Table 1 General information and basic data of the two groups
|  | CN group (n = 334) | Control group (n = 52) | χ2(t/Z) value | P value |
|---|---|---|---|---|
Gender (n, %) | ||||
 Male | 86 (25.7%) | 12 (23.1%) | χ2 = 0.170 | 0.681 |
 Female | 248 (74.3%) | 40 (76.9%) | ||
Age (ss, years) | 44.0 ± 11.7 | 46.6 ± 13.0 | t = − 1.48 | 0.139 |
Thyroid size ( \( \overline{x}\pm s \),, cm)* | 4.5 ± 0.9 | 4.7 ± 1.1 | Z = − 1.064 | 0.287 |
Tumor size (n, %) | ||||
 T > 4 cm | 7 (2.1%) | 4 (7.7%) | χ2 = 5.746 | 0.125 |
 2 cm < T ≤ 4 cm | 62 (18.6%) | 11 (21.2%) | ||
 1 cm < T ≤ 2 cm | 131 (39.2%) | 20 (38.5%) | ||
 T ≤ 1 cm | 134 (40.1%) | 17 (32.7%) | ||
Range of CND (n, %) | ||||
 Bilateral CND | 115 (34.4%) | 19 (36.5%) | χ2 = 0.071 | 0.789 |
 Unilateral CND | 217 (65.0%) | 33 (63.5%) | ||
 Without CND | 2 (0.6%) | 0 (0%) | ||
Comorbidity (n, %) | ||||
 No | 241 (72.2%) | 38 (73.1%) | χ2 = 0.019 | 0.890 |
 Yes | 93 (27.8%) | 14 (26.9%) | ||
Accompanied by thyroiditis or hyperthyroidism (n, %) | ||||
 No | 256 (76.6%) | 39 (75%) | χ2 = 0.068 | 0.795 |
 Yes | 78 (23.4%) | 13 (25%) | ||
Preoperative PTH (\( \overline{x}\pm s \), pg/mL) | 46.6 ± 18.1 | 46.3 ± 16.9 | Z = − 0.12 | 0.905 |
Preoperative serum calcium (\( \overline{x}\pm s \),, mmol/L) | 2.24 ± 0.12 | 2.23 ± 0.12 | t = 0.038 | 0.969 |