Covariate in the univariate model | No of contrasts (k) | Regression coefficient (95% CI) | p-value | I^{2} (%) | R^{2} (%) |

Age (years) | 76 | 12.0 (−9.3 to 33.4) | 0.269 | 87 | 0.4 |

Percentage of females (%) | 72 | −0.83 (−12.6 to 11.0) | 0.891 | 88 | 0.0 |

Body mass index (kg/m^{2}) | 55 | 64.4 (−32.2 to 161) | 0.192 | 89 | 0.1 |

Sedentariness* (1=sedentary) | 78 | −28 (−588 to 530) | 0.920 | 87 | 0.0 |

Health status* (1=chronically ill) | 78 | 111 (−443 to 665) | 0.695 | 87 | 0.0 |

Healthcare setting* (1=from healthcare settings) | 78 | 247 (−322 to 817) | 0.395 | 87 | 0.0 |

Each row represents a single univariate meta-regression model with an intercept and the covariate of interest. The regression coefficients for the intercepts are not reported. For continuous covariates, the regression coefficients express an average change in the mean difference between intervention groups' and active controls' daily step count for a one-unit increase in the mean value of the covariate. For binary covariates, the regression coefficients express a change in the mean difference between intervention groups' and active controls' daily step count associated with the presence of the covariate.

*These covariates entered the models as binary variables (1=studies that specifically recruited participants who were sedentary, chronically ill and from healthcare settings, respectively; 0=studies that did not specifically recruit these patients).