Table 1.
Baseline characteristics of patients. Values are numbers (percentages) unless stated otherwise
| Characteristics | Thyroid hormone treatment | Total (n=5405) | P value* | |
|---|---|---|---|---|
| Yes (n=843) | No (n=4562) | |||
| Age: | 0.08 | |||
| Mean (SD) | 31.7 (4.7) | 31.3 (5.2) | 31.4 (5.1) | |
| Median (IQR) | 32 (29.0-35.0) | 31 (28.0-35.0) | 31 (28.0-35.0) | |
| Age group, years: | 0.01 | |||
| 18-24 | 49 (5.8) | 432 (9.5) | 481 (8.9) | |
| 25-34 | 571 (67.7) | 2944 (64.5) | 3515 (65.0) | |
| 35-44 | 220 (26.1) | 1163 (25.5) | 1383 (25.6) | |
| 45-54 | 3 (0.4) | 23 (0.5) | 26 (0.5) | |
| TSH concentration, mIU/L: | <0.01 | |||
| Mean (SD) | 4.8 (1.7) | 3.3 (0.9) | 3.5 (1.2) | |
| Median (IQR) | 4.6 (3.4-5.7) | 3.1 (2.7-3.6) | 3.2 (2.8-3.9) | |
| TSH concentration group, mIU/L: | <0.01 | |||
| 2.5- 4.0 | 330 (39.1) | 3865 (84.7) | 4195 (77.6) | |
| 4.1-10.0 | 513 (60.9) | 697 (15.3) | 1210 (22.4) | |
| Ethnicity: | <0.01 | |||
| White | 465 (55.2) | 2686 (58.9) | 3151 (58.3) | |
| Black | 49 (5.8) | 344 (7.5) | 393 (7.3) | |
| Hispanic | 100 (11.9) | 747 (16.4) | 847 (15.7) | |
| Asian | 188 (22.3) | 614 (13.5) | 802 (14.8) | |
| Unknown | 41 (4.9) | 171 (3.7) | 212 (3.9) | |
| Charlson index: | 0.77 | |||
| 0 | 744 (88.3) | 4001 (87.7) | 4745 (87.8) | |
| 1 | 79 (9.4) | 461 (10.1) | 540 (10.0) | |
| ≥2 | 20 (2.4) | 100 (2.2) | 120 (2.2) | |
| Household income: | 0.02 | |||
| <$40 000 | 90 (10.7) | 506 (11.1) | 596 (11.0) | |
| $40 000-$49 999 | 41 (4.9) | 295 (6.5) | 336 (6.2) | |
| $50 000-$59 999 | 63 (7.5) | 290 (6.4) | 353 (6.5) | |
| $60 000-$74 999 | 77 (9.1) | 503 (11.0) | 580 (10.7) | |
| $75 000-$69 999 | 139 (16.5) | 776 (17.0) | 915 (16.9) | |
| ≥$100 000 | 309 (36.7) | 1686 (37.0) | 1995 (36.9) | |
| Unknown | 124 (14.7) | 506 (11.1) | 630 (11.7) | |
| Region: | <0.01 | |||
| Midwest | 64 (7.6) | 416 (9.1) | 480 (8.9) | |
| Northeast | 215 (25.5) | 873 (19.1) | 1088 (20.1) | |
| South | 369 (43.8) | 2404 (52.7) | 2773 (51.3) | |
| West | 195 (23.1) | 869 (19.0) | 1064 (19.7) | |
| Obesity | 52 (6.2) | 224 (4.9) | 276 (5.1) | 0.13 |
| Diabetes mellitus | 24 (2.8) | 127 (2.8) | 151 (2.8) | 0.92 |
| Hypertension | 22 (2.6) | 221 (4.8) | 243 (4.5) | <0.01 |
| History of recurrent pregnancy loss | 23 (2.7) | 49 (1.1) | 72 (1.3) | <0.01 |
| History of thyroid disease | 52 (6.2) | 153 (3.4) | 205 (3.8) | <0.01 |
IQR=interquartile range; TSH=thyroid stimulating hormone.
*χ2 test; t test for continuous variables (age, TSH concentration).