Table 3. Socio-demographic, lifestyle and dietary predictors of nutritional biomarkers (folate, vitamin B-12, tHcy and 25(OH)D): OLS multiple regression analyses; NHANES 2005–06 (n = 2,459).
| Folate, nmol/L | Vitamin B-12, pmol/L | tHcy, µmol/L | 25(OH)D, ng/mL | |||||||||
| β | (SEE) | P-value | β | (SEE) | P-value | β | (SEE) | P-value | β | (SEE) | P-value | |
| Socio-demographic, lifestyle factors | ||||||||||||
| Age (y) | +0.21 | (0.03) | <0.001 | +1.05 | (0.29) | 0.003 | +0.069 | (0.003) | <0.001 | −0.059 | (0.017) | 0.004 |
| Female vs. male | +4.23 | (1.12) | 0.002 | +38.44 | (27.89) | 0.19 | −1.471 | (0.144) | <0.001 | +1.164 | (0.521) | 0.041 |
| Race/ethnicity | ||||||||||||
| Non-Hispanic White | Ref | Ref | Ref | |||||||||
| Non-Hispanic black | −4.94 | (0.86) | <0.001 | +39.22 | (27.95) | 0.18 | +0.461 | (0.280) | 0.120 | −8.363 | (0.726) | <0.001 |
| Mexican-American | −3.38 | (1.36) | 0.025 | +168.13 | (96.25) | 0.10 | −0.596 | (0.160) | 0.002 | −5.212 | (1.091) | <0.001 |
| Other ethnicity | −3.33 | (1.21) | 0.014 | −22.83 | (29.32) | 0.45 | −0.043 | (0.289) | 0.88 | −4.979 | (0.842) | <0.001 |
| Married vs. non-married | +1.42 | (1.05) | 0.19 | −12.71 | (39.60) | 0.75 | −0.252 | (0.071) | 0.003 | +1.104 | (0.842) | 0.007 |
| Education | ||||||||||||
| <High School | Ref | Ref | Ref | |||||||||
| High School | −0.49 | (1.70) | 0.78 | −228.4 | (153.5) | 0.16 | +0.367 | (0.320) | 0.27 | −0.984 | (1.054) | 0.37 |
| >High School | +0.42 | (1.55) | 0.79 | −219.1 | (142.1) | 0.14 | +0.164 | (0.323) | 0.35 | −1.256 | (0.905) | 0.19 |
| Poverty Income Ratio | ||||||||||||
| <100% | Ref | Ref | Ref | Ref | ||||||||
| 100%-<200% | −0.84 | (1.01) | 0.42 | +32.20 | (87.55) | 0.72 | −0.383 | (0.400) | 0.35 | +0.772 | (0.823) | 0.36 |
| ≥200% | +0.33 | (0.96) | 0.73 | −1.03 | (67.59) | 0.99 | −0.515 | (0.407) | 0.23 | +0.174 | (0.854) | 0.84 |
| Smoking status | ||||||||||||
| Never smoker | Ref | Ref | Ref | Ref | ||||||||
| Former smoker | −1.73 | (0.93) | 0.082 | −57.44 | (24.1) | 0.031 | +0.065 | (0.152) | 0.68 | −0.221 | (0.414) | 0.60 |
| Current smoker | −2.82 | (0.83) | 0.004 | −44.67 | (26.36) | 0.11 | +0.468 | (0.246) | 0.08 | −0.437 | (0.505) | 0.40 |
| Physical activity, Mets.hr.wk−1 | −0.010 | (0.013) | 0.52 | −0.164 | (0.492) | 0.74 | −0.007 | (0.005) | 0.15 | +0.027 | (0.010) | 0.020 |
| Body mass index, kg.m−2 | −0.05 | (0.11) | 0.64 | −2.969 | (1.551) | 0.075 | −0.014 | (0.010) | 0.19 | −0.264 | (0.029) | <0.001 |
| History of selected chronic conditions | ||||||||||||
| Type 2 diabetes | +0.02 | (1.12) | 0.99 | +193.64 | (161.91) | 0.25 | −0.013 | (0.229) | 0.95 | −0.864 | (0.680) | 0.22 |
| Cardiovascular disease | +3.03 | (2.00) | 0.15 | −59.19 | (53.65) | 0.29 | +0.628 | (0.302) | 0.06 | −1.348 | (0.9810 | 0.19 |
| Cancer | −0.52 | (1.66) | 0.76 | +105.79 | (140.68) | 0.46 | +0.189 | (0.175) | 0.30 | +0.706 | (0.648) | 0.29 |
| Anti-depressant medication use | −0.64 | (0.98) | 0.53 | −6.37 | (39.19) | 0.87 | −0.252 | (0.313) | 0.08 | +0.763 | (0.436) | 0.10 |
| Dietary Intakes | ||||||||||||
| Total Energy Intake, kcal/d | −0.001 | (0.000) | 0.015 | −0.005 | (0.011) | 0.63 | −0.000 | (0.000) | 0.98 | +0.000 | (0.000) | 0.82 |
| Alcohol intake, g/d | −0.010 | (0.014) | 0.50 | +0.509 | (0.499) | 0.32 | +0.012 | (0.005) | 0.037 | +0.033 | (0.012) | 0.015 |
| Caffeine, mg/d | −0.010 | (0.002) | 0.002 | −0.039 | (0.035) | 0.28 | +0.001 | (0.000) | 0.020 | +0.001 | (0.001) | 0.30 |
| Fiber, g/d | −0.047 | (0.079) | 0.57 | +1.206 | (1.923) | 0.54 | −0.018 | (0.010) | 0.09 | −0.005 | (0.030) | 0.87 |
| α-carotene, µg/d | −0.000 | (0.001) | 0.66 | +0.000 | (0.003) | 0.97 | −0.000 | (0.000) | 0.40 | +0.000 | (0.000) | 0.89 |
| β-carotene, µg/d | −0.000 | (0.000) | 0.58 | −0.002 | (0.006) | 0.79 | −0.000 | (0.000) | 0.69 | −0.000 | (0.000) | 0.92 |
| β-Cryptoxanthin, µg/d | −0.002 | (0.003) | 0.57 | +0.014 | (0.038) | 0.72 | −0.000 | (0.000) | 0.59 | −0.000 | (0.001) | 0.84 |
| Lutein+zeaxanthin, µg/d | −0.000 | (0.000) | 0.35 | +0.000 | (0.003) | 0.96 | +0.000 | (0.000) | 0.38 | +0.000 | (0.000) | 0.45 |
| Lycopene, µg/d | −0.000 | (0.000) | 0.18 | −0.000 | (0.001) | 0.95 | −0.000 | (0.000) | 0.016 | −0.000 | (0.000) | 0.45 |
| vitamin C, mg/d | +0.009 | (0.008) | 0.29 | +0.108 | (0.140) | 0.45 | −0.000 | (0.001) | 0.66 | −0.002 | (0.003) | 0.95 |
| vitamin E, mg/d | −0.125 | (0.107) | 0.26 | −0.291 | (2.063) | 0.89 | +0.026 | (0.010) | 0.029 | +0.003 | (0.06) | 0.95 |
| n-3 HUFA, g/d | +0.690 | (1.354) | 0.62 | +18.026 | (33.896) | 0.60 | −0.328 | (0.235) | 0.18 | −1.007 | (0.596) | 0.11 |
| Folate, µg/d | +0.017 | (0.002) | <0.001 | +0.080 | (0.050) | 0.13 | −0.002 | (0.000) | 0.002 | +0.001 | (0.001) | 0.20 |
| Vitamin B-12, µg/d | −0.025 | (0.049) | 0.61 | +0.502 | (1.400) | 0.73 | +0.003 | (0.013) | 0.79 | +0.126 | (0.027) | <0.001 |
| Dietary supplement use, past 30 d | ||||||||||||
| None | Ref | Ref | Ref | Ref | ||||||||
| One | +5.01 | (1.20) | 0.001 | +45.32 | (26.78) | 0.009 | −0.407 | (0.165) | 0.027 | +1.542 | (0.343) | <0.001 |
| Two or more | +11.98 | (1.42) | <0.001 | +90.42 | (30.34) | 0.25 | −0.792 | (0.159) | <0.001 | +2.666 | (0.446) | 0.22 |
| Fruits and vegetable intake, cup equivalent/d | +0.48 | (0.39) | 0.23 | −0.54 | (8.31) | 0.95 | +0.040 | (0.067) | 0.56 | 0.327 | (0.202) | 0.13 |
Abbreviations: 25(OH)D = 25-hydroxyvitamin D; n-3 HUFA = n-3 highly unsaturated fatty acids; NHANES = National Health and Nutrition Examination Survey; SEE = Standard error of the estimate; tHcy = Total homocysteine.