Socioeconomic differences in smoking in an urban Swedish population. The bias introduced by non-participation in a mailed questionnaire.
Stockholm Health of the Population Study is a cross-sectional study carried out from 1984-85. Postal questionnaires, telephone interviews and health interviews were used to get information from a sample of 5,199 persons, 18-64 years of age, on health status, risk exposures, healthcare consumption and social factors. Non-participation with respect to the postal questionnaire was 36.8%. With subsequent telephone interviews and an invitation to a health interview, non-participation was reduced to 17.8%. The estimated prevalence of daily smoking increased from 36.1% to 38.7. The non-responders had a higher prevalence of daily smoking in all sub-groups. This effect of the efforts to reduce non-participation differed socially. The prevalence of smoking for men, 40-64 years of age, who were reached by telephone was 60.3%. Male professionals and intermediate non-manual workers, 40-64 years of age reached by telephone had a prevalence of smoking, which was twice as high as for the responders of the questionnaire (62.5 and 26.8%, respectively). In the younger age-group, non-responders had the same socioeconomic pattern in smoking as the responders. Independent of socioeconomic group, there was a tendency of ill or disabled smokers to respond more quickly than healthy smokers. Using a postal questionnaire with a high non-response rate might lead to an overestimation of socioeconomic differences and an underestimation of smoking prevalence.
Boström
G
G
Karolinska Institute, Department of Social Medicine, Kronan Health Centre, Sundbyberg, Sweden.
Hallqvist
J
J
Haglund
B J
BJ
Romelsjö
A
A
Svanström
L
L
Diderichsen
F
F
D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012907:Smoking / Q000453:epidemiology*; D012923:Social Class; D012959:Socioeconomic Factors; D013548:Sweden / Q000453:epidemiology; D014505:Urban Population / Q000706:statistics & numerical data*