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Abstract Background Undiagnosed type 2 diabetes (T2D) is a global problem. Current strategies for diagnosis in Sweden include screening individuals within primary healthcare who are of high risk, such as those with hypertension, obesity, prediabetes, family history of diabetes, or those who smoke daily. In this study, we aimed to estimate the proportion of individuals with undiagnosed T2D in Stockholm County and factors associated with T2D being diagnosed by healthcare. This information could improve strategies for detection. Methods We used data from the Stockholm Diabetes Prevention Programme (SDPP) cohort together with information from national and regional registers. Individuals without T2D aged 35–56 years at baseline were followed up after two ten-year periods. The proportion of diagnosed T2D was based on register information for 7664 individuals during period 1 and for 5148 during period 2. Undiagnosed T2D was assessed by oral glucose tolerance tests at the end of each period. With logistic regression, we analysed factors associated with being diagnosed among individuals with T2D. Results At the end of the first period, the proportion of individuals with T2D who had been diagnosed with T2D or not was similar (54.0% undiagnosed). At the end of the second period, the proportion of individuals with T2D was generally higher, but they were less likely to be undiagnosed (43.5%). The likelihood of being diagnosed was in adjusted analyses associated with overweight (OR=1.85; 95% CI 1.22–2.80), obesity (OR=2.73; 95% CI 1.76–4.23), higher fasting blood glucose (OR=2.11; 95% CI 1.67–2.66), and self-estimated poor general health (OR=2.42; 95% CI 1.07–5.45). Socioeconomic factors were not associated with being diagnosed among individuals with T2D. Most individuals (>71%) who developed T2D belonged to risk groups defined by having at least two of the prominent risk factors obesity, hypertension, daily smoking, prediabetes, or family history of T2D, including individuals with T2D who had not been diagnosed by healthcare. Conclusions Nearly half of individuals who develop T2D during 10 years in Stockholm County are undiagnosed, emphasizing a need for intensified screening of T2D within primary healthcare. Screening can be targeted to individuals who have at least two prominent risk factors.

We tested the causality between education and smoking using the natural experiment of discordant twin pairs allowing to optimally control for background genetic and childhood social factors. Data from 18 cohorts including 10,527 monozygotic (MZ) and same-sex dizygotic (DZ) twin pairs discordant for education and smoking were analyzed by linear fixed effects regression models. Within twin pairs, education levels were lower among the currently smoking than among the never smoking co-twins and this education difference was larger within DZ than MZ pairs. Similarly, education levels were higher among former smoking than among currently smoking co-twins, and this difference was larger within DZ pairs. Our results support the hypothesis of a causal effect of education on both current smoking status and smoking cessation. However, the even greater intra-pair differences within DZ pairs, who share only 50% of their segregating genes, provide evidence that shared genetic factors also contribute to these associations.

Abstract Background The coronavirus disease 2019 (COVID-19) disproportionately affects minority populations in the USA. Sweden — like other Nordic countries — have less income and wealth inequality but lacks data on the socioeconomic impact on the risk of adverse outcomes due to COVID-19. Methods This population-wide study from March 2020 to March 2022 included all adults in Stockholm, except those in nursing homes or receiving in-home care. Data sources include hospitals, primary care (individual diagnoses), the Swedish National Tax Agency (death dates), the Total Population Register “RTB” (sex, age, birth country), the Household Register (size of household), the Integrated Database For Labor Market Research “LISA” (educational level, income, and occupation), and SmiNet (COVID data). Individual exposures include education, income, type of work and ability to work from home, living area and living conditions as well as the individual country of origin and co-morbidities. Additionally, we have data on the risks associated with living areas. We used a Cox proportional hazards model and logistic regression to estimate associations. Area-level covariates were used in a principal component analysis to generate a measurement of neighborhood deprivation. As outcomes, we used hospitalization and death due to COVID-19. Results Among the 1,782,125 persons, male sex, comorbidities, higher age, and not being born in Sweden increase the risk of hospitalization and death. So does lower education and lower income, the lowest incomes doubled the risk of death from COVID-19. Area estimates, where the model includes individual risks, show that high population density and a high percentage of foreign-born inhabitants increased the risk of hospitalization. Conclusions Segregation and deprivation are public health issues elucidated by COVID-19. Neighborhood deprivation, prevalent in Stockholm, adds to individual risks and is associated with hospitalization and death. This finding is paramount for governments, agencies, and healthcare institutions interested in targeted interventions.

Abstract Background The prevention of type 2 diabetes is challenging due to the variable effects of risk factors at an individual level. Data-driven methods could be useful to detect more homogeneous groups based on risk factor variability. The aim of this study was to derive characteristic phenotypes using cluster analysis of common risk factors and to assess their utility to stratify the risk of type 2 diabetes. Methods Data on 7317 diabetes-free adults from Sweden were used in the main analysis and on 2332 diabetes-free adults from Mexico for external validation. Clusters were based on sex, family history of diabetes, educational attainment, fasting blood glucose and insulin levels, estimated insulin resistance and β-cell function, systolic and diastolic blood pressure, and BMI. The risk of type 2 diabetes was assessed using Cox proportional hazards models. The predictive accuracy and long-term stability of the clusters were then compared to different definitions of prediabetes. Results Six risk phenotypes were identified independently in both cohorts: very low-risk (VLR), low-risk low β-cell function (LRLB), low-risk high β-cell function (LRHB), high-risk high blood pressure (HRHBP), high-risk β-cell failure (HRBF), and high-risk insulin-resistant (HRIR). Compared to the LRHB cluster, the VLR and LRLB clusters showed a lower risk, while the HRHBP, HRBF, and HRIR clusters showed a higher risk of developing type 2 diabetes. The high-risk clusters, as a group, had a better predictive accuracy than prediabetes and adequate stability after 20 years. Conclusions Phenotypes derived using cluster analysis were useful in stratifying the risk of type 2 diabetes among diabetes-free adults in two independent cohorts. These results could be used to develop more precise public health interventions.

Abstract We tested the causality between education and smoking using the natural experiment of discordant twin pairs allowing to optimally control for background genetic and childhood social factors. Data from 18 cohorts including 10,527 monozygotic (MZ) and same-sex dizygotic (DZ) twin pairs discordant for education and smoking were analyzed by linear fixed effects regression models. Within twin pairs, education levels were lower among the currently smoking than among the never smoking co-twins and this education difference was larger within DZ than MZ pairs. Similarly, education levels were higher among former smoking than among currently smoking co-twins, and this difference was larger within DZ pairs. Our results support the hypothesis of a causal effect of education on both current smoking status and smoking cessation. However, the even greater intra-pair differences within DZ pairs, who share only 50% of their segregating genes, provide evidence that shared genetic factors also contribute to these associations.

Abstract Background Parental self-efficacy (PSE) has been suggested as a key factor for enabling parents to support children in the development of healthy dietary and physical activity behaviors and to prevent childhood obesity. However, studies of intervention effects on PSE are lacking. The present study involved a secondary analysis of data on PSE collected in a previous primary prevention trial of childhood obesity called the PRIMROSE trial. The trial involved a family-based intervention using motivational interviewing and principles of cognitive-behavioral therapy within a social-cognitive theory framework. Methods In the PRIMROSE trial, parents and their children were randomly allocated to the intervention or usual care. In the present study, 928 mothers who responded to the Parental Self-Efficacy for Promoting Healthy Physical Activity and Dietary Behaviors in Children Scale (PSEPAD) at follow-up assessment were included. Data were analyzed using linear regression based on generalized estimating equations, with adjustment made for PSE at baseline. Results At follow-up assessment, there was a statistically significant difference of 1.4 units, 95% CI [0.4, 2.4], p = 0.009, between the intervention and control conditions on the subscale of the PSEPAD concerning PSE for promoting healthy dietary behaviors in children. However, this difference was deemed as without clinical importance. On the total scale or other subscales of the PSEPAD there were no statistically significant differences in PSE between conditions. Conclusions There was a statistically significant, but not clinically meaningful, intervention effect on PSE. However, because previous research repeatedly has shown positive associations of PSE with dietary and physical activity behaviors in children and that self-efficacy mediates behaviors, the construct may be important for influencing dietary and physical behaviors in children. Therefore, more research is warranted evaluating the effects of interventions on PSE in the context of childhood obesity prevention. Trial registration Retrospectively registered 9 October 2013 at ISRCTN (ISRCTN16991919 ).

Abstract Although exposure to overweight and obesity at different ages is associated to a higher risk of type 2 diabetes, the effect of different patterns of exposure through life remains unclear. We aimed to characterize life-course trajectories of weight categories and estimate their impact on the incidence of type 2 diabetes. We categorized the weight of 7203 participants as lean, normal or overweight at five time-points from ages 7–55 using retrospective data. Participants were followed for an average of 19 years for the development of type 2 diabetes. We used latent class analysis to describe distinctive trajectories and estimated the risk ratio, absolute risk difference and population attributable fraction (PAF) associated to different trajectories using Poisson regression. We found five distinctive life-course trajectories. Using the stable-normal weight trajectory as reference, the stable overweight, lean increasing weight, overweight from early adulthood and overweight from late adulthood trajectories were associated to higher risk of type 2 diabetes. The estimated risk ratios and absolute risk differences were statistically significant for all trajectories, except for the risk ratio of the lean increasing trajectory group among men. Of the 981 incident cases of type 2 diabetes, 47.4% among women and 42.9% among men were attributable to exposure to any life-course trajectory different from stable normal weight. Most of the risk was attributable to trajectories including overweight or obesity at any point of life (36.8% of the cases among women and 36.7% among men). The overweight from early adulthood trajectory had the highest impact (PAF: 23.2% for woman and 28.5% for men). We described five distinctive life-course trajectories of weight that were associated to increased risk of type 2 diabetes over 19 years of follow-up. The variability of the effect of exposure to overweight and obesity on the risk of developing type 2 diabetes was largely explained by exposure to the different life-course trajectories of weight.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Abstract Background Roux-en-Y Gastric Bypass (RYGB) patients overestimate their time spent in moderate-to-vigorous physical activity (MVPA) to a greater extent post-surgery than pre-surgery. However, there is no data on discrepancy between self-reported and accelerometer-measured MVPA beyond nine months post-RYGB. The aim was to investigate how the duration of MVPA (main outcome) differs when comparing a self-administered questionnaire to accelerometer-data from pre-surgery and up to 48 months post-RYGB. Methods Twenty-six (38%) RYGB-treated women with complete data from the original cohort (N = 69) were included. Participants were recruited from five Swedish hospitals. Mean pre-surgery BMI was 38.9 (standard deviation (SD) = 3.4) kg/m2 and mean age 39.9 (SD = 6.5) years. MVPA was subjectively measured by a self-administered questionnaire and objectively measured by the ActiGraph GT3X+ accelerometer at 3 months pre-RYGB and 9- and 48 months post-RYGB. Means and SD were calculated at 3 months pre- and 9- and 48 months post-RYGB. We calculated the P-values of the differences with Wilcoxon Signed-Rank test. For correlations between the self-administered questionnaire and the accelerometers, Spearman’s rank correlation was used. Results Participants significantly overestimated (i.e. self-reported more time spent in MVPA compared to accelerometry) their MVPA in a higher degree post- compared to pre-RYGB surgery. Compared to pre-surgery, self-reported MVPA increased with 46.9 and 36.5% from pre- to 9- and 48 months, respectively, whereas changes were a 6.1% increase and 3.5% decrease with accelerometers. Correlations between self-reported and accelerometer-measured MVPA-assessments were poor at all measurement points (r = 0.21–0.42) and only significant at 48 months post-RYGB (P = 0.032). Conclusions The discrepancy between self-reported and objectively assessed MVPA within the same individual is greater up to 48 months post-RYGB compared to before surgery. To help bariatric patients understand and hopefully increase their physical activity behaviors post-surgery, objective measures of physical activity should be used.

Aims: To study if machine learning methodology can be used to detect persons with increased type 2 diabetes or prediabetes risk among people without known abnormal glucose regulation. Methods: Machine learning and interpretable machine learning models were applied on research data from Stockholm Diabetes Preventive Program, including more than 8000 people initially with normal glucose tolerance or prediabetes to determine high and low risk features for further impairment in glucose tolerance at follow-up 10 and 20 years later. Results: The features with the highest importance on the outcome were body mass index, waist-hip ratio, age, systolic and diastolic blood pressure, and diabetes heredity. High values of these features as well as diabetes heredity conferred increased risk of type 2 diabetes. . The machine learning model was used to generate individual, comprehensible risk profiles, where the diabetes risk was obtained for each person in the data set. Features with the largest increasing or decreasing effects on the risk were determined. Conclusions: The primary application of this machine learning model is to predict individual type 2 diabetes risk in people without diagnosed diabetes, and to which features the risk relates. However, since most features affecting diabetes risk also play a role for metabolic control in diabetes, e.g. body mass index, diet composition, tobacco use, and stress, the tool can possibly also be used in diabetes care to develop more individualized, easily accessible health care plans to be utilized when encountering the patients.

Abstract Background People with mobility disability (MD) or obesity often have more health problems and are less able to participate in work than individuals without these conditions. This study investigated whether people burdened with MD and obesity have a greater risk of unemployment than people with either one (MD only or obesity only) or none of these conditions. Methods The study included two Swedish population-based cohorts, a national cohort (n = 39,947) and a regional cohort (n = 40,088). Six exposure groups were created using baseline self-reported data on MD and body mass index from participants aged 19 to 64 years. The MD definition differed between the cohorts. Various sources of socio-demographic factors were used to address confounding. Participants’ risks of unemployment were assessed longitudinally in a nationwide register with objective data and with almost no loss of follow-up (

Background The majority of Roux-en-Y gastric bypass (RYGB) patients are not sufficiently physically active post-surgery, yet little support from the Swedish healthcare system is offered. We investigated if a dissonance-based group intervention, aiming to increase health-related quality of life after surgery, had any effect on patients’ physical activity two years post-RYGB. Methods Women undergoing RYGB surgery were recruited from five Swedish hospitals and randomized to intervention or control group (standard post-surgery care). The dissonance-based intervention was conducted three months post-RYGB and consisted of four group sessions, each with a specific topic, of which one addressed physical activity. ActiGraph GT3X+ accelerometers were used to measure physical activity at pre-RYGB, one- and two-years post-surgery. Results At pre-RYGB, 259 women were recruited and randomized (intervention n = 156 and control n = 103). Participants had a mean age of 44.7 years (SD 10.3) and pre-RYGB body mass index of 40.8 (SD 4.5) kg/m2. At two-years follow-up, 99 participants (63.5%) in intervention group and 68 (66.0%) in control group had valid accelerometer-measurements. Pre- to post-surgery increases were seen in all physical activity outcomes, but no statistically significant differences between the groups were observed at the two-years follow-up, and intervention effects were poor (d = 0.02–0.35). Conclusion To our knowledge, this is the first dissonance-based intervention targeting women undergoing RYGB surgery. At two-years follow-up, we did not observe any differences in physical activity levels between the intervention group and control group. Trial registration number: ISRCTN16417174.

Background Preterm delivery and low birth weight are prospectively associated with low cardiorespiratory fitness (CRF). However, whether birth weight, within the at‐term range, is associated with later CRF is largely unknown. Thus, the aim of the current study was to examine this issue and whether such association, if any, is explained by shared and/or nonshared familial factors. Methods and Results We conducted a prospective cohort study, including 286 761 young male adults and a subset of 52 544 siblings born at‐term. Objectively measured data were retrieved from total population registers. CRF was tested at conscription and defined as the maximal load obtained on a cycle ergometer. We used linear and nonlinear and fixed‐effects regression analyses to explore associations between birth weight and CRF. Higher birth weight, within the at‐term range, was strongly associated with increasing CRF in a linear fashion. Each SD increase in birth weight was associated with an increase of 7.9 (95% CI, 7.8–8.1) and 6.6 (95% CI; 5.9–7.3) Wmax in the total and sibling cohorts, respectively. The association did not vary with young adulthood body mass index. Conclusions Birth weight is strongly associated with increasing CRF in young adulthood among men born at‐term, across all categories of body mass index. This association appears to be mainly driven by factors that are not shared between siblings. Hence, CRF may to some extent be determined already in utero. Prevention of low birth weight, also within the at‐term‐range, can be a feasible mean of increasing adult CRF and health.

Abstract Background Roux-en-Y gastric bypass (RYGB) surgery is the most common bariatric procedure in Sweden and results in substantial weight loss. Approximately one year post-surgery weight regain for these patient are common, followed by a decrease in health related quality of life (HRQoL) and physical activity (PA). Our aim is to investigate the effects of a dissonance-based intervention on HRQoL, PA and other health-related behaviors in female RYGB patients 24 months after surgery. We are not aware of any previous RCT that has investigated the effects of a similar intervention targeting health behaviors after RYGB. Methods The ongoing RCT, the “WELL-GBP”-trial (wellbeing after gastric bypass), is a dissonance-based intervention for female RYGB patients conducted at five hospitals in Sweden. The participants are randomized to either control group receiving usual follow-up care, or to receive an intervention consisting of four group sessions three months post-surgery during which a modified version of the Stice dissonance-based intervention model is used. The sessions are held at the hospitals, and topics discussed are PA, eating behavior, social and intimate relationships. All participants are asked to complete questionnaires measuring HRQoL and other health-related behaviors and wear an accelerometer for seven days before surgery and at six months, one year and two years after surgery. The intention to treat and per protocol analysis will focus on differences between the intervention and control group from pre-surgery assessments to follow-up assessments at 24 months after RYGB. Patients’ baseline characteristics are presented in this protocol paper. Discussion A total of 259 RYGB female patients has been enrolled in the “WELL-GBP”-trial, of which 156 women have been randomized to receive the intervention and 103 women to control group. The trial is conducted within a Swedish health care setting where female RYGB patients from diverse geographical areas are represented. Our results may, therefore, be representative for female RYGB patients in the country as a whole. If the intervention is effective, implementation within the Swedish health care system is possible within the near future. Trial registration The trial was registered on February 23th 2015 with registration number ISRCTN16417174.

Abstract Background Objectively measured levels of physical activity (PA) in patients undergoing Roux-en-Y Gastric Bypass (RYGB) surgery remain essentially unchanged from before to one year after surgery. Effects from RYGB on objectively measured levels of PA among women undergoing RYGB and appurtenant children beyond one year post-surgery are unknown. The aim of the present study was to objectively assess longitudinal changes in PA and sedentary time (ST), among women undergoing RYGB and appurtenant children, from three months before to nine and 48 months after maternal surgery. Methods Thirty women undergoing RYGB and 40 children provided anthropometric measures during home visits and valid accelerometer assessed (Actigraph GT3X+) PA data, three months before and nine and 48 months after maternal RYGB surgery. Results Women undergoing RYGB decreased time spent in moderate to vigorous PA (MVPA) with 2.0 min/day (p = 0.65) and increased ST with 14.4 min/day (p = 0.35), whereas their children decreased time spent in MVPA with 13.2 min/day (p = 0.04) and increased ST with 110.5 min/day (p

Abstract Background Physical activity (PA) improves health outcomes accumulating evidence suggests that sedentary time (ST), especially parent-reported screen-time, is associated with negative health outcomes in children. The aim of the present study is to describe levels and patterns of PA and ST across the day and week and activity pattern differences between the sexes, across all weekdays and time spent in and outside the preschool in four-year old children. Methods In total 899 four-year old Swedish children who had both complete questionnaire data on screen-time behaviors and objective activity variables and at least 4 days, including one weekend day, with more than 10 h of GT3X+ Actigraph accelerometer wear time data were included in the study. Patterns of PA and ST across the day and week and differences between sexes, weekdays vs. weekend days and time in preschool vs. time spent outside preschool were assessed. Results Children engaged in 150 min (SD 73) and 102 min (SD 60) of screen-time on weekend days and weekdays, with 97% and 86% of children exceeding the 1 h guideline for screen-time on weekend days and weekdays, respectively. Accelerometer data showed that boys are more active and less sedentary compared with girls and both sexes were more active and less sedentary on weekdays compared with weekend days, while parent-reported data showed that boys engage in more screen-time compared with girls. Children accumulated 24.8 min (SD. 19) MVPA during preschool time and 26.6 min (SD. 16) outside preschool hours on weekdays, compared with 22.4 min (SD. 18) MVPA during preschool time and 25.3 min (SD. 22) outside preschool hours on weekend days. Conclusions Four-year old Swedish children display different activity patterns across the day on weekdays compared to weekend days, with preschool hours during weekdays being the most active segments and preschool hours during weekend days being the least active segments of the day.

BackgroundHigh body mass index (BMI) is associated with mortality, but the pervasive problem of confounding and reverse causality in observational studies limits inference about the direction and magnitude of causal effects. We aimed to obtain estimates of the causal association of BMI with all-cause and cause-specific mortality.Methods and findingsIn a record-linked, intergenerational prospective study from the general population of Sweden, we used two-sample instrumental variable (IV) analysis with data from 996,898 fathers (282,407 deaths) and 1,013,083 mothers (153,043 deaths) and their sons followed up from January 1, 1961, until December 31, 2004. Sons' BMI was used as the instrument for parents' BMI to compute hazard ratios (HRs) for risk of mortality per standard deviation (SD) higher parents' BMI. Using offspring exposure as an instrument for parents' exposure is unlikely to be affected by reverse causality (an important source of bias in this context) and reduces confounding. IV analyses supported causal associations between higher BMI and greater risk of all-cause mortality (HR [95% confidence interval (CI)] per SD higher fathers' BMI: 1.29 [1.26-1.31] and mothers' BMI: 1.39 [1.35-1.42]) and overall cancer mortality (HR per SD higher fathers' BMI: 1.20 [1.16-1.24] and mothers' BMI: 1.29 [1.24-1.34]), including 9 site-specific cancers in men (bladder, colorectum, gallbladder, kidney, liver, lung, lymphatic system, pancreas, and stomach) and 11 site-specific cancers in women (gallbladder, kidney, liver, lung, lymphatic system, ovaries, pancreas, stomach, uterus, cervix, and endometrium). There was evidence supporting causal associations between higher BMI in mothers and greater risk of mortality from kidney disease (HR: 2.17 [1.68-2.81]) and lower risk of mortality from suicide (HR: 0.77 [0.65-0.90]). In both sexes, there was evidence supporting causal associations between higher BMI and mortality from cardiovascular diseases (CVDs), stroke, diabetes, and respiratory diseases. We were unable to test the association between sons' and mothers' BMIs (as mothers' data were unavailable) or whether the instrument was independent of unmeasured or residual confounding; however, the associations between parents' mortality and sons' BMI were negligibly influenced by adjustment for available confounders.ConclusionsConsistent with previous large-scale meta-analyses and reviews, results supported the causal role of higher BMI in increasing the risk of several common causes of death, including cancers with increasing global incidence. We also found positive effects of BMI on mortality from respiratory disease, prostate cancer, and lung cancer, which has been inconsistently reported in the literature, suggesting that the causal role of higher BMI in mortality from these diseases may be underestimated. Furthermore, we expect different patterns of bias in the current observational and IV analyses; therefore, the similarities between our findings from both methods increases confidence in the results. These findings support efforts to understand the mechanisms underpinning these effects to inform targeted interventions and develop population-based strategies to reduce rising obesity levels for disease prevention.

BackgroundChildhood obesity is a major clinical and economic health concern. Alongside the clinical understanding of obesity, there is a growing interest in designing and implementing interventions that are worth their money given the scarce resources in the health care sector. This study is one of the first efforts to provide evidence by assessing the effects and costs of a population-based primary prevention intervention targeting pre-school children attending child health centers in Sweden.MethodsThe economic evaluation is based on the PRIMROSE cluster-randomized controlled trial aiming to establish healthy eating and physical activity among pre-school children (9–48 months of age) through motivational interviewing applied by trained nurses at child health centers. The cost-effectiveness is assessed over the trial period from a societal perspective. The primary outcome was BMI at age 4. Cost data was prospectively collected alongside the trial. Scenario analyses were carried out to identify uncertainty.ResultsThe estimated additional mean total costs of the PRIMROSE intervention were 342 Euro (95% CI: 334; 348) per child. During pre-school years direct costs mainly consist of training costs and costs for the additional time used by nurses to implement the intervention compared to usual care. Early indirect costs mainly consist of parents’ absence from work due to their participation in the intervention. The incremental cost-effectiveness ratio in the base case analysis was 3,109 Euro per 1 BMI unit prevented.ConclusionWe cannot provide evidence that the PRIMROSE intervention is cost-effective, given the uncertainty in the effect measure. Until further evidence is provided, we recommend resources to be spent elsewhere within the field of obesity prevention. Furthermore, to achieve valid and reliable cost-effectiveness results, the economic evaluation of obesity prevention programs in early childhood should incorporate the life time impact to capture all relevant costs and benefits.

BACKGROUND:Smokers tend to weigh less than never smokers, while successful quitting leads to an increase in body weight. Because smokers and non-smokers may differ in genetic and environmental family background, we analysed data from twin pairs in which the co-twins differed by their smoking behaviour to evaluate if the association between smoking and body mass index (BMI) remains after controlling for family background. METHODS AND FINDINGS:The international CODATwins database includes information on smoking and BMI measured between 1960 and 2012 from 156,593 twin individuals 18-69 years of age. Individual-based data (230,378 measurements) and data of smoking discordant twin pairs (altogether 30,014 pairwise measurements, 36% from monozygotic [MZ] pairs) were analysed with linear fixed-effects regression models by 10-year periods. In MZ pairs, the smoking co-twin had, on average, 0.57 kg/m2 lower BMI in men (95% confidence interval (CI): 0.49, 0.70) and 0.65 kg/m2 lower BMI in women (95% CI: 0.52, 0.79) than the never smoking co-twin. Former smokers had 0.70 kg/m2 higher BMI among men (95% CI: 0.63, 0.78) and 0.62 kg/m2 higher BMI among women (95% CI: 0.51, 0.73) than their currently smoking MZ co-twins. Little difference in BMI was observed when comparing former smoking co-twins with their never smoking MZ co-twins (0.13 kg/m2, 95% CI 0.04, 0.23 among men; -0.04 kg/m2, 95% CI -0.16, 0.09 among women). The associations were similar within dizygotic pairs and when analysing twins as individuals. The observed series of cross-sectional associations were independent of sex, age, and measurement decade. CONCLUSIONS:Smoking is associated with lower BMI and smoking cessation with higher BMI. However, the net effect of smoking and subsequent cessation on weight development appears to be minimal, i.e. never more than an average of 0.7 kg/m2.

BACKGROUND/OBJECTIVES: There is a lack of research exploring the effects of Roux-en-Y gastric bypass (RYGB) surgery on the patient's family's eating behaviour and food choices. The aim of the current study was to investigate changes in partners' and children's eating behaviour and food choices following maternal RYGB. SUBJECTS/METHODS: Sixty-nine women and their families were recruited from RYGB waiting lists at five Swedish surgical clinics. Data were collected during home visits 3 months before and 9 months after RYGB. Anthropometrical measures were taken, the adults completed the Three-Factor Eating Questionnaire and the children completed the Children's Eating Attitudes Test (ChEAT). All participants also completed a short food frequency questionnaire. RESULTS: Changes in scores were analysed using paired t-tests for unadjusted estimates or linear regression models with robust variance (General Estimating Equations) in order to enable age- and sex-adjusted estimates for the children. There were no meaningful differences in the partners' eating behaviour or food choices. The boys, but not the girls, improved their ChEAT scores, as did the overweight/obese children in comparison with the normal-weight children. The boys, unlike the girls, also decreased their intake of soft drinks, as did the normal-weight children when compared with the overweight/obese children. CONCLUSIONS: No clear-cut changes were found in partners' eating behaviour and food choices. Eating attitudes and soft drinks intake were improved among boys but not among girls. Differing modelling behaviour may partially explain these findings, but available data did not allow us to understand the underlying mechanisms. doi:10.1038/ejcn.2015.136; published online 2 September 2015, INTRODUCTION For morbidly obese patients, bariatric surgery produces significant long-term weight loss and reduction in comorbidities, together with relatively low complication rates. (1-3) Laparoscopic Roux-en-Y gastric bypass (RYGB) accounts for [...]

Human height variation is determined by genetic and environmental factors, but it remains unclear whether their influences differ across birth-year cohorts. We conducted an individual-based pooled analysis of 40 twin cohorts including 143,390 complete twin pairs born 1886–1994. Although genetic variance showed a generally increasing trend across the birth-year cohorts, heritability estimates (0.69-0.84 in men and 0.53-0.78 in women) did not present any clear pattern of secular changes. Comparing geographic-cultural regions (Europe, North America and Australia, and East Asia), total height variance was greatest in North America and Australia and lowest in East Asia, but no clear pattern in the heritability estimates across the birth-year cohorts emerged. Our findings do not support the hypothesis that heritability of height is lower in populations with low living standards than in affluent populations, nor that heritability of height will increase within a population as living standards improve.

Research on training in motivational interviewing (MI) has shown eroding skills after workshops not followed by additional training input (supervision/coaching). There is a need for more research evaluating different types and lengths of post-workshop training with follow-up periods extending six months. This study is an extension of a previous evaluation of the level of proficiency in MI after workshop and four sessions of supervision among nurses in Swedish child health services.To explore the level of MI proficiency among nurses participating in an intervention to prevent childhood obesity (n = 33), after receiving five additional sessions of supervision including feedback on observed practice, as well as level of proficiency at follow-up.Level of proficiency was measured 4 and 12 months after completed supervision using recorded practice samples coded according to the Motivational Interviewing Treatment Integrity (MITI) Code. Potential predictors of outcome were investigated.Proficiency remained on the same levels after nine sessions of supervision as after four sessions, and was generally low. The percentage of nurses reaching the proficiency level ranged from 18.2 to 54.5% across indicators. MI-spirit had increased significantly at follow-up, and the rest of the indicators remained on the same levels. No predictors of outcome were found.Comprehensive training programs with prolonged post-workshop supervision and feedback on observed practice may help to sustain but not improve participants' proficiency in MI. Potential explanations to the results and suggestions for future research are discussed.