Table 2

 Characteristics of included studies

AuthorsStudy characteristicsPatient characteristics
Date publishedStudy typeCountryCentresAssessors blinded?Assessment toolDates of birthBirth weightDuration of follow-up (months)*Follow-up (%)Number with NEC (n)Total number of patients (N)
*All duration of follow-up times refer to corrected age unless marked with †. Corrected age is gestational age at birth plus chronological age (ie, corrected for prematurity). BSID, Bayley Standardised Infant Development Scale (I and II); GQ, Griffiths Quotient; Denver, Denver developmental screening test.
Castro172004CohortUSAMultiYesBSID II1993–1994<1000 g18–2278721483
Chacko181999Case–controlAustraliaSingleNoGQ1990–1993<1000 g12–591004060
Hintz212005CohortUSAMultiYesBSID II1995–1998401–1000 g18–22795324933
Holmsgaard191996CohortDenmarkSingleNoClinical1987–1990994 g mean42 (mean)994136
Mayr121994CohortAustriaSingleNoDenver1978–1991<1501 g12–156†631218
Simon241993CohortUSASingleNoBSID I1986–1988<1500 g15†1001818
Sonntag202000Case–controlGermanySingleNoGQ1992–1996<1500 g20912060
Tobiansky101995Case–controlAustraliaSingleNoGQ1986–1991⩽1500 g36–60914989
Walsh141989CohortUSASingleNoBSID I1975–1983<1500 g209036802
Waugh221996CohortAustraliaSingleYesGQ1977–1990<1000 g248923199
Yeh112004Case–controlTaiwanSingleNoBSID II1991–2002<1500 g18541545