Table 1.
Comparison of Cohort Characteristics
| BLSA, n = 1294 | Phenotyping, n = 640 | p-Valuea | |
|---|---|---|---|
| Male | 52.9% | 53.9% | NS |
| White | 67.9% | 65.2% | <0.05 |
| Baseline age (years) | 64.1 | 66.3 | <0.01 |
| Baseline TSH (mIU/L) | 2.6 | 2.6 | NS |
| Baseline fT4 (ng/dL) | 0.97 | 0.97 | NS |
| Baseline fT3 (pg/mL) | 3.08 | 3.01 | <0.05 |
| Education (high school grad) | 99.2% | 99.4% | NS |
| Smoking (within 10 years) | 5.2% | 5.4% | NS |
| Walking index | 8.4 | 8.4 | NS |
| Self-rated health (SF-12) | 1.9 | 1.9 | NS |
| Later levothyroxine useb | 5.0% | 3.8% | NS |
| Body mass index | 27.1 | 26.9 | NS |
| Active cohort | 75% | 82% | <0.01 |
| Deceased | 13% | 10% | |
| Lost to follow-up | 12% | 8% |
a
p-Values are derived using the chi-square test for categorical variables or two-sided t-test for continuous variables between included and excluded participants.
b
Participants can initiate thyroid hormone during observation; visits were censored once on therapy.
BLSA, Baltimore Longitudinal Study of Aging; TSH, thyrotropin; fT4, free thyroxine; fT3, free triiodothyronine; NS, not significant.