Determinants of quality of interview and impact on risk estimates in a case-control study of bladder cancer.
The authors evaluated potential determinants of the quality of the interview in a case-control study of bladder cancer and assessed the effect of the interview quality on the risk estimates. The analysis included 1,219 incident bladder cancer cases and 1,271 controls recruited in Spain in 1998-2001. Information on etiologic factors for bladder cancer was collected through personal interviews, which were scored as unsatisfactory, questionable, reliable, or high quality by the interviewers. Eight percent of the interviews were unsatisfactory or questionable. Increasing age, lower socioeconomic status, and poorer self-perceived health led to higher proportions of questionable or unreliable interviews. The odds ratio for cigarette smoking, the main risk factor for bladder cancer, was 6.18 (95% confidence interval: 4.56, 8.39) overall, 3.20 (95% confidence interval: 1.13, 9.04) among unsatisfactory or questionable interviews, 6.86 (95% confidence interval: 4.80, 9.82) among reliable interviews, and 7.70 (95% confidence interval: 3.64, 16.30) among high-quality interviews. Similar trends were observed for employment in high-risk occupations, drinking water containing elevated levels of trihalomethanes, and use of analgesics. Higher quality interviews led to stronger associations compared with risk estimation that did not take the quality of interview into account. The collection of quality of interview scores and the exclusion of unreliable interviews probably reduce misclassification of exposure in observational studies.
Villanueva
Cristina M
CM
Centre for Research in Environmental Epidemiology, Barcelona, Spain. cvillanueva@creal.cat
Silverman
Debra T
DT
Malats
Núria
N
Tardon
Adonina
A
Garcia-Closas
Reina
R
Serra
Consol
C
Carrato
Alfredo
A
Fortuny
Joan
J
Rothman
Nathaniel
N
Dosemeci
Mustafa
M
Kogevinas
Manolis
M
D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D016001:Confidence Intervals; D004781:Environmental Exposure / Q000009:adverse effects*; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007407:Interviews as Topic / Q000592:standards*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011786:Quality Control; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D012959:Socioeconomic Factors; D013030:Spain / Q000453:epidemiology; D011795:Surveys and Questionnaires; D001749:Urinary Bladder Neoplasms / Q000453:epidemiology* / Q000209:etiology