|
|
Study author, year, country | Selection |
Comparability of cases and controls on the basis of the design or analysis | Exposure |
Comment |
| Is the case definition adequate? | Representativeness of the cases
| Selection of controls
| Definition of controls
| Ascertainment of exposure | The same method of ascertainment of cases and controls | Nonresponse rate |
|
| Carpenter et al. 2004, Europe [25] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, infants matched for age and the same survey area, randomly selected from the birth records (*) | Yes, groups comparable and also adjusted for most potential confounders (**) | Yes, interviews (*) | Yes (*) | Described (*) | Good quality |
|
| Blair et al. 1999, United Kingdom [22] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, infants born immediately before and after the index case (*) | Yes, groups comparable and also adjusted for most potential confounders (**) | Yes, interviews (*) | Yes (*) | Described (*) | Good quality |
|
| Arnestad et al. 2001, Norway [23] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, infants matched for sex and date of birth, randomly picked from the national register (*) | Yes, groups comparable and also adjusted for most potential confounders (**) | Yes, mailed questionnaire (*) | Yes (*) | Described, 31% and 25% loss for the cases and controls, respectively (*) | Good quality |
|
| Bubnaitiene et al. 2005, Lithuania [26] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, infants matched for date of birth and region, randomly picked (*) | Yes, groups comparable. Not adjusted for most potential confounders (*) | Yes, home visits in cases and mailed questionnaire in controls (*) | No | Described only for the cases, 22.2% loss (*) | Good quality |
|
| Ruys et al. 2007, The Netherlands [28] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, infants who participated in another survey (*) | No, groups not comparable. Adjusted for most potential confounders (*) | Yes, home visits and direct interview in cases and direct interview in controls (*) | Yes (*) | Not described | Good quality |
|
| McGarvey et al. 2006, Ireland [27] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, infants matched for date of birth and population based area, randomly picked from birth register (*) | Yes, groups comparable and also adjusted for most potential confounders (**) | Yes, home interview in both cases and controls (*) | Yes (*) | Described, 14% loss (*) | Good quality |
|
| Fu et al. 2010, USA [30] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, infants matched for birth race, age, and birth weight, randomly picked from birth register (*) | Yes, groups comparable. Not adjusted for most potential confounders (*) | Yes, home visits and direct interview in cases and direct interview in controls (*) | Yes (*) | Described, 25% loss (*) | Good quality |
|
| Klonoff-Cohen and Edelstein 1995, USA [19] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, infants matched for birth hospital, sex, race, and date of birth, randomly picked from birth register (*) | Yes, groups comparable and also adjusted for most potential confounders (**) | Yes, telephonic interview in cases and controls (*) | Yes (*) | Described, 25% loss (*) | Good quality |
|
| Blair et al. 2009/England [9] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, from the maternity database of hospital (*) | No, groups not comparable. Not adjusted for most potential confounders | Yes, home visits and questionnaire in cases and questionnaire in controls (*) | No | Described, 5–14% loss in the two groups (*) | Good quality |
|
| Vennemann et al. 2009, Germany [29] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, matched for age, gender, region, and sleep time (*) | Yes, groups comparable and also adjusted for most potential confounders (**) | Yes, home visits and questionnaire in cases and controls (*) | Yes (*) | Described, 18–42% loss in the two groups (*) | Good quality |
|
| L’Hoir et al. 1998, The Netherlands [21] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, matched for date of birth (*) | No, groups not comparable. Not adjusted for most potential confounders | Yes, home visits and questionnaire in cases and controls (*) | Yes (*) | Not described | Good quality |
|
| Brooke et al. 1997, Scotland [20] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, matched for age, season, and maternity unit (*) | Yes, groups comparable and also adjusted for most potential confounders (**) | Yes, home visits and questionnaire in cases and controls (*) | Yes (*) | Described, ~25% loss (*) | Good quality |
|
| Fleming 1996, England | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, infants born immediately before and after the index case (*) | Yes, groups comparable and also adjusted for most potential confounders (**) | Yes, home visits and questionnaire in cases and controls (*) | Yes (*) | Described, ~9% loss (*) | Good quality |
|
| Williams et al. 2002, New Zealand [24] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, randomly selected from all births, except home births (*) | No, groups not comparable and also adjusted for most potential confounders (*) | Yes, interview based in cases and controls (*) | Yes (*) | Described, 10–19% loss (*) | Good quality |
|
| Ball 2003, United Kingdom [12] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, healthy infants and mothers, delivered at 36+ weeks. Followed up till 4 months of age (*) | Yes, groups comparable. Not adjusted for most potential confounders (*) | Yes, sleep logs were used to measure the exposure status (*) | Yes (*) | Described, ~40% loss (*) | Good quality |
|
| McCoy et al. 2004, USA [14] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, followup of infants born at selected study hospitals (*) | Yes, groups comparable and also adjusted for most potential confounders (**) | Yes, mailed questionnaire (*) | Yes (*) | Described, ~30% loss (*) | Good quality |
|
| Lahr et al. 2007, USA [15] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, stratified sample drawn each month from recently filed birth certificates (*) | Yes, groups comparable. Not adjusted for most potential confounders (*) | Questionnaire based (*) | Yes (*) | Described, 26.5% loss (*) | Good quality |
|
| Tan 2011, Malaysia [17] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, controls attending health facility (*) | Yes, infants up to 6 months attending health clinics (*) | Yes, groups comparable and also adjusted for most potential confounders (**) | Face-to-face interviews using a pretested structured questionnaire (*) | Yes (*) | Described, <5% loss (*) | Good quality |
|
| Mllborg et al. 2011, Sweden [18] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, randomly selected families with infants who had reached 6 months of age (*) | Yes, groups comparable and also adjusted for most potential confounders (**) | Yes, mailed questionnaire (*) | Yes (*) | Described, 31.5% loss (*)
| Good quality |
|
| Flick et al. 2001, USA [11] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, pregnant women enrolled at 28 wk, contacted at around 8 weeks after delivery (*) | Yes, groups comparable. Not adjusted for most potential confounders (*) | Yes, mailed questionnaire (*) | Yes (*) | Described, 2.2% loss (*) | Good quality |
|
| Blair and Ball 2004, United Kingdom [13] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, healthy newborn infants and mothers at home (*) | Yes, groups comparable. Not adjusted for most potential confounders (*) | Yes, sleep logs and interviews (*) | Yes (*) | Described, <20% loss (*)
| Good quality |
|
| Blair et al. 2010, United Kingdom [16] | Yes, record validation (*) | Yes, obviously representative series of cases (*) | Yes, community controls (*) | Yes, infants of all pregnant women residing in the 3 health districts of Avon; age group: birth to 4 years (*) | Yes, groups comparable. Not adjusted for most potential confounders (*) | Yes, mailed questionnaire (*)
| Yes (*) | Described, ~50% loss (*)
| Good quality |
|
