Trajectories of body mass index in adulthood and all-cause and cause-specific mortality in the Melbourne Collaborative Cohort Study

Gender differences in midlife to later-life cumulative burden and variability of obesity measures and risk of all-cause and cause-specific mortality

BACKGROUND/OBJECTIVES

Previous studies have reported the gender-specific association between general and central obesity measures, using snapshot assessments, and mortality events. This study seeks to further explore this link by examining how the longitudinal cumulative burden and variability of obesity measures from midlife to later-life impact mortality events in the Atherosclerosis Risk in Communities (ARIC) study population, specifically in relation to gender differences.

SUBJECTS/METHODS

Using data from the ARIC study, a total of 7615 (4360 women) participants free of cardiovascular disease, cancer, and early mortality events were included in the data analysis. Longitudinal cumulative burden (estimated by the area under the curve (AUC) using a quadratic mixed-effects method) and variability (calculated according to average successive variability (ASV)) were considered as exposures, separately and all together. Cox proportional hazard regression models were used to estimate multivariable-adjusted standardized hazard ratios.

RESULTS

The mean age was 62.4 and the median follow-up was 16.9 years. In men, AUCs of waist-related obesity measures, and also ASVs of all obesity measures were associated with increased all-cause mortality risk. In women, waist circumference and waist-to-height ratio AUCs were associated with increased all-cause mortality risk. Regarding cardiovascular mortality, all adiposity measures ASVs in both genders and waist-related obesity measures AUCs in men were associated with increased risk. Significant gender differences were found for the associations between cumulative and variability of waist-to-hip ratio for all-cause mortality and all adiposity measures ASVs for cardiovascular mortality risk with higher impact among men.

CONCLUSIONS

Cumulative burden and variability in general and central obesity measures were associated with higher all-cause and cardiovascular mortalities among men. In women, general obesity measures variability, as well as cumulative and variability of central adiposity measure, increased all-cause mortality risk.

Risk assessment of obesity-related noncommunicable diseases through body mass index trajectories in adulthood: NHANES 2007-2018

AIM

To assess the impact of adult body mass index (BMI) trajectories on the risk of obesity-related noncommunicable diseases (NCDs) in the U.S. adults after adjustment for sociodemographic and lifestyle factors.

METHODS

Data were extracted from the National Health and Nutrition Examination Survey conducted from 2007 to 2018, including male and female participants aged 29-59 years. Rao-Scott adjusted chi-square was employed to detect associations between categorical variables in descriptive analyses. Cox proportional hazards models estimated hazard ratios (HR) and 95% confidence intervals (CI) for NCDs and BMI trajectories, adjusted for sociodemographic and lifestyle factors. Kaplan-Meier curves illustrated the cumulative incidence over time.

RESULTS

Analyses were carried out on 15 721 participants and revealing significant differences among BMI trajectories in terms of demographic, lifestyle, and health characteristics. The overall prevalence of NCDs was 28.0% (95%CI:26.6-28.9). The cumulative incidence over time was higher in the high increase, moderate increase, and mixed trajectory groups, with a correspondingly higher cumulative risk (p < 0.001). Non-overweight trajectory was considered reference category in Cox models. The BMI trajectories were independently associated with an increased risk of NCDs, even after adjusting for potential confounders (HR: 1.7; 95%CI: 1.4-1.9 for moderate increase; HR: 3.6; 95%CI: 3.2-4.1 for high increase; and HR: 2.4; 95%CI: 2.1-2.7, for mixed). Furthermore, differences between males and females were also observed.

CONCLUSION

The transition to and persistence of obesity into adulthood increases the risk of NCDs. The implementation of targeted interventions with long-term monitoring of BMI may be beneficial in the prevention of future obesity-related NCDs.

Work- and mental health-related events and body mass index trajectories during the Covid-19 lockdown. Evidence from the lifelines cohort study in the Netherlands

BACKGROUND

The aim of this study was to identify heterogeneity in trajectories of body mass index (BMI) during the Covid-19 pandemic in the Netherlands. Moreover, we aimed to investigate whether work- and mental health-related disruptive events experienced during the pandemic, such as job insecurity or depression, were associated with such BMI trajectories.

METHODS

Longitudinal data from the Lifelines Covid Questionnaire was used (21 waves between April 2020 and July 2021; n = 64,630). Different trajectories were identified using group-based trajectory models. Multinomial regression models were fitted to analyse the main determinants of experiencing changes in BMI during the pandemic.

RESULTS

Trajectories of increased BMI, and, to a lesser extent also trajectories of decreased BMI, were more common among those who experienced disruptive work-related events (e.g., being laid-off or having a temporary contract) and mental health-related events (e.g., anxiety or depression) during the pandemic. Those experiencing multiple events were particularly likely to show trajectories of increased or decreased BMI.

CONCLUSIONS

During the Covid-19 pandemic, strong heterogeneity was observed in BMI trajectories. This was partially related to work- and mental health-related events.

Body mass index trajectories and mortality risk in Japan using a population-based prospective cohort study: the Japan Public Health Center-based Prospective Study

BACKGROUND

Recent studies have found that long-term changes in weight during adulthood are associated with a high risk of mortality. The objective of this study was to characterize body mass index (BMI) trajectories during adulthood and to examine the association between BMI trajectories and risk of death in the Japanese population.

METHODS

The data were extracted from Japan Public Health Center-based Prospective Study-a population-based prospective cohort study in Japan with participants aged 40-69 years followed over 20 years. The participants were categorized into multiple BMI trajectory groups using the latent class growth model. The Cox proportional-hazards model was conducted using all-cause mortality and cause-specific mortality as outcomes and the identified BMI trajectory groups as a predictor. In total, 65 520 participants were included in the analysis.

RESULTS

Six BMI trajectory groups were identified: underweight stable (Group 1), low-to-high normal (Group 2), high-to-low normal (Group 3), normal to overweight (Group 4), overweight to normal (Group 5) and normal to obese (Group 6). Our Cox models showed a higher hazard (risk) of all-cause mortality among participants in the BMI-declining groups [Group 3, adjusted hazard ratio (aHR): 1.10, 95% CI: 1.05-1.16; Group 5, aHR: 1.16, 95% CI: 1.08-1.26], underweight stable group (Group 1, aHR: 1.27, 95% CI: 1.21-1.33) and normal to obese group (Group 6, aHR: 1.22, 95% CI: 1.13-1.33) than Group 2 (low-to-high normal BMI trajectory).

CONCLUSIONS

Stable underweight and weight loss were associated with a high risk of mortality, both of which were uniquely observed in a Japanese population.

BMI trajectory in adulthood in relation to all-cause and cause-specific mortality: A retrospective cohort study in Taiwan

A dynamic change of weight over time has been known as an important factor that impacts mortality risk. The aims of this study were to identify the heterogeneity of BMI trajectory groups and to examine the association of the trajectories of BMI and all-cause and cause-specific mortality. The data for this study were obtained from a large prospective cohort study in Taiwan between 1998 and 2019 that was linked to the National Death Registry for death information. The participants were stratified into four groups by age and gender; self-reported demographics and measured BMI data were used. We used group-based trajectory analysis to identify the distinct trajectories of changes in BMI. A Cox proportional hazards model was used to assess the hazard ratio (HR) of all-cause and cause-specific mortality risk. Data were analyzed in April 2020 and included 89,886 participants. Four trajectory groups were identified by the pattern of BMI change over time. Our study shows that different trajectories were associated with mortality. Our findings suggest that the mortality risk differs in each trajectory group and in each age and gender stratification. It appears that obesity is a protective factor in cancer-related mortality in females but not in males in group of old age participants; low-normal weight is a risk factor in respiratory-related mortality in all participants. Our findings can be used to suggest the appropriate BMI in each age and gender groups and thereby earlier health interventions can be taken to avoid mortality.

Trajectories of body mass index from early adulthood to late midlife and incidence of total knee arthroplasty for osteoarthritis: findings from a prospective cohort study

OBJECTIVE

To examine the association between body mass index (BMI) trajectories from early adulthood to late midlife and risk of total knee arthroplasty (TKA) for osteoarthritis.

METHODS

24,368 participants from the Melbourne Collaborative Cohort Study with weight collected during 1990-1994, 1995-1998, and 2003-2007, recalled weight at age 18-21 years, and height measured during 1990-1994 were included. Incident TKA from 2003 to 2007 to December 2018 was determined by linking cohort records to the National Joint Replacement Registry.

RESULTS

Using group-based trajectory modelling, six distinct trajectories (TR) of BMI from early adulthood (age 18-21 years) to late midlife (approximately 62 years) were identified: lower normal to normal BMI (TR1; 19.7% population), normal BMI to borderline overweight (TR2; 36.7%), normal BMI to overweight (TR3; 26.8%), overweight to borderline obese (TR4; 3.5%), normal BMI to class 1 obesity (TR5; 10.1%), overweight to class 2 obesity (TR6; 3.2%). Over 12.4 years, 1,328 (5.4%) had TKA. The hazard ratios for TKA increased in all TR compared to TR1 [from TR2: 2.03 (95% CI 1.64-2.52) to TR6: 8.59 (6.44-11.46)]. 28.4% of TKA could be prevented if individuals followed the trajectory one lower, an average weight reduction of 8-12 kg from early adulthood to late midlife, saving $AUS 373 million/year. Most reduction would occur in TR2 (population attributable fraction 37.9%, 95% CI 26.7-47.3%) and TR3 (26.8%, 20.0-31.2%).

CONCLUSIONS

Prevention of weight gain from young adulthood to late midlife in order to reduce overweight/obesity has the potential to significantly reduce the cost and burden of TKA.

Factors associated with changes in the objectively measured physical activity among Japanese adults: A longitudinal and dynamic panel data analysis

Factors associated with dynamic changes in the objectively measured physical activity have not been well understood. We aimed to 1) evaluate the longitudinal change in the physical activity trajectory according to sex which is associated with age and to 2) determine the factors associated with the dynamic change in physical activity-related variables across a wide age range among Japanese adults. This longitudinal prospective study included 689 Japanese adults (3914 measurements) aged 26-85 years, whose physical activity data in at least two surveys were available. Physical activity-related variables, such as intensity (inactive, light [LPA; 1.5 to 2.9 metabolic equivalents (METs)], moderate-to-vigorous [MVPA; ≥3.0 METs]), total energy expenditure (TEE), physical activity level (PAL), and step count, were evaluated using a validated triaxial accelerometer. Statistical analysis involved the latent growth curve models and random-effect panel data multivariate regression analysis. During a mean follow-up period of 6.8 years, physical activity was assessed an average of 5.1 times in men and 5.9 times in women. The profiles for the inactive time, LPA (only men), MVPA, step count, PAL, and TEE showed clear curvature, indicating an accelerated rate of change around the age of 70. In contrast, other variables exhibited minimal or no curvature over the age span. The MVPA trajectory was positively associated with alcohol consumption, hand grips, leg power, and trunk flexibility and negatively associated with age, local area, body mass index (BMI), comorbidity score, and heart rate over time. Our results indicated that the physical activity trajectory revealed clear curvature, accelerated rate of change around the age of 70, and determined physical health and fitness and BMI as dynamic factors associated with physical activity changes. These findings may be useful to help support populations to achieve and maintain the recommended level of physical activity.

Obesity at age 20 and weight gain during adulthood increase risk of total and premature all-cause mortality: findings from women attending breast screening in Manchester

BACKGROUND

Obesity in early adulthood is associated with lower breast cancer rates in later life. This could be interpreted as a positive reinforcement of excess weight amongst younger women however, the wider implications of higher weights are less well known. This study examined the association between both obesity in early adulthood and body mass index (BMI) change through adulthood, and all-cause mortality.

METHODS

The Predicting Risk of Cancer At Screening (PROCAS) study recruited 57,902 women aged 46-73 years (median age 57.2, IQR 51.8-63.7 years) from the Greater Manchester National Health Service breast screening programme in North West England between 2009 and 2015. It was used to assess associations between BMI at 20 years and cohort entry with all-cause mortality ascertained via deaths recorded on the National Breast Screening System to June 2020. Hazard ratios were estimated using proportional hazards (Cox) regression adjusted for factors at entry to the cohort: age, deprivation, bilateral oophorectomy, hormone-replacement therapy, menopausal status, ethnicity, alcohol intake, physical activity, and BMI.

RESULTS

The prevalence of overweight (25-30 kg/m²) and obesity (> 30 kg/m²) were 10.4% and 2.5% respectively at 20 years, increasing to 35.2% and 25.9% respectively at cohort entry. After a mean 8.7 years follow-up we observed that overweight (HR = 1.27, 95%CI = 1.10-1.47) and obesity (HR = 2.11, 95%CI = 1.67-2.66) at 20 years had a higher mortality rate compared with healthy weight. Women who were underweight/healthy weight at 20 years and gained weight to obesity at entry had a slightly increased mortality rate compared with women who were underweight/healthy weight at both time points (HR 1.16, 95%CI = 1.02-1.32). Women with overweight (HR = 1.36, 95%CI = 1.06-1.75) or obesity (HR = 1.90, 95%CI = 1.45-2.48) at both 20 years and entry had a higher mortality rate than women who were underweight/healthy weight at both points.

CONCLUSIONS

Women who self-reported overweight and obesity at 20 years had a shorter life expectancy in this cohort of women attending breast cancer screening. Weight gain from 20 years was common in this group. Girls and women should be supported to maintain a healthy weight throughout the lifespan to help increase life expectancy. Trial registration number NCT04359420, retrospectively registered 24/04/2020.

Causal inference under over-simplified longitudinal causal models

Many causal models of interest in epidemiology involve longitudinal exposures, confounders and mediators. However, repeated measurements are not always available or used in practice, leading analysts to overlook the time-varying nature of exposures and work under over-simplified causal models. Our objective is to assess whether - and how - causal effects identified under such misspecified causal models relates to true causal effects of interest. We derive sufficient conditions ensuring that the quantities estimated in practice under over-simplified causal models can be expressed as weighted averages of longitudinal causal effects of interest. Unsurprisingly, these sufficient conditions are very restrictive, and our results state that the quantities estimated in practice should be interpreted with caution in general, as they usually do not relate to any longitudinal causal effect of interest. Our simulations further illustrate that the bias between the quantities estimated in practice and the weighted averages of longitudinal causal effects of interest can be substantial. Overall, our results confirm the need for repeated measurements to conduct proper analyses and/or the development of sensitivity analyses when they are not available.

The impact of sex on blood pressure and anthropometry trajectories from early adulthood in a Nigerian population: insights into women's cardiovascular disease risk across the lifespan

BACKGROUND

Sex disparities in blood pressure and anthropometry may account for differences in cardiovascular (CV) risk burden with advancing age; modulated by ethnic variability. We explored trajectories of blood pressures (BPs) and anthropometric indices with age on the basis of sex in an urban Nigerian population.

METHODS

We conducted a secondary analysis on data from 5135 participants (aged 16-92 years; 2671(52%) females) from our population-based cross-sectional study of BP profiles. We utilized the WHO STEPS and standardized methods for documenting BPs, body mass index (BMI) and waist circumference (WC). Data was analyzed using Analysis of variance (ANOVA), Spearman correlation analysis and mean difference in variables (with 95% confidence interval). We explored the influence of age and sex on BP profiles and specific anthropometric indices using generalized regression analysis.

RESULTS

In those aged 15-44 years, males had significantly higher systolic BP (SBP) and pulse pressure (PP). However, mean SBP and PP rose more steeply in females from 25 to 34 years, intersected with that of males from 45 to 54 years and remained consistently higher. Difference in mean BPs (95% Confidence Interval) (comparing < and > 45 years) was higher in females compared to males for SBP (17.4 (15.8 to 19.0) v. 9.2 (7.7 to 10.7), DBP (9.0 (7.9 to 10.1) v. 7.8 (6.7 to 8.9)), and PP (8.4 (7.3 to 9.5) v. 1.4 (0.3 to 2.5)). Females had significantly higher BMI and WC across all age groups (p < 0.001). Age more significantly correlated with BPs, BMI and WC in females. Interaction models revealed that SBP was significantly predicted by age category in females from (15-54 years), while DBP was only significantly predicted by age in the 15-34-year category (p < 0.01). BMI and WC were significantly predicted by age only in the 25-34-year category in females, (p < 0.01).

CONCLUSIONS

Our population demonstrates sex disparity in trajectories of SBP, PP, BMI and WC with age; with steeper rise in females. There is a need to focus on CV risk reduction in females, starting before, or during early adulthood.

Concurrent changes in physical activity and body mass index among 66 852 public sector employees over a 16-year follow-up: multitrajectory analysis of a cohort study in Finland

OBJECTIVES

To identify concurrent developmental trajectories of physical activity and body mass index (BMI) over time.

DESIGN

Prospective cohort study, repeated survey.

SETTING

Cohort study in Finland.

PARTICIPANTS

66 852 public sector employees, who have been followed up for 16 years.

OUTCOME MEASURES

Shapes of trajectories of changes in physical activity and BMI.

RESULTS

At baseline, mean age was 44.7 (SD 9.4) years, BMI 25.1 (SD 4.1) kg/m² and physical activity 27.7 (SD 24.8) MET hours/week. Four clusters of concurrent BMI and physical activity trajectories were identified: (1) normal weight (BMI <25 kg/m²) and high level of physical activity (30-35 MET hours/week), (2) overweight (BMI 25-30 kg/m²) and moderately high level of physical activity (25-30 MET hours/week), (3) obesity (BMI 30-35 kg/m²) and moderately low level of physical activity (20-25 MET hours/week) and (4) severe obesity (BMI >35 kg/m²) and low level of physical activity (<20 MET hours/week). In general, BMI increased and physical activity decreased during the follow-up. Decline in physical activity and increase in BMI were steeper among obese respondents with low level of physical activity.

CONCLUSIONS

Changes in BMI and physical activity might be interconnected. The results may be of interest for both clinicians and other stakeholders with respect to informing measures targeting increasing physical activity and controlling weight, especially among middle-aged people. Additionally, the information on the established trajectories may give individuals motivation to change their health behaviour.

Association Between Temporal Changes in Diet Quality and Concurrent Changes in Dietary Intake, Body Mass Index, and Physical Activity Among Japanese Adults: A Longitudinal Study

Background

Many cross-sectional studies have identified modifiable factors such as dietary intake, physique, and physical activity associated with diet quality but were unable to determine how a specific individual's diet quality changes with these factors. These relationships may vary depending on an individual's dietary intake. We aimed to determine the association between temporal changes in diet quality and concurrent changes in dietary intake, body mass index (BMI), and physical activity according to the diet quality trajectory pattern.

Methods

This longitudinal prospective study included 697 Japanese adults aged 26–85 years, at baseline, with available data from at least two dietary intake surveys (4,118 measurements). Dietary intake and physical activity were evaluated using validated dietary questionnaires and a triaxial accelerometer. Diet quality was calculated using the Nutrient-Rich Food Index 9.3 (NRF9.3), while physical activity was calculated based on the duration of activity performed at each level of intensity (sedentary, light, moderate, and vigorous). Body mass index was calculated from the measured height and weight. Statistical analyses involved latent class growth models (LCGM) and random-effect panel data analysis.

Results

During a mean follow-up period of 6.8 years, NRF9.3 scores were assessed, on average, 5.4 times in men and 6.1 times in women. Based on the NRF9.3 score, three separate trajectory groups—“low-increasing,” “medium-increasing,” and “high-stable”—among individuals aged 26–90 years were identified using LCGM. In the multivariate analysis, the NRF9.3 score trajectory was positively associated with intake of energy, protein, dietary fiber, vitamins A and C, magnesium, and food items, such as fruits and vegetables, and was negatively associated with BMI and the intake of added sugar, saturated fats, sodium, and food items, such as meat and sugar and confectioneries, even after adjusting for covariates. These relationships displayed heterogeneity across the identified NRF9.3 score trajectory groups. In the low-increasing group, an inverse relationship was observed between sedentary behavior and NRF9.3 score trajectory.

Conclusions

We identified modifiable factors associated with temporal changes in diet quality across a wide age range; however, these factors may vary according to the diet quality trajectories. Our findings may help develop effective strategies for improving diet quality, according to the trajectory of diet quality.

Adding Estimated Cardiorespiratory Fitness to the Framingham Risk Score and Mortality Risk in a Korean Population-Based Cohort Study

BACKGROUND

The added value of non-exercise-based estimation of cardiorespiratory fitness (eCRF) to cardiovascular disease (CVD) risk factors for mortality risk has not been examined in Korean populations.

METHODS

This population-based prospective cohort study examined the relationship of the 10-year Framingham risk score (FRS) for CVD risk and eCRF with all-cause and CVD mortality in a representative sample of Korean adults aged 30 years and older. Data regarding a total of 38,350 participants (16,505 men/21,845 women) were obtained from the 2007-2015 Korea National Health and Nutrition Examination Survey (KNHANES). All-cause and CVD mortality were the main outcomes. The 10-year FRS point sum and eCRF level were the main exposures.

RESULTS

All-cause and CVD mortality was positively correlated with the 10-year FRS point summation and inversely correlated with eCRF level in this study population. The protective of high eCRF against all-cause and CVD mortality was more prominent in the middle and high FRS category than in the low FRS category. Notably, the FRS plus eCRF model has better predictor power for estimating mortality risk compared to the FRS only model.

CONCLUSIONS

The current findings indicate that eCRF can be used as an alternative to objectively measured CRF for mortality risk prediction.

Specific body mass index trajectories were related to musculoskeletal pain and mortality: 19-year follow-up cohort

OBJECTIVE

We aimed to study 19-year body mass index (BMI) patterns and their (1) bidirectional relationship with musculoskeletal pain and (2) mortality risk.

STUDY DESIGN AND SETTING

We used data from the Chingford study and group-based trajectory modelling to define 19-year BMI patterns. We investigated whether baseline back, hand, hip, and knee pain (as single- and multi-site) predicted 19-year BMI trajectory, and whether 19-year BMI patterns predicted pain in year 20. We explored BMI trajectories and mortality risk over 25 years (life expectancy).

RESULTS

We included 938 women (mean age: year-1=54, year-20=72) and found seven distinct 19-year BMI trajectories: two normal-weighted (reference), slightly overweight, lower and upper overweight-to-obese, lower and upper obese. BMI patterns capturing the increase overweight-to-obese (BMI 27-34 overtime) were bidirectionally related to knee and multi-site pain. The lower obese pattern (BMI 33-38) was unidirectionally associated with lower limb pain. Women with BMI above 40 had an increased all-cause and cardiovascular mortality risk.

CONCLUSION

For most postmenopausal women, the overweight WHO category was a transition. Two patterns capturing increase overweight-to-obese were mutually related to musculoskeletal pain, i.e., knee and multi-site pain contributed to becoming obese, and trajectories of becoming obese increased the odds of experiencing pain later.

Three-year trajectories of metabolic risk factors predict subsequent long-term mortality in patients with type 2 diabetes

AIM

This study aims to evaluate the associations between 3-year trajectories of metabolic risk factors and subsequent mortality in patients with type 2 diabetes.

METHODS

A total of 6400 persons aged ≥ 30 years with type 2 diabetes and ≥ 3 years of follow-up period were included. The cluster analysis determined the patterns of 3-year trajectories, and Cox proportional hazards models evaluated the associations between patterns and mortality.

RESULTS

Three trajectory subgroups of metabolic risk factors, namely, cluster 1, normal; cluster 2, high-stable or reducing with high level at baseline; and cluster 3, fluctuation: elevated and decreasing, were generated. The clusters 2 and 3 of body mass index (BMI), fasting plasma glucose (FPG), HbA1c, and triglyceride (TG) trajectories were associated with increased risks of all-cause mortality compared with cluster 1 (hazard ratio = 1.27, 95% confidence interval = 1.06-1.51 and 1.45, 1.19-1.78 for BMI; 1.41, 1.22-1.62 and 1.81, 1.38-2.38 for FPG; 1.42, 1.23-1.64 and 1.47, 1.23-1.75 for HbA1c; 1.34, 1.10-1.63 and 2.40, 1.30-4.37 for TG, respectively). For the systolic blood pressure trajectory, only cluster 3 was associated with an increased mortality risk relative to cluster 1 (1.76, 1.13-2.77).

CONCLUSIONS

Long-term metabolic risk factor trajectories may be associated with subsequent mortality.

Relations between body mass index trajectories and habitual physical activity measured by smartwatch in the electronic cohort of the Framingham Heart Study: Cohort Study (Preprint)

Background

Objective

Methods

Results

Conclusions

Weight gain in Chinese youth during a 4-month COVID-19 lockdown: a retrospective observational study

OBJECTIVES

To observe the weight change in Chinese youth during a 4-month COVID-19 lockdown, and the association between weight change and mental health, physical activity and sedentary time changes, and dietary habits.

DESIGN

A retrospective observational study.

SETTINGS

Two universities located in Zhejiang and Hunan provinces, China.

PARTICIPANTS

This study enrolled 12 889 college students whose body weight was measured before the lockdown (1 December 2019-20 January 2020) at the two universities, and reported their weight measured at home or community after the end of the lockdown (1-23 May 2020) via an online follow-up questionnaire.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the weight change in Chinese youth during a 4-month lockdown resulting from the COVID-19 pandemic. The secondary outcomes were the relationships of weight change to COVID-19-related stress, depression, anxiety, physical activity and sedentary time changes, and dietary habits.

RESULTS

Participants' ages ranged from 17 to 27 years (M=19, SD=1) with 80.2% identified as female. The average absolute and relative changes in body weight were 2.6 (95% CI 2.0 to 3.2)) kg and 4.2% (95% CI 4.0% to 4.3%) for men, and 2.1 (1.9 to 2.4) kg and 4.2% (95% CI 3.9% to 4.4%) for women. An increase in overweight and obese individuals according to Asian cut-off points as a demographic percentage by 4.5% and 2.7% and 4.8% and 3.4% in men and women, respectively (P<0.001), was observed. Weight gain was significantly associated with increased sedentary time and an increase in COVID-19-related stress and depression score.

CONCLUSION

The present study's results suggest that the risk of weight gain in Chinese youth during the lockdown increased and that strategies to decrease sedentary time and improve mental health may be warranted to mitigate weight gain during and after the COVID-19 pandemic.

Life-course trajectories of weight and their impact on the incidence of type 2 diabetes

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.

Body mass index trajectories during mid to late life and risks of mortality and cardiovascular outcomes: Results from four prospective cohorts

BACKGROUND

Our understanding of the weight-outcome association mainly comes from single-time body mass index (BMI) measurement. However, data on long-term trajectories of within-person changes in BMI on diverse study outcomes are sparse. Therefore, this study is to determine the associations of individual BMI trajectories and cardiovascular outcomes.

METHODS

The present analysis was based on data from 4 large prospective cohorts and restricted to participants aged ≥45 years with at least two BMI measurements. Hazard ratios (HR) and 95% confidence intervals(95%CI) for each outcome according to different BMI trajectories were calculated in Cox regression models.

FINDINGS

The final sample comprised 29,311 individuals (mean age 58.31 years, and 77.31% were white), with a median 4 BMI measurements used in this study. During a median follow-up of 21.16 years, there were a total of 10,192 major adverse cardiovascular events (MACE) and 11,589 deaths. A U-shaped relation was seen with all study outcomes. Compared with maintaining stable weight, the multivariate adjusted HR for MACE were 1.53 (95%CI 1.40-1.66), 1.26 (95%CI 1.16-1.37) and 1.08 (95%CI 1.02-1.15) respectively for rapid, moderate and slow weight loss; 1.01 (95%CI 0.95-1.07), 1.13 (95%CI 1.05-1.21) and 1.29 (95%CI 1.20-1.40) respectively for slow, moderate and rapid weight gain. Identical patterns of association were observed for all other outcomes. The development of BMI differed markedly between the outcome-free individuals and those who went on to experience adverse events, generally beginning to diverge 10 years before the occurrence of the events.

INTERPRETATION

Our findings may signal an underlying high-risk population and inspire future studies on weight management.

FUNDING

National Natural Science Foundation of China, Guangdong Natural Science Foundation.

Body mass index trajectories among people with obesity and association with mortality: Evidence from a large Israeli database

Objective

Previous studies using longitudinal weight data to characterize obesity are based on populations of limited size and mostly include individuals of all body mass index (BMI) levels, without focusing on weight changes among people with obesity. This study aimed to identify BMI trajectories over 5 years in a large population with obesity, and to determine the trajectories' association with mortality.

Methods

For inclusion, individuals aged 30–74 years at index date (1 January 2013) with continuous membership in Clalit Health Services from 2008 to 2012 were required to have ≥1 BMI measurement per year in ≥3 calendar years during this period, of which at least one was ≥30 kg/m². Latent class analysis was used to generate BMI trajectories over 5 years (2008–2012). Cox proportional hazards models were used to assess the association between BMI trajectories and all‐cause mortality during follow‐up (2013–2017).

Results

In total, 367,141 individuals met all inclusion criteria. Mean age was 57.2 years; 41% were men. The optimal model was a quadratic model with four classes of BMI clusters. Most individuals (90.0%) had stable high BMI over time. Individuals in this cluster had significantly lower mortality than individuals in the other trajectory clusters (p < 0.01), including clusters of people with dynamic weight trajectories.

Conclusions

The results of the current study show that people with stable high weight had the lowest mortality of all four BMI trajectories identified. These findings help to expand the scientific understanding of the impact that weight trajectories have on health outcomes, while demonstrating the challenges of discerning the cumulative effects of obesity and weight change, and suggest that dynamic historical measures of BMI should be considered when assessing patients' future risk of obesity‐related morbidity and mortality, and when choosing a treatment strategy.

Latent Class Trajectory Modeling of Adult Body Mass Index and Risk of Obesity-Related Cancer: Findings from the Melbourne Collaborative Cohort Study

BACKGROUND

Obesity increases the risk of 13 cancer types. Given the long process of carcinogenesis, it is important to determine the impact of patterns of body mass over time.

METHODS

Using data from 30,377 participants in the Melbourne Collaborative Cohort Study, we identified body mass index (BMI) trajectories across adulthood and examined their association with the risk of obesity-related cancer. Participants completed interviews and questionnaires at baseline (1990-1994, age 40-69 years), follow-up 1 (1995-1998), and follow-up 2 (2003-2005). Body mass was recalled for age 18 to 21 years, measured at baseline, self-reported at follow-up 1, and measured at follow-up 2. Height was measured at baseline. Cancer diagnoses were ascertained from the Victorian Cancer Registry and the Australian Cancer Database. A latent class trajectory model was used to identify BMI trajectories that were not defined a priori. Cox regression was used to estimate HRs and 95% confidence intervals (CI) of obesity-related cancer risks by BMI trajectory.

RESULTS

Six distinct BMI trajectories were identified. Compared with people who maintained lower normal BMI, higher risks of developing obesity-related cancer were observed for participants who transitioned from normal to overweight (HR, 1.29; 95% CI, 1.13-1.47), normal to class I obesity (HR, 1.50; 95% CI, 1.28-1.75), or from overweight to class II obesity (HR, 1.66; 95% CI, 1.32-2.08).

CONCLUSIONS

Our findings suggest that maintaining a healthy BMI across the adult lifespan is important for cancer prevention.

IMPACT

Categorization of BMI by trajectory allowed us to identify specific risk groups to target with public health interventions.

Incremental Effect of Aging on Obesity-Related Incident Chronic Kidney Disease in the Korean General Population

OBJECTIVES

Obesity may increase the risk of kidney function decline. However, few studies have addressed how age modifies obesity-associated risk of chronic kidney disease (CKD) in the Asian general population.

DESIGN

A community-based prospective cohort study.

SETTING AND PARTICIPANTS

6538 Korean general population with normal kidney function from the Korean Genome and Epidemiology Study Database.

METHODS

Participants were stratified according to age (40-49, 50-59, and 60-69 years old) and body mass index [≥18.5-<23 (normal-weight), ≥23-<27.5 (overweight), and ≥27.5 (obese)]. We conducted Kaplan-Meier and multivariable-adjusted Cox regression analyses to investigate the association of aging and obesity with incident CKD.

RESULTS

During the 12-year follow-up, an overall incidence rate of CKD was 6.1 cases per 1000 person-years. Obese, but not overweight, people had an increased risk of incident CKD compared with normal-weight people in multivariable models adjusted for metabolic factors. When analyzed by 10-year increments, this association was significant only in 60-69-year-old individuals. Kaplan-Meier analysis showed that the incidence of CKD associated with overweight or obesity showed an accentuated increase with age. With reference to normal-weight individuals aged 40-49 years, the adjusted hazard ratio of CKD increased with age regardless of body mass index, and the positive association between obesity and incident CKD was more prominent with increasing age.

CONCLUSIONS AND IMPLICATIONS

Obesity-associated risk of incident CKD was accentuated in older people, and this association was independent of metabolic abnormalities.

The role of overweight and obesity in adverse cardiovascular disease mortality trends: an analysis of multiple cause of death data from Australia and the USA

BACKGROUND

In recent years, there have been adverse trends in premature cardiovascular disease (CVD) mortality rates (35-74 years) in the USA and Australia. Following long-term declines, rates in the USA are now increasing while falls in Australia have slowed rapidly. These two countries also have the highest adult obesity prevalence of high-income countries. This study investigates the role of overweight and obesity in their recent CVD mortality trends by using multiple cause of death (MCOD) data-direct individual-level evidence from death certificates-and linking the findings to cohort lifetime obesity prevalence.

METHODS

We identified overweight- and obesity-related mortality as any CVD reported on the death certificate (CVD MCOD) with one or more of diabetes, chronic kidney disease, obesity, lipidemias or hypertensive heart disease (DKOLH-CVD), causes strongly associated with overweight and obesity. DKOLH-CVD comprises 50% of US and 40% of Australian CVD MCOD mortality. Trends in premature age-standardized death rates were compared between DKOLH-CVD and other CVD MCOD deaths (non-DKOLH-CVD). Deaths from 2000 to 2017 in the USA and 2006-2016 in Australia were analyzed. Trends in in age-specific DKOLH-CVD death rates were related to cohort relative lifetime obesity prevalence.

RESULTS

Each country's DKOLH-CVD mortality rate rose by 3% per annum in the most recent year, but previous declines had reversed more rapidly in Australia. Non-DKOLH-CVD mortality in the USA increased in 2017 after declining strongly in the early 2000s, but in Australia it has continued declining in stark contrast to DKOLH-CVD. There were larger increases in DKOLH-CVD mortality rates at successively younger ages, strongly related with higher relative lifetime obesity prevalence in younger cohorts.

CONCLUSIONS

The increase in DKOLH-CVD mortality in each country suggests that overweight and obesity has likely been a key driver of the recent slowdown or reversal of CVD mortality decline in both countries. The larger recent increases in DKOLH-CVD mortality and higher lifetime obesity prevalence in younger age groups are very concerning and are likely to adversely impact CVD mortality trends and hence life expectancy in future. MCOD data is a valuable but underutilized source of data to track important mortality trends.

Association of bariatric surgery with all-cause mortality and incidence of obesity-related disease at a population level: A systematic review and meta-analysis

BACKGROUND

Previous clinical trials and institutional studies have demonstrated that surgery for the treatment of obesity (termed bariatric or metabolic surgery) reduces all-cause mortality and the development of obesity-related diseases such as type 2 diabetes mellitus (T2DM), hypertension, and dyslipidaemia. The current study analysed large-scale population studies to assess the association of bariatric surgery with long-term mortality and incidence of new-onset obesity-related disease at a national level.

METHODS AND FINDINGS

A systematic literature search of Medline (via PubMed), Embase, and Web of Science was performed. Articles were included if they were national or regional administrative database cohort studies reporting comparative risk of long-term mortality or incident obesity-related diseases for patients who have undergone any form of bariatric surgery compared with an appropriate control group with a minimum follow-up period of 18 months. Meta-analysis of hazard ratios (HRs) was performed for mortality risk, and pooled odds ratios (PORs) were calculated for discrete variables relating to incident disease. Eighteen studies were identified as suitable for inclusion. There were 1,539,904 patients included in the analysis, with 269,818 receiving bariatric surgery and 1,270,086 control patients. Bariatric surgery was associated with a reduced rate of all-cause mortality (POR 0.62, 95% CI 0.55 to 0.69, p < 0.001) and cardiovascular mortality (POR 0.50, 95% CI 0.35 to 0.71, p < 0.001). Bariatric surgery was strongly associated with reduced incidence of T2DM (POR 0.39, 95% CI 0.18 to 0.83, p = 0.010), hypertension (POR 0.36, 95% CI 0.32 to 0.40, p < 0.001), dyslipidaemia (POR 0.33, 95% CI 0.14 to 0.80, p = 0.010), and ischemic heart disease (POR 0.46, 95% CI 0.29 to 0.73, p = 0.001). Limitations of the study include that it was not possible to account for unmeasured variables, which may not have been equally distributed between patient groups given the non-randomised design of the studies included. There was also heterogeneity between studies in the nature of the control group utilised, and potential adverse outcomes related to bariatric surgery were not specifically examined due to a lack of available data.

CONCLUSIONS

This pooled analysis suggests that bariatric surgery is associated with reduced long-term all-cause mortality and incidence of obesity-related disease in patients with obesity for the whole operated population. The results suggest that broader access to bariatric surgery for people with obesity may reduce the long-term sequelae of this disease and provide population-level benefits.