TABLE 1.
Baseline characteristics of the study participants stratified by region.
| Characteristics | Se-marginal region1 | Se-sufficient region | Se-rich region |
| N | 736 | 1,463 | 400 |
| Male, n (%) | 383 (52.0) | 779 (53.2) | 227 (56.8) |
| Age, years | |||
| <60 | 306 (41.6) | 587 (40.1) | 163 (40.8) |
| 60 to <70 | 178 (24.2) | 373 (25.5) | 113 (28.2) |
| ≥70 | 252 (34.2) | 503 (34.4) | 124 (31.0) |
| Body mass index, kg/m2 | |||
| <24 | 242 (32.9) | 550 (37.6)* | 202 (50.5) †† |
| 24 to <28 | 317 (43.1) | 648 (44.3) | 147 (36.8) |
| ≥28 | 177 (24.0) | 265 (18.1) | 51 (12.8) |
| Smoking status, n (%) | |||
| Never | 528 (71.7) | 1,006 (68.8)** | 286 (71.5) |
| Past | 42 (5.7) | 202 (13.8) | 27 (6.8) |
| Current | 166 (22.6) | 255 (17.4) | 87 (21.8) |
| Alcohol drinking status, n (%) | |||
| Never | 564 (76.6) | 1072 (73.3)* | 312 (78.0) † |
| Past | 32 (4.3) | 126 (8.6) | 33 (8.2) |
| Current | 140 (19.0) | 265 (18.1) | 55 (13.8) |
| SBP, mm Hg | 147.0 (135.0–156.1) | 139.3 (130.0–150.0) ** | 143.2 (133.0–153.3) † |
| DBP, mm Hg | 90.0 (80.7–97.0) | 85.7 (78.7–92.3) ** | 86.8 (81.3–92.3) † |
| Antihypertensive drug use, n (%) | 557 (75.7) | 1,102 (75.3) | 99 (24.8) †† |
| Multivitamin use, n (%) | 52 (7.1) | 148 (10.1) * | 9 (2.2) †† |
| History of hypertension, n (%) | 592 (80.4) | 1423 (97.3) ** | 352 (88.0) † |
| Meat consumption frequency, n (%) | |||
| <1 time/week | 183 (24.9) | 326 (22.3)** | 84 (21.0) †† |
| 1–2 times/week | 273 (37.1) | 596 (40.7) | 94 (23.5) |
| 3–5 or more times/week | 280 (38.0) | 541 (37.0) | 222 (55.5) |
| Fruits and vegetables consumption, n (%) | |||
| <0.5 kg/week | 183 (24.9) | 326 (22.3) | 84 (21.0) †† |
| 0.5–1.5 kg/week | 273 (37.1) | 596 (40.7) | 94 (23.5) |
| >1.5 kg/week | 280 (38.0) | 541 (37.0) | 222 (55.5) |
| Se, μg/L | 69.3 ± 20.7 | 74.0 ± 19.3 ** | 85.1 ± 18.5 †† |
For continuous variables, the values are presented as median interquartile range (IQR) or mean ± SD.
1Se-marginal areas in China include four provinces (Gansu, Heilongjiang, Liaoning, and Shandong), Se-sufficient areas in China include eight provinces (Anhui, Beijing, Hebei, Jiangsu, Ningxia, Shanxi, Sichuan, and Yunnan), and Se-rich areas in China include two provinces (Guangxi and Hunan).
2Plasma Se concentrations were adjusted for sex, age, BMI, SBP, DBP, history of hypertension, antihypertensive drug use, multivitamin use, smoking, alcohol drinking, meat consumption, and consumption of fruits and vegetables.
*p < 0.05, **p < 0.001; the values significantly differed among the participants from Se-marginal and Se-sufficient areas in China.
†p < 0.05, ††p < 0.001; the values significantly differed among the participants from Se-marginal and Se-rich areas in China.