Table 3 Demographic characteristics of patients with nonradiographic axial spondyloarthritis across geographic regions

Sex

0.609

 Male, n (%)

18 (54.55 %)

57 (64.77 %)

90 (64.29 %)

  95 % CI

(37.45–71.64)

(54.73–74.82)

(56.30–72.27)

 Female (%)

15 (45.45 %)

31 (35.23 %)

50 (35.71 %)

  95 % CI

(28.36–62.55)

(25.18–45.27)

(27.73–43.70)

Age, years mean ± SD

36.67 ± 10.73

36.02 ± 10.56

33.24 ± 9.26

0.035

BMI category

0.21

 Underweight, n (%)

1 (3.03 %)

4 (4.55 %)

7 (5.00 %)

  95 % CI

(0.00–8.92)

(0.17–8.93)

(1.37–8.63)

 Normal weight, n (%)

16 (48.48 %)

51 (57.95 %)

81 (57.86 %)

  95 % CI

(31.32–65.65)

(47.57–68.34)

(49.62–66.09)

 Overweight, n (%)

13 (39.39 %)

19 (21.59 %)

44 (31.43 %)

  95 % CI

(22.61–56.17)

(12.94–30.24)

(23.69–39.17)

 Obese, n (%)

2 (6.06 %)

14 (15.91 %)

7 (5.00 %)

  95 % CI

(0.00–14.25)

(8.22–23.6)

(1.37–8.63)

 Unknown, n (%)

1 (3.03 %)

0 (0.00 %)

1 (0.71 %)

  95 % CI

(0.00–8.92)

–

(0.00–2.12)

Years since CLBP presentation

0.462

 Number of patients

29

74

124

 Mean ± SD, years

8.02 ± 10.01

6.68 ± 9.33

5.67 ± 5.70

Age of IBP onset

0.115

 Number of patients

33

87

139

 Mean ± SD, years

28.4 ± 8.7

28.3 ± 6.5

27.1 ± 7.3