Underweight, overweight, and obesity in childhood and adolescence are associated with adverse health consequences throughout the life-course. Our aim was to estimate worldwide trends in mean body-mass index (BMI) and a comprehensive set of BMI categories that cover underweight to obesity in children and adolescents, and to compare trends with those of adults. We pooled 2416 population-based studies with measurements of height and weight on 128·9 million participants aged 5 years and older, including 31·5 million aged 5-19 years. We used a Bayesian hierarchical model to estimate trends from 1975 to 2016 in 200 countries for mean BMI and for prevalence of BMI in the following categories for children and adolescents aged 5-19 years: more than 2 SD below the median of the WHO growth reference for children and adolescents (referred to as moderate and severe underweight hereafter), 2 SD to more than 1 SD below the median (mild underweight), 1 SD below the median to 1 SD above the median (healthy weight), more than 1 SD to 2 SD above the median (overweight but not obese), and more than 2 SD above the median (obesity). Regional change in age-standardised mean BMI in girls from 1975 to 2016 ranged from virtually no change (-0·01 kg/m2 per decade; 95% credible interval -0·42 to 0·39, posterior probability [PP] of the observed decrease being a true decrease=0·5098) in eastern Europe to an increase of 1·00 kg/m2 per decade (0·69-1·35, PP>0·9999) in central Latin America and an increase of 0·95 kg/m2 per decade (0·64-1·25, PP>0·9999) in Polynesia and Micronesia. The range for boys was from a non-significant increase of 0·09 kg/m2 per decade (-0·33 to 0·49, PP=0·6926) in eastern Europe to an increase of 0·77 kg/m2 per decade (0·50-1·06, PP>0·9999) in Polynesia and Micronesia. Trends in mean BMI have recently flattened in northwestern Europe and the high-income English-speaking and Asia-Pacific regions for both sexes, southwestern Europe for boys, and central and Andean Latin America for girls. By contrast, the rise in BMI has accelerated in east and south Asia for both sexes, and southeast Asia for boys. Global age-standardised prevalence of obesity increased from 0·7% (0·4-1·2) in 1975 to 5·6% (4·8-6·5) in 2016 in girls, and from 0·9% (0·5-1·3) in 1975 to 7·8% (6·7-9·1) in 2016 in boys; the prevalence of moderate and severe underweight decreased from 9·2% (6·0-12·9) in 1975 to 8·4% (6·8-10·1) in 2016 in girls and from 14·8% (10·4-19·5) in 1975 to 12·4% (10·3-14·5) in 2016 in boys. Prevalence of moderate and severe underweight was highest in India, at 22·7% (16·7-29·6) among girls and 30·7% (23·5-38·0) among boys. Prevalence of obesity was more than 30% in girls in Nauru, the Cook Islands, and Palau; and boys in the Cook Islands, Nauru, Palau, Niue, and American Samoa in 2016. Prevalence of obesity was about 20% or more in several countries in Polynesia and Micronesia, the Middle East and north Africa, the Caribbean, and the USA. In 2016, 75 (44-117) million girls and 117 (70-178) million boys worldwide were moderately or severely underweight. In the same year, 50 (24-89) million girls and 74 (39-125) million boys worldwide were obese. The rising trends in children's and adolescents' BMI have plateaued in many high-income countries, albeit at high levels, but have accelerated in parts of Asia, with trends no longer correlated with those of adults. Wellcome Trust, AstraZeneca Young Health Programme.

Objectives To evaluate the individual risk factors composing the CHADS₂ (Congestive heart failure, Hypertension, Age≥75 years, Diabetes, previous Stroke) score and the CHA₂DS₂-VASc (CHA₂DS₂-Vascular disease, Age 65-74 years, Sex category) score and to calculate the capability of the schemes to predict thromboembolism. Design Registry based cohort study. Setting Nationwide data on patients admitted to hospital with atrial fibrillation. Population All patients with atrial fibrillation not treated with vitamin K antagonists in Denmark in the period 1997-2006. Main outcome measures Stroke and thromboembolism. Results Of 121 280 patients with non-valvular atrial fibrillation, 73 538 (60.6%) fulfilled the study inclusion criteria. In patients at “low risk” (score=0), the rate of thromboembolism per 100 person years was 1.67 (95% confidence interval 1.47 to 1.89) with CHADS₂ and 0.78 (0.58 to 1.04) with CHA₂DS₂-VASc at one year’s follow-up. In patients at “intermediate risk” (score=1), this rate was 4.75 (4.45 to 5.07) with CHADS₂ and 2.01 (1.70 to 2.36) with CHA₂DS₂-VASc. The rate of thromboembolism depended on the individual risk factors composing the scores, and both schemes underestimated the risk associated with previous thromboembolic events. When patients were categorised into low, intermediate, and high risk groups, C statistics at 10 years’ follow-up were 0.812 (0.796 to 0.827) with CHADS₂ and 0.888 (0.875 to 0.900) with CHA₂DS₂-VASc. Conclusions The risk associated with a specific risk stratification score depended on the risk factors composing the score. CHA₂DS₂-VASc performed better than CHADS₂ in predicting patients at high risk, and those categorised as low risk by CHA₂DS₂-VASc were truly at low risk for thromboembolism.

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities^1,2. This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity^3–6. Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017—and more than 80% in some low- and middle-income regions—was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing—and in some countries reversal—of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.

Objective To use the rs1229984 variant in the alcohol dehydrogenase 1B gene (ADH1B) as an instrument to investigate the causal role of alcohol in cardiovascular disease. Design Mendelian randomisation meta-analysis of 56 epidemiological studies. Participants 261 991 individuals of European descent, including 20 259 coronary heart disease cases and 10 164 stroke events. Data were available on ADH1B rs1229984 variant, alcohol phenotypes, and cardiovascular biomarkers. Main outcome measures Odds ratio for coronary heart disease and stroke associated with the ADH1B variant in all individuals and by categories of alcohol consumption. Results Carriers of the A-allele of ADH1B rs1229984 consumed 17.2% fewer units of alcohol per week (95% confidence interval 15.6% to 18.9%), had a lower prevalence of binge drinking (odds ratio 0.78 (95% CI 0.73 to 0.84)), and had higher abstention (odds ratio 1.27 (1.21 to 1.34)) than non-carriers. Rs1229984 A-allele carriers had lower systolic blood pressure (−0.88 (−1.19 to −0.56) mm Hg), interleukin-6 levels (−5.2% (−7.8 to −2.4%)), waist circumference (−0.3 (−0.6 to −0.1) cm), and body mass index (−0.17 (−0.24 to −0.10) kg/m²). Rs1229984 A-allele carriers had lower odds of coronary heart disease (odds ratio 0.90 (0.84 to 0.96)). The protective association of the ADH1B rs1229984 A-allele variant remained the same across all categories of alcohol consumption (P=0.83 for heterogeneity). Although no association of rs1229984 was identified with the combined subtypes of stroke, carriers of the A-allele had lower odds of ischaemic stroke (odds ratio 0.83 (0.72 to 0.95)). Conclusions Individuals with a genetic variant associated with non-drinking and lower alcohol consumption had a more favourable cardiovascular profile and a reduced risk of coronary heart disease than those without the genetic variant. This suggests that reduction of alcohol consumption, even for light to moderate drinkers, is beneficial for cardiovascular health.

To systematically review and summarize the evidence of an association between preoperative smoking status and postoperative complications elaborated on complication type. The conclusions of studies examining the association between preoperative smoking and postoperative complications are inconsistent, thus there is a need for a review and meta-analysis to summarize the existing evidence. A systematic review and meta-analysis based on a search in MEDLINE, EMBASE, CINAHL, and PsycINFO. Included were original studies of the association between smoking status and postoperative complications occurring within 30 days of operation. In total, 9354 studies were identified and reviewed for eligibility and data were extracted. Forest plots and summarized relative risks (RR) including 95% confidence intervals (CIs) were estimated for various complication types. Of the 9354 identified studies, 107 studies were included in the meta-analyses and based on these, 157 data sets were extracted. Preoperative smoking was associated with an increased risk of various postoperative complications including general morbidity (RR=1.52, 95% CI: 1.33-1.74), wound complications (RR=2.15, 95% CI: 1.87-2.49), general infections (RR=1.54, 95% CI: 1.32-1.79), pulmonary complications (RR=1.73, 95% CI: 1.35-2.23), neurological complications (RR=1.38, 95% CI: 1.01-1.88), and admission to intensive care unit (RR=1.60, 95% CI: 1.14-2.25). Preoperative smoking status was not observed to be associated with postoperative mortality, cardiovascular complications, bleedings, anastomotic leakage, or allograft rejection. Preoperative smoking was found to be associated with an increased risk of the following postoperative complications: general morbidity, wound complications, general infections, pulmonary complications, neurological complications, and admission to the intensive care unit.

It was the aim of this study to determine the efficacy and safety of vitamin K antagonists (VKAs) and acetylsalicylic acid (ASA) in patients with non-valvular atrial fibrillation (AF), with separate analyses according to predicted thromboembolic and bleeding risk. By individual levellinkage of nationwide registries, we identified all patients discharged with non-valvular AF in Denmark (n=132,372). For every patient, the risk of stroke and bleeding was calculated by CHADS₂, CHA₂DS₂-VASc, and HAS-BLED. During follow-up, treatment with VKA and ASA was determined time-dependently. VKA consistently lowered the risk of thromboembolism compared to ASA and no treatment; the combination of VKA+ASA did not yield any additional benefit. In patients at high thromboembolic risk, hazard ratios (95% confidence interval) for thromboembolism were: 1.81 (1.73–1.90), 1.14 (1.06–1.23), and 1.86 (1.78–1.95) for ASA, VKA+ASA, and no treatment, respectively, compared to VKA. The risk of bleeding was increased with VKA, ASA, and VKA+ASA compared to no treatment, the hazard ratios were: 1.0 (VKA; reference), 0.93 (ASA; 0.89–0.97), 1.64 (VKA+ASA; 1.55–1.74), and 0.84 (no treatment; 0.81–0.88), respectively. There was a neutral or positive net clinical benefit (ischaemic stroke vs. intracranial haemorrhage) with VKA alone in patients with a CHADS₂ score of ≥ 0, and CHA₂DS₂-VASc score of ≥ 1. This large cohort study confirms the efficacy of VKA and no effect of ASA treatment on the risk of stroke/thromboembolism. Also, the risk of bleeding was increased with both VKA and ASA treatment, but the net clinical benefit was clearly positive, in favour of VKA in patients with increased risk of stroke/thromboembolism.