TABLE 1

Characteristics of included studies investigating the association between maternal age and type 1 diabetes, ordered by publication date

First author, year* (reference)DesignCountryType 1 diabetic subjectsControl subjectsAvailable confounders‡
Ascertainment method (year case subjects diagnosed)Age at dx (years)nResp rate (%)Source (matching criteria)nResp rate (%)BOBWGAMDCSBF# (months)
Dahlquist, 1992 (9)C-CSwedenSwedish childhood diabetes register (78–88)0–142,75798Medical birth registry (birth year, unit)8,271100
Bock, 1994 (10)C-CDenmarkHosp. admission from National Patient Registry (78–89)<1683798Birth registry (age, sex)837NA
Patterson, 1994 (11)C-CScotlandHosp. admission/childhood diabetes register (76–88)0–14271100Maternal discharge records (age, sex, area)1,340100✓(any)
Wadsworth, 1997 (25)C-CU.K.British Paediatric Association Surveillance Unit (92)0–521389Health Authority Immunization Register31870✓(4)
Gimeno, 1997 (26)C-CBrazilDiabetes association/ Hospital admission (95)0–1934491Unclear (neighborhood, sex, age)‖333100✓(3)
McKinney, 1999 (28)C-CEnglandYorkshire Childhood Diabetes Register (93–94)0–1522094General practitioner's records (age, sex)42382✓(any)
Rami, 1999 (29)C-CAustriaVienna type 1 diabetes register (89–94)0–1410386Schools (age, sex)37380✓§✓(any)
Bache, 1999 (19)**C-CDenmarkHospital admission (78–95)0–14857100Medical birth registry (month, sex, district)1,404100
Dahlquist, 1999 (14)C-CBulgariaW. Bulgaria type 1 diabetes register (91–94)0–1412573Schools and policlinics (age)44079✓§✓(any)
C-CLatviaLatvian type 1 diabetes register (89–94)0–1414099Population register (age)30179✓§✓(any)
C-CLithuaniaLithuanian type 1 diabetes register (89–94)0–1411794Policlinics (age)26673✓§✓(any)
C-CLuxembourgLuxembourg type 1 diabetes register (89–95)0–1459100Preschools and schools (age)17295✓§✓(any)
C-CRomaniaBucharest type 1 diabetes register (89–94)0–148174Preschools and schools (age)27781✓§✓(any)
Stene, 2001 (13)CohortNorwayNorwegian Childhood Diabetes Registry (89–98)0–141,810100¶Norwegian medical birth registry1,382,602NA
Visalli, 2003 (30)C-CItalyLazio type 1 diabetes register (89–95)0–14139100Schools (age)70391✓(3)
Stene, 2004 (31)C-CNorwayNorwegian Childhood Diabetes Registry (98–00)0–1434673Norwegian population registry1,62656✓§✓(3)
Sadauskaite-Kuehne, 2004 (15)C-CSwedenSE Sweden type 1 diabetes register (95–00)0–15442100Population register1,08473✓§✓(3)
C-CLithuaniaLithuanian type 1 diabetes register (96–00)0–15281100Outpatient clinic‖80795✓§✓(3)
Sumnik, 2004 (32)C-CCzech RepublicCzech Republic type 1 diabetes registry (95–00)0–1564079National Birth registry (age)32,000100
Marshall, 2004 (33)C-CEnglandMorecambe Bay/E. Lancashire diabetes clinics (98)0–1519683Health Authorities (sex, birth date)38153✓§✓(any)
Cardwell, 2005 (34)CohortN. IrelandN. Ireland type 1 diabetes register (71–01)0–1499092¶Northern Ireland Child Health register439,647NA✓(any)
Sipetić, 2005 (35)C-CSerbiaBelgrade Hospital admission (94–97)0–1610591Hospital outpatients with skin disease‖ (age, sex, area)210100✓§✓(4)
Svensson, 2005 (36)C-CDenmarkDanish register of childhood diabetes (96–99)0–14602100Danish population register (age, sex)1,459100✓(4)
Bottini, 2005 (20)**C-CSardiniaHospital diagnosis?189?Consecutive births in northern Sardinia5,460?
Polańka, 2006 (37)C-CPolandUpper Silesia Diabetes Register (89–96)0–1439487Central Bureau for Statistics994,460100
Wei, 2006 (38)C-CTaiwanSchool-based urine screening program & questionnaire (92–97)0–1826087Randomly selected negatives from screening program53388✓(3)
Tenconi, 2007 (39)C-CItalyPavia type 1 diabetes register (88–00)0–199985Hospital (age, sex, week)194?
Haynes, 2007 (40)CohortAustraliaW. Australian Children's Diabetes Register (80–02)0–1492699¶W. Australia Midwives' Notification System∼557,707NA
Ievins, 2007 (41)CohortEnglandHosp. admission [ICD diabetes code] (63–99)0–14410Oxfordshire/W. Berkshire maternity records266,665NA✓(any)
Borras Perez, 2007 (42)C-CSpainCatalonia type 1 diabetes register (97–08)0–1462672Catalonia Public Health Birth Register3,32098✓(any)
Rosenbauer, 2008 (12)C-CGermanyNationwide hosp. based surveillance (92–95)0–474771Local registration offices (age, sex, area)1,82043✓§✓(4)
Waldhoer, 2008 (43)CohortAustriaAustrian diabetes register (89–05)0–544485¶Birth certificate registry1,435,385NA
  • *Year of publication.

  • †Number included in analysis of maternal age.

  • ‡Tick denotes data recorded in study and available for analysis.

  • §Maternal type 1 diabetes used in analyses.

  • ‖Not randomly selected and population based.

  • ¶Percentage of case subjects identified in cohort.

  • #Duration of breast-feeding used in adjusted analysis shown in brackets.

  • **Only included in sensitivity analyses. dx, diagnosis; Resp, response; BF, breast-feeding (in months); BO, birth order; BW, birth weight; C-C, case-control; CS, cesarean section; GA, gestational age; Hosp., hospital; MD, maternal diabetes; NA, not applicable.