TABLE 3.
Regression estimates and R2 regression values of ln-transformed nutrient intake on corresponding ln-transformed nutrient biomarker and study participant characteristics in the NPAAS-FS 1
| Variable2 | β ± SE | R2 |
| Total energy intake, kcal/d | ||
| Intercept | 7.454 ± 0.039 | |
| Biomarker: Ein | 0.680 ± 0.055 | 0.51 |
| Race-ethnicity (white) | 0.102 ± 0.040 | 0.02 |
| Overall | 0.53 | |
| Total protein intake, g/d | ||
| Intercept | 4.302 ± 0.034 | |
| Biomarker: protein | 0.437 ± 0.046 | 0.37 |
| BMI | 0.010 ± 0.003 | 0.04 |
| Supplement use3 | 0.062 ± 0.036 | 0.01 |
| Overall | 0.43 | |
| Vitamin B-12, μg/d | ||
| Intercept | 2.190 ± 0.286 | |
| Biomarker: vitamin B-12 | 1.869 ± 0.192 | 0.40 |
| BMI | 0.081 ± 0.027 | 0.05 |
| Physical activity | −0.016 ± 0.008 | 0.01 |
| Supplement use | 1.227 ± 0.312 | 0.05 |
| Overall | 0.51 | |
| Dietary folate equivalents, μg/d | ||
| Intercept | 6.730 ± 0.147 | |
| Biomarker: folate | 0.808 ± 0.091 | 0.43 |
| Supplement use | 0.380 ± 0.123 | 0.04 |
| College degree or higher | −0.244 ± 0.107 | 0.02 |
| Overall | 0.49 | |
| α-Carotene, μg/d | ||
| Intercept | 6.362 ± 0.160 | |
| Biomarker: α-carotene4 | 1.241 ± 0.101 | 0.45 |
| BMI | 0.082 ± 0.019 | 0.06 |
| Spring | −0.325 ± 0.219 | 0.0001 |
| Summer | −0.534 ± 0.207 | 0.02 |
| Fall | −0.258 ± 0.232 | 0.004 |
| Overall | 0.53 | |
| β-Carotene, μg/d | ||
| Intercept | 8.478 ± 0.040 | |
| Biomarker: β-carotene4 | 0.624 ± 0.066 | 0.28 |
| BMI | 0.050 ± 0.010 | 0.10 |
| Overall | 0.39 | |
| Lutein + zeaxanthin, μg/d | ||
| Intercept | 7.426 ± 0.228 | |
| Biomarker: lutein + zeaxanthin4 | 1.101 ± 0.100 | 0.37 |
| Age | −0.028 ± 0.014 | 0.01 |
| BMI | 0.049 ± 0.012 | 0.05 |
| Race-ethnicity (white) | 0.593 ± 0.233 | 0.02 |
| Overall | 0.46 | |
| Lycopene, μg/d | ||
| Intercept | 8.262 ± 0.060 | |
| Biomarker: lycopene4 | 1.052 ± 0.127 | 0.30 |
| BMI | 0.035 ± 0.015 | 0.03 |
| Overall | 0.32 | |
| α-Tocopherol, mg/d | ||
| Intercept | 2.885 ± 0.162 | |
| Biomarker: α-tocopherol4 | 2.077 ± 0.231 | 0.43 |
| Supplement use | 0.510 ± 0.177 | 0.03 |
| Weight variability5 | 0.117 ± 0.060 | 0.01 |
| Overall | 0.47 | |
| Percentage of energy from PUFAs | ||
| Intercept | 1.940 ± 0.054 | |
| Biomarker: PUFAs | 4.284 ± 0.707 | 0.19 |
| Age | −0.012 ± 0.0058 | 0.02 |
| Physical activity | 0.003 ± 0.0014 | 0.02 |
| Supplement use | 0.111 ± 0.058 | 0.02 |
| Weight variability | 0.035 ± 0.021 | 0.01 |
| Overall | 0.27 |
Presented nutrients are restricted to those with overall R2 > 0.25. Included were study participant characteristics that remained significant for inclusion in the model on the basis of a backward-selection procedure (P = 0.1). Ein, energy intake (derived from doubly labeled water); NPAAS-FS, Nutrition and Physical Activity Assessment Study Feeding Study.
Age was centered at 75.36 y; BMI (in kg/m2) was centered at 26.39; physical activity was centered at 15.78 metabolic equivalent task-hours/wk; weight variability was centered at 1.33 kg. For biomarker measures, ln Ein was centered at 7.48 ln kcal/d; ln protein was centered at 4.33 ln g/d; ln vitamin B-12 was centered at ln 6.27 pg/mL; ln folate was centered at ln 2.99 ng/mL; ln %PUFAs was centered at 3.71 ln % relative abundance. Serum cholesterol-adjusted biomarkers were residuals from the model of biomarker and cholesterol; these residuals were entered into the calibration equation without centering.
Self-reported use of any dietary supplements from the NPAAS-FS baseline 4-d food record.
Serum cholesterol-adjusted.
Weight variability over the 2-wk controlled feeding period.