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 dating sites Austin 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 total of 450,691 teenagers (boys: 51.4%) aged 12–16 ages regarding 138 places surveyed ranging from 2010 and you will 2019 had been integrated to guess the new frequency out-of most recent smokeless cigarette smoking and you may the relevant circumstances. One of 138 integrated countries surveyed this season–2019, 23 (16.7%) were regarding the African region, 30 (21.7%) about American area, 23 (16.7%) in the East Mediterranean area, 29 (22.5%) throughout the European region, 9 (six.5%) in the South-East Asian region, and you may 22 (15.9%) regarding the West Pacific region (Additional file 1: Table S2).
According to research by the current research out-of 138 places in 2010-2019, the general prevalence away from newest smokeless tobacco use try cuatro.4% (95% CI cuatro.0–cuatro.9), which have 5.7% (5.1–6.3) to possess people, 3.1% (dos.6–3.5) for women, step 3.9% (step three.5–4.4) to own teens old several–fourteen age, and you can 5.cuatro% (4.8–5.9) for those old 15–sixteen years (Desk 1). The new frequency ranged significantly round the all of the 138 countries (out of 0.0% within the Tokelau so you’re able to 51.6% in Kiribati), and also by intercourse and you can generation inside every one of very regions (Fig. step one, and extra document 1: Fig. S2 and you can Desk S3). Brand new prevalence is almost 5 times large among newest smokers compared to non-cigarette smokers (fourteen.3% versus. step three.0%), and you may nearly 7 minutes higher certainly one of other tobacco device pages opposed with non-pages (twenty two.5% compared to. 3.2%). The newest frequency among teens whose both parents (9.8%), and you will mommy merely (5.6%) smoked try higher than men and women whoever dad merely (4.4%) and you can none parent (4.7%) smoked. The latest frequency is highest on Southern area-East Western region (6.1%), with this new African region (5.4%), and you will lower on West Pacific region (2.0%). The fresh prevalence was high inside all the way down-middle-earnings places (5.5%), followed closely by reasonable-income countries (4.7%), and you may lower in the higher-money countries (2.8%) (Desk step one).
