Table 3

Results for the association between exposures related to a higher risk of infection and wheeze/asthma

StudyHome environmentAnimal contactContact with other childrenEarly-life infectionDemonstrated infection
House*Sanitation†Water‡EndotoxinHousingGar bage§InsideOutsidePetsFarm animalInsects¶OvercrowdingDay careOlder
ARIGIIntestinal parasiteVirus**Bacteria**
Pelotas cohortNA4NA4NA5NA5
Cuban studyNANANANANA/↓
Zepeda et al27NANANA
Uruguaiana studyNA/↓13NA/↓
Azalim et al32NANA
Barraza et al33NA
Barreto and Sole281515
Bragagnoli and Silva63NA/↓
Casagrande et al29NANANANANANA
Cooper et al64NA
Del-Ri­o-Navarro et al44
Endara et al65NA
Freitas et al66NANA
Garci­a et al6717
Gomes et al68NA
Guimarães et al69NANA
Hagel et al70NA
Han et al71NANANANA18
Kuschnir and Alves da Cunha73
Lima et al74NA
Maia et al75
Palvo et al76
Prietsch et al77NANA
Quiroz-Arcentales et al4219NA
Ribeiro et al78NANA
Rojas et al34
Silva et al79NA
Solis-Soto et al35NA20NA20NANA21
Soto-Quiros et al80
Souza et al81NA
Tintori et al82NA/
Toledo et al83NANANA
Boneberger et al43NANA
Cadore et al84NA/
Coelho et al47NANANANA/↑24NANA
Jucá et al85
López et al86NA
Mendoza et al87
Moraes et al88NANA
Oliveira-Santos et al89NA/
Rizzo et al90NA
  • 1: increased risk of current wheeze at 6 years,45 no association at 13–14 years of age when adjusted46; 2: increased risk of non-atopic wheeze compared with non-atopic non-wheezing9: animals inside: rats; 3: only Toxocara IgG increased risk of atopic wheeze when compared with non-atopic non-wheezers21; 4: only in Chatkin et al23; 5: only in Muiño et al, 2008; 6: current helminth infection62 past Ascaris lumbricoides, Trichuris trichiura and hookworm infection (Werff 2013) were NA, history of Ascaris infection increased the risk of current wheeze62; 7: maternal geohelminths increased the risk of current wheeze, childhood geohelminths to 36 months decreased risk of current wheeze and asthma; 8: NA in Cooper et al30; 9: increased risk of wheeze with lack of potable drinking water in Cooper et al30; 10: dog inside the house increased risk of current wheeze in urban setting; 11: only in Cooper et al30; 12: no association for any geohelminth, hookworm or Ascaris10 31 ,30, decreased risk of atopic wheeze with T. trichiura infection10 31; 13: decreased risk of active asthma, NA for wheeze; 14: high load of Ascaris increased risk of active asthma,14 Giardia infection decreased risk and high load of helminth infection increased risk13; 15: history of measles or tuberculosis increased the risk of asthma; 16: the risk of wheeze decreased with light A. lumbricoides infections and increased with heavy infections and with A. lumbricoides and T. trichiura coinfections; 17: no association in 13–14 year group; 18: bronchiolitis increased risk of current wheeze and asthma in 6–7 years; 19: absence of sewage disposal increased the risk of asthma; 20: precarious household conditions together as one exposure including: precarious floor, precarious walls, precarious source of water, precarious sewage system; 21: presence of disease vectors at home: fleas, ticks, kissing bugs, mice, bedbugs, flies; 22: dogs in the house increased the risk of current wheeze, no association for cats; 23: contact with cats increased risk of asthma, with dogs had no association; 24: kindergarten increased risk, day care was not associated; 25: dogs inside the house currently not associated, during 1 year of life decreased the risk of current wheeze. Worm infection in the past not associated with current wheeze.

  • *Infrequent house cleaning.

  • †No toilet or latrine.

  • ‡No clean drinking water.

  • §No garbage disposal.

  • ¶Cockroaches in the house.

  • **Positive serology for Helicobacter pylori, hepatitis A virus, herpes zoster virus, herpes simplex virus, Epstein-Barr virus.

  • ARI, acute respiratory tract infection; GI, gastrointestinal;; SCAALA, Social Changes, Asthma and Allergy in Latin America.

  • –: exposure measured not represented; NA: no association (P≤0.05); ↑: increased risk of asthma (OR>1, P<0.05); ↓: decreased risk of asthma (OR<1, P<0.05).