Table 1.
Comparison of characteristics between cases and controls (matched for age, duration of follow-up and smoking habits) at baseline, 1 year prior to event and at the time of event in study A (de novo occurrence of TPO-Ab) and in study B (development of overt hypothyroidism)
| Study A: development of TPO-Ab, 81 cases and 162 controls |
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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| baseline |
1 year before event |
at event |
p value |
|||||||||||||||
| cases | controls | cases | controls | cases | controls | baseline | 1 year before event | at event | ||||||||||
| TSH, mU/1 | 1.5 (1.2–2.2) | 1.5 (1.1–1.9) | 1.4 (1.1–2.2) | 1.4 (1.0–1.9) | 1.5 (1.1–2.2) | 1.4 (1.0–2.0) | 0.88 | 0.69 | 0.44 | |||||||||
| fT4, pmol/1 | 13.1 (11.6–14.5) | 13.4 (12.0–14.9) | 13.0 (11.7–14.4) | 13.6 (12.1–14.8) | 13.1 (11.9–14.5) | 13.3 (12.0–14.3) | 0.94 | 0.71 | 0.27 | |||||||||
| TPO-Ab, kU/1 | <25 (<25–<25) | <25 (<25–<25) | <25 (<25–50) | <25 (<25–50) | 140 (110–160) | <25 (<25–50) | 0.48 | 0.45 | <0.001 | |||||||||
| Tg-Ab, kU/1 | 15 (<10–25) | <10 (<10–15) | 18 (<10–35) | <10 (<10–14) | 17 (<10–43) | <10 (<10–20) | 0.19 | 0.01 | 0.01 | |||||||||
| Current smokers | 38% | 38% | 31% | 30% | 31% | 31% | NS | NS | NS | |||||||||
| Alcohol consumers* | 14.5% | 13.4% | 14.1% | 15.1% | 11.3% | 13.7% | 0.82 | 0.84 | 0.60 | |||||||||
| Study B: development of overt hypothyroidism, 38 cases and 76 controls |
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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| baseline |
1 year before event |
at event |
p value |
|||||||||||||||
| cases | controls | cases | controls | cases | controls | baseline | 1 year before event | at event | ||||||||||
| TSH, mU/1 | 4.2 (2.7–5.7) | 1.5 (1.1–2.5) | 4.0 (2.6–6.1) | 1.5 (0.9–2.4) | 14.8 (6.3–16.9) | 1.5 (1.0–2.4) | 0.06 | 0.03 | 0.005 | |||||||||
| fT4, pmol/1 | 10.7 (9.7–11.6) | 13.0 (11.3–15.1) | 10.6 (9.5–12.0) | 13.4 (11.9–14.3) | 7.1 (4.8–8.4) | 13.0 (11.5–14.5) | 0.38 | 0.17 | 0.02 | |||||||||
| TPO-Ab, kU/1 | 1,123 (304–2,239) | <25 (<25–150) | 1,076 (666–2,326) | 50 (<25–320) | 3,000 (1,620–6,670) | <25 (<25–180) | 0.004 | 0.008 | <0.001 | |||||||||
| Tg-Ab, kU/1 | 75 (40–238) | 15 (<5–40) | 123 (42–235) | 15 (<10–40) | 140 (100–500) | 10 (<10–50) | 0.03 | 0.02 | 0.001 | |||||||||
| Current smokers | 18% | 18% | 18% | 18% | 13% | 13% | NS | NS | NS | |||||||||
| Alcohol consumers* | 8.3% | 14.5% | 5.3% | 19.7% | 6.7% | 23.7% | 0.36 | 0.04 | 0.04 | |||||||||
*
>10 units/week. Data given as median (interquartile range).