Table 2. Socio-demographic, lifestyle and dietary predictors of nutritional biomarkers (retinol, retinyl esters, vitamin C, vitamin E and total carotenoids): OLS multiple regression analyses; NHANES 2005–06 (n = 2,459).

	Retinol µmol/L			Retinyl esters µmol/L			Vitamin C µmol/L			Vitamin E µmol/L			Total carotenoids µmol/L
	β	(SEE)	P-value	β	(SEE)	P-value	β	(SEE)	P-value	β	(SEE)	P-value	β	(SEE)	P-value
Socio-demographic, lifestyle factors
Age (y)	+0.006	(0.001)	<0.001	+0.000	(0.000)	0.061	+0.115	(0.041)	0.014	+0.204	(0.011)	<0.001	+0.004	(0.001)	0.001
Female vs. male	−0.226	(0.046)	<0.001	−0.005	(0.004)	0.20	+7.674	(2.100)	0.002	+0.161	(0.506)	0.76	+0.153	(0.034)	<0.001
Race/ethnicity
Non-Hispanic White	Ref			Ref			Ref			Ref			Ref
Non-Hispanic black	−0.244	(0.036)	<0.001	+0.003	(0.004)	0.50	+2.617	(1.633)	0.13	−2.113	(0.510)	0.001	+0.176	(0.054)	0.005
Mexican-American	−0.168	(0.029)	<0.001	−0.003	(0.005)	0.57	+0.476	(2.276)	0.84	+1.251	(0.819)	0.147	+0.175	(0.061)	0.012
Other ethnicity	−0.186	(0.031)	<0.001	−0.011	(0.004)	0.013	+1.759	(2.814)	0.54	−0.610	(1.019)	0.558	+0.117	(0.061)	0.073
Married vs. non-married	−0.037	(0.030)	0.24	−0.001	(0.003)	0.77	+0.671	(1.345)	0.63	+1.520	(0.587)	0.020	+0.114	(0.037)	0.007
Education
<High School	Ref			Ref			Ref			Ref			Ref
High School	+0.032	(0.047)	0.50	+0.005	(0.008)	0.60	−2.029	(2.527)	0.44	−0.649	(0.995)	0.70	−0.020	(0.074)	0.79
>High School	+0.018	(0.059)	0.77	+0.011	(0.007)	0.15	−1.351	(2.631)	0.62	−0.362	(0.910)	0.52	−0.095	(0.083)	0.28
Poverty Income Ratio
<100%	Ref			Ref			Ref			Ref			Ref
100%-<200%	+0.027	(0.055)	0.63	+0.000	(0.005)	0.99	−1.170	(1.460)	0.44	−0.431	(0.968)	0.66	+0.006	(0.072)	0.69
≥200%	+0.013	(0.052)	0.81	−0.004	(0.005)	0.42	+1.490	(1.392)	0.30	+0.714	(0.966)	0.47	−0.021	(0.051)	0.69
Smoking status
Never smoker	Ref			Ref			Ref			Ref			Ref
Former smoker	+0.022	(0.019)	0.28	+0.002	(0.006)	0.78	−0.921	(1.948)	0.64	−0.928	(0.669)	0.19	−0.055	(0.064)	0.69
Current smoker	−0.020	(0.033)	0.56	−0.007	(0.004)	0.12	−9.414	(1.491)	<0.001	−0.877	(0.612)	0.17	−0.257	(0.052)	<0.001
Physical activity, Mets.hr.wk−1	+0.001	(0.001)	0.17	+0.000	(0.000)	0.90	+0.032	(0.032)	0.33	−0.015	(0.010)	0.14	+0.003	(0.001)	0.009
Body mass index, kg.m−2	−0.006	(0.002)	0.003	−0.001	(0.000)	0.001	−0.773	(0.064)	<0.001	+0.022	(0.024)	0.37	−0.028	(0.002)	<0.001
History of selected chronic conditions
Type 2 diabetes	+0.156	(0.042)	0.002	+0.006	(0.006)	0.38	−3.988	(1.930)	0.057	+1.494	(1.215)	0.24	−0.115	(0.064)	0.09
Cardiovascular disease	0.048	(0.111)	0.674	−0.016	(0.006)	0.024	−0.029	(2.627)	0.991	−3.311	(0.973)	0.004	−0.266	(0.056)	<0.001
Cancer	+0.124	(0.064)	0.071	+0.007	(0.008)	0.41	+2.501	(2.886)	0.400	+2.031	(0.714)	0.012	+0.040	(0.056)	0.48
Anti-depressant medication use	+0.127	(0.042)	0.009	−0.010	(0.005)	0.080	−1.074	(2.329)	0.65	+0.730	(1.079)	0.51	−0.099	(0.062)	0.13
Dietary Intakes
Total Energy Intake, kcal/d	+0.000	(0.000)	0.12	−0.000	(0.000)	0.10	−0.001	(0.064)	0.26	−0.000	(0.000)	0.10	−0.000	(0.000)	0.001
Alcohol intake, g/d	+0.003	(0.001)	0.001	+0.000	(0.000)	0.13	+0.045	(0.035)	0.22	+0.040	(0.012)	0.007	+0.001	(0.001)	0.19
Caffeine, mg/d	−0.000	(0.000)	0.30	−0.000	(0.000)	0.36	−0.004	(0.003)	0.26	−0.001	(0.001)	0.42	+0.000	(0.000)	0.46
Fiber, g/d	−0.005	(0.002)	0.032	+0.000	(0.000)	0.85	+0.269	(0.130)	0.06	−0.003	(0.049)	0.94	+0.007	(0.003)	0.022
α-carotene, µg/d	+0.000	(0.000)	0.62	+0.000	(0.000)	0.16	−0.001	(0.001)	0.52	−0.001	(0.001)	0.26	+0.000	(0.000)	0.07
β-carotene, µg/d	−0.000	(0.000)	0.37	+0.000	(0.000)	0.45	+0.000	(0.000)	0.45	+0.000	(0.000)	0.43	+0.000	(0.000)	0.013
β-Cryptoxanthin, µg/d	−0.000	(0.000)	0.80	−0.000	(0.000)	0.38	+0.000	(0.004)	0.94	−0.000	(0.002)	0.93	+0.000	(0.000)	0.12
Lutein+zeaxanthin, µg/d	+0.000	(0.000)	0.45	+0.000	(0.000)	0.77	−0.000	(0.000)	0.40	−0.000	(0.000)	0.65	+0.000	(0.000)	0.14
Lycopene, µg/d	+0.000	(0.000)	0.74	+0.000	(0.000)	0.009	−0.000	(0.011)	0.97	−0.000	(0.000)	0.36	+0.000	(0.000)	0.022
vitamin C, mg/d	+0.000	(0.000)	0.34	+0.000	(0.000)	0.60	+0.070	(0.011)	<0.001	+0.005	(0.004)	0.23	+0.000	(0.000)	0.50
vitamin E, mg/d	+0.002	(0.006)	0.68	+0.001	(0.001)	0.13	+0.014	(0.103)	0.89	+0.182	(0.053)	0.004	+0.002	(0.005)	0.67
n-3 HUFA, g/d	+0.024	(0.044)	0.59	−0.008	(0.007)	0.30	+1.684	(1.767)	0.36	+0.805	(1.159)	0.50	+0.221	(0.069)	0.006
Folate, µg/d	−0.000	(0.017)	0.98	+0.000	(0.000)	0.061	−0.004	(0.003)	0.25	+0.003	(0.002)	0.037	−0.000	(0.000)	0.95
Vitamin B-12, µg/d	+0.006	(0.004)	0.10	+0.010	(0.003)	0.032	+0.274	(0.122)	0.041	−0.016	(0.050)	0.75	−0.005	(0.004)	0.19
Dietary supplement use, past 30 d
None	Ref			Ref			Ref			Ref			Ref
One	+0.076	(0.037)	0.044	+0.010	(0.004)	0.032	+5.736	(1.347)	0.001	+2.803	(0.716)	0.001	+0.064	(0.035)	0.09
Two or more	+0.226	(0.030)	<0.001	+0.030	(0.003)	<0.001	+17.198	(1.480)	<0.001	+8.419	(0.778)	<0.001	+0.266	(0.036)	<0.001
Fruits and vegetable intake, cup equivalent/d	+0.000	(0.017)	0.98	−0.001	(0.002)	0.68	+0.661	(0.833)	0.44	−0.153	(0.252)	0.55	+0.033	(0.022)	0.16