| Variable | Data Type | Pack Year Components | Allowable Codes |
|---|---|---|---|
| age | float | Calculated subject's age at time of interview. (days(popdate - dob)/365.25) |
2-3 digits Null = Missing |
| q1smo | integer | Do you smoke cigarettes now? | 1 = Yes 2 = No 8 = Refused 9 = Don't know Null = Missing |
| q2smo | integer | Did you ever smoke cigarettes regularly? | 1 = Yes 2 = No 8 = Refused 9 = Don't know Null = Missing |
| q1asmo | integer | On the average, how many cigarettes a day do you smoke? | 1-200 888 = Refused 999 = Don't know Null = Missing |
| q1bsmo | integer | How old were you when you first smoked cigarettes regularly? | 0-115 888 = Refused 999 = Don't know Null = Missing |
| q2asmo | integer | On the average, how many cigarettes a day did you usually smoke? | 1-200 888 = Refused 999 = Don't know Null = Missing |
| q2bsmo | integer | How old were you when you lasted smoked cigarettes regularly? | 0-115 888 = Refused 999 = Don't know Null = Missing |
| q2csmo | integer | How old were you when you first smoked cigarettes regularly? | 0-115 888 = Refused 999 = Don't know Null = Missing |
| q3smo | integer | During that period of your life when you were smoking the most, about how many cigarettes a day did you usually smoke? | 1-200 888 = Refused 999 = Don't know Null = Missing |
| q4smo | integer | Altogether, about how many years did you smoke this much? | 1 = Yes 2 = No 8 = Refused 9 = Don't know Null = Missing |
All refused, don't know, and missing are equated to null.
if q1smo = (null, refused, don't know), then packyr = null
if q1smo = (null, refused, don't know) and q2smo = (null, refused, don't know) then packyr = null
if q1smo = 2 and q2smo = 2 then packyr = 0
Note: Question q2smo is skipped if subject is a current smoker.
if q1smo = 1 and q2smo = null then packyr = q1asmo/20 * (age - q1bsmo - q4smo) + q3smo/20 * q4smo
Note: Questions q1asmo and q1bsmo are skipped if subject is not a current smoker.
if q1smo = 2 and q2smo = 1 and (q2bsmo != q2csmo) then packyr = q2asmo/20 * (q2bsmo - q2csmo - q4smo) + q3smo/20 * q4smo
if year started smoking (q2asmo) equals the year stopped smoking (q2bsmo) then assume years smoked = 0.5 and packyr = q2asmo/20 * 0.5