Table 3.

Population attributable fraction

PAF	Back pain incidence (95% CI)	P-value
Attributable to current and former smoking behaviors (vs never smoke)	7.8% (6.8-8.8)	<0.001
Attributable to current smoking behaviors (vs former smoke)	5.4% (4.5-6.2)	<0.001
Attributable to more cigarettes smoked daily (vs number of cigarettes smoked daily was up to 10)	9.8% (6.9-12.7)	<0.001
Attributable to more Pack-years of own smoking (vs pack-years of own smoking was up to 10)	18.0% (15.0-21.0)	<0.001

PAF – population-attributable fraction, CI – confidence interval

*Population-attributable fraction (PAF) analysis was used to estimate the proportion of risks which could be prevented by not smoking (never vs current and former), quit smoking (former vs current) and reducing smoking volume and intensity (‘’Up to 10” vs more smoking volume and intensity).