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*fcuatro, 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.
Performance
A total of 450,691 teenagers (boys: 51.4%) old a dozen–sixteen many years regarding 138 nations interviewed between 2010 and you will 2019 were incorporated to help you estimate this new frequency away from newest smokeless cigarette smoking and the associated points. One of 138 included regions interviewed this present year–2019, 23 (sixteen.7%) was basically regarding African part, 29 (21.7%) from the https://www.datingmentor.org/nl/tendermeets-overzicht Western region, 23 (sixteen.7%) in the Eastern Mediterranean region, 30 (twenty-two.5%) regarding European area, nine (6.5%) regarding the Southern area-Eastern Asian region, and you may twenty-two (15.9%) about Western Pacific region (A lot more file 1: Table S2).
In accordance with the latest data regarding 138 regions this year-2019, the entire frequency off latest smokeless tobacco use is actually 4.4% (95% CI cuatro.0–4.9), having 5.7% (5.1–6.3) to own males, step three.1% (dos.6–step 3.5) for girls, step three.9% (3.5–cuatro.4) getting teenagers old twelve–fourteen years, and you will 5.cuatro% (4.8–5.9) of these aged 15–sixteen many years (Table step 1). The newest prevalence ranged rather all over the 138 nations (of 0.0% in the Tokelau in order to 51.6% within the Kiribati), and by sex and you may generation within this each of extremely nations (Fig. 1, and additional file step one: Fig. S2 and Table S3). The fresh prevalence is actually almost 5 times highest certainly most recent smokers compared to low-smokers (fourteen.3% compared to. step three.0%), and you will almost 7 moments high one of most other smoke unit profiles opposed that have non-profiles (22.5% versus. 3.2%). The fresh prevalence certainly one of teens whoever both parents (9.8%), and mom only (5.6%) smoked was higher than those people whose dad simply (4.4%) and you can neither mother or father (4.7%) used. The fresh prevalence try higher regarding the Southern area-Eastern Far eastern region (six.1%), followed by the new African region (5.4%), and lower regarding Western Pacific part (dos.0%). Brand new prevalence is high when you look at the down-middle-income places (5.5%), with reduced-money regions (cuatro.7%), and you may lower within the high-income places (2.8%) (Dining table step one).
