Attrition in a population-based cohort eight years after baseline interview: The Cornella Health Interview Survey Follow-up (CHIS.FU) Study.
OBJECTIVE
To examine how response at follow-up varied from baseline sociodemographic data in a Spanish population-based cohort after 8 years of follow-up.


METHODS
The Cornella Health Interview Survey Follow-up (CHIS.FU) Study is a population-based cohort study on lifestyle risk factors and their consequences on health status with 2500 participants at baseline. We have compared the distribution of baseline characteristics according to the results at follow-up (interview, decease, migration, or refusal).


RESULTS
Almost two-thirds of the subjects who did not respond to the follow-up interview had died or moved to another town. Sex was a determinant of attrition in deceased and non-traced participants. Refusal appeared to be associated with working status and place of birth. Self-perceived health was one of the characteristics associated with mortality; subjects who perceived their health as poor were 2.6 times more likely to die than those who felt they were in good health. Disabled and retired subjects together with housewives showed a higher risk of dying than individuals still working. The determinants of attrition among emigrated subjects were civil status, age, level of studies, working status, and birth place.


CONCLUSIONS
Although the attrition was non-random, there was no serious bias in estimates of change and in determinants of change due to attrition.
Garcia
Montse
M
Catalan Institute of Oncology, L'Hospitalet de Llobregat, Spain.
Fernandez
Esteve
E
Schiaffino
Anna
A
Borrell
Carme
C
Marti
Merce
M
Borras
Josep Maria
JM
D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D004641:Emigration and Immigration; D005260:Female; D005500:Follow-Up Studies; D015438:Health Behavior; D006306:Health Surveys; D006801:Humans; D007407:Interviews as Topic; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009026:Mortality; D016017:Odds Ratio; D012959:Socioeconomic Factors; D013030:Spain / Q000453:epidemiology