TABLE 2—

Relative Risk (RR) and 95% Confidence Interval (CI) Results for Highest Cumulative or Intensity of Exposure Groups: Meta-analysis of Data From Multiple Locations Worldwide, 2003

Reference	Gender Included in Study	Exposure Measurea	RR (95% CI)
Boffetta et al.31	Both	≥ 89 level × hours per day × yearsb	2.07 (1.33, 3.21)
Johnson et al.38	Women	≥ 64 smokers × years	1.58 (0.6, 4.0)
Kabat et al.18	Men	Smokers × hours per week × yearsc	1.21 (0.47, 3.13)
Kabat et al.18	Women	Smokers × hours per week × yearsc	1.35 (0.64, 2.84)
Kalandidi et al.24	Women	Duration × number coworkersd	1.08 (0.24, 4.87)
Kreuzer et al.35	Both	> 100.6 level × hours per day × yearsb	2.64 (1.07, 6.54)e
Lee et al.36	Men	Average to a lot	0.46 (0.05, 4.65)f
Zhong et al.15	Women	≥ 4 coworkers smoked	3.0 (1.8, 4.9)
Meta-analysis
Fixed effects			2.01 (1.55, 2.60)
Mixed effects			2.01 (1.33, 2.60)

^a The measure of exposure used to categorize workers varied from study to study. For studies that presented more than 1 measure, preference was given to exposure measures that reflected both intensity and duration (i.e., cumulative exposures).

^b The total number of years of exposure weighted for the number of hours of exposure per day and for a subjective index of level of smokiness at the workplace (1 = very smoky, 0.5 = fairly smoky, and 0.2 = a little smoky).

^c The highest tertile of exposure was compared with the lowest tertile. The actual values of the tertiles were not presented in the article.

^d The results are for a comparison between the highest and lowest quartiles of “the time-weighted sum of exposure at work, the exposure being based on the number of smokers among people working in the same closed space.” The units of these quartiles are not presented in the article.

^e Results are from an analysis that excluded cases and controls that were in the analysis by Boffetta et al.,31 which was not presented in the original analysis.

^f Crude results not adjusted for any risk factors.