Risk of bias: reporting of exposures measured, adjustment for confounders and proportion of variables associated with asthma or wheeze
| Design | Study | ISAAC questionnaire | Exposures measured | Exposures reported | Criteria for presentation | Adjustment for confounders | Hygiene exposures with association (P<0.005) | Non-hygiene exposures with association (P<0.05) | Total exposures with association (P<0.005) |
| Cohort | Brandão et al45 46 | Yes | 43 (6–7 years)? 34 (13–14 years)? | 26 21 | Not described for univariate analysis. Variables reported varied between the different ages | Yes | 3/7 | 3/15 | 6/22 |
| SCAALA Brazil9 15 16 20 21 | Yes | 55 | 50 | ‘Meaningfully associated’ in univariate or multivariate analysis (with Schistosoma mansoni and hookworm excluded from analysis) | Yes | 4/28 | 1/22 | 5/50 | |
| Pelotas cohort23 24 26 | Modified | 20? | 20 | Not described for multivariate. No hygiene exposure in multivariate* | Yes* | 1/5 | 7/15 | 8/20 | |
| Cuban study60–62 | Modified | 25 | 24 | One more variable only used as confounder in multivariate | Yes | 2/15 | 6/10 | 8/25 | |
| ECUAVIDA22 25 | Modified | 47? | 25 | Not described, except confounders chosen for significant associations with the 5-year AW phenotype and on previously reported associations with asthma or with microbiome shifts | Yes | 3/12 | 4/13 | 7/25 | |
| Zepeda et al27 | No | 15 | 14 | Not described | No | 1/12 | 0/3 | 1/15 | |
| Cross-sectional | SCAALA Ecuador10 30 31 | Yes | 47 | 27 | P<0.2 in univariate analysis or included in multivariate analysis. Parasites with low prevalence not represented | Yes | 5/15 | 2/32 | 7/47 |
| Uruguaiana study13 14 | Yes | 41? | 11–12 | Risk factors known to be associated with wheeze/asthma and those significantly associated in the bivariate analysis. Intestinal parasites | Yes† | 1/11 | 6/30 | 7/41? | |
| Azalim et al32 | Modified | ? | 12 | Not described | Yes | 0/2 | 4/11 | 4/13 | |
| Barraza et al33 | Yes | ? | 16 | Not described | Yes | 2/3 | 8/13 | 10/16 | |
| Barreto and Sole28 | Yes | 33 | 15 | P<0.2 in univariate analysis and P<0.05 in bivariate analysis | No | 3/? | 12/? | 15/33 | |
| Bragagnoli and Silva63 | Yes | 18 | 15 | Only presented results for the Ascaris lumbricoides coinfections with other parasites (not those other parasites alone) | No | 3/14 | 2/4 | 5/18 | |
| Casagrande et al29 | Yes | 33? | 31 | Not described (P<0.2 in univariate analysis to include in bivariate) | Yes | 0/11 | 2/20 | 2/31 | |
| Cooper et al64 | Yes | 4 | 3 | Not specified (low proportion of Ancylostoma duodenale?) | Yes | 0/3 | – | 0/3 | |
| Del-Rio-Navarro et al44 | Yes | 43 (6–7 years) 34 (13–14 years) | 6–10 7–14 | Statistically significant results (for univariate and multivariate) | Unclear | 1/1 8/13 | 7/9 1/1 | 8/10 9/14 | |
| Endara et al‡ 65 | Yes | 1 (+6 parasites) | 1 | No association with intestinal parasites | Yes | 0/1 (7) | 0 | 0/1 (7) | |
| Freitas et al66 | Yes | 65 | 10 | P<0.2 in univariate was included in multivariate. Final model variables P<0.05 | Yes | 1/10 | 2/55 | 3/65 | |
| Garcia et al67 | Yes | 35 | 12 | P<0.25 in bivariate analysis | Yes | 1/3 | 5/32 | 6/35 | |
| Gomes de Luna et al68 | Modified | 34 | 34 | Yes | 0/1 | 4/33 | 4/34 | ||
| Guimarães et al69 | No | 14 | 14 | No | 0/2 | 2/12 | 2/14 | ||
| Hagel et al70 | – | 2 | 2 | No | 0/2 | – | 0/2 | ||
| Han et al71 72 | Modified | 37? | 21/26 | Not specified | Yes§ | 2/13 | 11/24 | 13/37 | |
| Kuschnir and Alves da Cunha73 | Yes | 34 | 10 | Not stated | Yes | 2/3 | 3/31 | 5/34 | |
| Lima et al74 | Modified | 9 | 9 | Yes | 0/1 | 3/8 | 3/9 | ||
| Maia et al75 | No | 8 | 3 | P<0.05 in final multivariate model | Yes | 1/1 | 2/7 | 3/8 | |
| Palvo et al76 | Modified | 14 | 9 | P<0.2 in univariate analysis and P<0.05 in multivariate analysis | Yes | 1/4 | 5/10 | 6/14 | |
| Prietsch et al77 | No | 28? | 17 | P<0.2 in univariate analysis (to be included in multivariate) | Yes | 1/6 | 6/22 | 7/28 | |
| Quiroz-Arcentales et al42 | No | 15? | 5 | Not stated | No | 4?/5 | 6?/10 | 10?/15 | |
| Ribeiro et al78 | No | 17 | 7 | Not stated | No | 0/5 | 1/12 | 1/17 | |
| Rojas Molina et al34 | Modified | ? | 3–4 | Only significant variables | No | 1/? | 2–3/? | 3–4/? | |
| Silva et al79 | No | 1 | 1 | Yes | 0/1 | - | 0/1 | ||
| Solis-Soto et al35 | Yes | ? | 9 | Not specified | Yes | 1/5 | 2/4 | 3/9 | |
| Soto-Quiros et al80 | No | 10 | 10 | No | 1/1 | 4/9 | 5/10 | ||
| Souza et al81 | – | 1 | 0 | No result for asthma alone (only for respiratory allergy) | No | 0/1 | – | 0/1 | |
| Tintori et al82 | No | 14? | 14 | P<0.5 in univariate was included in multivariate. Final model variables P<0.05 | Yes | 1/2 | 11/12 | 12/14 | |
| Toledo et al83 | Modified | 12 | 4 | Not stated | No | 0/4 | 0/8 | 0/12 | |
| Case–control | Boneberger et al43 | Modified | 13 | 11 | Matched by sex and age (not represented) | Yes | 3/6 | 1/7 | 4/13 |
| Cadore et al84 | No | 14? | 14 | Yes | 1/4 | 5/10 | 6/14 | ||
| Coelho et al47 | Yes | 67? | 35 | Not stated. P<0.2 in bivariate included in multivariate | Yes | 2/11 | 4/24 | 6/35 | |
| Jucá et al85 | Yes | 67? | 26 | Not stated. P<0.2 in bivariate included in multivariate | Yes | 1/10 | 7/58 | 8/68 | |
| López et al86 | – | 1 | 1 | No | 0/1 | – | 0/1 | ||
| Mendoza et al87 | – | 6 | 6 | No | 1/6 | – | 1/6 | ||
| Moraes et al88 | No | 22 | 22 | Unclear¶ | 1/3 | 1/19 | 2/22 | ||
| Oliveira-Santos et al89 | Yes | 67? | 26 | Not stated. P<0.25 in bivariate included in multivariate | Yes | 2/6 | 1/20 | 3/26 | |
| Rizzo et al90 | No | 3 | 0 | ‘No significant difference’ in text, but no numbers represented | No | 0/2 | 0/1 | 0/3 |
?: unclear number or not included.
*Muiño et al26: no description of variables measured and represented. No adjustment.
†Only for Pereira et al14 not da Silva et al.13
‡Same questionnaire as SCAALA Ecuador.
§Only rural residence and antibiotic use and bronchiolitis in the first year of life were adjusted for in multivariable analysis, as was the objective of the study.
¶Not published.
Exposures associated to wheeze or asthma: shown over total exposures measured or represented (when number of exposures measured was not clear). When results presented were divided in subgroups, highest number of associated variables from any of the subgroups was selected for the table.
AW, atopic wheeze; ISAAC, International Study on Asthma and Allergies in Children; SCAALA, Social Changes, Asthma and Allergy in Latin America.