Introduction:
In Croatia GYTS (Global Youth Tobacco Survey) was conducted in 2016, while HBSC was conducted in 2014. Objectives: Comparison of HBSC and GYTS data on smoking.

Results:
Surveys included: 3.587 adolescents, aged 13 and 15 (HBSC), and 2991, aged 13 and 15 (GYTS). In HBSC Lifetime prevalence has been determined with question: On how many days (if any) have you smoked cigarettes? “In your life time”. Answer categories: Never, 1-2 days, 3-5 days, 6-9 days,10-19 days, 20-29 days,30 days (or more) ”Never” answered: 78.5% (76.6% boys, 80.3% girls) age 13; 51.3% (50.7% boys, 52% girls). In GYTS: Have you ever tried or experimented with cigarette smoking, even one or two puffs? “Yes” answered: 30% adolescents aged 13, 59.9% aged 15, almost equally boys and girls (46.9%:44%). Current smokers (smoked cigarettes at least once during last 30 days), were also determined with similar question in both Surveys: How many days you smoked cigarettes during last 30 days? Answers offered in GYTS questionnaire was: none, 1-2, 3-5, 6-9, 10-19, 20-29, or each day, and in HBSC: Never, 1-2 days, 3-5 days, 6-9 days,10-19 days, 20-29 days, 30 days (or more). GYTS founds that: 6.5% aged 13 and 24.4% aged 15 almost equally boys and girls (15.1%:14.1%), are current smokers, and HBSC: 7.7% aged 13 (8.7% boys:6.8% girls), and 28.7% aged 15 (29.9% boys: 27.2% girls).

Conclusions:
Both surveys determined that tobacco smoking habits between youths increases with the age. Concerning determination of Prevalence shows that a small difference in the asked question can lead to large differences in the responses.

Funding:
Conducting of GYTS was funded by WHO.