Table 1 Summary of individual characteristics for the 3081 participants across long-term PM2.5 exposure tertiles
|  | All Study Participants | PM2·5 (μg/m3) Tertiles | P-value | ||
|---|---|---|---|---|---|
T1 (< 38.2041) | T2 (38.2041-51.6069) | T3 (> 51.6069) | |||
No. Individuals | 3081 | 1026 | 1026 | 1029 | Â |
No. Clusters | 37 | 26 | 35 | 32 | Â |
No. Eventsa | 1060 | 307 | 300 | 453 | Â |
Age \(\left(\overline{\mathrm{x}},\mathrm{sd}\right)\) | 49.55 (11.57) | 50.11 (11.72) | 49.56 (11.54) | 48.99 (11.43) | 0.090 |
Female (%) | 1589 (51.6) | 556 (54.2) | 517 (50.4) | 516 (50.1) | 0.121 |
Low SES (%) | 1045 (33.9) | 323 (31.5) | 344 (33.5) | 378 (36.7) | 0.079 |
Ever Smoker (%) | 517 (16.8) | 144 (14.0) | 188 (18.3) | 185 (18.0) | 0.049 |
Low Physical Activity (%) | 772 (25.1) | 267 (26.0) | 270 (26.3) | 235 (22.8) | 0.373 |
Poor diet (%) | 296 (9.6) | 109 (10.6) | 89 (8.7) | 98 (9.5) | 0.320 |
BMI | Â | Â | Â | Â | 0.399 |
 Overweightb (%) | 1223 (40.7) | 425 (42.2) | 387 (38.8) | 411 (41.0) |  |
 Obesityc (%) | 774 (25.7) | 260 (25.8) | 270 (27.1) | 244 (24.3) |  |
History of heart disease in the family (%) | 162(5.3) | 52(5.1) | 45(4.4) | 65(6.3) | 0.138 |
Hypertensiond (%) | 771(25.0) | 266(25.9) | 238(23.2) | 267(25.9) | 0.254 |
Diabetes (%) | 233(7.6) | 80(7.8) | 84(8.3) | 69(6.8) | 0.422 |
Cholesterol (\(\overline{\mathrm{x}},\mathrm{sd}\)) | 217.85(50.22) | 215.80(48.71) | 221.63(49.11) | 216.16(52.56) | 0.014 |
Triglycerides (\(\overline{\mathrm{x}},\mathrm{sd}\)) | 203.82(124.14) | 204.53(127.50) | 202.15(128.60) | 204.76(116.11) | 0.872 |
Normal LDL to HDL ratio (%) | 2710(97.6) | 901(97.8) | 904(97.1) | 905(97.7) | 0.425 |
Urban (%) | 2429(78.8) | 983(95.8) | 825(80.4) | 621(60.3) | < 0.001 |