Table 1.

Variables included in the study and their coding for analysis

Variable	Question asked in the survey	Coding for analysis
	Response variable
	(a) Smoked tobacco
Variable ID: CR3 BDR15 NPR12	During the past 30 days, on how many days did you smoke cigarettes/bidis? Options included: 1 = 0 days, 2 = 1 or 2 days, 3 = 3 to 5 days, 4 = 6 to 9 days, 5 = 10 to 19 days, 6 = 20 to 29 days, 7 = All 30 days	0 = Not using cigarettes (option 1) 1 = Any use (option 2 to 7)
Variable ID: NPR17 CR8	During the past 30 days, did you use any form of smoked tobacco products other than cigarettes and bidis such as cigars, water pipe (hukkah), cigarillos, little cigars, pipe etc.? Options included: 1 = yes, 2 = no	0 = Not using other smoked tobacco products (option 2) 1 = Any use (option 1)
	(b) Smokeless tobacco
Variable ID: BDR23 NPR20	(A) During the past 30 days, on how many days did you use smokeless tobacco (chewing or applying or snuff) such as surti, khaini, panmasala, gutka, parag, gul etc.? Options included: 1 = 0 days, 2 = 1 or 2 days, 3 = 3 to 5 days, 4 = 6 to 9 days, 5 = 10 to 19 days, 6 = 20 to 29 days, 7 = All 30 days	0 = Not using any smokeless products (option 1) 1 = Any use (option 2 to 7)
Variable ID: CR9	(B) During the past 30 days, did you use any form of smokeless tobacco products (e.g. chewing tobacco, snuff, dip)? Options included: 1 = yes, 2 = no	0 = Not using any smokeless tobacco products (option 2) 1 = Any use (option 1)
Variable Name	Question asked in the survey	Coding for analysis
Independent variables
Age in years CR52	How old are you? Options included: 11 to 17 years	1 = youths (13 to 15 years of age); 0 = others
Gender: CR53	What is your sex?	1 = male, 2 = female
Education gradeBDR73, NPR75, LKR54	In what grade are you?	Seventh, Eighth, Ninth, Tenth
Parental tobacco use CR12, BDR25, BDR26	Do your parents smoke cigarettes/bidis or use smokeless tobacco? 1 = none, 2 = both, 3 = father only, 4 = mother only, 5 = I don’t know	0 = no (option 1 & 5) 1 = yes (option 2 to 4)
Friends tobacco use CR25	Do any of your closest friends smoke? 1 = none of them, 2 = some of them, 3 = most of them, 4 = all of them	0 = no (option 1) 1 = yes (option 2 to 4)
Smoking at home CR30	During the past 7 days, on how many days have people smoked in your home, in your presence? Options included:	0 = no (option 1) 1 = 1-4 days (option 2 & 3) 3 = 5-7 days (option 4 & 5)
Smoking at other places than home CR31	During the past 7 days, on how many days have people smoked in your presence, in places other than in your home? 1 = 0, 2 = 1 to 2, 3 = 3 to 4, 4 = 5 to 6, 5 = 7 days	0 = no (option 1) 1 = 1-4 days (option 2 & 3) 3 = 5-7 days (option 4 & 5)
Offer free tobacco products by sales men: CR47	Has a cigarette company representative ever offered you a free cigarette? Options included: 1 = yes, 2 = no	0 = no (option 2) 1 = yes (option 1)
Advertisement seen in hoarding, bus-stop, station CR44	During the past 30 days, how many advertisements for cigarettes have you seen on hoardings, buses, bus-stops, trains, railway platforms, shops or as writings on walls? Options included: 1 = a lot, 2 = a few, 3 = none	0 = none (option 3) 1 = a few (option 2) 2 = a lot (option 1)
Taught in class about danger of smoking: CR48	During this school year, were you taught in any of your classes about the dangers of smoking? Options included: 1 = yes, 2 = no, 3 = not sure	0 = no (option 2 and 3) 1 = yes (option 1)
Discussed smoking and health as part of a lesson BDR70, CR51	How long ago did last discuss smoking and health as part of a lesson? 1 = never, 2 = this year/term, 3 = last year/term, 4 = 2 years/terms ago, 5 = 3 years/terms ago, 6 = more than 3 years/terms ago	0 = never (option 1) 1 = during this survey year (option 2); 2 = before year of survey (option 3 to 6)

CR indicates the core questions that were asked for all countries in GYTS. Country specific questions were labeled as BDR for Bangladesh, NPR for Nepal and LKR for Sri Lanka.