Epidemiologic reviews
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Epidemiologic reviews · Jan 1998
ReviewExposure measurement in cohort studies: the challenges of prospective data collection.
Cohort study designs have several advantages over case-control studies in terms of exposure measurement. If exposure measurement occurs before disease occurrence, cohort studies are much less prone to differential measurement error. Prospective data collection should also reduce measurement error due to poor recall of past exposures. ⋯ Long-term cohort studies which cover the etiologically relevant time period could improve the accuracy of measures of exposures by use of repeated biologic measures or repeated updates of self-reported exposures. Measurement error also can be reduced by judicious choice of a cohort to study and by careful attention to quality control procedures. Continued emphasis on the evaluation and improvement of the measurement properties of instruments used in epidemiologic studies will improve the validity of the results of cohort studies.
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Knowledge of the epidemiology of tobacco use and dependence can be used to guide research initiatives, intervention programs, and policy decisions. Both the reduction in the prevalence of smoking among US adults and black adolescents and the decline in per capita consumption are encouraging. These changes have probably been influenced by factors operating at the individual (e.g., school-based prevention programs and cessation programs) and environmental (e.g., mass media educational strategies, the presence of smoke-free laws and policies, and the price of tobacco products) levels (for a discussion of these factors, see, e.g., refs. 2, 48, 52, 183, and 184). ⋯ To estimate their sensitivity and specificity, comparisons of the National Household Survey on Drug Abuse indicators of dependence with DSM-based criteria are needed. Public health action continues to be warranted to reduce the substantial morbidity and mortality caused by tobacco use (195). A paradigm for such action has been recommended and involves preventing the onset of use, treating tobacco dependence, protecting non-smokers from exposure to secondhand smoke, promoting nonsmoking messages while limiting the effect of tobacco advertising and promotion on young people, increasing the real (inflation-adjusted) price of tobacco products, and regulating tobacco products (186).
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Sleep-disturbed breathing, which includes apneas, hypopneas, and oxygen desaturations, occurs in asymptomatic individuals and increases with age. Obstructive apnea is the most frequent type of respiratory disturbance documented by polysomonography, the gold standard test for assessing sleep-disturbed breathing. Many of the prevalence studies done to date have had one or more methodological weaknesses, including selection biases, varying definitions of obstructive sleep apnea, failure to distinguish types of apneas, failure to control for confounding variables, and small sample size. ⋯ Although endocrine changes such as growth hormone, thyroid hormone, and progesterone deficiency also have been suggested as risk factors for exacerbating obstructive sleep apnea syndrome, there is minimal epidemiologic evidence to support this. Case-control studies are recommended to assess the relation of endocrine factors to obstructive sleep apnea syndrome in a rigorous fashion. A limited number of mortality studies have suggested decreased survival in persons with the obstructive sleep apnea syndrome, possibly primarily due to vascular-related disease.(ABSTRACT TRUNCATED AT 400 WORDS)