evidence that a trend arises from age-, cohort-, or period-related phenomena can indicate the relative plausibility of different explanations of the trend. Conversely, the relative plausibility of each explanation may indicate whether the trend is most appropriately viewed over the axis of age, birth cohort, or calendar time. Nevertheless, studies of short duration relative to an apparent trend (such as most case-control studies) must invoke strong assumptions to justify focusing on a particular axis. Illustrations are given from studies of electronic fetal monitoring and of smoking and lung cancer.

This paper uses a detailed example to illustrate how to detect individual observations that disproportionately influence the results of hypothesis testing with relative risk regression models.

Little is known about how generosity of insurance and population characteristics affect quantity or appropriateness of antibiotic use. Using insurance claims for antibiotics from 5765 non-elderly people who lived in six sites in the United States and were randomly assigned to insurance plans varying by level of cost-sharing, we describe how antibiotic use varies by insurance plan, diagnosis and health status, geographic area, and demographic characteristics. People with free medical care used 85% more antibiotics than those required to pay some portion of their medical bills (controlling for all other variables). Antibiotic use was significantly more common among women, the very young, patients with poorer health, and persons with higher income. Use of antibiotics for viral, viral-bacterial, and bacterial conditions did not differ between free and cost-sharing insurance plans, given antibiotics were the treatment of choice. Cost sharing reduced inappropriate and appropriate antibiotic use to a similar degree.

Hospital admissions for herniated lumbar intervertebral disc or sciatica were followed up over a period of 11 years in 57,000 men and women who had participated in medical check-ups in various parts of Finland. Information on their hospitalizations after the baseline examination was obtained by record linkage to the National Hospital Discharge Register. To identify factors predicting back diseases, four controls matched individually for sex, age and place of residence were chosen for each of the 592 incidence cases who were free from severe back trouble and aged 20–59 at entry. Low or intermediate social class and blue-collar occupations in services or industry in men and symptoms suggesting psychological distress in women proved significant predictors for hospitalization due to herniated lumbar disc or sciatica. An association with the risk was suggested for smoking or chronic cough in men and parity in women. Marital status or leisure time physical activity were not predictive of herniated lumbar intervertebral disc or sciatica.