Question/objective sufficiently described? | 2 | 2 | 2 | 2 | 1 | 1 | 1 | 2 | 1 |

Study design evident and appropriate? | 2 | 2 | 2 | 2 | 1 | 2 | 2 | 2 | 2 |

Method of subject/comparison group selection or source of information/input variables described and appropriate? | 1 | 2 | 1 | N/A | 1 | 2 | 1 | 1 | 1 |

Subject (and comparison group) characteristics sufficiently described? | 1 | 2 | 0 | N/A | 0 | 1 | 1 | 1 | 1 |

If interventional and random allocation was possible, was it described? | 0 | 2 | 2 | N/A | N/A | 2 | 1 | N/A | 1 |

If interventional and blinding of investigators was possible, was it reported? | 0 | 2 | 2 | N/A | N/A | N/A | N/A | N/A | 2 |

If interventional and blinding of subjects was possible, was it reported? | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A |

Outcome and exposure measure(s) well defined and robust to measurement/misclassification bias? | 1 | 2 | 2 | 1 | 2 | 1 | 2 | 2 | 2 |

Sample size appropriate? | 1 | 2 | 1 | 1 | 0 | 1 | 2 | 1 | 1 |

Analytic methods described/justified and appropriate? | 1 | 2 | 1 | 2 | 0 | 1 | 2 | 2 | 2 |

Some estimate of variance is reported for the main results? | 1 | 2 | 2 | 2 | 0 | 0 | 2 | 2 | 2 |

Controlled for confounding? | 0 | 2 | 0 | 1 | 0 | 1 | 0 | 1 | 0 |

Results reported in sufficient detail? | 1 | 2 | 1 | 2 | 1 | 1 | 2 | 2 | 2 |

Conclusions supported by the results? | 1 | 2 | 1 | 2 | 1 | 1 | 1 | 2 | 2 |

Summary score | 0.46 | 1.00 | 0.65 | 0.83 | 0.32 | 0.58 | 0.71 | 0.82 | 0.73 |