Table 1.

Characteristics of the included studies.

First Author	Year	Country	Study Years	Data Source	Total Sample (Males)	Mean Age in Years (SD)
Janszky [23]	2008	Sweden	1987–2006	Swedish Registry of Acute Myocardial Infarction (no further detail provided)	>24,000 * (NR)	NR
Janszky [19]	2012	Sweden	1995–2007	Register of Information and Knowledge about Swedish Heart Intensive Care Admission (RIKS-HIA), including all patients with a diagnosis of AMI admitted to the Coronary care Units of 74 Swedish hospitals	>7300 * (>4650)	NR
Culic [20]	2013	Croatia	1990–1996	Hospital Discharge Abstracts of all patients with a primary diagnosis of AMI discharged from the Split University Hospital	2412 (1666)	64.1 (11.9)
Jiddou [22]	2013	USA	2006–2012	Hospital Discharge Abstracts of all patients with a primary diagnosis of AMI discharged from the Royal Oak and Troy Campuses of Beaumont Hospitals (Michigan)	935 (551)	70.0 (14.8)
Sandhu [21]	2014	USA	2010–2013	Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2) Database, including all Michigan residents with a diagnosis of AMI undergoing a PCI	42,060 (NR)	NR
Kirchberger [17]	2015	Germany	1985–2010	MONICA-KORA Myocardial Infarction Registry, including all residents in the County of Augsburg with a diagnosis of AMI, discharged from the Klinikum Augsburg Hospital (80%) or from minor County hospitals	25,499 (18,524)	62.6 (9.2)
Sipilä [18]	2015	Finland	2001–2009	Hospital Discharge Abstracts of all patients with a primary diagnosis of AMI (ICD-10 code 121x), discharged from one of the 22 Finnish hospitals with a coronary catheterization lab and treating emergency cardiac patients	14,459 (8748)	71.2 (12.8)

AMI = Acute Myocardial Infarction; PCI = Percutaneous coronary intervention; NR = Not reported. * When a study did not provide the total sample, we reported the overall number of patients with AMI among cases and controls.