Background Secondhand smoke exposure can cause morbidity and premature mortality. However, the global prevalence of, and trends in, secondhand smoke exposure among adolescents are poorly documented. We aimed to assess the prevalence of, and trends in, secondhand smoke exposure among adolescents from 1999 to 2018. MethodsWe did an analysis of the most recent data from the Global Youth Tobacco Survey (GYTS), a nationally representative, self-administered, school-based cross-sectional survey of tobacco use and related factors among adolescents aged 12-16 years worldwide. Data from 142 countries and territories that had done a GYTS between 2010 and 2018, comprising 711 366 participants, were used to assess the prevalence of secondhand smoke exposure. Data from 131 countries and territories that had done two or more surveys between 1999 and 2018, comprising 1 405 458 participants, were used to assess trends in secondhand smoke exposure. The frequency of secondhand smoke exposure at home, in public places, or in any place was defined as follows, based on students' responses: 1 or more days, 3 or more days, 5 or more days, or daily during the past 7 days. FindingsBased on the most recent surveys done in 142 countries between Jan 1, 2010, and Dec 31, 2018, the global prevalence of secondhand smoke exposure in any place was 62•9% (95% CI 61•7-64•1) on 1 or more days, 51•0% (49•8-52•1) on 3 or more days, 40•1% (38•9-41•2) on 5 or more days, and 32•5% (31•5-33•6) daily during the past 7 days. The prevalence of secondhand smoke exposure at home was 33•1% (95% CI 32•1-34•1) on 1 or more days, 20•1% (19•3-20•9) on 3 or more days, 14•9% (14•2-15•7) on 5 or more days, and 12•3% (11•7-13•0) daily during the past 7 days; and in public places the prevalence of secondhand smoke exposure was 57•6% (56•4-58•8) on 1 or more days, 43•4% (42•2-44•6) on 3 or more days, 30•3% (29•2-31•5) on 5 or more days, and 23•5% (22•5-24•5) daily during the past 7 days. Between Jan 1, 1999, and Dec 31, 2018, the prevalence of secondhand smoke exposure (on ≥1 day during the past 7 days) in any place decreased in 57 (43•5%) of 131 countries, increased in 27 (20•6%), and remained unchanged in 47 (35•9%). Although the prevalence of secondhand smoke exposure at home decreased in 86 (65•6%) countries, the prevalence in public places did not change in 46 (35•1%) countries and increased in 40 (30•5%).Interpretation Secondhand smoke exposure among adolescents remains a serious public health challenge worldwide. Although the prevalence of secondhand smoke exposure at home decreased in most countries, the prevalence in public places increased or remained unchanged in most countries between 1999 and 2018. These findings emphasise the need to strengthen smoke-free policies, especially in public places.

balance and walking speed tests are simple clinical procedures that can indicate hierarchical risk of ADL dependence in older adults.

Background: Interventions to increase physical activity or reduce sedentary behaviour within the workplace setting have shown mixed effects. This cluster randomised controlled trial assessed whether multi-component interventions, focusing on changes at the individual, environmental, and organisational levels, either increased physical activity or reduced sedentary behaviour, compared to a passive control group. Methods: Teams of office-workers from two companies participated in one of two interventions (iPA: targeting physical activity; or iSED: targeting sedentary behaviour), or wait-list control group (C). Exclusion criterion was very high physical activity level (MVPA ≥30 min/day in ≥10 min bouts every day). Randomisation occurred at the level of workplace cluster, and groups were randomly allocated (1:1) with stratification for company and cluster size. Personnel involved in data collection and processing were blinded to group allocation. Both interventions included five sessions of cognitive behavioural therapy counselling for 6 months. iPA included counselling focused on physical activity, access to a gym, and encouragement to exercise, and go for lunch walks. iSED included counselling on sedentary behaviour and encouragement to reduce sitting and increase engagement in standing-and walking-meetings. At baseline and the 6-month mark accelerometers were worn on the hip and thigh for 7 days. The primary outcomes were group differences in time spent in moderate-to-vigorous intensity physical activity (%MVPA) and in sedentary behaviour (%), analysed using Bayesian multilevel modelling for those with complete data.

In 2017, the American Academy of Pediatrics (AAP) updated the clinical practice guideline for high blood pressure (BP) in the pediatric population. In this study, we compared the difference in prevalence of elevated and hypertensive BP values defined by the 2017 AAP guideline and the 2004 Fourth Report and estimated the cardiovascular risk associated with the reclassification of BP status defined by the AAP guideline. A total of 47 200 children and adolescents aged 6 to 17 years from 6 countries (China, India, Iran, Korea, Poland, and Tunisia) were included in this study. Elevated BP and hypertension were defined according to 2 guidelines. In addition, 1606 children from China, Iran, and Korea who were reclassified upward by the AAP guideline compared with the Fourth Report and for whom laboratory data were available were 1:1 matched with children from the same countries who were normotensive by both guidelines. Compared with the Fourth Report, the prevalence of elevated BP defined by the AAP guideline was lower (14.9% versus 8.6%), whereas the prevalence of stages 1 and 2 hypertension was higher (stage 1, 6.6% versus 14.5%; stage 2, 0.4% versus 1.7%). Additionally, comparison of laboratory data in the case-control study showed that children who were reclassified upward were more likely to have adverse lipid profiles and high fasting blood glucose compared with normotensive children. In conclusion, the prevalence of elevated BP and hypertension varied significantly between both guidelines. Applying the new AAP guideline could identify more children with hypertension who are at increased cardiovascular risk.