TY - JOUR
T1 - Binary regression in truncated samples, with application to comparing dietary instruments in a large prospective study
AU - Midthune, Douglas
AU - Kipnis, Victor
AU - Freedman, Laurence S.
AU - Carroll, Raymond J.
PY - 2008/3
Y1 - 2008/3
N2 - We examine two issues of importance in nutritional epidemiology: the relationship between dietary fat intake and breast cancer, and the comparison of different dietary assessment instruments, in our case the food frequency questionnaire (FFQ) and the multiple-day food record (FR). The data we use come from women participants in the control group of the Dietary Modification component of the Women's Health Initiative (WHI) Clinical Trial. The difficulty with the analysis of this important data set is that it comes from a truncated sample, namely those women for whom fat intake as measured by the FFQ amounted to 32% or more of total calories. We describe methods that allow estimation of logistic regression parameters in such samples, and also allow comparison of different dietary instruments. Because likelihood approaches that specify the full multivariate distribution can be difficult to implement, we develop approximate methods for both our main problems that are simple to compute and have high efficiency. Application of these approximate methods to the WHI study reveals statistically significant fat and breast cancer relationships when a FR is the instrument used, and demonstrate a marginally significant advantage of the FR over the FFQ in the local power to detect such relationships.
AB - We examine two issues of importance in nutritional epidemiology: the relationship between dietary fat intake and breast cancer, and the comparison of different dietary assessment instruments, in our case the food frequency questionnaire (FFQ) and the multiple-day food record (FR). The data we use come from women participants in the control group of the Dietary Modification component of the Women's Health Initiative (WHI) Clinical Trial. The difficulty with the analysis of this important data set is that it comes from a truncated sample, namely those women for whom fat intake as measured by the FFQ amounted to 32% or more of total calories. We describe methods that allow estimation of logistic regression parameters in such samples, and also allow comparison of different dietary instruments. Because likelihood approaches that specify the full multivariate distribution can be difficult to implement, we develop approximate methods for both our main problems that are simple to compute and have high efficiency. Application of these approximate methods to the WHI study reveals statistically significant fat and breast cancer relationships when a FR is the instrument used, and demonstrate a marginally significant advantage of the FR over the FFQ in the local power to detect such relationships.
KW - Biased sampling
KW - Breast cancer
KW - Case-control studies
KW - Comparison of instruments
KW - Measurement error
KW - Misspecified models
KW - Nutritional epidemiology
KW - Truncation
KW - Women's Health Initiative
UR - http://www.scopus.com/inward/record.url?scp=39849083923&partnerID=8YFLogxK
U2 - 10.1111/j.1541-0420.2007.00833.x
DO - 10.1111/j.1541-0420.2007.00833.x
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C2 - 17651458
AN - SCOPUS:39849083923
SN - 0006-341X
VL - 64
SP - 289
EP - 298
JO - Biometrics
JF - Biometrics
IS - 1
ER -