[Did hypertension diminish in The Netherlands between 1974 and 1993?].
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Adolescent↗
Biomedical subjects
P J van de Mheen
Publications and source records attributed to P J van de Mheen.
Variation in reported prevalences of hypertension in The Netherlands: the impact of methodological variables.
STUDY OBJECTIVE: To estimate the prevalence of hypertension in The Netherlands and to quantify the influence of methodological variables on the reported prevalences. DESIGN: A pooled analysis was performed based on reported age specific prevalences of hypertension. A logistic model was used to estimate the probability of hypertension. MAIN RESULTS: The age standardised prevalence of hypertension varies more than fivefold between studies carried out in The Netherlands. The probability of having hypertension was lower if blood pressure was measured at more than one point in time (Odds ratio 0.44 (OR) (95% confidence interval (95% CI) 0.38, 0.51) for men and 0.47 (0.41, 0.54) for women, and if the study was carried out more recently (OR 0.92 (0.91, 0.93) per year). The probability was higher if the study was carried out in a general practice (OR 1.14 (1.03, 1.27) for men and 1.52 (1.36, 1.69) for women). The inclusion of treated people as hypertensive yields contradictory results for men and women. CONCLUSIONS: The strong variation in prevalence is explained by methodology and by a period effect indicating a decrease of the prevalence of hypertension over time. Whether this decrease is true or caused by confounding due to unknown or unreported methodological variation over time is unknown. For future studies, a standardised method could reduce the influence of methodological variables and thereby the variation in reported prevalences.
Adult↗
Reported prevalences of former smokers in survey data: the importance of differential mortality and misclassification.
The purpose of this study was to determine whether the reported increase in the percentage of never smokers in the group of men born between 1924 and 1938, as observed in survey data in the Netherlands, can be attributed to differential mortality or to misclassification. In a spreadsheet program, the mortality experiences of the men born in 1924 and 1938 were simulated with the use of lifetable techniques. Due to differential mortality, the percentage of true never smokers would be expected to increase from 9% to 9.3% for men born in 1938 and from 9% to 10.3% for men born in 1924. In the survey, the percentage of people who reported that they had never smoked increased from 9% to 36% for the men born between 1924 and 1938. Differential mortality can only explain a very small part of the reported increase in the percentage of "never" smokers. Misclassification of former smokers as never smokers is the most likely cause for the reported increase. This is reason for concern, because even a small percentage of misclassified former smokers may bias the estimated relative risk of mortality associated with current smoking to a considerable extent. Because former smoking status cannot be measured correctly, the percentage of former smokers may be calculated by modeling the percentage of ever smokers.
Adolescent↗
Differences between studies in reported relative risks associated with smoking: an overview.
Reported Relative Risks associated with smoking differ between studies; these differences may reflect true biological differences between populations or may be research artifacts introduced by differences in factors such as amount smoked or smoking duration. The authors reviewed the literature published before June 1992 on relative risks associated with smoking for heart disease, stroke, lung cancer, and chronic obstructive lung disease. They quantified the effect of variables such as age, amount smoked, and smoking duration on reported relative risks. The main reasons for the variation in reported relative risks were: misclassification of former smokers as never smokers, the use of mortality rate ratios rather than incidence rate ratios, a possible period effect suggesting increasing relative risks over time, and differences in the amounts smoked. It is far more likely that these factors are responsible for the observed variation between studies than that the variations reflect true biological differences between populations. Using relative risks from other studies is therefore justified in calculating a population attributable risk if the studies are carefully selected and address factors such as amount smoked and period effects.
Cardiovascular Diseases↗