Factors relating to eating style, social desirability, body image and eating meals at home increase the precision of calibration equations correcting self-report measures of diet using recovery biomarkers: findings from the Women’s Health Initiative

Table 7 Protein density, regression of log(biomarker) on log(self-report) and other predictors in NPAAS (n = 450) and R ²

	Food frequency questionnaire			Four day food record			24 Hr diet recall
Variable	β	SE	R²	β	SE	R²	β	SE	R²
Intercept	2.602*	0.057		2.629*	0.055		2.659*	0.058
Log(PD)C	0.325*	0.073	6.254	0.511*	0.071	12.416	0.427*	0.074	8.578
BMI-C	-0.004	0.003	0.66	-0.004	0.003	0.658	-0.004	0.003	0.448
Age-C	-0.003	0.003	0.06	-0.001	0.002	0	-0.004	0.003	0.222
Race:			2.396			2.988			3.323
Black	-0.107*	0.043		-0.129*	0.041		-0.138*	0.042
Hispanic	-0.101*	0.045		-0.080	0.044		-0.092*	0.045
Other	-0.042	0.081		-0.005	0.078		-0.060	0.080
Meals at Home:			0.413			0.189			0.182
Med	0.044	0.036		0.039	0.034		0.031	0.035
High	0.055	0.037		0.038	0.035		0.039	0.037
Body Image:			0.669			0.664			0.664
Med	0.043	0.043		0.055	0.042		0.031	0.043
High	0.109	0.071		0.102	0.068		0.073	0.071
TFEQ-R18
Restraint:			0.209			0.234			0.234
Med	-0.030	0.034		-0.030	0.032		-0.026	0.033
High	-0.023	0.041		-0.019	0.040		0.005	0.041
Unc. Eat.:			0.319			0.439			0.439
Med	-0.052	0.038		-0.062	0.037		-0.055	0.038
High	-0.061	0.044		-0.055	0.043		-0.074	0.043
Emo. Eat.:			0.561			0.605			0.605
Med	0.057	0.038		0.056	0.037		0.057	0.038
High	0.032	0.052		0.014	0.050		0.020	0.051
Social Desirability:			0.189			0.524			0.524
Med	-0.012	0.035		-0.029	0.034		-0.016	0.035
High	0.021	0.038		0.027	0.036		0.032	0.037
Total¹			11.731			18.707			14.729

BMI, body mass index.
^*β Coefficient differs from zero at p = 0.05 significance level.
¹Total – percent of variation explained by all variables. R² values for specific variables arise from analyses with only these regression variables, with subsequent rescaling so that these R² values add to the total regression R². R² values for race/ethnicity pertain to comparisons among the four groups (white, black, Hispanic, other minority).
Suffix C (e.g. BMI-C) = Centered values; for psychosocial & meals at home variables: medium and high are compared to low.

ISSN: 1475-2891