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S1 Annex -

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PRISMA 2009 checklist.

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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.

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

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

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

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Characteristics of the included studies.