Contribution of follow-up of nonresponders to prevalence and risk estimates: a Norwegian respiratory health survey.

Achieving a high response rate is often expensive and time consuming. Does an extensive survey effort change prevalence estimates and exposure-disease relations? In 1998-1999, the authors conducted a population-based respiratory health survey in two Norwegian counties (Oslo, n = 20,000; Hordaland, n = 5,000) of a random sample of the adult population aged 15-70 years. A postal questionnaire was mailed, with as many as two reminder letters.

Predictors of outcome and comparison of different drug regimens for the prevention of relapse in patients with Graves' disease.

Objective: To investigate the effect of different antithyroid drug (ATD) regimens on relapse rates of Graves' disease, and to look for predictors of relapse.

Design And Methods: In a prospective two-way factorial randomized clinical trial, 218 patients with Graves' disease were assigned to ATD combined with l-thyroxine (l-T(4)) or ATD alone for 12 Months. After discontinuation of antithyroid therapy, each group was stratified to either 12 Months further treatment with l-T(4) or no treatment.

Nonresponse in a community cohort study: predictors and consequences for exposure-disease associations.

We have assessed predictors for response in a Norwegian community cohort study, with an 11-year follow-up. We also examined to what extent the association of gender, age, and smoking to the incidence of respiratory symptoms and asthma differed if the analyses were based on the 65% (n = 2,079) initial responders, or were based on the 89% (n = 2,819) who responded after three reminders. The associations between the six symptoms/asthma and the gender, age, and smoking groups amounted to 42 odds ratios.

Occupational airborne exposure and the incidence of respiratory symptoms and asthma.

Several prevalence studies have suggested an association between occupational exposure and respiratory symptoms and asthma, but there has been a lack of incidence studies to verify this. This study examined the incidence of respiratory symptoms and asthma in an 11-year Norwegian community cohort study with 2,819 subjects. Predictors examined were sex, age, educational level, lifetime exposure to quartz, asbestos, and dust or fumes, as well as smoking habits and pack-years.

Comparison of telephone and postal survey modes on respiratory symptoms and risk factors.

Little is known about the comparability of postal and telephone survey modes in epidemiology. A cross-sectional, population-based study (n = 25,000) of lung disease was performed in 1998-1999 in two regions of Norway. Initial surveying was done by postal questionnaire.