| CMN group (n = 29) | SN group (n = 30) | t/χ2/Z | P value |
---|---|---|---|---|
Age (y), mean ± SD | 26.38 ± 4.72 | 27.50 ± 4.56 |  − 0.927 | 0.358 |
Years of work (y) | 3.67 ± 3.03 | 2.97 ± 2.16 | 1.028 | 0.309 |
Sex | / | / | / | / |
 Male, n (%) | 3 (10.34%) | 6 (20.00%) | 1.063 | 0.302 |
 Female (n, %) | 26 (89.66%) | 24 (80.00%) |  |  |