Table 1.

Characteristics of Included Studies

Author, Year	Country	Design	Setting	Year Recruited	Sample Size	Inclusion Age	Mean or Median Age
Diehr, 19847	United States	Prospective	ED	Not reported	1758	Adults	Not reported
Gennis, 198920	United States	Prospective	ED	1984 to 1985	308	≥16 years	53.6 years (mean)
Singal, 198914	United States	Prospective	ED	1986 to 1987	255	≥18 years	Not reported
Heckerling, 19907	United States	Prospective	ED	1987 to 1988	1436	≥16 years	45.4 years (mean): Illinois/Nebraska; 41.4 years (mean): Virginia
Melbye, 199217	Norway	Prospective	ED	1988 to 1989	581	≥18 years	32.1 (mean)
Hopstaken, 200318	The Netherlands	Cross-sectional/prospective	Primary care	1998 to 1999	246	≥18 years	52 years (mean)
O'Brien, 200616	United States	Case-control/prospective	Outpatient/ED	2004 to 2005	700	≥18 years	65 years (mean): cases; 66 years (mean): controls
Holm, 200719	Denmark	Prospective	Primary care	2002 to 2003	364	≥18 years	50 years (median)
Saldias, 200715	Chile	Prospective	ED	2005	325	>15 years	53.4 years (mean)
Steurer, 20118	Switzerland	Prospective	Primary care	2006 to 2009	621	≥18 years	46.8 years (mean)
van Vugt, 20139	12 European countries	Prospective	Primary care	2007 to 2010	2820	Adults	50 years (mean)
Ebrahimzadeh, 201521	Iran	Case-control/prospective	Outpatient/ED	2008 to 2009	840	≥18 years	60 years (mean): cases; 63 years (mean): controls

ED, emergency department.