| 1 | Were the criteria for inclusion in the sample clearly defined? | √(28) | | | |
| 2 | Were the study subject and the setting described in detail? | √(28) | | | |
| 3 | Was the exposure measure in valid and reliable way? | √(25) | √(3) | | |
| 4 | Were objective, standard criteria used for measurement of the condition? | √(28) | | | |
| 5 | Were confounding factors identified? | √(12) | | √(16) | |
| 6 | Were strategies to deal with confounding factor stated? | √(7) | | √(19) | |
| 7 | Was the outcome measured in a valid and reliable way? | √(23) | | √(5) | |
| 8 | Was appropriate statistical analysis used? | √(28) | | | |
