Table 1.
Distribution of Baseline Characteristics and Cardiovascular Risk Factors According to Baseline Thyroid Function Status Among 3663 Postmenopausal Women From the Women's Health Initiative Observational Study
| Characteristics | Subclinical Hypothyroidism |
P Valuea | |||
|---|---|---|---|---|---|
| Euthyroid (n = 3381) | Any SCH (n = 282) | Mild SCH (n = 193) | Mod/Sev SCH (n = 89) | ||
| Thyroid measures | |||||
| Median TSH, mU/L (IQR) | 1.91 (1.31–2.69) | 5.85 (5.12–7.70) | 5.38 (4.95–5.90) | 9.14 (7.79–12.70) | |
| Median fT4, ng/dL (IQR) | — | 0.98 (0.88–1.10) | 1.02 (0.92–1.13) | 0.92 (0.81–1.00) | |
| TPOAb present, n (%) | — | 133 (47.2) | 71 (36.8) | 62 (69.3) | |
| Age at baseline, y | |||||
| 50–64 | 1107 (32.8) | 66 (23.4) | 40 (20.7) | 26 (29.2) | <.001 |
| 65–70 | 999 (29.5) | 78 (27.7) | 55 (28.5) | 23 (25.8) | |
| 71–79 | 1275 (37.7) | 138 (48.9) | 98 (50.8) | 40 (44.9) | |
| Race or ethnic group | |||||
| White | 2828 (83.8) | 264 (94.0) | 182 (94.8) | 82 (92.1) | <.001 |
| Black | 286 (8.5) | 6 (2.1) | 5 (2.6) | 1 (1.1) | |
| Hispanic | 90 (2.7) | 8 (2.8) | 3 (1.6) | 5 (5.6) | |
| Asian or Pacific Islander | 123 (3.7) | 1 (0.4) | 0 (0.0) | 1 (1.1) | |
| American Indian | 21 (0.6) | 0 (0.0) | 0 (0.0) | 0 (0.0) | |
| Unknown | 24 (0.7) | 2 (0.7) | 2 (1.0) | 0 (0.0) | |
| Smoking | |||||
| None | 1714 (51.5) | 143 (51.6) | 102 (53.7) | 41 (47.1) | .93 |
| Prior | 1408 (42.4) | 119 (43.0) | 81 (42.6) | 38 (43.7) | |
| Current | 202 (6.1) | 15 (5.4) | 7 (3.7) | 8 (9.2) | |
| Diabetes | |||||
| No | 3150 (93.8) | 265 (94.6) | 179 (93.7) | 86 (96.6) | .70 |
| Yes | 207 (6.2) | 15 (5.4) | 12 (6.3) | 3 (3.4) | |
| Waist to hip ratio | |||||
| ≤0.80 | 1581 (47.0) | 142 (50.5) | 101 (52.6) | 41 (46.1) | .35 |
| >0.80–0.85 | 856 (25.5) | 61 (21.7) | 40 (20.8) | 21 (23.6) | |
| >0.85 | 924 (27.5) | 78 (27.8) | 51 (26.6) | 27 (30.3) | |
| Body mass index, kg/m2 | .73 | ||||
| <25.00 | 1345 (40.2) | 106 (37.9) | 73 (37.8) | 33 (37.9) | |
| 25.00 to < 30.00 | 1194 (35.7) | 103 (36.8) | 72 (37.3) | 31 (35.6) | |
| ≥30 | 806 (24.1) | 71 (25.3) | 48 (24.9) | 23 (26.4) | |
| Hormone therapy use | |||||
| Never | 1532 (45.4) | 126 (44.7) | 83 (43.0) | 43 (48.3) | .95 |
| Past | 580 (17.2) | 50 (17.7) | 38 (19.7) | 12 (13.5) | |
| Current | 1264 (37.4) | 106 (37.6) | 72 (37.3) | 34 (38.2) | |
| Years from menopause, y | |||||
| 0–15 | 966 (31.6) | 59 (22.2) | 39 (21.2) | 20 (24.4) | .002 |
| 16–23 | 1087 (35.5) | 99 (37.2) | 69 (37.5) | 30 (36.6) | |
| 24–26 | 1005 (32.9) | 108 (40.6) | 76 (41.3) | 32 (39.0) | |
| Hypertension | |||||
| Never | 1670 (49.6) | 142 (50.4) | 90 (46.6) | 52 (57.8) | .89 |
| Past or controlled | 698 (20.8) | 55 (19.5) | 42 (21.8) | 13 (14.4) | |
| Current | 995 (29.6) | 85 (30.1) | 61 (31.6) | 25 (27.8) | |
| Antihyperlipidemic useb | |||||
| No | 2672 (96.6) | 233 (98.3) | 155 (98.7) | 78 (97.5) | .18 |
| Yes | 95 (3.4) | 4 (1.7) | 2 (1.3) | 2 (2.5) | |
Abbreviations: IQR, interquartile range; Mod/Sev, moderate/severe. Mild is TSH 4.7 to 6.99 mU/L; moderate or severe is TSH 7.00 mU/L or greater; —, data not collected.
Comparison of euthyroid with all with subclinical hypothyroidism using a t test with unequal variance for continuous variables and Fisher's exact test for categorical variables.
Antihyperlipidemic medication use is defined by the WHI-OS as use of bile sequestrants, fibric acid derivatives, intestinal cholesterol absorption inhibitors, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, nicotinic acid derivatives, or combinations. Information at baseline was missing for 614 observations and 45 observations for participants with normal thyroid and with any subclinical hypothyroidism, respectively.