Table 1 General and clinical characteristics according to the quartiles of serum ferritin

Variables

Quartile 1 (≤ 66.82)

Quartile 2 (66.83–100.78)

Quartile 3 (100.79–149.13)

Quartile 4 (> 149.13)

P for trend

N

1111

1110

1111

1110

Age (year)

43.87 (0.512)

42.10 (0.486)

42.34 (0.459)

42.31 (0.443)

0.025

SBP (mm Hg)

119.58 (0.503)

119.15 (0.553)

119.26 (0.545)

120.95 (0.522)

0.083

DBP (mm Hg)

78.96 (0.411)

79.41 (0.422)

79.65 (0.392)

81.58 (0.400)

< 0.001

WC (cm)

82.29 (0.311)

83.97 (0.376)

84.11 (0.338)

86.05 (0.377)

< 0.001

BMI (kg/m²)

23.56 (0.106)

24.14 (0.132)

24.20 (0.116)

24.82 (0.141)

< 0.001

FBS (mg/dL)

95.48 (0.613)

96.63 (0.673)

98.33 (0.893)

101.28 (0.878)

< 0.001

TC (mg/dL)

184.81 (1.204)

188.77 (1.180)

191.67 (1.301)

193.25 (1.396)

< 0.001

Triglyceride (mg/dL)

130.68 (3.151)

143.87 (3.559)

155.31 (4.443)

182.03 (6.145)

< 0.001

AST (IU/L)

21.08 (0.245)

21.89 (0.228)

23.00 (0.292)

24.38 (0.305)

< 0.001

ALT (IU/L)

20.72 (0.371)

23.47 (0.433)

24.78 (0.441)

28.70 (0.548)

< 0.001

Hb (g/dL)

15.23 (0.039)

15.45 (0.036)

15.49 (0.033)

15.60 (0.041)

< 0.001

TIBC (μg/dL)

320.41 (1.401)

309.24 (1.316)

306.42 (1.266)

302.56 (1.539)

< 0.001

Cr (mg/dL)

0.95 (0.004)

0.96 (0.005)

0.96 (0.004)

0.96 (0.004)

0.011

WBC (10³/uL)

6.20 (0.050)

6.29 (0.054)

6.31 (0.050)

6.43 (0.051)

0.001

VitD (ng/mL)

18.36 (0.249)

18.35 (0.243)

18.45 (0.243)

18.13 (0.234)

0.540

Variables

Quartile 1 (≤ 66.82)

Quartile 2 (66.83–100.78)

Quartile 3 (100.79–149.13)

Quartile 4 (> 149.13)

p-value

 Quit smoker or non-smoker

681 (58.7)

635 (52.5)

586 (46.9)

605 (50.7)

< 0.001

 Current smoker

430 (41.3)

473 (47.5)

524 (53.1)

504 (49.3)

 Less than once a month

445 (37.1)

339 (29.5)

307 (28.3)

258 (20.6)

< 0.001

 More than twice a month

664 (62.9)

764 (70.5)

797 (71.7)

845 (79.4)

 Hypertension (−)

770 (74.8)

760 (73.7)

779 (73.0)

723 (68.5)

0.029

 Hypertension (+)

341 (25.2)

350 (26.3)

332 (27.0)

387 (31.5)