Table 3

  Adjusted odds ratios for respiratory symptoms and physician consultations by number of smokers at work in males

1 smoker OR† (95% CI)2 smokers OR† (95% CI)3 smokers OR† (95% CI)⩾4 smokers OR† (95% CI)p for linear trend
*p<0.05; **p<0.01; ***p<0.001.
†Within each smoking category, the reference group is current smokers with no co-workers smoking nearby at work; odds ratios are adjusted for age, marital status, educational attainment, police rank, type of police duties, exposure to self perceived dusty or polluted environment in previous job, and SHS exposure at home. Additional adjustment for amount of smoking and duration of smoking was made in current smokers, and for smoking status in the analysis of current smokers and never-smokers combined.
‡Western physicians and Chinese traditional doctors
§p for interaction for SHS exposure variables and smoking status. A significant p value indicates significant difference in odds ratios between current smokers and never-smokers.
Throat problems
    Current smokers1.52**(1.16 to 1.99)1.53***(1.19 to 1.97)1.63***(1.28 to 2.07)1.73***(1.39 to 2.16)<0.001
    Never-smokers1.48**(1.12 to 1.96)1.98***(1.56 to 2.51)2.08***(1.64 to 2.62)2.62***(2.12 to 3.24)<0.001
    p for interaction§0.7020.2030.393<0.05
Cough, morning
    Current smokers1.37*(1.01 to 1.87)1.63***(1.23 to 2.16)1.73***(1.32 to 2.27)2.03***(1.58 to 2.61)<0.001
    Never-smokers1.55*(1.08 to 2.22)1.78***(1.31 to 2.43)1.69**(1.24 to 2.29)1.76***(1.32 to 2.33)<0.001
    p for interaction0.7430.6390.5990.294
Cough, day or night
    Current smokers1.40*(1.02 to 1.93)1.66***(1.24 to 2.23)1.84***(1.39 to 2.43)2.03***(1.57 to 2.63)<0.001
    Never-smokers1.46*(1.01 to 2.11)1.77***(1.29 to 2.43)1.74***(1.27 to 2.37)1.99***(1.50 to 2.65)<0.001
    p for interaction0.9270.8930.5360.679
Cough, chronic
    Current smokers2.26**(1.24 to 4.15)1.90*(1.06 to 3.42)2.45**(1.41 to 4.26)3.02***(1.80 to 5.06)<0.001
    Never-smokers2.10*(1.01 to 4.37)2.22*(1.16 to 4.27)2.62**(1.40 to 4.92)3.02***(1.68 to 5.44)<0.001
    p for interaction0.7900.8450.9390.850
Phlegm, morning
    Current smokers1.12(0.85 to 1.47)1.26(0.98 to 1.61)1.28*(1.01 to 1.63)1.47***(1.18 to 1.83)<0.001
    Never-smokers1.36(0.97 to 1.91)1.91***(1.44 to 2.53)1.94***(1.47 to 2.55)2.15***(1.67 to 2.77)<0.001
    p for interaction0.5490.0580.0670.070
Phlegm, day or night
    Current smokers1.43*(1.06 to 1.94)1.71***(1.29 to 2.25)1.65***(1.26 to 2.16)1.64***(1.28 to 2.10)<0.001
    Never-smokers1.25(0.83 to 1.89)1.93***(1.38 to 2.69)1.93***(1.39 to 2.68)2.47***(1.83 to 3.34)<0.001
    p for interaction0.4710.7800.7150.105
Phlegm, chronic
    Current smokers1.27(0.82 to 1.98)1.48(0.99 to 2.19)1.48*(1.01 to 2.16)2.04***(1.44 to 2.88)<0.001
    Never-smokers0.89(0.45 to 1.75)2.01**(1.23 to 3.29)1.60(0.97 to 2.65)2.83***(1.82 to 4.40)<0.001
    p for interaction0.3820.3420.8310.327
Any cough or phlegm
    Current smokers1.27(0.98 to 1.65)1.54***(1.21 to 1.96)1.58***(1.25 to 1.98)1.69***(1.37 to 2.09)<0.001
    Never-smokers1.34*(1.01 to 1.77)1.92***(1.51 to 2.43)1.80***(1.43 to 2.28)2.09***(1.69 to 2.59)<0.001
    p for interaction0.9830.3390.7180.344
Increased cough or phlegm
    Current smokers1.53*(1.09 to 2.13)1.71***(1.26 to 2.32)1.78***(1.32 to 2.39)1.96***(1.49 to 2.57)<0.001
    Never-smokers1.56*(1.10 to 2.21)1.57**(1.15 to 2.13)1.95***(1.45 to 2.62)2.18***(1.67 to 2.85)<0.001
    p for interaction0.8040.3560.9020.993
Ever wheezing
    Current smokers1.29(0.86 to 1.96)1.24(0.84 to 1.82)1.26(0.87 to 1.83)1.53*(1.09 to 2.13)<0.05
    Never-smokers1.58(0.99 to 2.51)1.66*(1.10 to 2.50)1.97**(1.33 to 2.91)1.74**(1.21 to 2.51)<0.01
    p for interaction0.3800.4140.1390.651
Blocked or running nose
    Current smokers1.32*(1.01 to 1.72)1.44**(1.13 to 1.84)1.22(0.96 to 1.54)1.21(0.98 to 1.51)0.340
    Never-smokers1.51**(1.15 to 1.98)1.75***(1.39 to 2.21)1.82***(1.45 to 2.29)2.07***(1.69 to 2.55)<0.001
    p for interaction0.4500.236<0.05<0.001
Any symptoms above
    Current smokers1.48**(1.12 to 1.96)1.76***(1.35 to 2.29)1.58***(1.23 to 2.02)1.73***(1.38 to 2.17)<0.001
    Never-smokers1.79***(1.39 to 2.30)2.17***(1.75 to 2.70)2.28***(1.84 to 2.82)2.73***(2.25 to 3.31)<0.001
    p for interaction0.3530.3840.096<0.05
Physician consultations in past 14 days for respiratory symptoms‡
    Current smokers1.55*(1.09 to 2.20)1.48*(1.06 to 2.05)1.48*(1.08 to 2.03)1.47**(1.10 to 1.98)0.051
    Never-smokers1.13(0.82 to 1.56)1.17(0.89 to 1.53)1.32*(1.01 to 1.72)1.41**(1.11 to 1.80)<0.01
    p for interaction0.1230.1890.4120.489