The Association Between Psoriasis and Trace Element Serum Levels and Dietary Intake: Results from USA National Health and Nutrition Examination Survey 2011–2014

Figures & data

Table 1 Demographic Data of the Populations

Variable	Psoriasis (n=221)	Non-Psoriasis (n=9010)	P value
Age (years)a	42.7±1.1	37.8±0.4	0.0002***
BMI (kg/m²)a	29.6±0.7	28.6±0.2	0.1353
Waist circumference (cm)	100.4±1.6	97.0±0.4	0.0439*
Gender, n (%)			0.6585
Male	104 (47.06)	4396 (48.79)
Female	117 (52.94)	4614 (51.21)
Marital status, n (%)			0.7290
Married	97 (43.89)	3736 (41.47)
Never married	50 (22.62)	2061 (22.87)
Others	63 (28.51)	1912 (21.22)
Race, n (%)			<0.0001*
Mexico American	12 (5.43)	1251 (13.88)
Other Hispanic	21 (9.50)	868 (9.63)
Non-Hispanic White	120 (54.30)	3129 (34.73)
Non-Hispanic Black	27 (12.22)	2166 (24.04)
Non-Hispanic Asian	41 (18.55)	1596 (17.71)
Birth country, n (%)			<0.0001*
Born in 50 US states or Washington, DC	176 (79.64)	6342 (70.39)
Others	45 (20.36)	2662 (29.54)
Education level, n (%)			0.0328*
Less than 9th grade	11 (4.98)	520 (5.77)
9–11th grade	33 (14.93)	1882 (20.89)
High school graduate	46 (20.81)	2071 (22.99)
Some college or AA degree	64 (28.96)	2473 (27.45)
College graduate or above	67 (30.32)	2060 (22.86)
Had at least 12 alcohol drinks/1 year, n (%)			0.6762
Yes	139 (62.90)	5256 (58.34)
No	43 (19.46)	1911 (21.21)
Smoke, n (%)			<0.0001***
Every day	43 (19.46)	1515 (16.81)
Some days	4 (1.81)	363 (4.03)
Not at all	50 (22.62)	1272 (14.12)
BMI grade (kg/m²), n (%)			0.0633
Underweight (<18)	1 (0.45)	137 (1.52)
Normal weight (18.0–24.9)	52 (23.53)	3005 (33.35)
Overweight (25.0–29.9)	70 (31.67)	2538 (28.17)
Obesity (≥ 30.0)	79 (35.75)	2952 (32.76)
Family income ($), n (%)			0.2842
0–19,999	51 (23.08)	2162 (24.00)
20,000–34,999	48 (21.72)	1914 (21.24)
35,000–74,999	50 (22.62)	2238 (24.84)
≥ 75,000	64 (28.96)	2259 (25.07)

Notes: a, Mean±SE is used for continuous variables, and the P values are weighted; *P<0.05; ***P<0.001.

Abbreviations: n, number; BMI, body mass index; $, United States dollar.

Table 2 Comparison of Serum Concentrations and Dietary Intake Levels of Trace Elements Between Psoriasis and Non-Psoriasis Populations

Variables	Psoriasis (n=221)	Non-Psoriasis (n=9010)	P value
Serum level
Se (μg/L)	131.0±3.0	129.8±0.8	0.6722
Cu (μg/dL)	115.9±3.7	117.9±1.1	0.5947
Zn (μg/dL)	81.7±2.6	82.8±0.6	0.6541
Cu/Zn	1.5±0.1	1.5±0.0	0.9697
Dietary intake
Se (mcg/day)	103.4±6.3	120.6±1.1	0.0107*
Cu (mg/day)	1.3±0.1	1.3±0.0	0.7736
Zn (mg/day)	10.5±0.7	11.7±0.1	0.0787

Note: *P<0.05.

Abbreviation: n, number.

Table 3 Weighted Risk of Psoriasis by Dietary Intake and Serum Levels of Trace Elements

Parameters	OR (95% CI) of Psoriasis			P
Serum Se (μg/L)	<120	120–140	>140
Overall	1.00	0.903 (0.524–1.556)	1.211 (0.668–2.195)	0.595
Men	1.00	0.929 (0.398–2.168)	0.908 (0.356–2.312)	0.977
Women	1.00	0.900 (0.441–1.838)	1.727 (0.796–3.746)	0.215
Normal weight	1.00	0.898 (0.429–1.882)	1.144 (0.508–2.577)	0.830
Overweight	1.00	0.900 (0.403–2.012)	1.326 (0.552–3.183)	0.651
Serum Cu (μg/dL)	<100	100–130	>130
Overall	1.00	0.911 (0.521–1.592)	1.158 (0.648–2.069)	0.693
Men	1.00	0.733 (0.359–1.498)	0.000 (0.000-)#	0.696
Women	1.00	1.470 (0.482–4.482)	1.987 (0.682–5.794)	0.374
Normal weight	1.00	1.400 (0.669–2.928)	1.358 (0.582–3.170)	0.644
Overweight	1.00	0.357 (0.149–0.859)	0.577 (0.256–1.301)	0.070
Serum Zn (μg/dL)	<75	75–90	>90
Overall	1.00	1.101 (0.648–1.872)	0.883 (0.478–1.631)	0.759
Men	1.00	0.992 (0.420–2.346)	0.883 (0.355–2.196)	0.953
Women	1.00	1.223 (0.622–2.404)	0.952 (0.402–2.250)	0.779
Normal weight	1.00	1.330 (0.623–2.837)	1.177 (0.506–2.738)	0.762
Overweight	1.00	0.969 (0.455–2.066)	0.667 (0.265–1.678)	0.660
Dietary intake of Se (mcg/day)	<75	75–150	>150
Overall	1.00	0.789 (0.565–1.102)	0.695 (0.464–1.042)	0.179
Men	1.00	0.567 (0.333–0.967)	0.480 (0.268–0.858)	0.034*
Women	1.00	0.966 (0.629–1.484)	1.049 (0.577–1.905)	0.958
Normal weight	1.00	0.663 (0.411–1.070)	0.819 (0.485–1.385)	0.240
Overweight	1.00	0.937 (0.585–1.499)	0.587 (0.306–1.126)	0.240
Dietary intake of Cu (mg/day)	<1	1–2	>2
Overall	1.00	1.294 (0.951–1.759)	0.998 (0.599–1.663)	0.214
Men	1.00	1.346 (0.828–2.186)	0.872 (0.416–1.828)	0.301
Women	1.00	1.309 (0.873–1.963)	1.344 (0.652–2.770)	0.388
Normal weight	1.00	1.505 (0.974–2.325)	0.974 (0.464–2.046)	0.134
Overweight	1.00	1.162 (0.749–1.803)	1.101 (0.543–2.234)	0.797
Dietary intake of Zn (mg/day)	<10	10–20	>20
Overall	1.00	0.973 (0.721–1.313)	0.618 (0.338–1.129)	0.290
Men	1.00	0.830 (0.527–1.309)	0.582 (0.280–1.210)	0.327
Women	1.00	1.153 (0.769–1.728)	0.717 (0.223–2.308)	0.637
Normal weight	1.00	0.877 (0.573–1.341)	0.730 (0.345–1.546)	0.652
Overweight	1.00	1.124 (0.734–1.721)	0.527 (0.188–1.477)	0.352

Notes: ^#not enough data; *P<0.05.

Abbreviations: OR, odds ratio; CI, Confidence interval.