On secondary analysis , there was an interaction between smoking and body mass index ( BMI ; Pinteraction = 0.017 ) : current smokers with BMI 25 kg/m ( 2 ) had an increased risk of low-grade ( OR = 1.54 , P = 0.043 ) and high-grade disease ( OR = 2.45 , P = 0.002 ) , with null associations for BMI 25 kg/m ( 2 ) .