1.

PRISMA 2009 checklist.

1.

PRISMA flow diagram of the included studies.

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Rate of uncontrolled asthma assessed using the GINA symptom control.

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Regression plot of rate of uncontrolled asthma against smoking.

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Rate of well-controlled asthma assessed using the GINA symptom control.

1.

Rate of partly controlled asthma assessed using the GINA symptom control.

1.

The rate of well-controlled asthma assessed using the Asthma Control Test (ACT).

1.

The rate of uncontrolled asthma assessed using the Asthma Control Test (ACT).

1.

Characteristics of the included studies.

1.

Diagnostic criteria and the outcomes of the studies.