According to the complex sampling design of the GYTS, the weighted prevalence estimates and their 95% confidence intervals (CI) of smokeless tobacco use in each country were calculated using original sampling weights, strata, and pripling units provided in the datasets using the SAS PROC SURVEYFREQ procedure. The original weights were calculated by the following formula: W=W1*W2*f1*f2*f3*f4, where W1 is the inverse of the selection probability of each school; W2 is the inverse of selection probability of each class; f1 is the school-level non-response adjustment factor calculated by school enrolment size; f2 is the class-level non-response adjustment factor for each school; f3 is the student-level non-response adjustment factor for each class; f4 is the post-adjustment stratification factor calculated by grade and sex. We rescaled the original weights to calculate the overall and subgroups’ prevalence of smokeless tobacco use based on each country’s sample size. The rescaled weights were calculated as the maximum country sample size (i.e., U. Chi-square trend test was used to examine the secular trend in the prevalence with consideration of data from all surveys in each country between 1999 and 2019. The prevalence estimates of secular trends were calculated per 5 calendar years. Multivariable logistic regression models were used to assess the association of potential associated factors (sex, age, cigarette smoking, other tobacco product use, parental smoking, smoking status of closest friends, tobacco advertisement exposure, being offered free tobacco products, being taught about dangers of smoking, and World Bank income level) with current smokeless tobacco use, and the code for each variable is shown in Additional file 1: Table S1. In order to correct the overall probability of type I error in multiple statistical tests (?=0.05), the Bonferroni’s correction was used to adjust the critical significance level of each statistical test. The corrected critical significance level was equal to the original critical significance level (0.05) divided by the number of tests performed. A two-sided P-value less than the Bonferroni’s corrected critical significance level was regarded as statistical significance and SAS 9.4 (SAS Institute, Cary, NC, US) was used for all analyses.
Overall performance
A maximum of 450,691 teens (boys: 51.4%) old twelve–sixteen age of 138 countries surveyed between 2010 and you may 2019 was in fact included to imagine the fresh prevalence regarding most recent smokeless cigarette smoking and their relevant issues. Among 138 integrated places interviewed in 2010–2019, 23 (16.7%) was indeed from the African region, 31 (21.7%) regarding the Western part, 23 (16.7%) throughout the East Mediterranean area, 29 (twenty two.5%) about European region, nine (6.5%) throughout the Southern area-East Western area, and you will twenty-two (fifteen.9%) regarding the West Pacific region (More file 1: Dining table S2).
According to research by the newest study off 138 nations this current year-2019, the general incidence regarding latest smokeless using tobacco are cuatro.4% (95% CI cuatro.0–4.9), with 5.7% (5.1–6.3) for males, 3.1% (2.6–3.5) for girls, step 3.9% (3.5–cuatro.4) to own teens old 12–fourteen years, and 5.4% (cuatro.8–5.9) of these aged fifteen–16 decades (Table 1). The fresh new frequency varied notably across the the 138 places (out-of 0.0% from inside the Tokelau in order to 51.6% when you look at the Kiribati), and by sex and age bracket in this each one of most nations (Fig. step one, and additional file step one: Fig. S2 and Desk S3). This new prevalence is actually nearly 5 times highest among newest cigarette smokers weighed against low-smokers https://datingmentor.org/nl/telegraph-dating-overzicht/ (14.3% against. step 3.0%), and you will nearly 7 minutes high certainly other cig equipment profiles compared which have non-pages (22.5% versus. step 3.2%). The brand new prevalence among teens whose both dad and mom (9.8%), and mom simply (5.6%) smoked is actually more than people whoever dad just (cuatro.4%) and you can none father or mother (4.7%) used. The newest incidence is higher on Southern-East Western area (six.1%), with the brand new African region (5.4%), and you will reasonable on the Western Pacific region (2.0%). The new prevalence was highest from inside the lower-middle-earnings countries (5.5%), followed by reduced-money nations (4.7%), and you may lower inside higher-income countries (dos.8%) (Desk 1).