Table 1.

Epidemiologic studies of cryptorchidism and testicular germ cell tumors (TGCT) included in the meta-analysis.

First author	Year published	Country	Ethnicitya	Number of TGCT cases	Number of controls	Source of casesb	Source of controlsb	Spontaneous descent includedc	Number of variables matched and/or adjusted for	Source of cryptorchidism datad
A. STUDIES THAT PROVIDED DATA ON TGCT CASES AND COMPARABLE REFERENCE GROUP
i. Case-control studies
Morrison (Morrison, 1976)	1976	USA	NS	596	602	Reg	Pop	No	0	TCMR
Henderson (Henderson et al., 1979)	1979	USA	WP	79	79	Reg	Neigh	NS	2	M
Loughlin (Loughlin et al., 1980)	1980	USA	WO	24	35	Hosp	Hosp	No	2	C + M
Schottenfold (Schottenfeld et al., 1980)	1980	USA	WO	157	309	Hosp	Hosp + Neigh	NS	3	C + M
Coldman (Coldman et al., 1982)	1982	Canada	NS	93	79	Hosp	Hosp	Yes	2	C, TCMR
Depue (Depue et al., 1983)	1983	USA	WO	107	108	Reg	Neigh	NS	2	C
Mills (Mills et al., 1984)	1984	USA	WP	347	347	Hosp	Hosp	NS	3	TCMR
Pottern (Pottern et al., 1985)	1985	USA	WP	271	259	Hosp	Hosp	Yes	2	C + M
Moss (Moss et al., 1986)	1986	USA	WP	246	252	Reg + Hosp	Friends	NS	3	C, M
Swerdlow (Swerdlow et al., 1987)	1987	England	NS	259	489	Reg + Hosp	Hosp	Yes	2	C
Gershman (Gershman and Stolley, 1988)	1988	USA	NS	79	79	Reg	Pop	NS	2	C
Strader (Strader et al., 1988)	1988	USA	WO	326	675	Reg	Pop	No	1	C
Haughey (Haughey et al., 1989)	1989	USA	WO	247	247	Reg	Neigh	NS	2	C
UK (United Kingdom Testicular Cancer Study Group (UK), 1994)	1994	UK	WO	794	794	Reg + Hosp	Pop	No	1	C + M
Gallagher (Gallagher et al., 1995)	1995	Canada	WP	506	994	Reg	Pop	NS	1	C
Prener (Prener et al., 1996)	1996	Denmark	NS	171	366	Reg	Pop	Yes	4	PTCMR
Davies (Davies et al., 1996)	1996	England	NS	129	395	Reg	Pop + Reg	NS	6	C + M
Møller (Moller et al., 1996)	1996	Denmark	NS	514	720	Reg	Pop	Yes	1	C
Petridou (Petridou et al., 1997)	1997	Greece	NS	97	198	Hosp	Pop	NS	2	C + M
Sabroe (Sabroe and Olsen, 1998)	1998	Denmark	NS	357	704	Reg	Pop	Yes	2	BR
Sigurdson (Sigurdson et al., 1999)	1999	USA	WP	160	136	Hosp	Friends	NS	4	C
Weir (Weir et al., 2000)	2000	Canada	NS	325	490	Reg	Pop	No	5	C
Stang (Stang et al., 2001)	2001	Germany	NS	262	797	Reg	Pop	Yes	2	C, M
Bonner (Bonner et al., 2002)	2002	USA	WO	116	328	Hosp	Hosp	NS	1	C
Herrinton (Herrinton et al., 2003)	2003	USA	WP	183	551	Hosp	Hosp	Yes	2	PTCMR
Dieckmann (Dieckmann and Pichlmeier, 2004)	2004	Unknown	Unknown	538	551	Unknown	Unknown	Unknown	Unknown	Unknown
Hardell (Hardell et al., 2007)	2007	Sweden	NS	888	870	Reg	Pop	NS	1	C
McGlynn (McGlynn et al., 2007)	2007	USA	WP	767	928	Reg	Pop	NS	3	C
Walschaerts (Walschaerts et al., 2007)	2007	France	NS	200	585	Hosp	Hosp	NS	1	C
Dusek (Dusek et al., 2008)	2008	Czech Republic	WO	356	317	Hosp	Hosp + Neigh	NS	1	C
Lacson (Lacson et al., 2012)		USA	WP	163	284	Reg	Neigh	Yes	3	C
ii. Cohort studies of boys with Cryptorchidism
Giwercman (Giwercman et al., 1987)	1987	Denmark	NS	6	–	Hosp	–	No	2	PTCMR
Benson (Benson et al., 1991)	1991	USA	NS	2	–	Hosp	–	Yes	1	PTCMR
Swerdlow (Swerdlow et al., 1997)	1997	England	NS	11	–	Hosp	–	No	2	PTCMR
Pettersson (Pettersson et al., 2007)	2007	Sweden	NS	56	–	Reg	–	No	2	PTCMR
Myrup (Myrup et al., 2007)	2007	Denmark	NS	110	–	Reg	–	No	2	PTCMR
B. STUDIES THAT PROVIDED DATA ON TGCT CASE SERIES, ESTIMATING RISK RATIOS USING CRYPTORCHIDISM FREQUENCY FROM EXTERNAL POPULATION
Miller (Miller and Seljelik, 1971)	1971	Norway	NS	314	–	Reg	–	NS	–	TCMR
Mostofi (Mostofi, 1973)	1973	USA	NS	2000	–	Army Reg	–	NS	–	TCMR
Wobbes (Wobbes et al., 1980)	1980	Netherlands	NS	230	–	Hosp	–	No	–	TCMR
Fonger (Fonger et al., 1981)	1981	Canada	NS	646	–	Hosp	–	Yes	–	TCMR
Thornhill (Thornhill et al., 1988)	1988	Ireland	NS	240	–	Reg	–	NS	–	TCMR
Stone (Stone et al., 1991)	1991	Australia	NS	778	–	Hosp	–	Yes	–	TCMR
Kanto (Kanto et al., 2004)	2004	Japan	J	240	–	Hosp	–	Yes	–	TCMR

^aNS, not specified; WO, white only; WP, white plus other ethnicities; J, Japanese.

^bReg, cancer registry; Hosp, hospital; Neigh, neighborhood; Pop, population.

^cNS, not specified.

^dC, case/control self report; M, case/control mother's report; C + M, case/control self report supplemented by mother's report; BR, birth record; PTCMR, pre-testicular cancer medical record, TCMR: testicular cancer medical record.