Trends In Body Mass Index Research Articles

Trends in body mass index changes among Korean adolescents between 2005-2020, including the COVID-19 pandemic period: a national representative survey of one million adolescents.

The impact of the coronavirus disease 2019 (COVID-19) pandemic on weight gain in children and adolescents remains unknown. We aimed to identify an estimated 15-year trend in mean body mass index (BMI) changes and prevalence of obesity and overweight among Korean adolescents from 2005 to 2020, including the period of the COVID-19 pandemic. We analyzed data taken from a nationwide survey (Korea Youth Risk Behavior Survey), between 2005 and 2020. Representative samples of one million Korean adolescents aged 13-18 years (n=1,057,885) were examined. The 15-year trends in mean BMI and proportion of obesity or overweight, and the changes due to the COVID-19 pandemic were analyzed. The data of 1,057,885 Korean adolescents were analyzed (mean age: 14.98 years; females, 48.4%). The estimated weighted mean BMI was 20.5 kg/m2 [95% confidence interval (CI), 20.4-20.5] from 2005 to 2008 and 21.5 kg/m2 (95% CI, 21.4-21.6) in 2020 (during the COVID-19 pandemic). Although the 15-year trend of mean BMI gradually increased, the change in mean BMI before and during the pandemic significantly lessened (βdiff, -0.027; 95% CI, -0.028 to -0.026). The 15-year (2005-2020) trend changes in the prevalence of obesity and overweight were similar (obesity prevalence from 2005-2008, 3.2%; 95% CI, 3.1-3.3 vs. obesity prevalence in 2020, 8.6%; 95% CI, 8.2-9.0; βdiff, -0.309; 95% CI, -0.330 to -0.288). The 15-year trend of overall mean BMI and obesity and overweight prevalence demonstrated a significant increase; however, its slope decreased during the pandemic. These landmark results suggest the need for the development of precise strategies to prevent pediatric obesity and overweight during the COVID-19 pandemic.

Body Mass Index (BMI) Is Up, but Not Significantly in College-Aged Young Adults During the COVID-19 Pandemic

ObjectivesIt has been suggested that the pandemic has contributed to weight gain in the general population. Increased weight is associated with health problems such as cardiovascular disease and diabetes. This study examined whether BMI changed over the course of the COVID-19 pandemic in a sample of college-aged young adults. MethodsCollege-aged young adults completed a survey wherein they self-reported their height (in inches) and weight (in pounds). This survey was conducted at two time points during the COVID-19 pandemic, in the Spring of 2020 and in the Fall of 2021. These data were used to calculate Body Mass Index (BMI) and the year of entry was coded. Independent t-tests were used to measure differences between years of the study. Results are reported as mean ± standard deviation. ResultsDuring year 1,146 of 196 respondents reported height and weight. For year 2,128 of 143 respondents reported height and weight. The average BMI during year 1 of the study was 24.80 ± 5.12 kg/m2. This result creeped up to 25.03 ± 5.68 kg/m2 during year 2 of the study. However, the increase in BMI was not significant (p = 0.73). During both study years, the majority of respondents were of healthy weight, according to BMI classifications with 5 participants classified as underweight, 80 classified as healthy weight, and 63 classified as overweight or obese in year 1. In year 2, 9 participants were classified as underweight, 77 were classified as healthy weight, and 50 were classified as overweight or obese. ConclusionsThe proportion of participants classified as overweight or obese in our sample was less than the United States’ national level of 73.6%. Numerous factors may have contributed to the maintenance of BMI status in this age group during the pandemic, including youthful age, diet or activity changes, or differences in stress, work status, and familial responsibilities. While the BMI change was not significant, an increase in the number of underweight participants (3% to 7%), in addition to the overall upward BMI trend suggests that an increased focus on and awareness of healthy diets and physical activity as a means of managing stress may improve overall physical and mental wellbeing in this age group. Funding SourcesNot applicable.

Trends and Disparities in Adult Body Mass Index Across the 47 Prefectures of Japan, 1975-2018: A Bayesian Spatiotemporal Analysis of National Household Surveys.

BackgroundAmong high-income countries, Japan has a low prevalence of obesity, but little is understood about subnational trends and variations in body mass index (BMI), largely owing to the lack of data from representative samples of prefectures. We aimed to examine long-term trends and distributions of adult BMI at the prefecture level in Japan from the late 1970s using a spatiotemporal model.MethodsWe obtained cross-sectional data for 233,988 men and 261,086 women aged 20–79 years from the 44 annual National Health and Nutrition Surveys (NHNS) conducted during 1975–2018. We applied a Bayesian spatiotemporal model to estimate the annual time series of age-standardized and age-specific mean BMI by 20-year age group and sex for each of the 47 prefectures. We assessed socioeconomic inequalities in BMI across prefectures using the concentration index, according to population density.ResultsIn men, the age-standardized prefectural mean BMI ranged from 21.7 kg/m2 (95% credible interval, 21.6–21.9) to 23.1 kg/m2 (22.9–23.4) in 1975 and from 23.5 kg/m2 (23.3–23.7) to 24.8 kg/m2 (24.6–25.1) in 2018. In women, the age-standardized prefectural mean BMI ranged from 22.0 kg/m2 (21.9–22.2) to 23.4 kg/m2 (23.2–23.6) in 1975 and from 21.7 kg/m2 (21.6–22.0) to 23.5 kg/m2 (23.2–23.8) in 2018. Mean BMI was highest in the southernmost prefecture for most of the study period, followed by northeast prefectures. The increase in mean BMI was largest in southwest prefectures, which caught up with northeast prefectures over time. The concentration index was negative, indicating higher BMI in less-populated prefectures. Absolute values of the concentration index were greater in women than in men and increased over time.ConclusionsThere were variations in adult mean BMI across prefectures, and geographic distributions changed over time. Further national and local efforts are needed to address the rising trend in mean BMI, particularly among men in rural prefectures, and socioeconomic inequalities among women. Bayesian hierarchical modeling is useful for reconstructing long-term spatiotemporal trends of mean BMI by integrating small-sized survey samples at the prefecture level in the NHNS.

Shifting educational gradients in body mass index trajectories of Indonesians: an age period cohort analysis

BackgroundGlobally, the number of obese adults has increased rapidly in many developing countries. The links between increased educational attainment and lower risks of overweight/obesity have been studied in a number of high-income contexts. However, educational attainment can have a different association with obesity at different levels of economic development and different stages of the nutritional transition, and these associations may vary by period and cohort. This study aims to provide evidence on the shifting of educational gradients in overweight/obesity in Indonesia, a low middle income country.MethodsUsing five waves of Indonesian Family Life Survey (IFLS), this study examines the Body Mass Index (BMI) trajectories of 14,810 individuals from 1993 to 2014. This study analyses how educational gradients in BMI have shifted over time and across cohorts using a hierarchical age-period-cohort (HAPC) model to account for the effects of age and the changes in historical periods (social and environmental contexts).ResultsIn older generations, higher educational attainment is associated with higher BMI, but the gap between educational groups shrinks in more recently-born cohorts. The BMI of lower educational groups is catching up with that of the tertiary educated, leading to an increased risk of overweight/obesity among low educated individuals. Having tertiary education lowers the risk of weight gain (-0.04 point) among recently-born cohort of women, but it still increases the risk (+ 0.04 point) for men.ConclusionChanges in access to education and the ongoing nutritional transition in Indonesia are leading to a shifting of educational gradients in overweight/obesity over time. The rising trends in BMI among low-educated and younger individuals are of substantial concern for Indonesian public health due to their implications for the risk of communicable and non-communicable diseases in the future.

Trends in growth and nutritional status of high school graduates in Hangzhou, China, 2011\u20132020

BackgroundDuring past decades, there was a positive trend in growth and nutrition status of adolescents in China, but there was significant regional disparity. The purpose of this study is to investigate the trends in growth and nutritional status of high school graduates in Hangzhou between 2011 and 2020.Methods High school graduates (Grade 12) who finished the physical examination of the national college entrance examination between 2011 and 2020 (n=481,353)were included in this study. Data were obtained from the database of physical examination of the national college entrance exam. Height and weight were measured; body mass index (BMI) was calculated from height and weight. Thinness, overweight and obesity were defined according to the International Obesity Task Force criteria. For the vast majority of the high school graduates were 18 years old or nearly 18 years old, the cutoffs of 18 years were adopted. Those are 18.5, 25 and 30 kg/m2, for thinness, overweight and obesity respectively.ResultsThere was a significant growth trend in height, weight and BMI in both sexes (P < 0.001). Height increased by 1.80 cm in boys and 1.45 cm in girls. Weight increased by 4.62 kg in boys and 2.51 kg in girls. BMI increased by 1.09 kg/m2 in boys and 0.60 kg/m2 in girls. An increase trend was found in the prevalence of overweight and obesity in both sexes (P < 0.001). Overweight increased by 7.43% (from 9.05 to 16.48%) among boys and 4.05% (from 4.57 to 8.62%) among girls. Obesity increased by 3.85% (from 2.29 to 6.14%) among boys and 1.76% (from 0.64 to 2.40%) among girls. The prevalence of thinness fluctuated in both boys and girls, 12.42–15.59% among boys and 18.97–23.68% among girls. Boys had higher odds of overweight and obesity and lower odds of thinness than girls (P < 0.001).ConclusionsThere is a positive trend in growth and nutritional status of high school graduates in Hangzhou. However, there is still a considerable prevalence of thinness, it indicates a double burden of undernutrition and overnutrition.

Body Mass Index And Natriuretic Peptides Trends Before And After Left Ventricular Assist Device: Evidence That Gains In Body Mass Follow On Resolution Of Heart Failure

Purpose To evaluate the hypothesis that weight gain after left ventricular assist device (LVAD) occurs after the nadir of natriuretic peptides (nt-proBNP), and that persistently elevated natriuretic peptides is associated with failure to gain weight after LVAD implantation. Methods Body mass index (BMI) and nt-proBNP trends before and after LVAD in a single center continuous flow cohort (n=505) were computed and plotted using Locally Estimated Scatterplot Smoothing (LOESS). Linear mixed effects modeling was performed to test the association between nt-proBNP and BMI. CT measures of sarcopenia (pectoralis muscle mass index to body surface area and tissue attenuation, n=194) was correlated with pre-LVAD BMI trend. Results The plots of BMI and log nt-proBNP for the entire cohort before and after LVAD are demonstrated (Figure). The rise in BMI did not occur until after the nadir of post implant nt-proBNP. Downward slope of BMI prior to LVAD was associated with lower pectoralis muscle measures prior to implantation. Patients who failed to gain weight post LVAD had the highest 6 month post LVAD natuetic peptides (lowest pecent BMI gain tertile nt-proBNP: 2,208 vs. highest 1,635 pg/mL, p <0.001). Post LVAD nt-pro BNP and BMI trends were significantly associated (a decrease of 1 unit log nt-proBNP was associated with an increase in 0.81 BMI, 95 % CI: 0.53-1.09, p < 0.001). Conclusions Weight gain post LVAD did not occur until the nadir of natriuretic peptides. Failure to gain weight post LVAD was associated with persistently elevated natriuretic peptides. These data collectively suggest that gains in body mass may be dependent on resolution of heart failure. To evaluate the hypothesis that weight gain after left ventricular assist device (LVAD) occurs after the nadir of natriuretic peptides (nt-proBNP), and that persistently elevated natriuretic peptides is associated with failure to gain weight after LVAD implantation. Body mass index (BMI) and nt-proBNP trends before and after LVAD in a single center continuous flow cohort (n=505) were computed and plotted using Locally Estimated Scatterplot Smoothing (LOESS). Linear mixed effects modeling was performed to test the association between nt-proBNP and BMI. CT measures of sarcopenia (pectoralis muscle mass index to body surface area and tissue attenuation, n=194) was correlated with pre-LVAD BMI trend. The plots of BMI and log nt-proBNP for the entire cohort before and after LVAD are demonstrated (Figure). The rise in BMI did not occur until after the nadir of post implant nt-proBNP. Downward slope of BMI prior to LVAD was associated with lower pectoralis muscle measures prior to implantation. Patients who failed to gain weight post LVAD had the highest 6 month post LVAD natuetic peptides (lowest pecent BMI gain tertile nt-proBNP: 2,208 vs. highest 1,635 pg/mL, p <0.001). Post LVAD nt-pro BNP and BMI trends were significantly associated (a decrease of 1 unit log nt-proBNP was associated with an increase in 0.81 BMI, 95 % CI: 0.53-1.09, p < 0.001). Weight gain post LVAD did not occur until the nadir of natriuretic peptides. Failure to gain weight post LVAD was associated with persistently elevated natriuretic peptides. These data collectively suggest that gains in body mass may be dependent on resolution of heart failure.

The association of the age, period, and birth cohort with 15-year changes in body mass index and waist circumference in adults: Tehran lipid and glucose study (TLGS)

ObjectiveTo examine the association of age, period, and birth cohort with body mass index (BMI) and waist circumference (WC) changes among the participants of the Tehran Lipid and Glucose Study from 1999 to 2015.MethodsThis prospective cohort study included 4895 participants aged ≥20 years (41.3% men), who were divided into twelve gender stratified groups, having a ten-year age difference between them. Analyses were conducted to explicitly assess the association of age vs. period on BMI and WC changes. In addition, we evaluated BMI and WC changes among different birth cohorts.ResultsUpon 15 years of follow-up, the mean BMI of men and women increased from 26.0 ± 3.9 to 27.5 ± 4.3 kg/m2 and from 27.5 ± 4.8 to 29.9 ± 5.4 kg/m2 (P trend < 0.001), and this trend was accompanied by an increase in WC from 88.8 ± 10.9 to 97.8 ± 10.4 cm and from 87.3 ± 12.4 to 95.8 ± 12.1 cm, respectively (P trend < 0.001). Men and women in all age cohorts tended to have a rise in their BMI and WC with aging throughout the follow-up period. For men, this trend was more prominent in younger birth cohorts at phase III for BMI and at phases III and V for WC (indicating a significant negative association with birth cohort). For women, this trend was more prominent in older birth cohorts at both phases III and V for BMI and WC (indicating a significant positive association with the birth cohort).ConclusionThe rise in BMI and WC was strongly associated with age in both sexes. The men born in the recent birth cohorts and the women born in earlier birth cohorts had the most alarming BMI and WC trends. More efforts must be spent on obesity prevention policies, especially for younger men.

Establishing a new body mass index cutoff value for malnutrition diagnosis using the Global Leadership Initiative on Malnutrition (GLIM) tool in Chinese older adults.

The body weight of the Chinese population rose rapidly over the past two decades. The old 2001 body mass index (BMI) cutoff value for malnutrition may underestimate malnutrition diagnosis. We explored the BMI cutoff value for malnutrition diagnosis based on national BMI data from the past 30 years and applied it to the Global Leadership Initiative on Malnutrition (GLIM) criteria when investigating malnutrition in hospitalized older patients. To explore the BMI cutoff value for malnutrition, we established a linear stepwise model to predict the annual increasing BMI trend based on data from the national BMI data set. The new cutoff value was applied to a large-scale data set from a cross-sectional study pertaining to older hospitalized patients recruited from 30 large hospitals in China. The BMI increased from 21.8 to 23 kg/m2 in two decades. We calculated that the net BMI increase will be 1.49 kg/m2 from 1999 to 2019. We subsequently proposed that the BMI cutoff value for malnutrition should rise to 20kg/m2 . This cutoff value was applied to the validation data set, containing 8725 patients, and the GLIM-determined malnutrition rate was 24.58% (using the Nutrition Risk Screening 2002 [NRS-2002]) and 23.32% (using the Mini Nutritional Assessment-Short Form [MNA-SF]). The results significantly differed from those obtained using the 2001 Chinese BMI criteria. The GLIM tool has good applicability in Asian populations, especially in Chinese older patients. The BMI cutoff value for malnutrition should be adjusted to 20 kg/m2 for Chinese adults.

Weight gain post-ART in HIV+ Latinos/as differs in the USA, Haiti, and Latin America

SummaryBackgroundAn obesity epidemic has been documented among adult Latinos/as in Latin America and the United States (US); however, little is known about obesity among Latinos/as with HIV (PWH). Moreover, Latinos/as PWH in the US may have different weight trajectories than those in Latin America due to the cultural and environmental contexts. We assessed weight and body mass index (BMI) trajectories among PWH initiating antiretroviral therapy (ART) across 5 countries in Latin America and the Caribbean and the US.MethodsART-naÿve PWH ≥18 years old, enrolled in Brazil, Honduras, Mexico, Peru, and Haiti (sites within CCA-SAnet) and the US (NA-ACCORD) starting ART between 2000 and 2017, with at least one weight measured after ART initiation were included. Participants were classified according to site/ethnicity as: Latinos/as in US, non-Latinos/as in US, Haitians, and Latinos/as in Latin America. Generalized least squares models were used to assess trends in weight and BMI. Models estimating probabilities of becoming overweight/obese (BMI ≥25 kg/m2) and of becoming obese (BMI ≥30 kg/m2) post ART initiation for males and females were fit using generalized estimating equations with a logit link and an independence working correlation structure.FindingsAmong 59,207 PWH, 9% were Latinos/as from Latin America, 9% Latinos/as from the US, 68% non-Latinos/as from the US and 14% were Haitian. At ART initiation, 29% were overweight and 14% were obese. Post-ART weight and BMI increases were steeper for Latinos/as in Latin America compared with other sites/ethnicities; however, BMI at 3-years post ART remained lower compared to Latinos/as and non-Latinos/as in the US. Among females, at 3-years post ART initiation the greatest adjusted probability of obesity was found among non-Latinas in the US (15·2%) and lowest among Latinas in Latin America (8.6%). Among males, while starting with a lower BMI, Latinos in Latin America had the greatest adjusted probability of becoming overweight or obese 3-years post-ART initiation.InterpretationIn the Americas, PWH gain substantial weight after ART initiation. Despite environmental and cultural differences, PWH in Latin America, Haiti and Latinos and non-Latinos in the US share similar BMI trajectories on ART and high probabilities of becoming overweight and obese over time. Multicohort studies are needed to better understand the burden of other metabolic syndrome components in PWH across different countries.

Percentiles of body mass index and waist circumference for Costa Rican children and adolescents.

Introduction: body mass index (BMI) and waist circumference (WC) are anthropometric indicators used to define overweight/obesity and to predict the risk of cardiovascular disease, respectively, in adolescents and children. Objectives: to describe and provide estimations of BMI and WC distribution according to percentiles in a sample of Costa Rican students, and to test group differences at the 50th percentile with the international references by the National Center for Health Statistics of the United States of America in 2012, 2016 and 2021. Material and methods: a cross-sectional and descriptive study was carried out with 2,684 students from 7 to 17 years of age in 64 educational centers of Costa Rica. The weight of the students was determined with a Tanita model SC-331 S, and height was measured with a SECA stadiometer, model 217, to estimate BMI. To determine abdominal circumference a measuring tape was used. All procedures were approved by the INCIENSA Scientific Ethics Committee. The statistical analysis of the data was made with the SPSS 22.0 package. Results: the first percentile distribution of BMI and WC is provided. According to BMI, 16.3 % of the student population had obesity and 26.2 % had overweight. WC values increased over the years and some significant differences were found between genders. The BMI and WC curves of Costa Rican children showed patterns similar to the three international references they were compared to. Conclusions: obesity has become the main nutritional problem in Costa Rica. The BMI and WC trend graphs proposed in this study are a useful public health tool to monitor the overweight/obesity epidemic.

Trends of Obesity Rates Between Patients Undergoing Primary Total Knee Arthroplasty and the General Population from 2013 to 2020.

Obesity is a recognized risk factor for severe knee osteoarthritis. However, it remains unclear how obesity prevalence trends in the current population undergoing total knee arthroplasty (TKA) compare with those seen in individuals not undergoing this procedure. In this study, we assessed the yearly trends in body mass index (BMI) and obesity rates between patients who have undergone primary TKA and those in the general population. We retrospectively reviewed all patients ≥18 years of age from January 2013 through December 2020 who underwent primary, elective TKA and those who had an annual routine physical examination at our institution within the same period. Baseline demographic characteristics were collected. The independent samples t test was used to compare means and the chi-square test was used to compare proportions between the 2 cohorts, and a linear regression was used to determine the significance of the yearly trends. A total of 11,333 patients who underwent primary TKA and 1,158,168 patients who underwent an annual physical examination were included in this study. After adjusting for age, we found the mean BMI for the TKA group to be significantly greater (p < 0.001) every year compared with the annual physicals group. The proportion of patients who were categorized into any obesity class (BMI, ≥30 kg/m2), Class-I obesity (BMI, 30 to 34.9 kg/m2), Class-II obesity (BMI, 35 to 39.9 kg/m2), and Class-III obesity (BMI, ≥40 kg/m2) was significantly higher for the TKA group each year compared with the annual physicals group. An analysis of trends over time showed a significantly increasing trend (p < 0.001) in BMI and obesity rates for the annual physicals group, but a stable trend for patients undergoing TKA. Patients who underwent TKA continued to have higher BMI than the general population, which showed a steady increase over time. Physicians need to continue in their efforts to educate patients on weight management and healthy lifestyles to potentially delay the need for a surgical procedure. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Trends in maternal body mass index in Northern Ireland: a cross-sectional and longitudinal study

ObjectivesExplore (1) associations between maternal body mass index (BMI), demographic and clinical characteristics, (2) longitudinal trends in BMI, (3) geographical distributions in prevalence of maternal overweight and obesity.DesignRetrospective population-based study.SettingLinked,...

Nutritional Status as a Predictive Biomarker for Immunotherapy Outcomes in Advanced Head and Neck Cancer.

Simple SummaryTumors of head and neck cancer are a heterogenous collection of malignancies affecting the upper aerodigestive tract, the majority of which are head and neck squamous cell carcinomas (HNSCCs). Development of immune checkpoint inhibitors (ICIs) have revolutionized the treatment of advanced HNSCCs, albeit only in a minority of patients. Due to the low clinical response rates for HNSCCs and the potential for immune-related adverse side effects, predictive biomarkers are necessary to characterize patients who are most likely to respond to treatment. Previous studies have indicated that patient nutritional status may impact immune response. However, the effects of pretreatment nutritional status, specifically on immunotherapy-treated HNSCC patients, remains unclear. The aim of our study is to explore the associations between baseline prognostic nutritional index and pretreatment body mass index trends on the outcomes of HNSCC patients treated with anti-PD-1 or anti-CTLA-4 immunotherapy, or both.The association between pretreatment nutritional status and immunotherapy response in patients with advanced head and neck cancer is unclear. We retrospectively analyzed a cohort of 99 patients who underwent treatment with anti-PD-1 or anti-CTLA-4 antibodies (or both) for stage IV HNSCC between 2014 and 2020 at the Johns Hopkins Hospital. Patient demographics and clinical characteristics were retrieved from electronic medical records. Baseline prognostic nutritional index (PNI) scores and pretreatment body mass index (BMI) trends were calculated. Associations between PNI and BMI were correlated with overall survival (OS), progression-free survival (PFS), and immunotherapy response. In univariate analysis, there was a significant correlation between OS and PFS with baseline PNI (OS: HR: 0.464; 95% CI: 0.265–0.814; PFS: p = 0.007 and HR: 0.525; 95% CI: 0.341–0.808; p = 0.003). Poor OS was also associated with a greater decrease in pretreatment BMI trend (HR: 0.42; 95% CI: 0.229–0.77; p = 0.005). In multivariate analysis, baseline PNI but not BMI trend was significantly associated with OS and PFS (OS: log (HR) = −0.79, CI: −1.6, −0.03, p = 0.041; PFS: log (HR) = −0.78, CI: −1.4, −0.18, p = 0.011). In conclusion, poor pretreatment nutritional status is associated with negative post-immunotherapy outcomes.

Time-series deep survival prediction for hemodialysis patients using an attention-based Bi-GRU network

Background and objectiveThe number of end-stage renal disease (ESRD) patients treated with hemodialysis (HD) has significantly increased, but the prognosis remains poor. Time-series features have been included in only a few studies to predict HD patient survival, and how to utilize such features effectively remains unclear. This article aims to develop a more accurate, interpretable, and clinically practical personalized survival prediction model for HD patients. MethodsThis study proposed and evaluated an attention-based Bi-GRU network using time-series features for survival prediction. A distance-based loss function was proposed to improve performance. We used data from 1232 ESRD patients who received regular hemodialysis treatment for ≥ 3 months from 2007 to 2016 at the First Affiliated Hospital of Zhejiang University. The proposed model was compared with representative sequence modeling deep learning architectures and existing survival analysis methods in terms of the C-index and IBS value. Post hoc tests were used to test statistical significance. The attention map was used to assess feature importance over time. The impact of time-series changes on survival was investigated after controlling initial values (using BMI as an example). ResultsThe proposed method outperformed other sequence modeling architectures and the state-of-the-art survival analysis approaches in terms of the C-index and the integrated Brier score (IBS) value. Our method achieved a C-index of 0.7680 (95% confidence intervals [CI]: 0.7645, 0.7716) and an IBS of 0.1302 (95% confidence intervals [CI]: 0.1292, 0.1313), showing an improvement of up to 5.4% in terms of the C-index and a decrease of 3.2% in terms of the IBS value. The addition of the distance-based loss function improved the performance. The predicted risk and actual risk levels closely agreed. This study also found that even after controlling the initial body mass index (BMI) values, different 3-month BMI trends could produce different survival outcomes. ConclusionsThis study proposed a more effective and interpretable method to use time-series information in survival analysis. The proposed method may help promote personalized medicine and improve patient prognosis.

The Prognostic Significance of Body Mass Index and Metabolic Parameter Variabilities in Predialysis CKD: A Nationwide Observational Cohort Study.

The association between variabilities in body mass index (BMI) or metabolic parameters and prognosis of patients with CKD has rarely been studied. In this retrospective observational study on the basis of South Korea's national health screening database, we identified individuals who received ≥3 health screenings, including those with persistent predialysis CKD (eGFR <60 ml/min per 1.73 m2 or dipstick albuminuria ≥1). The study exposure was variability in BMI or metabolic parameters until baseline assessment, calculated as the variation independent of the mean and stratified into quartiles (with Q4 the highest quartile and Q1 the lowest). We used Cox regression adjusted for various clinical characteristics to analyze risks of all-cause mortality and incident myocardial infarction, stroke, and KRT. The study included 84,636 patients with predialysis CKD. Comparing Q4 versus Q1, higher BMI variability was significantly associated with higher risks of all-cause mortality (hazard ratio [HR], 1.66; 95% confidence interval [95% CI], 1.53 to 1.81), P [for trend] <0.001), KRT (HR, 1.20; 95% CI, 1.09 to 1.33; P<0.001), myocardial infarction (HR, 1.19; 95% CI, 1.05 to 1.36, P=0.003), and stroke (HR, 1.19; 95% CI, 1.07 to 1.33, P=0.01). The results were similar in the subgroups divided according to positive or negative trends in BMI during the exposure assessment period. Variabilities in certain metabolic syndrome components (e.g., fasting blood glucose) also were significantly associated with prognosis of patients with predialysis CKD. Those with a higher number of metabolic syndrome components with high variability had a worse prognosis. Higher variabilities in BMI and certain metabolic syndrome components are significantly associated with a worse prognosis in patients with predialysis CKD.

Body mass index trend and variability in rheumatoid arthritis.

To characterize and compare trends in body mass index (BMI) and variability in BMI between subjects with rheumatoid arthritis (RA) and matched non-RA subjects and to determine predictors of BMI trends and variability within RA subjects. This retrospective population-based cohort study included 1114 Olmsted County, Minnesota residents, 558 with incident RA (age≥18years, 1987 ACR criteria met in 1995-2009) and 556 non-RA subjects from the same underlying population with similar age, sex, and index calendar year. All subjects were followed until death, migration, or 12/31/2018. Generalized linear models with smoothing splines and random effects to account for multiple measurements per subject were used to examine trends in BMI measurements over time. Mean BMI of patients with incident RA (28.8kg/m2) was not significantly different from that of non-RA subjects (28.9kg/m2). There was no significant difference in BMI trends over time between RA and non-RA cohorts, or between seropositive for rheumatoid factor (RF) and/or citrullinated antibody (CCP-antibody) and seronegative RA patients, or between male and female subjects. RA subjects were noted to have significantly higher BMI variability following diagnosis compared to non-RA subjects [difference in standard deviation between RA and non-RA subjects prior to index (p = 0.12), 0-5years after index (p = 0.044), and 5-15years after index (p = 0.013)]. The BMI trajectory of the RA population is not significantly different compared to that of the non-RA population, but patients with RA demonstrate higher variability in BMI following diagnosis compared to the non-RA population. Key Points • This study uniquely characterizes longitudinal trajectory in BMI measures and their variability in the RA population versus the non-RA population • This study suggests that RA patients have greater BMI variability compared to the non-RA population, which is highly relevant as BMI variability is increasingly understood as a cardiovascular risk factor.

1249Trends and disparities in adult body mass index across 47 prefectures in Japan, 1975–2018

Abstract Background Consistent and comparable health information across prefectures is necessary for monitoring progress in improving population health and reducing geographic health disparities in Japan. We aimed to examine long-term trends and variations in adult body mass index (BMI) by prefecture. Methods We obtained a total sample of 233,988 males and 261,086 females aged 20–79 years with anthropometric measurements from National Health and Nutrition Surveys conducted annually during 1975–2018. We applied a spatio-temporal Bayesian hierarchical model to estimate the annual time series of prefectural mean BMI by 20-year age group and sex. Results Prefectural mean BMI consistently increased in males regardless of age but decreased in younger females. It increased in older females until starting to decrease in the early 2000s. Mean BMI was noticeably higher in Okinawa, the southernmost prefecture, than in other prefectures from 1975 in males and from the 1990s in females. The interquartile range of mean BMI across prefectures was consistently higher in females than in males. It decreased over time to plateau during the 2000s in both sexes. Conclusions Mean BMI increased in males across prefectures and there is a need for stimulating a further reduction in geographic disparities particularly for females. Okinawa once ranked first in longevity but has shown relatively poor performance in recent years, which may be partly attributable to the distinctive trends in adult BMI. Key messages Bayesian hierarchical modelling is useful for reconstructing long-term spatio-temporal trends of mean BMI by integrating small-size survey samples.

BMI and obesity trends in Chinese national survey data

Data assembled by the Global Burden of Disease project1 and the NCD Risk Factor Collaboration2 have shown increasing trends in body-mass index (BMI) and obesity worldwide. However, at the country level, these data cannot substitute for the detailed information available from national surveys. In The Lancet, Limin Wang and colleagues3 use data from six representative surveys in China that included 645 223 adults aged 18–69 years, done between 2004 and 2018 (in 2004 44·3% men, 55·7% women; in 2018 43·7% men, 56·3% women).

Body-mass index and obesity in urban and rural China: findings from consecutive nationally representative surveys during 2004–18

In China, mean body-mass index (BMI) and obesity in adults have increased steadily since the early 1980s. However, to our knowledge, there has been no reliable assessment of recent trends, nationally, regionally, or in certain population subgroups. To address this evidence gap, we present detailed analyses of relevant data from six consecutive nationally representative health surveys done between 2004 and 2018. We aimed to examine the long-term and recent trends in mean BMI and prevalence of obesity among Chinese adults, with specific emphasis on changes before and after 2010 (when various national non-communicable disease prevention programmes were initiated), assess how these trends might vary by sex, age, urban-rural locality, and socioeconomic status, and estimate the number of people who were obese in 2018 compared with 2004. We used data from the China Chronic Disease and Risk Factors Surveillance programme, which was established in 2004 with the aim to provide periodic nationwide data on the prevalence of major chronic diseases and the associated behavioural and metabolic risk factors in the general population. Between 2004 and 2018 six nationally representative surveys were done. 776 571 individuals were invited and 746 020 (96·1%) participated, including 33 051 in 2004, 51 050 in 2007, 98 174 in 2010, 189 115 in 2013, 189 754 in 2015, and 184 876 in 2018. After exclusions, 645 223 participants aged 18-69 years remained for the present analyses. The mean BMI and prevalence of obesity (BMI ≥30 kg/m2) were calculated and time trends compared by sex, age, urban-rural locality, geographical region, and socioeconomic status. Standardised mean BMI levels rose from 22·7 kg/m2 (95% CI 22·5-22·9) in 2004 to 24·4 kg/m2 (24·3-24·6) in 2018 and obesity prevalence from 3·1% (2·5-3·7) to 8·1% (7·6-8·7). Between 2010 and 2018, mean BMI rose by 0·09 kg/m2 annually (0·06-0·11), which was half of that reported during 2004-10 (0·17 kg/m2, 95% CI 0·12-0·22). Similarly, the annual increase in obesity prevalence was somewhat smaller after 2010 than before 2010 (6·0% annual relative increase, 95% CI 4·4-7·6 vs 8·7% annual relative increase, 4·9-12·8; p=0·13). Since 2010, the rise in mean BMI and obesity prevalence has slowed down substantially in urban men and women, and moderately in rural men, but continued steadily in rural women. By 2018, mean BMI was higher in rural than urban women (24·3 kg/m2vs 23·9 kg/m2; p=0·0045), but remained lower in rural than urban men (24·5 kg/m2vs 25·1 kg/m2; p=0·0007). Across all six surveys, mean BMI was persistently lower in women with higher levels of education compared with women with lower levels of education, but the inverse was true among men. Overall, an estimated 85 million adults (95% CI 70 million-100 million; 48 million men [95% CI 39 million-57 million] and 37 million women [31 million-43 million]) aged 18-69 years in China were obese in 2018, which was three times as many as in 2004. In China, the rise in mean BMI among the adult population appears to have slowed down over the past decade. However, we found divergent trends by sex, geographical area, and socioeconomic status, highlighting the need for a more targeted approach to prevent further increases in obesity in the Chinese general population. China National Key Research and Development Program, China National Key Project of Public Health Program, and Youth Scientific Research Foundation of the National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention.

Inequalities in early childhood body-mass index Z scores in Victoria, Australia: a 15-year observational study

Early childhood overweight and obesity increased substantially in high-income countries throughout the 1980s and 1990s. The flattening or reversal of this trend since the early 2000s might conceal widening inequalities. This study aimed to identify trends in body-mass index Z score (BMIz) among children aged 1-3·5 years in Victoria (Australia), by socioeconomic status and geographical location. This repeated, cross-sectional study used deidentified records of height, weight, and demographic information from electronic databases in the Victorian Maternal and Child Health system. Data from the consultations for children aged 1, 2, and 3·5 years were included in this analysis. We removed duplicate records; records with missing data for sex, age, weight, height, or postcode; and records with postcodes that were outside of Victoria. The coprimary outcomes were trends in mean BMIz (continuous linear models) and prevalence of high BMIz (>+1; generalised linear models), estimated for six independent age-sex groups. Secondary analysis was done for the prevalence of BMIz greater than 2. Effect modification by socioeconomic status and remoteness was evaluated. Electronic data were available for 48 local government areas collected between Jan 1, 2003, and Dec 31, 2017, representing approximately 63% of the Victorian population. Overall, 1 329 520 measurements from 675 991 children were included in the analysis. There were small, significantly decreasing trends in mean BMIz across all six age-sex groups, overall and in major cities. Similar patterns were observed for some subgroups in prevalence of high BMIz. These decreasing trends appear to be partly explained by migration. Conversely, in regional areas the trends in BMIz were consistently increasing in all age-sex groups and across socioeconomic strata, although not all groups were statistically significant. Inequalities in BMIz according to socioeconomic status persisted throughout the study period, such that the children from more advantaged areas had lower mean BMIz. This study showed that at a state level, mean BMIz and prevalence of high BMIz decreased in children aged 1, 2, and 3·5 years in Victoria between 2003 and 2017. We found metropolitan-regional differences to be key source of inequality in early childhood BMIz trends, alongside area-level socioeconomic status. These findings highlight the risk that analysis of overall trends in childhood BMIz might obscure important inequalities according to, for example, remoteness, socioeconomic status, and ethnicity. Future research requires monitoring data with large population samples to adequately examine differences in prevalence and trends between population subgroups. None.