Table 1.
Comparison of basic characteristics between individuals with different thyroid nodules status (N = 4,920,536).
| Characteristics | With thyroid nodules a | Without thyroid nodules a | P-value |
|---|---|---|---|
| N | 1,869,742 (38.00) | 3,050,794 (62.00) | – |
| Male | 803,102 (42.95) | 1,795,807 (58.86) | <0.0001 |
| Age (yrs) | 48 (37, 57) | 37 (30, 48) | <0.0001 |
| City scale | <0.0001 | ||
| Big city | 869,747 (46.52) | 1,502,032 (49.23) | |
| Small-medium city | 981,922 (52.52) | 1,509,690 (49.49) | |
| County | 18,073 (0.97) | 39,072 (1.28) | |
| History of hypertension b | 196,437 (12.44) | 156,471 (6.07) | <0.0001 |
| Treatment of hypertension b | 159,529 (10.10) | 112,694 (4.37) | <0.0001 |
| Systolic pressure (mmHg) c | 124 (112, 139) | 120 (110, 131) | <0.0001 |
| Diastolic pressure (mmHg) c | 76 (68, 84) | 74 (66, 82) | <0.0001 |
| History of diabetes b | 68,497 (4.34) | 50,958 (1.98) | <0.0001 |
| Treatment of diabetes b | 51,693 (3.27) | 35,571 (1.38) | <0.0001 |
| Fasting plasma glucose (mmol/L) | <0.0001 | ||
| ≤6.1 | 1,639,756 (87.70) | 2,825,449 (92.61) | |
| 6.1–7.0 | 111,583 (5.97) | 115,824 (3.80) | |
| ≥7.0 | 118,403 (6.33) | 109,521 (3.59) | |
| Body mass index (kg/m2) | <0.0001 | ||
| <24 | 860,069 (46.00) | 1,607,737 (52.70) | |
| 24.0–27.9 | 720,084 (38.51) | 1,043,207 (34.19) | |
| ≥28.0 | 289,589 (15.49) | 399,850 (13.11) | |
| History of dyslipidemia b | 25,201 (1.60) | 30,095 (1.17) | <0.0001 |
| Triglyceride (mmol/L) | <0.0001 | ||
| <1.7 | 1,305,479 (69.82) | 2,173,381 (71.24) | |
| ≥1.7 | 564,263 (30.18) | 877,413 (28.76) | |
| High-density lipoprotein (mmol/L) | <0.0001 | ||
| <1.03 | 238,922 (12.78) | 428,941 (14.06) | |
| 1.03–1.56 | 1,138,778 (60.91) | 1,886,320 (61.83) | |
| ≥1.56 | 492,042 (26.32) | 735,533 (24.11) | |
| Low Density lipoprotein (mmol/L) | <0.0001 | ||
| <2.59 | 824,510 (44.10) | 1,486,716 (48.73) | |
| 2.59–3.35 | 637,041 (34.07) | 1,007,338 (33.02) | |
| 3.36–4.13 | 299,364 (16.01) | 416,176 (13.64) | |
| 4.14–4.90 | 84,893 (4.54) | 109,003 (3.57) | |
| ≥4.91 | 23,934 (1.28) | 31,561 (1.03) | |
| Total cholesterol (mmol/L) c | 4.86 (4.25, 5.54) | 4.70 (4.12, 5.36) | <0.0001 |
| Thyroglobulin antibodies (+) d | 8,867 (14.35) | 8,436 (18.16) | <0.0001 |
| Anti-thyroid peroxidase antibody (+) d | 6,497 (17.78) | 5,834 (20.97) | <0.0001 |
| Total triiodothyronine (umol/l) d | 1.5 (1.3, 1.8) | 1.5 (1.3, 1.8) | <0.0001 |
| Total tetraiodothyronine (umol/l) d | 92.9 (75.7, 109.3) | 91.2 (74.7, 107.3) | <0.0001 |
| Thyroid Stimulating Hormone (mIU/L) d | 1.8 (1.1, 2.9) | 1.8 (1.1, 2.8) | <0.0001 |
| PM2.5 (ug/m3) | 52.4 (40.7, 66.6) | 50.1 (39.5, 62.2) | <0.0001 |
| PM10 (ug/m3) | 88.4 (69.2, 113.8) | 86.2 (65.0, 99.7) | <0.0001 |
| NO2 (ug/m3) | 41.7 (31.6, 45.7) | 41.7 (31.4, 46.4) | <0.0001 |
| SO2 (ug/m3) | 19.0 (13.7, 29.3) | 15.9 (13.1, 24.7) | <0.0001 |
| CO (mg/m3) | 0.98 (0.85, 1.27) | 0.97 (0.83, 1.24) | <0.0001 |
| O3 (ug/m3) | 58.8 (53.7, 66.5) | 57.9 (53.5, 63.1) | <0.0001 |
| Gross Domestic Product (GDP, thousand Yuan) | 81.24 (58.59, 115.05) | 80.14 (61.21, 116.56) | <0.0001 |
| Urine iodine (ug/L) | 64.2 (49.8, 100.9) | 72.1 (49.8 100.9) | <0.0001 |
Measures of medians and quartile for continuous variables were calculated and expressed as Median (Q25, Q75). Categorical variables were summarized using the frequencies of the levels of the variables and corresponding proportions, and presented as n (%).
There were 761,801 (15.5%) missing values for medical history, including history of hypertension, diabetes and dyslipidemia, as well as treatment of hypertension and diabetes.
There were 7,304 (0.1%), 7,445 (0.2%), 232 (0.005%) missing values for systolic pressure, diastolic pressure, and total cholesterol, respectively.
There were 4,812,304 (97.8%), 4,856,181 (98.7%), 3,949,760 (80.3%), 3,998,135 (81.3%), 3,688,224 (75.0%) missing values for thyroglobulin antibodies, anti-thyroid peroxidase antibody, total triiodothyronine (T3), total tetraiodothyronine (T4), and thyroid stimulating hormone (TSH), respectively.