Table 2.

Study quality assessment. (n = 9).

Study (Author, year)	Well-defined casesa	Well-defined controlsa	Matched controlsb	Timing of exposurec	Adjustment for confounding variablesd
Martinelli et al., 1996 (8)	Yes	Yes	Yes	Yes	Age
Martinelli et al., 1998 (9)	Yes	Yes	Yes	Yes	PT, FV
Reuner et al., 1998 (10)	No	No	Yes	No	None
de Bruijn et al., 1998 (11)	Yes	No	No	No	Age
Martinelli et al., 2003 (13)	No	Yes	Yes	Yes	Age, BMI, smoking, HyperHcy
Cantu et al., 2004 (14)	No	Yes	No	No	None
Rodrigues et al., 2004 (15)	No	No	No	No	None
Ventura et al., 2004 (16)	No	No	No	No	None
Gadelha et al., 2005 (17)	Yes	Yes	Yes	No	PT, FV

A study is defined as being of high quality if it satisfies at least four of the five criteria above.

^aWell-defined cases are objective confirmation of CVST in patients 15–50 years, without autoimmune, neoplastic, or infectious diseases and not post-traumatic, pregnant, post-partum, or post-menopausal). Well-defined controls are healthy individuals, between age 18 and 50 years, unrelated biologically to patient); Yes fulfills criteria for both or one of the above; “No” fulfills neither of the above criteria.

^bWell-matched controls matched for at least one of age, BMI, smoking status, educational status, and ethnicity.

^cExposure within 2 weeks of CVST for cases or time of assessment for controls.

^dAdjustment for confounding factors is defined as (1) Controls matched for at least one of age, body mass index (BMI), smoking status, educational status, and ethnicity and (2) adjustment during statistical analysis for age, BMI, smoking status, hyper-homocysteinemia, Prothrombin-gene mutation (PT) and factor V Leiden (FV).

HyperHcy is hyper-homocysteinemia.