2. Sensitivity analyses for heated tobacco use versus abstinence from tobacco.
| Outcomes | All data | No high risk of bias | ≥ 4 weeks' follow‐up | ||||||
| No. of participants (studies) | MD (95% CI) | I2 statistic | No. of participants (studies) | MD (95% CI) | I2 statistic | No. of participants (studies) | MD (95% CI) | I2 statistic | |
| Biomarkers of exposure | |||||||||
| 1‐OHPa | 382 (5) | 0.12 (−0.03 to 0.28) | 54% | 212 (3) | 0.11 (−0.03 to 0.25) | 12% | 170 (2) | 0.22 (−0.32 to 0.75) | 84% |
| 1‐Naphthol | None | N/A | N/A | None | N/A | N/A | None | N/A | N/A |
| 2‐Naphthol | None | N/A | N/A | None | N/A | N/A | None | N/A | N/A |
| Exhaled CO | None | N/A | N/A | None | N/A | N/A | None | N/A | N/A |
| COHba | 382 (5) | 0.30 (−0.40 to 1.00) | 99% | 212 (3) | 0.69 (0.07 to 1.31) | 97% | 170 (2) | −0.32 (−1.04 to 0.39) | 91% |
| 3‐HPMAa | 382 (5) | 0.56 (0.33 to 0.80) | 85% | 212 (3) | 0.64 (0.32 to 0.96) | 89% | 170 (2) | 0.35 (0.20 to 0.50) | 0% |
| Lead | None | N/A | N/A | None | N/A | N/A | None | N/A | N/A |
| Cadmium | None | N/A | N/A | None | N/A | N/A | None | N/A | N/A |
| MHBMAa | 382 (5) | 0.67 (−0.12 to 1.45) | 96% | 212 (3) | 0.97 (0.02 to 1.92) | 96% | 170 (2) | 0.07 (−0.16 to 0.30) | 0% |
| NNALa | 382 (5) | 0.50 (0.34 to 0.66) | 0% | 212 (3) | 0.42 (−0.01 to 0.85) | 0% | 170 (2) | 0.51 (0.34 to 0.69) | 0% |
| Biomarkers of harm | |||||||||
| FEV1a | 170 (2) | −0.00 (−0.06 to 0.06) | 38% | None | N/A | N/A | 170 (2) | −0.00 (−0.06 to 0.06) | 38% |
| FVC | 172 (2) | −0.02 (−0.29 to 0.26) | 0% | None | N/A | N/A | 172 (2) | −0.02 (−0.29 to 0.26) | 0% |
| FEV1/FVC | None | N/A | N/A | None | N/A | N/A | None | N/A | N/A |
| Systolic blood pressurea | 170 (2) |
0.02 (−0.01 to 0.05) | 0% | None | N/A | N/A | 170 (2) |
0.02 (−0.01 to 0.05) | 0% |
| Diastolic blood pressurea | 170 (2) | 0.00 (−0.04 to 0.04) | 0% | None | N/A | N/A | 170 (2) | 0.00 (−0.04 to 0.04) | 0% |
| Heart rate | None | N/A | N/A | None | N/A | N/A | None | N/A | N/A |
| Blood oxygen saturation | None | N/A | N/A | None | N/A | N/A | None | N/A | N/A |
aDifference in means calculated on the log‐scale.
1‐OHP: 1‐hydroxypyrene; 3‐HPMA: 3‐hydroxypropylmercapturic acid; CI: confidence interval; CO: carbon monoxide; COHb: carboxyhaemoglobin; FEV1: forced expiratory volume in one second; FVC: forced vital capacity; MD: mean difference; MHBMA: monohydroxy‐3‐butenyl mercapturic acid; N/A: not available; NNAL: 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanol.