| Bias in study design | Bias in instrument to measure physical activity | Bias in accounting for confounding variables | Overall quality of study |
---|---|---|---|---|
Cohort studies | ||||
Huerta [15] | Low | Low | Low | High |
Leitzmann [16] | Low | Low | Low | High |
Wannamethee [23] | Low | Low | Low | High |
Yun [24] | Low | Low | Low | High |
Case–control Studies | ||||
Balbuena [26] | High | High | High | Low |
Brownson [25] | High | High | Low | Low |
Etemadi [27] | High | High | High | Low |
Parent [13] | Low | High | Low | Low |
Vigen [14] | Low | High | Low | Low |