Table 1 Baseline characteristics of study participants by body mass index category and metabolic health status (n = 4,121,049)
Characteristics | Overall | Underweight (n = 110,084) | Normal Weight (n = 1,706,932) | Overweight (n = 1,377,896) | Metabolically healthy and Obese (n = 466,571) | Metabolically Unhealthya and Obese (n = 459,566) |
|---|---|---|---|---|---|---|
Age median (IQR) | 44.2 (30.4–60.6) | 29.5 (26.7–56.1) | 37.4 (26.7–56.1) | 48.7 (34.8–63.4) | 39.15 (29.7–50.1) | 58.4 (48.3–67.9) |
Sex n (%) | ||||||
 Males | 1,777,177 (43.1) | 27,134 (24.5) | 627,873 (36.8) | 720,650 (52.3) | 179,916 (38.6) | 221,604 (48.2) |
 Females | 2,343,872 (56.9) | 82,950 (75.5) | 1,079,059 (63.2) | 657,246 (47.7) | 286,655 (61.4) | 237,962 (51.8) |
Townsend index n (%) | ||||||
 1 | 957,722 (23.2) | 19,355 (17.6) | 399,720 (23.4) | 345,073 (25.0) | 94,968(20.4) | 98,606 (21.5) |
 2 | 868,163 (21.1) | 19,187 (17.4) | 351,685 (20.6) | 306,703 (22.3) | 93,059 (19.9) | 97,529 (21.2) |
 3 | 894,788 (21.7) | 23,498 (21.3) | 367,703 (21.6) | 297,443 (21.6) | 104,192(22.3) | 101,952 (22.2) |
 4 | 824,753 (20.0) | 27,044 (24.6) | 347,132 (20.3) | 255,910 (18.6) | 100,596(21.6) | 94,071 (20.5) |
 5 | 575,623 (14.0) | 21,000 (19.1) | 240,692 (14.1) | 172,767 (12.5) | 73,756 (15.8) | 67,408 (14.7) |
 Missing data | 560,566 | 16,834 | 245,888 | 178,864 | 62,445 | 56,535 |
Smoking status n (%) | ||||||
 Never smoker | 2,310,052 (56.0) | 62,861 (57.1) | 989,362 (58.0) | 755,361 (54.8) | 262,833 (56.3) | 239,635 (52.1) |
 Ex-smoker | 875,978 (21.3) | 12,920 (11.7) | 290,992(17.0) | 333,223(24.2) | 94,049 (20.2) | 144,794 (31.5) |
 Current smoker | 935,019 (22.7) | 34,303 (31.2) | 426,578 (25.0) | 289,312 (21.0) | 109,689 (23.5) | 75,137 (16.3) |
 Missing data | 61,503 | 2640 | 24,862 | 18,869 | 10,042 | 5090 |
Hypothyroidism n (%) | 165,477 (4.0) | 3290 (3.0) | 50,141 (2.9) | 56,102 (4.1) | 17,206 (3.7) | 38,738 (8.4) |
BMI (kg/m2) median (IQR) | 25.7 (22.7–29.4) | 17.6 (16.9–18.1) | 22.4 (20.9–23.7) | 27.1 (26–28.4) | 33 (31.2–36.1) | 33.4 (31.4–36.6) |