Table 2 Associations for the number of anti-carbamylated protein antibody isotypes or IgG subclasses with risk factors and baseline characteristics

Smoking (ever), n (%)

54 (42.9)

48 (43.6)

35 (48.6)

23 (60.5)

1.38 (0.94-2.03)

0.099

SE positivity, n (%)

79 (60.3)

74 (63.2)

57 (75.0)

33 (86.8)

1.91 (1.27-2.87)

0.002*

ESR (mm/h), mean ± SD

41.0 ± 25.6

40.2 ± 25.1

43.5 ± 27.7

47.8 ± 26.8

1.01 (1.00-1.01)

0.206

CRP (mg/L), mean ± SD

29.0 ± 32.2

32.3 ± 36.4

29.9 ± 30.3

50.8 ± 47.0

1.01 (1.00-1.01)

0.017 ^‡

Number of IgG subclasses

0 (n = 150)

1 (n = 104)

2 (n = 57)

3 (n = 44)

4 (n = 18)

Ordinal OR (95% CI)

p

Smoking (ever), n (%)

58 (41.1)

42 (42.4)

30 (58.8)

27 (65.9)

3 (20.0)

1.47 (1.00-2.16)

0.051^‡

SE positivity, n (%)

89 (60.5)

65 (64.4)

46 (80.7)

31 (75.6)

13 (76.5)

1.79 (1.19-2.69)

0.005*

ESR (mm/h), mean ± SD

37.9 ± 23.2

37.7 ± 24.3

50.4 ± 31.1

52.3 ± 28.5

48.8 ± 21.6

1.01 (1.01-1.02)

<0.001*

CRP (mg/L), mean ± SD

30.5 ± 32.9

28.1 ± 33.9

30.5 ± 34.8

45.4 ± 41.5

50.2 ± 42.9

1.01 (1.00-1.01)

0.020