Table 2.
Relationship between thyroid hormone levels and insulin resistance.
| Thyroid hormone | Total (N = 1560) | Univariate | Multivariate |
|---|---|---|---|
| Coefficient (95% CI) | Coefficient (95% CI) | ||
| Thyroid stimulating hormone (TSH) (mIU/L) | 2.01 ± 0.08 | ||
| Normal (0.24–5.4 mIU/L) | 1506 (97.0) | Reference | Reference |
| Low (<0.24 mIU/L) | 16 (0.8) | −0.632 (−1.291, 0.027) | −0.564 (−1.288, 0.161) |
| High (>5.4 mIU/L) | 38 (2.2) | 0.228 (−0.606, 1.061) | 0.204 (−0.418, 0.827) |
| Total triiodothyronine (TT3) (ng/dL) | 115.69 ± 1.01 | ||
| Normal (87–178 ng/dL) | 1445 (93.0) | Reference | Reference |
| Low (<87 ng/dL) | 97 (6.1) | −0.747 (−1.199, −0.294) | −0.486 (−0.936, −0.036) |
| High (>178 ng/dL) | 18 (0.9) | 0.661 (−0.321, 1.643) | 0.586 (−0.211, 1.382) |
| Free triiodothyronine (FT3) (pg/mL) | 3.27 ± 0.02 | ||
| Normal (2.5–3.9 pg/mL) | 1470 (94.3) | Reference | Reference |
| Low (<2.5 pg/mL) | 15 (0.7) | −0.647 (−1.493, 0.198) | −1.151 (−1.952, −0.35) |
| High (>3.9 pg/mL) | 75 (5.0) | 0.206 (−0.088, 0.501) | −0.092 (−0.449, 0.265) |
| Total thyroxine (TT4) (ug/dL) | 7.69 ± 0.06 | ||
| Normal (6.1–12.2 ug/dL) | 1372 (86.6) | Reference | Reference |
| Low (<6.1 ug/dL) | 174 (12.7) | −0.141 (−0.553, 0.270) | −0.054 (−0.347, 0.240) |
| High (>12.2 ug/dL) | 14 (0.7) | 0.056 (−0.693, 0.806) | −0.214 (−0.632, 0.203) |
| Free thyroxine (FT4) (ng/dL) | 0.78 ± 0.01 | ||
| Normal (0.6–1.6 ng/dL) | 1532 (97.9) | Reference | Reference |
| Low (<0.6 ng/dL) | 25 (2.0) | 1.925 (0.233, 3.617) | 1.372 (−0.282, 3.025) |
| High (>1.6 ng/dL) | 3 (0.1) | −0.606 (−1.389, 0.178) | −1.857 (−4.102, 0.387) |
| Thyroglobulin (ng/mL) | 15.49 ± 0.95 | ||
| Normal (0–35.0 ng/mL) | 1446 (93.5) | Reference | Reference |
| High (>35.0 ng/mL) | 114 (6.5) | 0.715 (−0.062, 1.492) | 0.523 (−0.373, 1.418) |
| Thyroid peroxidase antibodies (IU/mL) | 16.62 ± 1.85 | ||
| Normal (0–9.0 IU/mL) | 1422 (90.3) | Reference | Reference |
| High (>9.0 IU/mL) | 138 (9.7) | −0.022 (−0.472, 0.429) | 0.008 (−0.266, 0.282) |
CI, confidence interval.
Bold indicates significant factor, p < 0.05.
Thyroid hormone levels were shown mean ± standard error; thyroid hormone group numbers were shown unweighted counts (weighted %).
Multivariate model: Adjusted for thyroid hormones, race, liver function, depression, obesity, hypertension, dyslipidemia, smoking, physical activity, vigorous recreational activity, moderate recreational activity, 2-hour glucose, glycohemoglobin, high-density lipoprotein, triglyceride, vitamin D, and C-reactive protein.