Table 2.
Free thyroxine (FT4), thyrotropin (TSH) and frequency of thyroid diseases (number (%)) are presented for patients operated with gastric bypass (GBP), vertical banded gastroplasty (VBG), obese non-operated controls (OB-C) and controls from a random population based sample, WHO MONICA project, Gothenburg (MON-C). P values from a cross-sectional comparison for baseline and 10 years follow-up are presented. Laboratory methods changed during follow-up, making longitudinal comparison impossible. Means (SD) are given
| Analysis at baseline All methods used converted to Kodak Amerlite. Reference Range FT4 11.7–28.0 pmol/L, TSH 0.1–3.0 mUI/L | ||||||||||
| GBP | VBG | OB-C | MON-C | Test between groups, p value | ||||||
| GBP VBG | GBP OB-C | GBP MNC-C | VBG OB-C | VBG MNC-C | OB-C MNC-C | |||||
| FT4 (pmol/L) | 15.1 (4.1) n = 187 |
16.1 (3.6) n = 188 |
15.6 (3.9) n = 187 |
16.5 (3.5) n = 122 |
0.0032 | ns | <0.001 | ns | ns | 0.004 |
| TSH (mUI/L) | 1.23 (0.84) n = 185 |
1.79 (1.31) n = 188 |
1.83 (2.20) n = 187 |
2.18 (1.38) n = 122 |
<0.001 | <0.001 | <0.001 | ns | <0.001 | <0.001 |
| Overt hyperthyroidism | 0 | 0 | 1 (0.5) | 0 | ns | ns | ns | ns | ns | ns |
| Subclinical hyperthyroidism | 4 (2.1) | 3 (1.6) | 0 | 0 | ns | ns | ns | ns | ns | ns |
| Overt hypothyroidism | 2 (1.1) | 3 (1.6) | 6 (3.2) | 0 | ns | ns | ns | ns | ns | ns |
| Subclinical hypothyroidism | 6 (3.2) | 18 (9.6) | 15 (8.0) | 0 | 0.019 | 0.070§ | ns | ns | ns | ns |
| Analysis at 10 years All methods used converted to Abbott Architect. Reference Range FT4 9–22 pmol/L, TSH 0.2–4.0 mUI/L | ||||||||||
| GBP | VBG | OB-C | MNC-C | Test between groups, p-value | ||||||
| GBP VBG | GBP OB-C | GBP MNC-C | VBG OB-C | VBG MNC-C | OB-C MNC-C | |||||
| FT4 (pmol/L) | 15.3 (2.2) n = 136 |
15.9 (2.8) n = 152 |
15.5 (2.4) n = 135 |
16.6 (3.6) n = 118 |
0.083§ | ns | <0.001 | ns | 0.039 | 0.003 |
| TSH (mUI/L) | 2.29 (1.65) n = 136 |
2.03 (1.47) n = 151 |
2.48 (1.29) n = 135 |
2.44 (1.89) n = 118 |
ns | 0.020 | ns | <0.001 | 0.006 | ns |
| Overt hyperthyroidism | 0 | 4 (2.1) | 0 | 3 (1.6) | ns | ns | ns | ns | ns | ns |
| Subclinical hyperthyroidism | 1 (0.5) | 1 (0.5) | 1 (0.5) | 4 (2.2) | ns | ns | ns | ns | ns | ns |
| Overt hypothyroidism | 4 (2.1) | 0 | 0 | 1 (0.5) | ns | ns | ns | ns | ns | ns |
| Subclinical hypothyroidism | 9 (4.8) | 12 (6.4) | 13 (6.9) | 8 (4.3) | ns | ns | ns | ns | ns | ns |
Overt hyperthyroidism: TSH below the normal range and FT4 above the normal range; subclinical hyperthyroidism: TSH below the normal range and normal FT4; overt hypothyroidism: TSH above the normal range and FT4 below the normal range; subclinical hypothyroidism: TSH above the normal range and normal FT4
ns non-significant (p ≥ 0.10)
§Marginally significant (0.05 < p < 0.10)