Table 5.

Regression calibration equations from regression of log-calibrated biomarker on log total sugars intake and log total sugars density assessed by FFQ, 4DFR, and three 24HRs among NPAAS (2007–2009) participants (primary study, n = 384; reliability study, n = 78)

Total sugars intake, g/dTotal sugars density, g/1,000 kcal
VariableFFQ4DFRAvg. of three 24HRFFQ4DFRAvg. of three 24HR
Intercept3.51 (2.50)a2.72 (2.50)4.63 (2.45)0.49 (2.53)0.49 (2.51)0.64 (2.49)
Log self-reported intake0.23 (0.08)0.30 (0.10)0.26 (0.10)0.44 (0.13)0.36 (0.13)0.52 (0.14)
Log age0.17 (0.52)0.25 (0.53)−0.02 (0.52)0.77 (0.53)0.85 (0.54)0.73 (0.53)
Log BMI−0.11 (0.20)−0.07 (0.20)−0.19 (0.19)−0.37 (0.20)−0.38 (0.20)−0.46 (0.20)
Smoking status (current)−0.64 (0.24)−0.63 (0.24)−0.59 (0.24)−0.56 (0.24)−0.62 (0.25)−0.57 (0.24)
Education
 <High school graduate0.55 (0.23)0.53 (0.23)0.51 (0.22)0.64 (0.24)0.65 (0.24)0.41 (0.24)
 High school graduate0.30 (0.14)0.29 (0.14)0.23 (0.14)0.43 (0.15)0.44 (0.15)0.36 (0.14)
 Some college0.16 (0.09)0.16 (0.09)0.13 (0.09)0.18 (0.09)0.19 (0.09)0.16 (0.09)
 College graduate000000
Physical activity
 Square-root METs0.04 (0.02)0.04 (0.02)
For self-reported intake only
R20.010.020.020.030.020.04
 Adjustedb R20.050.060.060.100.070.18
Multiple
R20.060.060.040.090.090.10
 Adjustedb R20.180.170.160.340.290.40

NOTE: Calibrated using the measurement error parameters generated from the feeding study (17). Regression calibration models automatically included self-reported intake, log age, and log BMI as covariates: additional covariates were chosen by backward selection (P = 0.1) from the following covariates: square root physical activity (METs/wk), smoking status (current, former/never), supplement use (yes, no), race (black, white, Hispanic, other), education (<high school graduate, high school graduate, some college, college graduate), annual income (<$20,000, $20,000–$49,999, ≥$50,000), and percentage of meals eaten at home (<75, 75–94, >94).

Abbreviation: METs, metabolic equivalents.

  • aSE (all values in parentheses).

  • bR2 and multiple R2 are adjusted for within-subject error in the biomarker.