J Vestbo1, F V Rasmussen. 1. Medical Department P, Bispebjerg Hospital, Copenhagen NV, Denmark.
Abstract
STUDY OBJECTIVE: The aim was to examine whether baseline characteristics from a cross sectional survey provided sufficient information regarding non-response bias in a follow up study when compared with information on hospital admissions in the intervening years. DESIGN: This was an 11 year follow up study of a cohort selected in 1974 with register information on hospital admissions during follow up. SETTING: The study was based on a sample of cement workers from a particular Portland cement factory with suitable controls from other occupations. PARTICIPANTS: A total of 1404 men participated in the first survey in 1974, including a questionnaire and lung function tests. In 1985 1070 men were alive and of these, 928 men (87%) responded to a postal questionnaire. MAIN RESULTS: Non-responders in 1985 did not differ markedly from responders when smoking habits, respiratory symptoms, and lung function were examined in 1974. During follow up, non-responders had twice as high rates of hospital admission due to respiratory diseases as responders. These differences remained present after adjusting for minor differences in age and smoking habits. CONCLUSIONS: Equal distributions of baseline characteristics among responders and non-responders in a follow up study do not preclude non-response bias.
STUDY OBJECTIVE: The aim was to examine whether baseline characteristics from a cross sectional survey provided sufficient information regarding non-response bias in a follow up study when compared with information on hospital admissions in the intervening years. DESIGN: This was an 11 year follow up study of a cohort selected in 1974 with register information on hospital admissions during follow up. SETTING: The study was based on a sample of cement workers from a particular Portland cement factory with suitable controls from other occupations. PARTICIPANTS: A total of 1404 men participated in the first survey in 1974, including a questionnaire and lung function tests. In 1985 1070 men were alive and of these, 928 men (87%) responded to a postal questionnaire. MAIN RESULTS: Non-responders in 1985 did not differ markedly from responders when smoking habits, respiratory symptoms, and lung function were examined in 1974. During follow up, non-responders had twice as high rates of hospital admission due to respiratory diseases as responders. These differences remained present after adjusting for minor differences in age and smoking habits. CONCLUSIONS: Equal distributions of baseline characteristics among responders and non-responders in a follow up study do not preclude non-response bias.
Authors: Kennet Harald; Veikko Salomaa; Pekka Jousilahti; Seppo Koskinen; Erkki Vartiainen Journal: J Epidemiol Community Health Date: 2007-05 Impact factor: 3.710
Authors: A Stang; S Moebus; N Dragano; E M Beck; S Möhlenkamp; A Schmermund; J Siegrist; R Erbel; K H Jöckel Journal: Eur J Epidemiol Date: 2005 Impact factor: 8.082