Table 1.
Baseline characteristics of the study population stratified above and below 2-yr mean PM2.5 concentrations in China between 2007 and 2010
| Characteristic | 2-Yr Mean PM2.5 | |
|---|---|---|
| ≤2-Yr Mean Concentration | >2-Yr Mean Concentration | |
| Number of participants (%) | 25,188 (53.36) | 22,016 (46.64) |
| CKD, n (%) | ||
| Yes | 3205 (12.72) | 3108 (14.12) |
| eGFR (mL/min per 1.73 m2), mean±SD | 101.04±26.69 | 101.40±28.28 |
| eGFR category, n (%) | ||
| ≥60 ml/min per 1.73 m2 | 24,563 (97.52) | 21,456 (97.46) |
| <60 ml/min per 1.73 m2 | 625 (2.48) | 560 (2.54) |
| uACR (mg/g), mean (range) | 6.67 (3.24–13.58) | 6.60 (2.91–13.77) |
| uACR category, n (%) | ||
| <30 mg/g | 22,430 (89.05) | 19,302 (87.67) |
| ≥30 mg/g | 2758 (10.95) | 2714 (12.33) |
| Age (yr), mean±SD | 49.71±15.54 | 49.47±14.83 |
| Sex, n (%) | ||
| Male | 10,445 (41.47) | 9703 (44.07) |
| Female | 14,743 (58.53) | 12,313 (55.93) |
| Education, n (%) | ||
| < High-school education | 14,372 (57.24) | 11,763 (53.53) |
| ≥ High-school education | 10,737 (42.76) | 10,213 (46.47) |
| Family income, n (%) | ||
| Low income | 6388 (36.02) | 5843 (26.57) |
| Middle income | 10,324 (58.21) | 12,860 (58.47) |
| High income | 1022 (5.77) | 3290 (14.96) |
| Region, n (%) | ||
| Urban | 13,629 (54.11) | 11,716 (53.22) |
| Rural | 11,559 (45.89) | 10,300 (46.78) |
| BMI (kg/m2), mean±SD | 23.86±3.66 | 23.91±3.72 |
| BMI category, n (%) | ||
| <25 kg/m2 | 17,048 (68.41) | 13,370 (60.73) |
| ≥25 kg/m2 | 7871 (31.59) | 8582 (38.98) |
| Smoking, n (%) | ||
| Noncurrent smokers | 19,748 (78.4) | 16,362 (74.32) |
| Current smokers | 5440 (21.6) | 5654 (25.68) |
| Alcohol consumption, n (%) | ||
| Never | 19,728 (78.32) | 16,046 (72.88) |
| One to three times a month to three to five times a week | 3641 (14.46) | 4235 (19.24) |
| Almost once a day | 1819 (7.22) | 1735 (7.88) |
| History of CVD, n (%) | ||
| Yes | 641 (2.90) | 579 (2.86) |
| Diabetes mellitus, n (%) | ||
| Yes | 1752 (6.96) | 1736 (7.89) |
| Hypertension, n (%) | ||
| Yes | 8364 (33.45) | 8240 (37.52) |
| Nephrotoxic medication, n (%) | ||
| Yes | 915 (3.63) | 621 (2.82) |
There are missing values for some of the variables (numbers that do not add up to the total because of missing values), and the percentage of each category was calculated excluding the missing data. uACR, urinary albumin creatinine ratio.