Prevalence and trends in tobacco use among adolescents aged 13-15 years in 143 countries, 1999-2018: findings from the Global Youth Tobacco Surveys.

BACKGROUND: Tobacco use is a leading preventable cause of morbidity and mortality worldwide. Little is known about recent prevalence and trends in tobacco use among adolescents globally. We aimed to assess the recent global prevalence of tobacco use in young adolescents and the secular trends in prevalence between 1999 and 2018. METHODS: We used the most recent Global Youth Tobacco Surveys data on adolescents aged 13-15 years from 143 countries or territories that had done at least one survey between Jan 1, 2010, and Dec 31, 2018, to assess the recent prevalence of tobacco use; and data from 140 countries that had done two or more surveys between Jan 1, 1999, and Dec 31, 2018, to assess the trends in the prevalence of tobacco use. FINDINGS: 530 234 adolescents were included from the 143 countries that had done at least one survey between 2010 and 2018. 1 192 312 adolescents were included from the 140 countries that had done two or more surveys between 1999 and 2018. The most recent global prevalence of cigarette smoking was 11·3% (95% CI 10·3-12·3) in boys and 6·1% (5·6-6·6) in girls, based on cigarette smoking on at least 1 day during the past 30 days, 6·0% (5·5-6·6) and 2·6% (2·4-2·9) based on smoking on at least 3 days, and 4·2% (3·8-4·6) and 1·6% (1·4-1·8) based on smoking on at least 6 days. The most recent prevalence of the use of tobacco products other than cigarettes (eg, chewing tobacco, snuff, dip, cigars, cigarillos, pipe, electronic cigarettes) on at least 1 day during the past 30 days was 11·2% (9·9-12·6) in boys and 7·0% (6·4-7·7) in girls. The most recent prevalence of any tobacco use on at least 1 day during the past 30 days was 17·9% (16·1-19·6) in boys and 11·5% (10·5-12·4) in girls. The prevalence of cigarette smoking on at least 1 day during the past 30 days decreased between the first and last surveys in 80 (57·1%) of 140 countries, was unchanged in 39 countries (27·9%), and increased in 21 countries (15·0%). However, the prevalence of the use of tobacco products other than cigarettes was unchanged or increased in 81 (59·1%) of 137 countries. INTERPRETATION: The global prevalence of tobacco use among adolescents aged 13-15 years was substantial. Although the prevalence of cigarette smoking decreased over time in the majority of countries, the prevalence of the use of other tobacco products increased or did not change in the majority of countries during the past two decades. These findings re-emphasise the need to strengthen tobacco control efforts among young adolescents globally. FUNDING: Shandong University.

Metabolic syndrome, clustering of cardiovascular risk factors and high carotid intima-media thickness in children and adolescents.

OBJECTIVE: The clinical utility of screening for pediatric metabolic syndrome (MetS) in children and adolescents is still controversial. We examined the performance of pediatric MetS vs. clustering of cardiovascular risk factors (which are the components of MetS) for predicting high carotid intima-media thickness (cIMT) in children and adolescents. METHODS: Participants included 2427 children and adolescents aged 6-17 years from population-based studies in three countries (Brazil, China and Italy). Pediatric MetS was defined using either the modified National Cholesterol Education Program Adult Treatment Panel III criteria or the modified International Diabetes Federation criteria. Clustering of cardiovascular risk factors was calculated as the sum of five components of MetS (i.e. central obesity, elevated blood pressure, elevated triglycerides, reduced HDL-cholesterol and elevated fasting blood glucose). High cIMT was defined as cIMT at least 95th percentile values for sex and age developed from European children. RESULTS: Presence of one, two or at least three cardiovascular risk factors (using the National Cholesterol Education Program Adult Treatment Panel III criteria), as compared with none, was associated with gradually increasing odds of high cIMT [odds ratios (95% confidence intervals): 1.60 (1.29-1.99), 2.89 (2.21-3.78) and 4.24 (2.81-6.39), respectively]. High cIMT was also associated with presence (vs. absence) of MetS (odds ratio = 2.88, 95% confidence interval = 1.95-4.26). However, clustering of cardiovascular risk factors predicted high cIMT markedly better than MetS (area under the curve of 0.66 vs. 0.54, respectively). Findings were similar using the International Diabetes Federation criteria for pediatric MetS. CONCLUSION: In children and adolescents, a graded score based on five cardiovascular risk factors (used to define MetS) predicted high cIMT markedly better than MetS. These findings do not support the clinical utility of MetS for screening youth at increased cardiovascular risk, as expressed in this study by high cIMT.

Static cut-points of hypertension and increased arterial stiffness in children and adolescents: The International Childhood Vascular Function Evaluation Consortium.

Pediatric elevated blood pressure (BP) and hypertension are usually defined using traditional BP tables at the 90th and 95th percentiles, respectively, based on sex, age, and height, which are cumbersome to use in clinical practice. The authors aimed to assess the performance of the static cut-points (120/80 mm Hg and 130/80 mm Hg for defining elevated BP and hypertension for adolescents, respectively; and 110/70 mm Hg and 120/80 mm Hg for children, respectively) in predicting increased arterial stiffness. Using data from five population-based cross-sectional studies conducted in Brazil, China, Korea, and New Zealand, a total of 2546 children and adolescents aged 6-17 years were included. Increased arterial stiffness was defined as pulse wave velocity ≥sex-specific, age-specific, and study population-specific 90th percentile. Compared to youth with normal BP, those with hypertension defined using the 2017 American Academy of Pediatrics guideline (hereafter referred to as "percentile-based cut-points") and the static cut-points were at similar risk of increased arterial stiffness, with odds ratios and 95% confidence intervals of 2.35 (1.74-3.17) and 3.07 (2.20-4.28), respectively. Area under the receiver operating characteristic curve and net reclassification improvement methods confirmed the similar performance of static cut-points and percentile-based cut-points (P for difference > .05). In conclusion, the static cut-points performed similarly well when compared with the percentile-based cut-points in predicting childhood increased arterial stiffness. Use of static cut-points to define hypertension in childhood might simplify identification of children with abnormal BP in clinical practice.

Metabolically Healthy Obesity and High Carotid Intima-Media Thickness in Children and Adolescents: International Childhood Vascular Structure Evaluation Consortium.

OBJECTIVE: It has been argued that metabolically healthy obesity (MHO) does not increase cardiovascular disease (CVD) risk. This study examines the association of MHO with carotid intima-media thickness (cIMT), a proxy of CVD risk, in children and adolescents. RESEARCH DESIGN AND METHODS: Data were available for 3,497 children and adolescents aged 6-17 years from five population-based cross-sectional studies in Brazil, China, Greece, Italy, and Spain. Weight status categories (normal, overweight, and obese) were defined using BMI cutoffs from the International Obesity Task Force. Metabolic status (defined as "healthy" [no risk factors] or "unhealthy" [one or more risk factors]) was based on four CVD risk factors: elevated blood pressure, elevated triglyceride levels, reduced HDL cholesterol, and elevated fasting glucose. High cIMT was defined as cIMT ≥90th percentile for sex, age, and study population. Logistic regression model was used to examine the association of weight and metabolic status with high cIMT, with adjustment for sex, age, race/ethnicity, and study center. RESULTS: In comparison with metabolically healthy normal weight, odds ratios (ORs) for high cIMT were 2.29 (95% CI 1.58-3.32) for metabolically healthy overweight and 3.91 (2.46-6.21) for MHO. ORs for high cIMT were 1.44 (1.03-2.02) for unhealthy normal weight, 3.49 (2.51-4.85) for unhealthy overweight, and 6.96 (5.05-9.61) for unhealthy obesity. CONCLUSIONS: Among children and adolescents, cIMT was higher for both MHO and metabolically healthy overweight compared with metabolically healthy normal weight. Our findings reinforce the need for weight control in children and adolescents irrespective of their metabolic status.