Table 2.
Summary of percent change estimates (95%CI) for included studies of association between PM2.5 exposure (per 10 μg/m3 increase) and HRV indicators
| Subgroup | SDNN | rMSSD | HF | LF | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No. | Percent Change (95%CI) | I2 (%) | P | No. | Percent Change (95%CI) | I2 (%) | P | No. | Percent Change (95%CI) | I2 (%) | P | No. | Percent Change (95%CI) | I2 (%) | P | |
| Total | 29 | − 0.92 (− 1.26, − 0.59) | 85.1 | < 0.001 | 27 | − 1.47 (− 2.17, − 0.77) | 79.3 | < 0.001 | 24 | − 2.17 (− 3.24, − 1.10) | 88.9 | < 0.001 | 16 | − 1.52 (− 2.50, − 0.54) | 72.4 | < 0.001 |
| Study location | ||||||||||||||||
| North American | 15 | − 0.62 (− 1.05, − 0.19) | 82.0 | < 0.001 | 13 | − 1.64 (− 2.89, − 0.38) | 79.8 | < 0.001 | 10 | − 1.18 (− 3.22, 0.86) | 77.4 | < 0.001 | 6 | − 1.39 (− 2.99, 0.20) | 54.2 | 0.053 |
| Europe | 4 | − 0.85 (− 2.39, 0.70) | 75.3 | 0.007 | 5 | − 0.90 (− 2.47, 0.67) | 80.9 | < 0.001 | 2 | NA | − | − | 0 | NA | NA | NA |
| Asia | 10 | − 1.38 (− 2.13, − 0.62) | 87.2 | < 0.001 | 9 | − 1.58 (− 2.43, − 0.73) | 62.2 | < 0.001 | 12 | − 2.54 (− 3.91, − 1.17) | 91.8 | < 0.001 | 10 | − 1.63 (− 2.9, − 0.32) | 78.7 | < 0.001 |
| PM2.5 assessment | ||||||||||||||||
| Individual monitor | 14 | − 0.98 (− 1.40, − 0.55) | 91.3 | < 0.001 | 10 | − 1.54 (− 2.55, 0.53) | 84.1 | < 0.001 | 11 | − 3.84 (− 5.03, − 1.92) | 93.0 | < 0.001 | 6 | − 1.30 (− 2.79, 0.20) | 84.1 | < 0.001 |
| Fixed site or others | 15 | − 0.94 (− 1.56, − 0.32) | 56.7 | 0.004 | 17 | − 1.36 (− 2.30, − 0.42) | 68.7 | < 0.001 | 13 | − 0.73 (− 2.14, 0.67) | 68.9 | < 0.001 | 10 | − 1.75 (− 3.14, − 0.37) | 54.7 | 0.019 |
| Health status | ||||||||||||||||
| Healthy population | 13 | − 0.67 (− 1.02, − 0.32) | 84.7 | < 0.001 | 10 | − 2.18 (− 3.39, − 0.97) | 71.7 | < 0.001 | 11 | − 3.40 (− 4.97, − 1.83) | 93.8 | < 0.001 | 8 | − 1.91 (− 3.25, − 0.57) | 80.6 | < 0.001 |
| Patients | 16 | − 1.19 (− 2.04, − 0.34) | 84.1 | < 0.001 | 17 | − 1.08 (− 1.85, − 0.31) | 74.3 | < 0.001 | 13 | − 0.90 (− 2.34, 0.54) | 71.4 | < 0.001 | 8 | − 1.03 (− 2.73, 0.68) | 61.2 | < 0.001 |
| Age | ||||||||||||||||
| <40 years | 6 | − 0.87 (− 1.77, 0.03) | 80.0 | < 0.001 | 5 | − 0.20 (− 2.64, 2.23) | 79.8 | < 0.001 | 6 | − 1.19 (− 2.53, 0.15) | 84.7 | < 0.001 | 5 | − 0.71 (− 1.32, − 0.11) | 75.8 | < 0.001 |
| ≥ 40 years | 23 | − 0.97 (− 1.37, − 0.58) | 85.8 | < 0.001 | 22 | − 1.64 (− 2.39, − 0.88) | 81. | < 0.001 | 18 | − 2.70 (− 4.35, − 1.05) | 91.9 | < 0.001 | 11 | − 2.23 (− 4.00, − 0.46) | 17.4 | < 0.001 |
P for the heterogeneity Q test. NA not reported, due to the limited number of studies in this subgroup, the subgroup analysis was not conducted
HRV heart rate variability, SDNN standard deviation of all normal-to-normal intervals, rMSSD root mean square of successive differences in adjacent normal-to-normal intervals, HF high frequency power, LF low frequency power