TABLE 4.
General linear models predicting log2-transformed total plasma carotenoids, log2-transformed self-reported FV consumption, and log2-transformed self-reported dietary carotenoid intake using reflection spectroscopy–assessed skin carotenoids (per 100 units) and covariates among 211 participants1
| Model | Independent variables | Total plasma carotenoids | Self-reported FV intake | Self-reported carotenoid intake |
|---|---|---|---|---|
| Unadjusted | R 2 | 0.503 | 0.125 | 0.143 |
| Skin carotenoids | 0.33 (0.29, 0.38) | 0.25 (0.16, 0.34) | 0.30 (0.20, 0.40) | |
| Field based3 | R 2 | 0.5524 | 0.173 | 0.1955 |
| Skin carotenoids | 0.32 (0.27, 0.37) | 0.27 (0.18, 0.37) | 0.31 (0.21, 0.42) | |
| Age | 0.004 (–0.000, 0.009) | 0.007 (–0.002, 0.016) | 0.010 (–0.000, 0.020) | |
| Female | 0.13 (0.02, 0.24) | 0.14 (–0.09, 0.37) | 0.18 (–0.07, 0.44) | |
| Male | Reference | Reference | Reference | |
| Asian | –0.08 (–0.22, 0.06) | –0.16 (–0.44, 0.12) | –0.19 (–0.51, 0.12) | |
| Hispanic | 0.02 (–0.15, 0.19) | 0.35 (–0.00, 0.70) | 0.33 (–0.02, 0.72) | |
| Non-Hispanic black | –0.05 (–0.18, 0.08) | 0.08 (–0.19, 0.35) | 0.12 (–0.18, 0.42) | |
| Non-Hispanic white | Reference | Reference | Reference | |
| BMI | –0.023 (–0.037, –0.009) | –0.005 (–0.034, 0.024) | –0.017 (–0.049, 0.015) | |
| Research based | R 2 | 0.6622 | 0.183 | 0.205 |
| Melanin | 0.31 (–0.46, 1.09) | –0.01 (–1.82, 1.80) | –0.22 (–2.24, 1.79) | |
| Skin carotenoids | 0.004 (–0.22, 0.23) | 0.03 (–0.50, 0.55) | –0.02 (–0.60, 0.57) | |
| Melanin × skin carotenoids | 0.20 (0.01, 0.40) | 0.17 (–0.29, 0.63) | 0.24 (–0.27, 0.75) | |
| Hemoglobin | –0.15 (–0.26, –0.04) | –0.02 (–0.28, 0.23) | –0.10 (–0.39, 0.19) | |
| Age | 0.001 (–0.003, 0.005) | 0.007 (–0.002, 0.016) | 0.009 (–0.001, 0.020) | |
| Female | 0.12 (0.02, 0.22) | 0.15 (–0.08, 0.39) | 0.19 (–0.07, 0.46) | |
| Male | Reference | Reference | Reference | |
| Asian | –0.11 (–0.23, 0.01) | –0.16 (–0.46, 0.13) | –0.22 (–0.54, 0.10) | |
| Hispanic | –0.05 (–0.20, 0.10) | 0.31 (–0.05, 0.67) | 0.28 (–0.13, 0.68) | |
| Non-Hispanic black | –0.19 (–0.33, –0.04) | 0.03 (–0.31, 0.37) | 0.03 (–0.35, 0.40) | |
| Non-Hispanic white | Reference | Reference | Reference | |
| BMI | –0.022 (–0.035, –0.010) | –0.005 (–0.035, 0.024) | –0.017 (–0.050, 0.016) | |
| Plasma total cholesterol | 0.002 (0.001, 0.003) | 0.000 (–0.002, 0.003) | –0.000 (–0.003, 0.003) |
Model R2 and parameter estimates (95% CIs) are reported. A log2-transformation of the outcomes was used to stabilize variances and improve the linearity of the relations. FV, fruit and vegetables.
P < 0.001.
The field-based model includes covariates that are easily measured in a community or field-based setting, including age, sex, race or ethnicity, and BMI. The research-based model included covariates that are more difficult to assess and would require more resources, including those in the field-based model as well as total cholesterol and melanin.
P < 0.01.
P < 0.05 comparing to previous model R2.