Table 3.
Study quality and risk of bias assessment by study
| Asano et al. [96], | Bezerra et al. [97], | Biddle et al. [99], | Blodgett et al. [100], | Blodgett et al. [101], | Booker et al. [60], | Brakenridge et al. [61], | Brayton et al. [64] | Cabanas- Sánchez et al. [102] | Carson et al. [103] | Carson et al. [104] | Chao et al. [105] | Chastin et al. [54] | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. Was the research question or objective in this paper clearly stated? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 2. Was the study population clearly specified and defined? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No |
| 3. Was the participation rate of eligible persons at least 50%? | No | No | Other | Yes | Other | Yes | Yes | Yes | Yes | Yes | Yes | Other | Other |
| 4. Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants? | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes | Yes | No | Yes | Other | No |
| 5. Was a sample size justification, power description, or variance and effect estimates provided? | No | No | No | No | No | No | No | Yes | No | No | No | No | No |
| 6. For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured? | No | No | No | No | No | No | No | Yes | Yes | No | No | No | Yes |
| 7. Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed? | No | No | No | No | No | No | No | Yes | Yes | No | No | No | Yes |
| 8. For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)? | Yes | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 9. Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | No | Yes | Yes | No | No | Yes | No | Yes | No | No | Yes | No | No |
| 10. Was the exposure(s) assessed more than once over time? | No | Other | No | No | No | No | Other | No | Yes | No | No | No | No |
| 11. Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 12. Were the outcome assessors blinded to the exposure status of participants? | Other | Other | Other | Other | Other | No | Other | Other | Other | Other | Other | Other | Other |
| 13. Was loss to follow-up after baseline 20% or less? | Other | Other | Other | Other | Other | Other | Other | Yes | No | Other | Other | Other | No |
| 14. Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes | Yes | Yes |
| Totals | 6 | 7 | 7 | 7 | 5 | 7 | 7 | 11 | 10 | 6 | 8 | 4 | 6 |
| Chen et al. [62] | Chen et al. [106] | Chong et al. [107] | Chong et al. [108] | Clarke et al. [109] | Collings et al. [110]. D&MS | Collings et al. [111] Atherosclerosis | Curtis et al. [112] | Curtis et al. [113] | de Faria et al. [114] | del Pozo- Cruz et al. [115] | Domingues et al. [116] | Dumuid et al. [117] Qual Life Res | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. Was the research question or objective in this paper clearly stated? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 2. Was the study population clearly specified and defined? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 3. Was the participation rate of eligible persons at least 50%? | Yes | Yes | No | No | Yes | Yes | Yes | Yes | Yes | Yes | Other | No | Other |
| 4. Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants? | No | Other | Yes | Yes | Yes | Yes | Yes | Other | Yes | Yes | Yes | Yes | Yes |
| 5. Was a sample size justification, power description, or variance and effect estimates provided? | No | No | No | No | No | No | No | No | No | Yes | No | Yes | No |
| 6. For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured? | No | No | Yes | Yes | Yes | No | No | No | No | No | No | No | No |
| 7. Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed? | No | No | Yes | Yes | Yes | No | No | No | No | No | No | No | No |
| 8. For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 9. Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | No | No | Yes | No | No | Yes | Yes | No | No | Yes | No | No | Yes |
| 10. Was the exposure(s) assessed more than once over time? | No | No | Yes | Yes | No | No | No | No | No | No | No | No | No |
| 11. Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 12. Were the outcome assessors blinded to the exposure status of participants? | Other | Other | No | Other | Yes | No | Other | Other | Other | Other | Other | Other | Other |
| 13. Was loss to follow-up after baseline 20% or less? | Other | Other | No | Yes | Yes | Other | Other | Other | Other | Other | Other | Other | Other |
| 14. Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | Yes |
| Totals | 6 | 6 | 10 | 10 | 11 | 8 | 8 | 6 | 7 | 9 | 6 | 6 | 7 |
| Dumuid et al. [118] Maturitas | Dumuid et al. [119] BMC Pub Health | Dumuid et al. [120] | Dumuid et al. [121] | Dumuid et al. [122] | Dumuid et al. [123] | Dumuid et al. [35] JAD | Faircloug h et al. [124] | Fairclough et al. [125] | Fairclough et al. [65] | Farrahi et al. [126] | Feter et al. [127] | Franssen et al. [128] | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. Was the research question or objective in this paper clearly stated? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 2. Was the study population clearly specified and defined? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 3. Was the participation rate of eligible persons at least 50%? | Yes | Yes | No | No | Yes | Yes | Yes | No | Yes | Yes | Yes | Yes | Yes |
| 4. Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes |
| 5. Was a sample size justification, power description, or variance and effect estimates provided? | Yes | Yes | No | No | No | No | No | No | No | No | No | No | Yes |
| 6. For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured? | No | No | No | No | No | No | No | No | No | No | No | No | No |
| 7. Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed? | No | No | No | No | No | No | No | No | No | No | No | No | No |
| 8. For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes |
| 9. Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | No | Yes | No | Yes | Yes | No | No | Yes | Yes | No | Yes | No | No |
| 10. Was the exposure(s) assessed more than once over time? | No | No | Other | No | No | No | Other | No | No | No | No | Other | No |
| 11. Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 12. Were the outcome assessors blinded to the exposure status of participants? | No | Other | Other | Other | Other | No | Other | Yes | Other | No | No | Other | Other |
| 13. Was loss to follow-up after baseline 20% or less? | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | No | Other | Other |
| 14. Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Totals | 8 | 9 | 6 | 7 | 8 | 7 | 7 | 8 | 8 | 5 | 8 | 7 | 8 |
| Gupta et al. [129] | Gupta et al. [130] | Gupta et al. [131]. IJoO | Gupta et al. [132] IJBNPA | Healy et al. [53] | Hofman et al. [133] | Hyodo et al. [56] | Kastelic et al. [135], | Kandola et al. [134] | Kim et al. [59] | Kitano et al. [136] | Kuzik et al. [137] | Larisch et al. [138] | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. Was the research question or objective in this paper clearly stated? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 2. Was the study population clearly specified and defined? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No |
| 3. Was the participation rate of eligible persons at least 50%? | No | Yes | Yes | No | Other | Other | Other | Other | No | Yes | Other | No | No |
| 4. Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 5. Was a sample size justification, power description, or variance and effect estimates provided? | No | No | No | No | No | No | No | No | Yes | No | No | No | No |
| 6. For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured? | No | No | No | Yes | No | No | No | No | Yes | No | No | No | No |
| 7. Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed? | No | No | No | Yes | No | No | No | No | Yes | No | No | No | No |
| 8. For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 9. Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | Yes | Yes | No | No | Yes | No | Yes | No | Yes | Yes | No | No | No |
| 10. Was the exposure(s) assessed more than once over time? | No | No | No | No | No | Other | No | No | No | No | No | No | No |
| 11. Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 12. Were the outcome assessors blinded to the exposure status of participants? | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other |
| 13. Was loss to follow-up after baseline 20% or less? | Other | Other | Other | No | Other | Other | Other | Other | No | Other | Other | Other | Other |
| 14. Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Totals | 7 | 8 | 7 | 8 | 7 | 6 | 7 | 6 | 10 | 8 | 6 | 6 | 5 |
| Lau et al. [139] | Le et al. [140] | Lee et al. [141] | Lemons et al. [142] | Lewthwaite et al. [63] | Lin et al. [143] | Lu et al. [144] | Lund Rasmussen et al. [145] | Madden et al. [146] | Marshall et al. [147] | Marshall et al. [148] | Matricciani et al. [149] | McGee et al. [150] | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. Was the research question or objective in this paper clearly stated? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 2. Was the study population clearly specified and defined? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 3. Was the participation rate of eligible persons at least 50%? | No | No | Yes | Yes | No | Other | Yes | Yes | Yes | Other | Other | Yes | No |
| 4. Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants? | Yes | No | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 5. Was a sample size justification, power description, or variance and effect estimates provided? | No | No | No | No | Yes | No | Yes | No | No | No | No | No | Yes |
| 6. For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured? | No | No | No | No | Yes | No | No | No | No | No | No | No | No |
| 7. Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed? | No | No | No | No | Yes | No | No | No | No | No | No | No | No |
| 8. For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes | Yes |
| 9. Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | Yes | No | No | No | No | Yes | Yes | Yes | No | No | No | No | No |
| 10. Was the exposure(s) assessed more than once over time? | Other | No | No | Other | Yes | No | Other | No | No | Other | Other | No | No |
| 11. Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 12. Were the outcome assessors blinded to the exposure status of participants? | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other |
| 13. Was loss to follow-up after baseline 20% or less? | Other | Other | Other | Other | No | Other | Other | Other | Other | Other | Other | Other | Other |
| 14. Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Totals | 7 | 5 | 7 | 7 | 10 | 7 | 9 | 8 | 6 | 6 | 6 | 7 | 7 |
| McGregor et al. [151] | McGregor et al. [152] | Mellow et al. [153] | Mellow et al. [154] | Migueles et al. [155] | Migueles et al. [156] | Mitchell et al. [157] | Mota et al. [158] | Murray et al. [159] | Ng et al. [160] | Niemelä et al. [161] | Olds et al. [58] | Oviedo-Caro et al. [162] | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. Was the research question or objective in this paper clearly stated? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 2. Was the study population clearly specified and defined? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 3. Was the participation rate of eligible persons at least 50%? | Yes | Yes | Other | Yes | Yes | Other | Yes | No | Yes | No | No | Other | Other |
| 4. Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 5. Was a sample size justification, power description, or variance and effect estimates provided? | No | No | Yes | Yes | No | No | No | Yes | No | No | No | Yes | No |
| 6. For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured? | No | Yes | No | No | No | Yes | No | Other | No | No | Yes | Yes | No |
| 7. Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed? | No | Yes | No | No | No | Yes | No | No | No | No | Yes | No | No |
| 8. For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 9. Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | No | Yes | No | No | No | No | No | No | Yes | No | No | No | Yes |
| 10. Was the exposure(s) assessed more than once over time? | No | No | Other | No | Other | Yes | No | Other | Other | No | No | Yes | Other |
| 11. Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 12. Were the outcome assessors blinded to the exposure status of participants? | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other |
| 13. Was loss to follow-up after baseline 20% or less? | Other | Yes | Other | Other | Other | No | Other | Other | Other | Other | No | Yes | Other |
| 14. Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Totals | 7 | 11 | 7 | 8 | 7 | 9 | 7 | 7 | 8 | 6 | 8 | 10 | 7 |
| Pina et al. [163], | Powell et al. [164] | Rees-Punia et al. [165] | Runacres et al. [166] | Sampasa- Kanyinga et al. [57] | Sandborg et al. [167] | Segura-Jiménez et al. [168] | Smith et al. [169] SJMSS | Smith et al. [170], Clin Neurophysiol | St. Laurent et al. [171] | Su et al. [172], | Suorsa et al. [173] | Swindell et al. [174] | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. Was the research question or objective in this paper clearly stated? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 2. Was the study population clearly specified and defined? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | No | Yes | No | Yes | Yes |
| 3. Was the participation rate of eligible persons at least 50%? | Yes | No | No | Yes | Other | Yes | No | Other | Yes | No | Yes | No | Yes |
| 4. Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants? | Other | Yes | Yes | Other | Yes | Yes | Yes | Other | No | Yes | No | Yes | Yes |
| 5. Was a sample size justification, power description, or variance and effect estimates provided? | Yes | No | No | No | No | Yes | No | No | No | No | No | No | No |
| 6. For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured? | No | No | Yes | No | Yes | Yes | Yes | No | No | No | No | Yes | No |
| 7. Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed? | No | No | Yes | No | Yes | Yes | Yes | No | No | No | No | Yes | No |
| 8. For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 9. Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | No | No | Yes | No | No | No | Yes | No | No | Yes | No | No | No |
| 10. Was the exposure(s) assessed more than once over time? | Other | Other | No | No | Yes | Yes | Yes | No | No | No | No | Yes | No |
| 11. Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| 12. Were the outcome assessors blinded to the exposure status of participants? | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other | Other |
| 13. Was loss to follow-up after baseline 20% or less? | Other | Other | No | Other | No | No | No | Other | Other | Other | Other | Yes | Other |
| 14. Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Totals | 7 | 6 | 9 | 6 | 9 | 11 | 10 | 4 | 5 | 7 | 5 | 10 | 7 |
| Talarico et al. [175] | Tan et al. [176] | Taylor et al. [55] | Taylor et al. [177], | Taylor et al. [178], | Tyler et al. [179], | Vanderlinden et al. [180] | Verhoog et al. [181] | Walmsley et al. [182] | Wang et al. [183] | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. Was the research question or objective in this paper clearly stated? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | |||
| 2. Was the study population clearly specified and defined? | Yes | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes | Yes | |||
| 3. Was the participation rate of eligible persons at least 50%? | Yes | No | Yes | Other | Yes | Yes | Other | Yes | Yes | Yes | |||
| 4. Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants? | Yes | Yes | Yes | Yes | Yes | Other | Yes | Yes | Yes | Yes | |||
| 5. Was a sample size justification, power description, or variance and effect estimates provided? | No | No | No | No | No | No | No | No | No | Yes | |||
| 6. For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured? | No | Yes | Yes | No | Yes | No | No | No | Yes | Yes | |||
| 7. Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed? | No | Yes | Yes | No | Yes | No | No | No | Yes | Yes | |||
| 8. For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | |||
| 9. Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | No | Yes | No | Yes | Yes | No | No | No | No | Yes | |||
| 10. Was the exposure(s) assessed more than once over time? | No | Yes | Yes | No | Yes | Other | No | No | No | No | |||
| 11. Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | |||
| 12. Were the outcome assessors blinded to the exposure status of participants? | Other | Other | Yes | Other | Yes | Other | Other | Other | Other | Other | |||
| 13. Was loss to follow-up after baseline 20% or less? | Other | No | No | Other | No | Other | Other | Other | Yes | Yes | |||
| 14. Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)? | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | |||
| Totals | 7 | 10 | 11 | 7 | 12 | 5 | 6 | 7 | 10 | 12 |