TROMSO_SMO_YRS

Variables SMO_STAT_DAILY, SMO_START, SMO_STOP, and CONTACT_AGE are the CHANCES variables.

SAS code:

If SMO_STAT_DAILY EQ 1 then SMO_YRS = 0;

Else if SMO_STAT_DAILY EQ 9 or SMO_START EQ 9999 then SMO_YRS = 9999;

Else if SMO_STAT_DAILY EQ 2 and SMO_STOP NE 9999 and SMO_STOP >= SMO_START then SMO_YRS = SMO_STOP - SMO_START;

Else if SMO_STAT_DAILY EQ 2 and SMO_STOP NE 9999 and SMO_STOP < SMO_START then SMO_YRS = 9999;

Else if SMO_STAT_DAILY EQ 2 and SMO_STOP EQ 9999 then SMO_YRS = 9999;

Else if SMO_STAT_DAILY EQ 3 then SMO_YRS = CONTACT_AGE - SMO_START;

If SMO_YRS < 0 then SMO_YRS=9999;

SHARE_SMO_YRS

SMO_YRS is derived from SHARE variable br003

BR003_ HOW MANY YEARS SMOKED
For how many years [n]have you smoked all together[/n]?
Don't include periods without smoking Code 1 if respondent smoked for less than one year
___________ (1..150)

SENECA_SMO_YRS

Contact round 1:

SMO_YRS is based on SMO_STAT_DAILY and  SENECA variable SMOKEYRS (“Number of years smoking”)

IF SMO_STAT_DAILY=1 THEN SMO_YRS=0;

ELSE IF SMO_STAT_DAILY IN(2,3) AND SMOKEYRS NE . THEN SMO_YRS=SMOKEYRS;

ELSE IF SMO_STAT_DAILY IN(2,3) AND SMOKEYRS=. THEN SMO_YRS=.;

ELSE IF SMO_STAT_DAILY IN(9) THEN SMO_YRS=.;

Contact round 2:

SMO_YRS is based on SMO_STAT_DAILY  and SENECA variable FMOKEYR (“Number of years smoking”)

IF SMO_STAT_DAILY=1 THEN SMO_YRS=0;

ELSE IF SMO_STAT_DAILY IN(2,3) AND FSMOKEYR NE . THEN SMO_YRS=FSMOKEYR;

ELSE IF SMO_STAT_DAILY IN(2,3) AND FSMOKEYR=. THEN SMO_YRS=.;

ELSE IF SMO_STAT_DAILY IN(9) THEN SMO_YRS=.;

Contact round 3:

SMO_YRS is not available for contact round 3.

MORGAM_SMO_YRS

The SMO_YRS variable is defined using the MORGAM derived variable CIGYRS and the CHANCES variable SMO_STAT_DAILY.

CIGYRS Years of daily cigarette smoking before baseline
99 = insufficient data

HAPIEE_SMO_YRS

Based on  HAPIEE baseline variables, l39 for current smoking status, l41, age at which current and past smokers started smoking, and  l42, age at smoking cessation for past smokers. Contact_age is a CHANCES variable, based on HAPIEE variable age, rounded to the nearest integer.  

l39 "Do you smoke cigarettes?"

1 "Yes, regularly, at least 1 cigarette a day"
2 "Yes, occasionally, less than 1 cigarette a day"
3 "No, I smoked in the past but I stopped"
4 "No, I have never smoked" 
.   Missing 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
Stata code 

replace l42=. if l42==.c
gen smo_yrs=.
replace smo_yrs=0 if l39==4 
replace smo_yrs=9999 if (l39==. | l41==.) & smo_yrs==.
replace smo_yrs=l42-l41 if (l39==3 & l41~=.) & smo_yrs==.
replace smo_yrs=9999 if (l39==3 & l41==.) & smo_yrs==.
replace smo_yrs=contact_age - l41 if l39<3 & smo_yrs==.   
replace smo_yrs=9999 if smo_yrs==.

ESTHER_SMO_YRS

if smo_yrs = . then smo_yrs = 9999;

Source of smo_yrs are the variables L41RAU2 from the participant's questionnaire and contact_age (CHANCES variable).

EPIC_SMO_YRS

The variables DUR_SMOK and SMOKE_STAT_DAILY were used for the production of SMO_YRS according to the following definition and rule.

EPIC var definition(s):

DUR_SMOK: Epic elderly variable showing duration of smoking in years

SMOKE_STAT_DAILY: Epic elderly variable showing current daily smoking status (1=never daily smoker , 2=former daily smoker, 3=daily smoker, 9=unknown)

Coding rule:
Variable SMO_YRS shows the duration (in years) of smoking.

Is identical to DUR_SMOK.

Is equal to 0 if the person has never been a daily smoker (SMO_STAT_DAILY=1)

Otherwise SMO_YRS is coded as missing if the person's current daily smoking status is unavailable (SMO_STAT_DAILY=9) and for the rest of the cases.

Coding rule in STATA:

-gen SMO_YRS=DUR_SMOK

-replace SMO_YRS= 9999 if SMO_STAT_DAILY==9

-replace SMO_YRS= 0 if SMO_STAT_DAILY==1

-replace SMO_YRS= 9999 if SMO_YRS==.