Table 1.
Characteristics of the eligible participants in the Sodium and Potassium Study from PURE-China Cohort.
| Characteristics | % (n) | |||
|---|---|---|---|---|
| Total (n = 41,475) | Heavy-salt regions1 (n = 16,882) | Moderate-salt regions1 (n = 12,851) | Low-salt regions1 (n = 11,742) | |
| Female sex | 59.2 (24,546) | 60.1 (10,153) | 56.8 (7,295) | 60.5 (7,098) |
| Age at recruitment (years, mean ± STD) | 51.4 ± 9.4 | 52.3 ± 8.9 | 50.9 ± 9.6 | 50.5 ± 9.8 |
| Education level | ||||
| Less than high school graduate | 33.7 (13,973) | 28.9 (4,870) | 39.7 (5,104) | 34.1 (3,999) |
| High school graduate | 57.3 (23,765) | 64.7 (10,916) | 53.2 (6,840) | 51.2 (6,009) |
| Some college or more | 8.7 (3,608) | 6.2 (1,040) | 6.8 (868) | 14.5 (1,700) |
| Missing values | 0.3 (129) | 0.3 (56) | 0.3 (39) | 0.3 (34) |
| Body mass index (BMI, kg/m2, mean ± STD) | 24.6 ± 4.0 | 24.8 ± 4.0 | 24.6 ± 3.8 | 24.5 ± 4.0 |
| <25 | 54.8 (22,723) | 53.6 (9,054) | 56.0 (7,190) | 55.2 (6,479) |
| 25-29.9 | 35.4 (14,677) | 36.2 (6,108) | 35.32 (4,542) | 34.3 (4,027) |
| ≥ 30 | 7.1 (2,955) | 7.8 (1,310) | 6.4 (821) | 7.0 (824) |
| Missing values | 2.7 (1,120) | 2.4 (410) | 2.3 (298) | 3.5 (412) |
| Waist-to-hip ratio (WHR, mean ± STD) | 0.86 ± 0.07 | 0.86 ± 0.07 | 0.86 ± 0.06 | 0.86 ± 0.08 |
| > 0.9 for men or > 0.85 for women | 42.5 (17,605) | 41.8 (7,049) | 44.2 (5,685) | 41.5 (4,871) |
| Sodium excretion2 (g/day, mean ± STD) | 5.7 ± 1.7 | 5.5 ± 1.6 | 6.1 ± 1.8 | 5.3 ± 1.6 |
| <3 | 3.5 (1,447) | 3.8 (648) | 1.9 (243) | 4.7 (556) |
| 3-5 | 34.3 (14,211) | 36.0 (6,082) | 25.7 (3,299) | 41.1 (4,830) |
| > 5 | 62.3 (25,817) | 60.1 (10,152) | 72.4 (9,309) | 54.1 (6,356) |
| Potassium excretion2 (g/day, mean ± STD) | 2.1 ± 0.5 | 2.1 ± 0.5 | 2.1 ± 0.5 | 2.1 ± 0.5 |
| <1.9 | 36.5 (15,148) | 37.7 (6,356) | 34.8 (4,473) | 36.8 (4,319) |
| 1.9-2.5 | 44.9 (18,625) | 45.5 (7,675) | 45.0 (5,778) | 44.1 (5,172) |
| > 2.5 | 18.6 (7,702) | 16.9 (2,851) | 20.2 (2,600) | 19.2 (2,251) |
| Ratio for sodium vs. potassium2 (mean ± STD) | 2.8 ± 0.8 | 2.7 ± 0.7 | 3.0 ± 0.8 | 2.6 ± 0.7 |
| <2.0 | 15.1 (6,244) | 15.8 (2,660) | 10.2 (1,314) | 19.3 (2,270) |
| 2.0-3.0 | 51.7 (21,453) | 52.6 (8,880) | 46.8 (6,011) | 55.9 (6,562) |
| > 3.0 | 33.2 (13,778) | 31.6 (5,342) | 43.0 (5,526) | 24.8 (2,910) |
| Creatinine excretion3 (g/day, mean ± STD) | 1.2 ± 0.3 | 1.2 ± 0.3 | 1.3 ± 0.3 | 1.2 ± 0.3 |
| Systolic blood pressure (mmHg, mean ± STD) | 133.5 ± 22.0 | 132.3 ± 21.6 | 137.0 ± 22.5 | 131.2 ± 21.7 |
| <120 | 28.6 (11,856) | 30.2 (5,097) | 22.3 (2,864) | 33.2 (3,895) |
| 120-139 | 38.0 (15,764) | 38.2 (6,449) | 38.8 (4,981) | 36.9 (4,334) |
| ≥ 140 | 33.4 (13,855) | 31.6 (5,336) | 39.0 (5,006) | 29.9 (3,513) |
| Diastolic blood pressure (mmHg, mean ± STD) | 82.8 ± 12.3 | 82.3 ± 11.9 | 84.1 ± 12.7 | 82.2 ± 12.2 |
| <60 | 1.3 (552) | 1.3 (222) | 1.4 (177) | 1.3 (153) |
| 60-89 | 72.7 (30,148) | 74.4 (12,556) | 68.7 (8,828) | 74.6 (8,764) |
| ≥ 90 | 26.0 (10,775) | 24.3 (4,104) | 35.7 (3,846) | 24.1 (2,825) |
| Self-reported hypertension or had blood pressure medication or blood pressure ≥ 140/90 mmHg | ||||
| No | 56.8 (23,555) | 57.2 (9,664) | 52.6 (6,759) | 60.7 (7,132) |
| Yes | 43.2 (17,920) | 42.8 (7,218) | 47.4 (6,092) | 39.3 (4,610) |
| Self-reported diabetes or fasting glucose >7.0 mmol/L | ||||
| No | 90.8 (37,661) | 89.6 (15,124) | 92.3 (11,862) | 90.9 (10,675) |
| Yes | 9.2 (3,814) | 10.4 (1,758) | 7.7 (989) | 9.1 (1,067) |
| Self-reported stroke | ||||
| No | 97.9 (40,596) | 97.7 (16,488) | 98.1 (12,604) | 98.0 (11,504) |
| Yes | 1.9 (785) | 2.1 (362) | 1.6 (200) | 1.9 (223) |
| Missing values | 0.2 (94) | 0.2 (32) | 0.4 (47) | 0.1 (15) |
| Self-reported angina, heart attack or coronary artery diseases | ||||
| No | 93.7 (38,855) | 94.6 (15,968) | 92.7 (11,915) | 93.4 (10,972) |
| Yes | 6.3 (2620) | 5.4 (914) | 7.3 (936) | 6.6 (770) |
| Tobacco use | ||||
| Never | 72.3 (30,003) | 69.3 (11,702) | 77.4 (9,944) | 71.2 (8,357) |
| Former | 4.7 (1,964) | 4.4 (748) | 3.6 (468) | 6.4 (748) |
| Current | 21.8 (9,060) | 24.6 (4,153) | 18.4 (2,359) | 21.7 (2,548) |
| Missing values | 1.1 (448) | 1.7 (279) | 0.6 (80) | 0.8 (89) |
| Alcohol consumption | ||||
| Never | 75.4 (31,290) | 73.3 (12,376) | 81.4 (10,454) | 72.0 (8,460) |
| Former | 3.2 (1,329) | 2.6 (433) | 2.2 (285) | 5.2 (611) |
| Current | 20.8 (8,620) | 23.1 (3,902) | 16.2 (2,081) | 22.5 (2,637) |
| Missing values | 0.6 (236) | 1.0 (171) | 0.2 (31) | 0.3 (34) |
| Levels of physical activities | ||||
| Low | 12.2 (5,049) | 12.1 (2,036) | 13.7 (1,763) | 10.7 (1,250) |
| Medium | 41.7 (17,311) | 43.8 (7,398) | 43.9 (5,646) | 36.3 (4,267) |
| High | 41.6 (17,250) | 40.8 (6,886) | 37.2 (4,779) | 47.6 (5,585) |
| Missing values | 4.5 (1,865) | 3.3 (562) | 5.2 (663) | 5.5 (640) |
| Total cholesterol (mmol/L, mean ± STD) | 4.7 ± 1.0 | 4.7 ± 1.0 | 4.6 ± 1.0 | 4.8 ± 1.1 |
| ≥6.47 | 4.0 (1,642) | 3.4 (576) | 3.4 (442) | 5.3 (624) |
| Triglycerides (mmol/L, mean ± STD) | 1.6 ± 1.2 | 1.5 ± 1.2 | 1.6 ± 1.2 | 1.6 ± 1.1 |
| ≥4.50 | 2.4 (1,013) | 2.5 (423) | 2.6 (328) | 2.2 (262) |
| LDL cholesterol (mmol/L, mean ± STD) | 2.6 ± 0.8 | 2.6 ± 0.8 | 2.6 ± 0.8 | 2.6 ± 0.9 |
| >4.14 | 2.9 (1,199) | 2.5 (427) | 2.8 (362) | 3.5 (410) |
| HDL cholesterol (mmol/L, mean ± STD) | 1.4 ± 0.4 | 1.4 ± 0.4 | 1.3 ± 0.3 | 1.4 ± 0.4 |
| <0.91 | 8.8 (3,640) | 9.2 (1,552) | 10.3 (1,323) | 6.5 (765) |
| Fasting glucose (mmol/L, mean ± STD) | 5.6 ± 1.6 | 5.8 ± 1.5 | 5.1 ± 1.7 | 5.7 ± 1.4 |
| >7.00 | 7.6 (3,157) | 8.7 (1,467) | 6.1 (787) | 7.7 (903) |
Note: STD, standard deviance; LDL, low-density lipoprotein; HDL, high-density lipoprotein;
1Per National Diet Salt Intake in 200228, PURE-China centers were classified three salt-diet regions: heavy-salt regions (>8 grams of daily salt intake) included Beijing, Jiangsu Province, Jiangxi Province, and Liaoning Province; moderate-salt regions (7 to 8 grams) included Qinghai Province, Shaanxi Province, and Shandong Province; low-salt regions (<7 grams) included Inner Mongolia, Sichuan Province, and Yunnan Province, Shanxi Province, and Xinjiang Province.
2Estimated excretion was calculated by a fasting morning urine specimen on the basis of the Kawasaki formula18;
3Creatinine excretions were determined according to a formula including age, sex, weight, and height, which also was used in Kawasaki formula to estimate sodium and potassium excretion.