Table 2.

Bias assessment of included studies

Clinical trial	Randomization	Classification of the cause	Post-randomization	Contamination bias	Compliance bias study
		of death	exclusions	control group	group
UK Age Trial [17,18]	Low risk of bias	Low risk of bias	Low risk of bias	No risk of bias	No risk of bias
Goteborg [7,8,19,20]	High risk of bias	Low risk of bias	Low risk of bias	No risk of bias	No risk of bias
Malmö 1 [8,21]	Low risk of bias	Unclear risk of bias	Low risk of bias	Low risk of bias	+
Malmö 2 [7,22]	High risk of bias	Low risk of bias	Unclear risk of bias	No risk of bias	No risk of bias
Stockholm [8,23]	High risk of bias	Unclear risk of bias	Unclear risk of bias	No risk of bias	No risk of bias
Canada 1 [24,27]	Low risk of bias	Low risk of bias	Low risk of bias	+	No risk of bias
Canada 2 [25,26]	Low risk of bias	Low risk of bias	Low risk of bias	+	No risk of bias
2 Swedish counties [28-30]	High risk of bias	High risk of bias	High risk of bias	No risk of bias	No risk of bias
New York [31-33]	High risk of bias	Low risk of bias	Unclear risk of bias	Low risk of bias	+
Edinburgh [34]	High risk of bias	Low risk of bias	High risk of bias	No risk of bias	+