Table 2.

Smoking-related characteristics of the participants according to the lung cancer risk

Variable	Total (n=1,730)	Average risk (n=1,570)	High risk (n=160)
Smoking history
Never smoker	312 (18.0)	312 (19.9)	NA
Former smoker	290 (16.8)	239 (15.2)	51 (31.9)
Current smoker	1,128 (65.2)	1,019 (64.9)	109 (68.1)
Smoking pack-years in former and current smokers	NA	13.6±10.8	43.1±17.4
Years since quitting smoking among former smokers	NA	11.9±7.4	9.6±6.9
Total smoking years in former and current smokers	NA	31.9±8.4	42.8±6.7
Age at starting smoking	NA	20.2±2.9	20.1±2.3

Values are presented as number (%) or mean±standard deviation. NA, not applicable.