Table 1.
Baseline characteristics of the whole cohort, and according to thyroid function
| Characteristics | Total (N=2558) |
Euthyroidism (N=2163) |
SHypo (N=315) |
P-value a | SHyper with TSH
0.10–0.44mIU/L (N=58) |
P-value b | SHyper with TSH
<0.10mIU/L (N=22) |
P-value c |
|---|---|---|---|---|---|---|---|---|
|
| ||||||||
| Socio-demographics | ||||||||
|
| ||||||||
| Age, years | 75.1 (2.8) | 75.1 (2.9) | 75.3 (2.7) | 0.34 | 75.9 (3.0) | 0.04 | 75.8 (3.2) | 0.28 |
|
| ||||||||
| Women | 1326 (51.8) | 1095 (50.7) | 175 (55.6) | 0.10 | 42 (72.4) | 0.001 | 14 (63.6) | 0.23 |
|
| ||||||||
| Race, White | 1567 (61.3) | 1284 (59.4) | 236 (74.9) | <0.0001 | 34 (58.6) | 0.91 | 13 (59.1) | 0.98 |
|
| ||||||||
| Site, Memphis | 1286 (50.3) | 1082 (50.0) | 160 (50.8) | 0.80 | 31 (53.5) | 0.61 | 13 (59.1) | 0.40 |
|
| ||||||||
| Education level | 0.003 c | 0.48 c | 0.57 c | |||||
|
| ||||||||
| < High school graduate | 592 (23.2) | 523 (24.3) | 49 (15.6) | 13 (22.4) | 7 (31.8) | |||
| High school graduate | 833 (32.7) | 694 (32.2) | 111 (35.2) | 23 (39.7) | 5 (22.7) | |||
| College graduate | 1126 (44.1) | 939 (43.6) | 155 (49.2) | 22 (37.9) | 10 (45.5) | |||
|
| ||||||||
| REALM ≥60 (Y3) | 506 (20.9) | 433 (21.2) | 54 (17.8) | 12 (21.8) | 0.92 | 7 (33.3) | 0.18 | |
|
| ||||||||
| Smoking status | 0.20 c | 0.34 c | 0.08 c | |||||
|
| ||||||||
| Never | 1143 (44.7) | 956 (44.3) | 144 (45.7) | 28 (48.3) | 15 (68.2) | |||
| Former | 1179 (46.1) | 1000 (46.3) | 151 (47.9) | 8 (13.8) | 1 (4.6) | |||
| Current | 233 (9.1) | 204 (9.4) | 20 (6.4) | 22 (37.9) | 6 (27.3) | |||
|
| ||||||||
| Alcohol, drinks/week | 0.83 c | 0.11 c | 0.10 c | |||||
|
| ||||||||
| <1 | 1796 (70.4) | 1513 (70.1) | 215 (68.7) | 48 (82.8) | 20 (90.9) | |||
| 1–7 | 567 (22.2) | 483 (22.4) | 75 (24.0) | 8 (13.8) | 1 (4.6) | |||
| >7 | 187 (7.2) | 161 (7.5) | 23 (7.4) | 2 (3.5) | 1 (4.6) | |||
|
| ||||||||
| 3MS at Year 1 e | 90.6 (7.9) | 90.4 (8.1) | 91.7 (7.1) | 0.01 | 92.0 (6.8) | 0.15 | 91.0 (8.4) | 0.72 |
|
| ||||||||
| Depression at Year 1f | 113 (4.5) | 96 (4.5) | 13 (4.1) | 0.99 | 1 (1.7) | 0.42 | 1 (4.6) | 0.84 |
|
| ||||||||
| Physical activity, kcal/week | 0.02 c | 0.40 c | ||||||
|
| ||||||||
| <500 | 1293 (50.6) | 1112 (51.4) | 137 (43.5) | 33 (856.9) | 11 (50.0) | |||
| 500–<1500 | 714 (27.9) | 595 (27.5) | 95 (30.2) | 17 (29.3) | 7 (31.8) | |||
| ≥1500 | 551 (21.5) | 456 (21.1) | 83 (26.4) | 8 (13.8) | 4 (18.2) | |||
|
| ||||||||
| Hypertension | 1822 (71.2) | 1566 (72.4) | 199 (63.7) | 0.001 | 41 (70.7) | 0.77 | 16 (72.7) | 0.97 |
|
| ||||||||
| Diabetes mellitus | 468 (18.3) | 400 (18.5) | 48 (15.2) | 0.16 | 14 (24.1) | 0.28 | 6 (27.3) | 0.29 |
|
| ||||||||
| Body mass index, kg/m2 | 27.4 (4.8) | 27.5 (4.9) | 26.8 (4.5) | 0.02 | 26.6 (3.9) | 0.16 | 26.6 (4.1) | 0.39 |
|
| ||||||||
| Systolic blood pressure | 135.2 (20.7) | 135.7 (20.7) | 133.0 (20.6) | 0.04 | 132.3 (24.2) | 0.23 | 133.0 (20.6) | 0.54 |
|
| ||||||||
| Diastolic blood pressure | 71.1 (11.6) | 71.4 (11.8) | 69.7 (10.3) | 0.01 | 67.8 (12.1) | 0.02 | 71.7 (12.4) | 0.92 |
|
| ||||||||
| Lipoproteins | ||||||||
|
| ||||||||
| Total cholesterol, mmol/l | 5.3 (1.0) | 5.3 (1.0) | 5.5 (1.0) | 0.01 | 5.1 (0.9) | 0.22 | 4.6 (0.7) | 0.003 |
| HDL-cholesterol, mmol/l | 1.4 (0.4) | 1.4 (0.4) | 1.43 (0.4) | 0.03 | 1.5 (0.5) | 0.30 | 1.3 (0.3) | 0.33 |
| LDL-cholesterol, mmol/l | 3.1 (0.9) | 3.1 (0.9) | 3.2 (0.9) | 0.25 | 3.1 (0.8) | 0.60 | 2.8 (0.7) | 0.06 |
| Triglycerides, mmol/l | 1.6 (0.9) | 1.6 (0.9) | 1.7 (1.0) | 0.01 | 1.5 (0.8) | 0.74 | 1.6 (1.5) | 0.66 |
Abbreviations: FT4, free thyroxine; HDL, high-density lipoprotein; LDL, low-density lipoprotein; 3MS, Modified Mini-Mental State; N, number; REALM, Rapid Estimate of Adult Literacy in Medicine; SD, standard deviation; SHyper, subclinical hyperthyroidism; SHypo, subclinical hypothyroidism. There were seven participants with missing data for education level, 139 for REALM, three for smoking status, eight for alcohol consumption, 19 for depression, 119 for total cholesterol, 113 for LDL-cholesterol, and 82 for HDL-cholesterol. Values are mean (SD) or n (%). For some covariates, there were missing values that were excluded.
P-value for the difference between euthyroidism and SHypo.
P-value for the difference between euthyroidism and SHyper with mildly decreased TSH (0.10–0.44mIU/L).
P-value for the difference between euthyroidism and SHyper with suppressed TSH (<0.10mIU/L).
P-value over groups.
The 3MS ranges from 0 to a best score of 100 points.
Depression was defined as a score ≥16 on the 20-item Center for Epidemiologic Studies-Depression Scale (CES-D).