Table 1. Selected Characteristics of the Study Population.
| Characteristic | Participants, No. (%) |
|---|---|
| Total | 18 805 (100) |
| Age at study entry, y | |
| <30 | 1733 (9.2) |
| 30-39 | 3055 (16.2) |
| 40-49 | 4816 (25.6) |
| ≥50 | 9201 (48.9) |
| Sex | |
| Male | 4134 (22.0) |
| Female | 14 671 (78.0) |
| Hyperthyroidism diagnosis | |
| Graves disease | 17 615 (93.7) |
| Toxic nodular goiter | 934 (5.0) |
| Unknown | 256 (1.4) |
| Treatment combination | |
| RAI only | 7182 (38.2) |
| RAI and surgical procedure | 694 (3.7) |
| RAI and drugs | 8675 (46.1) |
| RAI, surgical procedure, and drugs | 2254 (12.0) |
| Vital status | |
| Alive or lost to follow-up | 3321 (17.7) |
| Deceased | 15 484 (82.3) |
| Study site | |
| Mount Sinai Hospital (New York, NY) | 3042 (16.2) |
| Mayo Clinic (Rochester, MN) | 1907 (10.1) |
| Massachusetts General (Boston, MA) | 1726 (9.2) |
| Sheffield Hospital (Sheffield, UK) | 1378 (7.3) |
| Columbia Presbyterian Hospital (New York, NY) | 1190 (6.3) |
| Cedars Sinai Medical Center (Los Angeles, CA) | 1093 (5.8) |
| Los Angeles County Hospitals (Los Angeles, CA) | 1065 (5.7) |
| University of Michigan (Ann Arbor, MI) | 978 (5.2) |
| University of Maryland (Baltimore, MD) | 899 (4.8) |
| University of California (San Francisco, CA) | 747 (4.0) |
| Beth Israel Hospital (Boston, MA) | 678 (3.6) |
| University Hospitals of Cleveland (Cleveland, OH) | 630 (3.4) |
| New York Hospital-Cornell (New York, NY) | 612 (3.3) |
| Lahey Clinic (Boston, MA) | 589 (3.1) |
| Montefiore Med Center (New York, NY) | 560 (3.0) |
| White Memorial Hospital (Los Angeles, CA) | 518 (2.8) |
| University of Cincinnati (Cincinnati, OH) | 492 (2.6) |
| Memorial Sloan-Kettering (New York, NY) | 283 (1.5) |
| Cleveland Metropolitan General Hospital (Cleveland, OH) | 198 (1.1) |
| Strong Memorial Hospital (Rochester, NY) | 125 (0.7) |
| St Louis University (St Louis, MO) | 52 (0.3) |
| Ochsner Clinic (New Orleans, LA) | 43 (0.2) |
Abbreviation: RAI, radioactive iodine.