BMI and mortality: results from a national longitudinal study of Canadian adults

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.

Association of behavior pattern with overweight and obesity in South Korean adults-A multi correspondence analysis (KNHANES-2018-2020)

The objective was to determine the association between health-related behaviour with overweight and obesity in South Korean adults by using the Korean National Health and Nutritional Examination Survey (KNHANES) 2018-2020. The study participants were 16,784 aged ≥ 20years. The variables were socio-demographic, lifestyle, food habits and metabolic conditions. The logistic regression analysis performed to find the association by the odds ratio (OR, 95% CI). MCA performed to identify risk factors were computed for overweight and obesity. Overweight and obesity were significantly associated with health behaviour, high income (OR = 1.26; 95% CI: 1.15-1.39), smoking(OR = 1.29; 95% CI: 1.08-1.53), low physical activity(OR = 3.23; 95% CI: 1.79-4.69), diabetes(OR = 2.70; 95% CI: 1.62-4.50), high cholesterol and low HDL(OR = 3.98; 95%CI:2.65-5.97). The high discriminant variables of MCA were aged over 60years, lower education, high income, diabetes, lack of physical activity, and high cholesterol. The findings confirm that the OR of obesity and overweight was likely associated with health behaviour patterns. Besides, it indicates the MCA would be very effective to identify the population-based data context than individual data and it may suggest that more research on association between health behaviours and obesity prevention interventions should be developed for each age group for better health outcomes.

Impacts of commute mode on body mass index: A longitudinal analysis before and during the COVID-19 pandemic

Introduction

COVID-19 has impacted millions of commuters by decreasing their mobility and transport patterns. While these changes in travel have been studied, less is known about how commute changes may have impacted individuals' body mass index (BMI). The present longitudinal study explores the relationship between commute mode and BMI of employed individuals in Montréal, Canada.

Methods

This study uses panel data drawn from two waves of the Montréal Mobility Survey (MMS) conducted before and during the COVID-19 pandemic (n = 458). BMI was modeled separately for women and men as a function of commuting mode, WalkScore©, sociodemographic, and behavioral covariates using a multilevel regression modeling approach.

Results

For women, BMI significantly increased during the COVID-19 pandemic, but telecommuting frequency, and more specifically telecommuting as a replacement of driving, led to a statistically significant decrease in BMI. For men, higher levels of residential local accessibility decreased BMI, while telecommuting did not have a statistically significant effect on BMI.

Conclusions

This study's findings confirm previously observed gendered differences in the relations between the built environment, transport behaviors, and BMI, while offering new insights regarding the impacts of the changes in commute patterns linked to the COVID-19 pandemic. Since some of the COVID-19 impacts on commute are expected to be lasting, findings from this research can be of use by health and transport practitioners as they work towards generating policies that improve population health.

Physical activity and body mass index were interactively related to health-related quality of life among older adults

PURPOSE

The purpose of this study was to examine how meeting physical activity (PA) guidelines (i.e., moderate-to-vigorous aerobic activity, muscle strengthening activity) and weight status were interactively related to health-related quality of life (HRQoL) among older adults.

METHODS

A cross-sectional analysis was conducted using data from 87,495 older adults aged 65+ years who participated in the U.S. 2019 Behavioral Risk Factor Surveillance System. PA, weight status, and HRQoL were assessed by validated questionnaires via phone interviews. Binomial logistic regression models were used to examine the interactive effects of meeting PA guidelines and weight status on the odds of having poor HRQoL after controlling for key confounders.

RESULTS

Compared to participants meeting both PA guidelines and with normal weight, both underweight and obese older adults had significantly higher odds of having poor general health (OR= 1.55-6.16) regardless of meeting PA guideline status, and those meeting muscle strengthening activities only or meeting neither PA guideline reported higher odds of poor physical health (OR= 1.83-6.22) regardless of weight status. Similarly, those meeting neither PA guideline had significantly higher odds of having poor mental health (OR= 1.69-2.78) regardless of weight status, and those meeting muscle strengthening activities only or meeting neither PA guideline reported higher odds of having frequent activity limitation days (OR= 2.18-7.05).

CONCLUSIONS

The positive associations between moderate-to-vigorous aerobic PA and HRQoL indicate the need to promote aerobic PA in older adults. Both sex and weight status should be considered when designing PA interventions to improve HRQoL among older adults.

The Real Ideal: Misestimation of Body Mass Index

In Western cultures, the ideal body for women is thin and toned. Idealization of thinness has led many women to desire bodies with an underweight body mass index (BMI). The present study investigated women's knowledge of BMI, particularly relating to their own body ideals, to determine whether women knowingly idealize bodies categorized as “underweight.” In August 2020, one-hundred and forty-seven US women aged 18 to 25 completed two online tasks in a repeated-measures design. First, participants estimated the BMIs of a series of bodies. Then, participants selected representations of their own and ideal bodies from a figure rating scale and estimated the BMIs of their selections. Participants generally mis-estimated the BMI of bodies, but did so to a greater extent when viewing bodies as an extension of their own, i.e., following the figure rating scale task. Further, if participants selected an underweight or overweight ideal body, they were likely to estimate this body was within a “normal” weight BMI range, demonstrating that women who idealize underweight–or overweight–bodies do so unknowingly. These findings suggest misperceptions of women's own ideal body size are often greater than misperceptions of other bodies, potentially driving the tendency to idealize underweight bodies.

The role of social context in own body size estimations: An investigation of the body schema

Women tend to overestimate their body size, including space needed to pass through gaps/apertures. These results were generated using static apertures resembling doorways. However, body image is influenced by other bodies around us, and how estimations of passability may be influenced by social context is unknown. To investigate, a series of apertures were created comprising two women facing each other, with the space between creating the 'doorway'. The apertures were created using either two larger-bodied or two smaller-bodied women. Non-social versions were generated using the social aperture silhouettes. Thirty-four undergraduate women viewed a series of apertures - varying in width relative to their own size - and judged whether they believed they could pass through them. State and trait body dissatisfaction measurements were also taken. Point of subjective equality (PSE) data suggested that participants did not overestimate the space needed to pass through apertures overall, but showed an overestimation of space for the larger-bodied social doorways. Correlations suggested higher levels of state body dissatisfaction associated with higher PSEs, but only in the social conditions. Results showed that participants may have been engaging in different mechanisms regarding social versus non-social doorways, and the importance of social context when investigating own body size estimations.

Prevalence of depressive symptoms in patients with rheumatoid arthritis at a regional hospital in KwaZulu-Natal, South Africa

Background

Depression affects 14.8% – 38.8% of patients with rheumatoid arthritis (RA) in developed countries. The prevalence and risk factors for depression in patients with RA in sub-Saharan Africa is not well established.

Aim

To determine the prevalence of depressive symptoms in patients with RA.

Setting

Public sector regional hospital in South Africa.

Methods

A cross-sectional descriptive study was undertaken with 110 adult RA patients. A structured socio-demographic and clinical questionnaire, the modified health assessment questionnaire (mHAQ), the simplified disease activity index (SDAI) for RA, the patient health questionnaire (PHQ-9), and the Household Food Insecurity Access scale (HFIAS) for nutritional status, were used. Correlates of depressive symptomatology in participants with RA were identified using t-tests and regression analyses.

Results

Most of the participants were women (90.9%), 67% had moderate to severe RA disease on the SDAI score, 92.7% reported functional disability (HAQ score of ≥ 1), and 87.2% reported mild to severe depressive symptoms. Unemployment (p < 0.01), severe food insecurity (p < 0.01) and functional disability (p = 0.02), were significantly associated with the depressive symptoms, but not with disease activity (p = 0.8) or inflammatory markers (p = 0.63). Unemployment (adjusted β = −5.07, p < 0.01) and severe food insecurity (adjusted β = −4.47, p < 0.01) were significantly associated with depressive symptoms, based on the adjusted regression model.

Conclusion

As RA effects functional status, with the impact of the resulting unemployment and food insecurity being associated with depression, affected people should be screened for depression and managed using a multidisciplinary approach, especially considering the role of social determinants in RA patients with depression.

Nationwide trends in prevalence of underweight, overweight, and obesity among people with disabilities in South Korea from 2008 to 2017

Objectives

This study investigated the 10-year trends of weight and prevalence of underweight, overweight and obesity according to disability grade and types compared with those without disabilities.

Methods

This serial cross-sectional analysis was conducted using national disability registration data with national general health checkup data from 2008 to 2017. Age-standardized prevalence of underweight and obesity were analyzed for each year, according to the presence, type, and severity of disabilities. Odds of underweight, overweight, obesity, and severe obesity were examined by multinomial logistic regression after adjusting for socio-demographic and clinical variables using data in 2017.

Results

Over 10 million subjects in each year were included in the analysis. In 2017, 14,246,785 people with age between 19 and 110 years were included and 53.1% was men. For 10 years, age-standardized prevalence of obesity and severe obesity showed significant increases regardless of sex and presence of disability. However, age-standardized underweight prevalence in people without disability tended to decrease whereas it was an increase in 2012 and the prevalence has remained steady since in people with disability. People with disabilities had higher odds of underweight compared to those without disability (OR 1.41, 95% CI 1.38–1.44 in male and OR 1.31, 95% CI 1.28–1.34 in female), especially in those with severe disabilities (OR 2.00, 95% CI 1.94–2.06 in male and OR 1.83, 95% CI 1.77–1.89 in female). Women with disabilities are more likely to be obese than those without disabilities regardless of disability severity (OR 1.40, 95% CI 1.38–1.41). Participants with mental disorder showed the highest prevalence of obesity, followed by epilepsy and developmental disability.

Conclusions

Having a disability was associated with higher odds/probability of both obesity and underweight. The intersection of female, severe disability, and mental/developmental disabilities was associated with probability of severe obesity. Simultaneous efforts are needed to develop health policy to reduce both the prevalence of obesity and underweight.

Relationship of domain-specific quality of life with body mass index and waist circumference in a Korean elderly population

BACKGROUND

Obesity affects health-related quality of life (QoL); however, their relationship among elderly Asians is not well known.

AIMS

Relationship of domain-specific QoL with body mass index (BMI) and waist circumference and the sex differences were investigated using a nationally representative sample of elderly Korean population.

METHODS

In the Korea National Health and Nutrition Examination Survey phase VII (2016-2018), 3659 adults aged ≥ 65 years (1551 men and 2108 women) participated. BMI and waist circumference were classified according to Asian- and Korean-specific criteria. QoL was evaluated using the European Quality of Life Scale-Five Dimensions (EQ-5D). Multivariable logistic regressions were used to examine the relationship of QoL with BMI and waist circumference.

RESULTS

Men with BMI < 18.5 kg/m² and ≥ 25.0 kg/m² had a significant association with poor QoL in mobility and self-care, but no relationship was found with the other domains. Women with BMI ≥ 25.0 kg/m² had poor QoL in mobility and self-care, and those with BMI ≥ 30.0 kg/m² had poor QoL in usual activities and pain/discomfort. There was no significant association with anxiety/depression. Both elderly men and women with abdominal obesity had a significant association with poor QoL in mobility, self-care, usual activities, and pain/discomfort; however, there was no significant relationship with waist circumference and anxiety/depression.

CONCLUSIONS

The association between QoL and BMI was different according to sex and the domains of QoL. Domain-specific QoL should be considered in the management of body weight of the elderly.

Is Obesity a Risk or Protective Factor for Open-Angle Glaucoma in Adults? A Two-Database, Asian, Matched-Cohort Study

Obesity contributes to multiple systemic disorders; however, extensive discussion regarding obesity and open-angle glaucoma (OAG) remains limited, and conclusions in the existing literature diverge. This study aims to analyze the risk of OAG among obese adults in Taiwan. In this study, adults (aged ≥18 years) with a diagnostic code of obesity or morbid obesity registered in the Longitudinal Health Insurance Database (LHID) 2000 and LHID2005 from 1 January 2001 to 31 December 2010 were included. All adults were traced until the diagnosis of OAG, the occurrence of death, or 31 December 2013. Risk of OAG was significantly higher in obese adults than in non-obese adults after multivariable adjustment (adjusted hazard ratio (aHR): 1.43 (95% confidence interval (CI) 1.11-1.84)/aHR: 1.54 (95% CI 1.23-1.94) in the LHID2000/LHID2005). Both databases demonstrated that young obese adults (aged ≤40 years) had a remarkably increased risk of OAG compared with young non-obese adults (aHR 3.08 (95% CI 1.82-5.21)/aHR 3.81 (95% CI 2.26-6.42) in the LHID2000/LHID2005). This two-database matched-cohort study suggests that obese adults have an increased risk of OAG. In young adults, in particular, obesity could be a potential risk factor of OAG.

The intersectional impact of sex and social factors on subjective health: analysis of the Canadian longitudinal study on aging (CLSA)

Background

Self-rated health (SRH) is a widely validated measure of the general health of older adults. Our aim was to understand what factors shape individual perceptions of health and, in particular, whether those perceptions vary for men and women and across social locations.

Methods

We used data from the Canadian Longitudinal Study on Aging (CLSA) of community-dwelling adults aged 45 to 85. SRH was measured via a standard single question. Multiple Poisson regression identified individual, behavioural, and social factors related to SRH. Intersections between sex, education, wealth, and rural/urban status, and individual and joint cluster effects on SRH were quantified using multilevel models.

Results

After adjustment for relevant confounders, women were 43% less likely to report poor SRH. The strongest cluster effect was for groupings by wealth (21%). When wealth clusters were subdivided by sex or education the overall effect on SRH reduced to 15%. The largest variation in SRH (13.6%) was observed for intersections of sex, wealth, and rural/urban status. In contrast, interactions between sex and social factors were not significant, demonstrating that the complex interplay of sex and social location was only revealed when intersectional methods were employed.

Conclusions

Sex and social factors affected older adults’ perceptions of health in complex ways that only became apparent when multilevel analyses were carried out. Utilizing intersectionality analysis is a novel and nuanced approach for disentangling explanations for subjective health outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02412-6.

Correlation of Body Mass Index with Oncologic Outcomes in Colorectal Cancer Patients: A Large Population-Based Study

It has been acknowledged that excess body weight increases the risk of colorectal cancer (CRC); however, there is little evidence on the impact of body mass index (BMI) on CRC patients' long-term oncologic results in Asian populations. We studied the influence of BMI on overall survival (OS), disease-free survival (DFS), and CRC-specific survival rates in CRC patients from the administrative claims datasets of Taiwan using the Kaplan-Meier survival curves and the log-rank test to estimate the statistical differences among BMI groups. Underweight patients (<18.50 kg/m²) presented higher mortality (56.40%) and recurrence (5.34%) rates. Besides this, they had worse OS (aHR:1.61; 95% CI: 1.53-1.70; p-value: < 0.0001) and CRC-specific survival (aHR:1.52; 95% CI: 1.43-1.62; p-value: < 0.0001) rates compared with those of normal weight patients (18.50-24.99 kg/m²). On the contrary, CRC patients belonging to the overweight (25.00-29.99 kg/m²), class I obesity (30.00-34.99 kg/m²), and class II obesity (≥35.00 kg/m²) categories had better OS, DFS, and CRC-specific survival rates in the analysis than the patients in the normal weight category. Overweight patients consistently had the lowest mortality rate after a CRC diagnosis. The associations with being underweight may reflect a reverse causation. CRC patients should maintain a long-term healthy body weight.

Shape of BMI-Mortality Risk Associations: Reverse Causality and Heterogeneity in a Representative Cohort of US Adults

OBJECTIVE

This study examines BMI-mortality associations and evaluates strategies intended to limit reverse causality. Heterogeneity in BMI-mortality risk associations across subgroups and causes of death is explored.

METHODS

A cohort of 654,382 adults from the US National Health Interview Survey was constructed. Associations between unit BMI levels and mortality were estimated using Cox proportional hazards models, including and excluding the first 5 years of follow-up, with and without controls for smoking or preexisting conditions, and including and excluding ever-smokers and individuals with preexisting conditions. Stratified analyses by individual characteristics were performed.

RESULTS

Addressing reverse causality led to reduced risk of mortality among those with low BMI levels (<18 kg/m² ). Excluding ever-smokers and individuals with preexisting conditions further led to increased risk among those with high BMI levels (between 33 kg/m² and >40 kg/m² ) and lowered the estimated nadir risk from 27 kg/m² to 23 kg/m² . After excluding ever-smokers and individuals with preexisting conditions, limiting the analysis to >5 years of follow-up produced no substantive changes. Heterogeneous results were observed across individual characteristics, particularly age and causes of death.

CONCLUSIONS

The exclusion of smokers and individuals with preexisting conditions alters the BMI-mortality risk association and results in a somewhat lower range of BMI with minimum mortality risk.

Sex-specific effects of ketogenic diet after pre-exposure to a high-fat, high-sugar diet in rats

BACKGROUND AND AIMS

The objectives were to evaluate the relationship between ketogenic diets, the ketone body beta-hydroxybutyrate (BHB), parameters known to increase risk for cardiovascular and metabolic diseases in both sexes, using a pre-clinical model of obesity.

METHODS AND RESULTS

Rats had access to a diet high in fat and sugar (HFS) for 12 weeks. After HFS, they switched to chow (HFS-CH) or ketogenic diet (HFS-KD) for 3 weeks to model a dietary intervention. Body weight, adiposity, and food intake were measured. Glucose tolerance and corticosterone response to stress were measured after HFS, then again after the intervention. Both sexes increased body weight, food intake, and adiposity compared to control (CTL) while on HFS. HFS females showed impaired glucose tolerance. HFS males developed a dampened corticosterone to stress, whereas HFS females developed an exacerbated response. The effects of HFS on adiposity and corticosterone were reversed in HFS-CH males. These same improvements were observed in HFS-CH females, although they still had impaired glucose tolerance. HFS-KD males showed some improvements, however, they still had higher body weight and adiposity than CTL. The same pattern was observed in females. These beneficial effects of KD correlated with plasma BHB levels in females but not in males.

CONCLUSIONS

These data model effects reported in clinical literature and serve as a valuable translational tool to further test causal mechanisms that lead to desirable outcomes of KD. These sex-specific relationships are important, as KD could potentially affect endocrine mechanisms differently in males and females.

Relationship Between Body Mass Index and Incidence of Atrial Fibrillation in Young Japanese Men - The Nishimura Health Survey

BACKGROUND

The associations between body mass index (BMI) and incidence of atrial fibrillation (AF) in young men are scarce, especially in Asian countries, given the differences in BMI between Asians and Western populations.Methods and Results:This study analyzed 17,865 middle-aged Japanese men without AF from a cohort of employees undergoing annual health examinations. AF incidence was evaluated during a follow-up period (median 4.0 years, interquartile range 2.0-7.1 years). Among young men aged 30-49 years, AF incidence was 0.64/1,000 person-years, whereas it was 2.54/1,000 and 7.60/1,000 person-years among men aged 50-59 and ≥60 years, respectively. Multivariable Cox regression analysis among young men revealed age (hazard ratio [HR] 3.28 by 10-years' increase, 95% confidence interval [CI] 1.72-6.25, P<0.001), BMI (BMI-quadratic, HR 1.01, 95% CI 1.00-1.01, P<0.001, BMI-linear, HR 0.95, 95% CI 0.86-1.05, P=0.33), and electrocardiogram (ECG) abnormalities, such as PQ prolongation, supraventricular beat, and p wave abnormality (HR 8.79, 95% CI 3.05-25.32, P<0.001), were significantly associated with AF incidence. There was a reverse J-shaped association between BMI and AF incidence in young men, whereby the presence of ECG abnormality inversely influenced the BMI-incident AF relationship. A linear association between BMI and AF incidence in men aged 50-59 and ≥60 years was present.

CONCLUSIONS

AF incidence displays a reverse J-shaped relationship with BMI in young men, but a linear association in men aged ≥50 years. The paradoxical relationship seen in young men only may reflect atrial electrical or structural abnormalities.

Prognostic factors for steroid-free remission in patients with idiopathic inflammatory myopathies: importance of anthropometric measurements

Background:

Several studies have been conducted on factors associated with mortality in idiopathic inflammatory myopathies (IIMs), but few studies have assessed prognostic factors for steroid-free remission in IIM. We investigated the various clinical factors, including body measurements, that affect IIM treatment outcomes.

Methods:

Patients who were newly diagnosed with IIM between 2000 and 2018 were included. Steroid-free remission was defined as at least 3 months of normalisation of muscle enzymes and no detectable clinical disease activity. The factors associated with steroid-free remission were evaluated by a Cox regression analysis.

Results:

Of the 106 IIM patients, 35 displayed steroid-free remission during follow-up periods. In the multivariable Cox regression analyses, immunosuppressants’ early use within 1 month after diagnosis [hazard ratio (HR) 6.21, 95% confidence interval (CI) 2.61–14.74, p < 0.001] and sex-specific height quartiles (second and third quartiles versus first quartile, HR 3.65, 95% CI 1.40–9.51, p = 0.008 and HR 2.88, 95% CI 1.13–7.32, p = 0.027, respectively) were positively associated with steroid-free remission. Polymyositis versus dermatomyositis (HR 0.21, 95% CI 0.09–0.53, p = 0.001), presence of dysphagia (HR 0.15, CI 0.05–0.50, p = 0.002) and highest versus lowest quartile of waist circumference (WC; HR 0.24, 95% CI 0.07–0.85, p = 0.027) were negatively associated with steroid-free remission.

Conclusion:

The early initiation of immunosuppressant therapy, type of myositis and presence of dysphagia are strong predictors of steroid-free remission in IIM; moreover, height and WC measurements at baseline may provide additional important prognostic value.

Suboptimal baseline mental health associated with 4-month premature all-cause mortality: Findings from 18 years of follow-up of the Canadian National Population Health Survey

OBJECTIVE

To investigate: 1) whether baseline non-flourishing mental health is associated with a higher probability of all-cause mortality over 18-year follow-up after controlling for many risk factors for premature mortality; and 2) what other factors, independent of mental health status, are associated with all-cause mortality after adjustment for known risk factors.

METHODS

Data were derived from waves 1 and 9 (1994/1995; 2010/2011) of the Canadian National Population Health Survey. An analytic sample of 12,424 participants 18 years and above was selected. Baseline information on flourishing and predictors of all-cause mortality was from wave 1 and mortality data was ascertained by the Canadian Vital Statistics-Death Database in wave 9. Mean time to all-cause mortality was estimated using Kaplan-Meir procedure. Cox proportional hazards models were used to assess the association of baseline non-flourishing mental health and potential predictors with time to all-cause mortality.

RESULTS

About one in five participants was classified as non-flourishing at baseline. At the end of the study period 2317 deaths were observed. Baseline non-flourishing mental health was associated with a 19% higher probability of all-cause mortality during 18-year follow-up (HR = 1.19; 95% CI 1.08-1.32), corresponding to a 4.7-month shorter survival time. After controlling for baseline chronic health conditions, past-year depression, sociodemographics, health behaviors, social support, pain and functioning, baseline non-flourishing mental health status was associated with a 14% higher probability of death (HR = 1.14; 95% CI 1.02-1.27).

CONCLUSIONS

Suboptimal mental health is associated with premature mortality even after accounting for many risk factors for early death. Future research should explore the physiological pathways through which non-flourishing influences mortality.

Predictors of perceived health in adults with an intellectual disability

BACKGROUND

The effects of Intellectual disability (ID) levels, body mass index (BMI) categories, and other factors on perceived health status of adults with ID are not well-known.

AIMS

We aimed to examine: (a) the relationship between perceived health and level of intellectual function; (b) the influence of different BMI categories on a perceived health; and (c) the effect of the modifiable behavioral factors on perceived health.

METHODS AND PROCEDURES

We examined the aims using data from the 2013-2014 Adult Consumer Survey of the National Core Indicator. We extracted demographic (e.g. age, BMI) and modifiable behavior-related variables (e.g. physical activity participation, having a job) and used logistic regression models to analyze the relationships.

OUTCOMES AND RESULTS

Logistic regressions showed that more severe ID level is associated with worse perceived health, but when other variables related to personal and behavioral characteristics were accounted for, this relationship was no longer significant. Obese adults with ID had worse perceived health than those with normal weight; this effect remained significant even after considering other variables. Those in the overweight category did not differ in perceived health status from those of normal weight. The effects of all modifiable behaviors on perceived health were significant.

CONCLUSIONS AND IMPLICATIONS

Health promotion programs for adults with ID may benefit by consideration of modifiable behaviors.

Parainfluenza Virus in Hospitalized Adults: A 7-Year Retrospective Study

Background

Parainfluenza virus (PIV) is a cause of respiratory tract infection in children and the immunocompromised population, but its clinical manifestations, impact, and outcomes in hospitalized adults are not well studied.

Methods

This retrospective study included adults (≥18 years old) admitted to Northwestern Memorial Hospital or Prentice Women's Hospital (both in Chicago, Illinois) between 1 August 2009 and 31 July 2016 with a positive molecular test result for PIV. Epidemiologic, clinical, and outcomes data were collected from the enterprise data warehouse and patient electronic health records after institutional review board approval. Descriptive statistics were used to summarize the data.

Results

A total of 550 adults with a positive molecular test for PIV were identified. Differences in seasonality, clinical presentation, and prevalence between the different PIV serotypes (PIV-1, PIV-2, and PIV-3) were identified. The most common signs/symptoms were cough (88%), productive sputum (55%), fever (63%), and dyspnea (49%). Of the patients administered antibiotics, 349 (79.6%) had no confirmed bacterial infection throughout their hospitalization. The average length of hospitalization was 7.7 days. Presence of bacterial coinfection (P = .01), fungal coinfection (P < .01), decreased body mass index (P = .03), and increased respiratory rate (P < .01) were associated with significant differences in mortality rates.

Conclusions

PIV infection is associated with substantial morbidity in hospitalized adults. Such data will be useful in understanding the impact on epidemiology and outcomes if a PIV-specific vaccine becomes available. Furthermore, this highlights the need for novel preventive and therapeutic approaches to PIV infection.

Diagnosis: a critical social reflection in the genomic era

Abstract Diagnosis is a pivotal tool for the work of medicine as they categorise and classify individual ailments via a generalised schema. However diagnosis is also a profoundly social act, which reflects society, its values and how it makes sense of illness and disease. Considering diagnosis critically, as well as practically, is an important job of the sociologist. This paper reviews how a social model can provide a critical tool for viewing diagnosis in the genomic era. It explores how the formulation of diagnosis, be it via genetic explanations or microbiological ones, are the product of social discovery, negotiation, and consensus.

Does Dog Ownership Affect Physical Activity, Sleep, and Self-Reported Health in Older Adults?

Physical activity (PA) is crucial for maintaining good health of older adults and owning a dog and walking it can enforce it. The purpose of this study was to evaluate the effect of dog ownership on PA in older adults as well as its positive impact on perceived degree of health, and sleep. There were 44 participants of mean age 68 ± 5.4 years (18 males, 26 females) enrolled in this study (dog owners—DO, n = 26; non-dog owners—NDO, n = 18). Xiaomi Mi Band 2 accelerometer, International Physical Activity Questionnaire- Short form (IPAQ-Short Form) and SF-36 questionnaires were used to measure the level of PA, sleep, and subjective health. A statistically significant difference was observed in favor of dog owners in most of the monitored parameters. All accelerometer PA parameters (step count, activity time, distance, calories) showed a significant difference at a p < 0.01. Sleep parameters were significant in total sleep length (p = 0.05) and light sleep length (p < 0.05). DO reported higher total PA time (min/week), MET/min/week spent in walking, and spent calories/week (p < 0.05). In SF-36 they reported higher score (p < 0.05) in general health, physical functioning, social functioning, pain, vitality, and emotional well-being. Body mass index (BMI) was significantly lower in the DO group (p < 0.01). The results suggest that dog ownership may affect the overall PA and health of older adults.

Risk factors outperform intracranial large artery stenosis predicting unfavorable outcomes in patients with stroke

Background

This study examined how intracranial large artery stenosis (ILAS), symptomatic and asymptomatic ILAS, and risk factors affect unfavorable outcome events after medical treatment in routine clinical practice.

Methods

This was a 24-month prospective observational study of consecutively recruited stroke patients. All participants underwent magnetic resonance angiography, and their clinical characteristics were assessed. Outcome events were vascular outcome, recurrent stroke, and death. Cox regression analyses were performed to identify potential factors associated with an unfavorable outcome, which included demographic and clinical characteristics, the risk factors, and stenosis status.

Results

The analysis included 686 patients; among them, 371 were assessed as ILAS negative, 231 as symptomatic ILAS, and 84 as asymptomatic ILAS. Body mass index (p < .05), hypertension (p = .01), and old infarction (p = .047) were factors relating to vascular outcomes. Hypertension was the only factor for recurrent stroke (p = .035). Poor glomerular filtration rate (< 30 mL/min/1.73 m²) (p = .011) and baseline National Institutes of Health Stroke Scale scores (p < .001) were significant predictors of death.

Conclusions

This study extended previous results from clinical trials to a community-based cohort study by concurrently looking at the presence/absence of stenosis and a symptomatic/asymptomatic stenotic artery. Substantiated risk factors rather than the stenosis status were predominant determinants of adverse outcome. Although the degree of stenosis is often an indicator for treatment, we suggest risk factors, such as hypertension and renal dysfunction, should be monitored and intensively treated.

The relationship between maternal body mass index and pregnancy outcomes in twin compared with singleton pregnancies

OBJECIVE

Women with twins have an a priori increased risk for many of the complications associated with maternal obesity. Thus, the impact of maternal obesity in twins may differ from that reported in singletons. In addition, given the increased metabolic demands in twin pregnancies, the impact of maternal underweight may be greater in twin compared with singleton gestations. Our objective was to test the hypothesis that the relationship between maternal pre-pregnancy body mass index (BMI) and adverse pregnancy outcomes differ between twin and singleton gestations.

METHODS

This was a retrospective population-based study of all women who had a singleton or twin hospital birth in Ontario, Canada, between April 2012 and March 2016. Data were obtained from the Better Outcomes Registry & Network (BORN) Ontario. The relationship between maternal BMI category and pregnancy complications was assessed separately in twin and singleton gestations. The primary outcome was a composite variable that included any of the following complications: preeclampsia, gestational diabetes, or preterm birth before 32^0/7 weeks. Relative risk (aRR) and 95% confidence intervals (CI) for adverse outcomes for each BMI category as defined by WHO (using normal weight category as reference) were generated using modified Poisson regression, adjusting for maternal age, nulliparity, smoking, previous preterm birth, and fetal sex.

RESULTS

A total of 487,870 women with singleton (n = 480,010) and twin (n = 7860) pregnancies met the inclusion criteria. The risk of the composite primary outcome, preeclampsia, gestational diabetes, and cesarean delivery increased with high maternal BMI in both singleton and twin gestations, but these associations were weaker in twin compared with singleton gestations (association of BMI ≥ 40.0 kg/m² with primary outcome: aRR = 3.10, 95%-CI 2.96-3.24 in singletons compared with aRR = 1.74, 95%-CI 1.37-2.20 in twins). In singleton pregnancies the risk of preterm birth at < 32^0/7 weeks increased with maternal BMI, mainly due to an increased risk of provider-initiated preterm birth. In twin gestations, however, underweight (but not overweight or obesity) was associated with the greatest risk of preterm birth at < 32 weeks (aRR 1.67, 95%-CI 1.17-2.37), mainly due to an increased risk of spontaneous preterm birth (aRR 2.10, 95%-CI 1.44-3.08).

CONCLUSION

In healthy women with twin pregnancies, underweight is associated with the greatest risk for preterm birth, while the association of maternal obesity with adverse pregnancy outcomes is weaker than that observed in singletons.

The relationship of education and acculturation with vigorous intensity leisure time physical activity by gender in Latinos

OBJECTIVES

Latinos have poorer health outcomes among certain conditions (e.g. diabetes, obesity, mental health) compared to non-Latino Whites in the U.S., in part due to difference in the amount of physical activity, which are heavily influenced by sociocultural factors such as educational attainment and acculturation. Vigorous-intensity leisure time physical activity (VLTPA) may provide health benefits with a shorter amount of time than moderate-to-light physical activity. However, VLTPA has been significantly understudied compared to LTPA in general. The purpose of this study is to examine the associations between educational attainment, acculturation, and VLTPA by gender among Latino adults in the U.S.

DESIGN

Nationally representative samples of Latino adults aged 25 years and older (n = 4393) from the 2010 National Health Interview Survey were analyzed. VLTPA was measured as the number of hours per week of VLTPA consisting of heavy sweating or large increases in breathing and heart rate. Acculturation was measured as the degree to which the English language versus the Spanish language was spoken most often. The zero-inflated Poisson regression model was constructed using the full information maximum likelihood estimation and controlling for a series of sociodemographic characteristics and relevant health behaviors.

RESULTS

Educational attainment was positively associated with VLTPA among Latino adults [exp(b) = 1.09, p < 0.05)]. Similarly, greater acculturation was associated with greater hours/week of VLTPA [exp(b) = 1.10, p < 0.05)]. Lastly, the effect of educational attainment on VLTPA significantly varied by gender.

CONCLUSIONS

Education had a positive association and acculturation had negative association with the hours/week of VLTPA among Latinos. Also, the association between education and VLTPA was significantly stronger among women than men. These findings inform culturally and socially sensitive approaches to improve the health of Latinos, in hopes to address health disparities by race/ethnicity the U.S.

Interaction between cardiovascular risk factors and body mass index and 10-year incidence of cardiovascular disease, cancer death, and overall mortality

The effect of above-normal body mass index (BMI) on health outcomes is controversial because it is difficult to distinguish from the effect due to BMI-associated cardiovascular risk factors. The objective was to analyze the impact on 10-year incidence of cardiovascular disease, cancer deaths and overall mortality of the interaction between cardiovascular risk factors and BMI. We conducted a pooled analysis of individual data from 12 Spanish population cohorts with 10-year follow-up. Participants had no previous history of cardiovascular diseases and were 35-79years old at basal examination. Body mass index was measured at baseline being the outcome measures ten-year cardiovascular disease, cancer and overall mortality. Multivariable analyses were adjusted for potential confounders, considering the significant interactions with cardiovascular risk factors. We included 54,446 individuals (46.5% with overweight and 27.8% with obesity). After considering the significant interactions, the 10-year risk of cardiovascular disease was significantly increased in women with overweight and obesity [Hazard Ratio=2.34 (95% confidence interval: 1.19-4.61) and 5.65 (1.54-20.73), respectively]. Overweight and obesity significantly increased the risk of cancer death in women [3.98 (1.53-10.37) and 11.61 (1.93-69.72)]. Finally, obese men had an increased risk of cancer death and overall mortality [1.62 (1.03-2.54) and 1.34 (1.01-1.76), respectively]. In conclusion, overweight and obesity significantly increased the risk of cancer death and of fatal and non-fatal cardiovascular disease in women; whereas obese men had a significantly higher risk of death for all causes and for cancer. Cardiovascular risk factors may act as effect modifiers in these associations.

Trajectories of body mass index among Canadian seniors and associated mortality risk

Background

This study aims to characterize the heterogeneity in BMI trajectories and evaluate how different BMI trajectories predict mortality risk in Canadian seniors.

Methods

Data came from the Canadian National Population Health Survey (NPHS, 1994–2011) and 1480 individuals aged 65–79 years with at least four BMI records were included in this study. Group-based trajectory model was used to identify distinct subgroups of longitudinal trajectories of BMI measured over 19 years for men and women. Cox proportional hazards models were used to examine the association between BMI trajectories and mortality risks.

Results

Distinct trajectory patterns were found for men and women: ‘Normal Weight-Down’(N-D), ‘Overweight-Normal weight’ (OV-N), ‘Obese I-Down’ (OB I-D), and ‘Obese II- Down’ (OB II-D) for women; and ‘Normal Weight-Down’ (N-D), ‘Overweight-Normal weight’ (OV-N), ‘Overweight-Stable’ (OV-S), and ‘Obese-Stable’ (OB-S) for men. Comparing with OV-N, men in the OV-S group had the lowest mortality risk followed by the N-D (HR = 1.66) and OB-S (HR = 1.98) groups, after adjusting for covariates. Compared with OV-N, women in the OB II-D group with three or more chronic health conditions had higher mortality risk (HR = 1.61); however, women in OB II-D had lower risk (HR = 0.56) if they had less than three conditions.

Conclusion

The course of BMI over time in Canadian seniors appears to follow one of four different patterns depending on gender. The findings suggest that men who were overweight at age 65 and lost weight over time had the lowest mortality risk. Interestingly, obese women with decreasing BMI have different mortality risks, depending on their chronic health conditions. The findings provide new insights concerning the associations between BMI and mortality risk.

Ten-Year Mortality in the WISE Study (Women's Ischemia Syndrome Evaluation)

BACKGROUND

The WISE study (Women's Ischemia Syndrome Evaluation) was a prospective cohort study of 936 clinically stable symptomatic women who underwent coronary angiography to evaluate symptoms and signs of ischemia. Long-term mortality data for such women are limited.

METHODS AND RESULTS

Obstructive coronary artery disease (CAD) was defined as ≥50% stenosis on angiography by core laboratory. We conducted a National Death Index search to assess the mortality of women who were alive at their final WISE contact date. Death certificates were obtained. All deaths were adjudicated as cardiovascular or noncardiovascular by a panel of WISE cardiologists masked to angiographic data. Multivariate Cox proportional hazards regression was used to identify significant independent predictors of mortality. At baseline, mean age was 58±12 years; 176 (19%) were non-white, primarily black; 25% had a history of diabetes mellitus, 59% hypertension, 55% dyslipidemia, and 59% had a body mass index ≥30. During a median follow-up of 9.5 years (range, 0.2-11.5 years), a total of 184 (20%) died. Of these, 115 (62%) were cardiovascular deaths; 31% of all cardiovascular deaths occurred in women without obstructive CAD (<50% stenosis). Independent predictors of mortality were obstructive CAD, age, baseline systolic blood pressure, history of diabetes mellitus, history of smoking, elevated triglycerides, and estimated glomerular filtration rate.

CONCLUSIONS

Among women referred for coronary angiography for signs and symptoms of ischemia, 1 in 5 died from predominantly cardiac pathogeneses within 9 years of angiographic evaluation. A majority of the factors contributing to the risk of death seem to be modifiable by existing therapies. Of note, 1 in 3 of the deaths in this cohort occurred in women without obstructive CAD, a condition often considered benign and without guideline-recommended treatments. Clinical trials are needed to provide treatment guidance for the group without obstructive CAD.

Time to redefine body mass index categories in chronic diseases? Spotlight on obesity paradox

Obesity is a complex condition classically characterised by excessive body fat accumulation and represents one of the most important public health problems worldwide. Although several epidemiological studies have shown that elevated BMI is associated with higher morbidity, and with increased rate of death from all causes and from cardiovascular disease, accumulating evidence suggests that being overweight or obese may be protective (the so-called obesity paradox), at least in chronic diseases. These observations, not only question the validity of the BMI system, but also raise the intriguing question of whether we should redefine what the normal range of BMI is in individuals suffering from a chronic disease. In the present article, we review the available information on the association between elevated BMI and increased morbidity and mortality including obesity-related paradoxes, explore key aspects of the role and limitations of BMI as a measure of increased adiposity and outline potential solutions to address the current controversies regarding the impact of obesity on human health.

A meta-analysis but not a systematic review: an evaluation of the Global BMI Mortality Collaboration

Meta-analyses of individual participant data (MIPDs) offer many advantages and are considered the highest level of evidence. However, MIPDs can be seriously compromised when they are not solidly founded upon a systematic review. These data-intensive collaborative projects may be led by experts who already have deep knowledge of the literature in the field and of the results of published studies and how these results vary based on different analytical approaches. If investigators tailor the searches, eligibility criteria, and analysis plan of the MIPD, they run the risk of reaching foregone conclusions. We exemplify this potential bias in a MIPD on the association of body mass index with mortality conducted by a collaboration of outstanding and extremely knowledgeable investigators. Contrary to a previous meta-analysis of group data that used a systematic review approach, the MIPD did not seem to use a formal search: it considered 239 studies, of which the senior author was previously aware of at least 238, and it violated its own listed eligibility criteria to include those studies and exclude other studies. It also preferred an analysis plan that was also known to give a specific direction of effects in already published results of most of the included evidence. MIPDs where results of constituent studies are already largely known need safeguards to their validity. These may include careful systematic searches, adherence to the Preferred Reporting Items for Systematic Review and Meta-Analyses of individual participant data guidelines, and exploration of the robustness of results with different analyses. They should also avoid selective emphasis on foregone conclusions based on previously known results with specific analytical choices.

Age-dependent relationships between body mass index and mortality: Singapore longitudinal ageing study

OBJECTIVES

The relationship between body mass index (BMI) with mortality risk, in particular the BMI category associated with the lowest all-cause and CVD-and-stroke mortality and the BMI threshold for defining overweight or obesity in older persons is controversial. This study investigated the age-dependent associations of BMI categories with all-cause and cardiovascular disease (CVD) and stroke mortality.

METHOD

Prospective cohort study (Singapore Longitudinal Ageing Studies) of older adults aged 55 and above, followed up from 2003 to 2011. Participants were 2605 Chinese with baseline BMI and other variables. Outcome Measurement: Mortality hazard ratios (HR) for all-cause and CVD and stroke mortality.

RESULTS

Overall, BMI showed a U-shaped relationship with all-cause and CVD and stroke mortality, being lowest at Normal Weight-II category (BMI 23.0-24.9 kg/m2). Most evidently among the middle-aged (55-64 years), all-cause mortality risks relative to Normal Weight-II were elevated for underweight (<BMI 18.5; HR = 4.92, p<0.0138), Normal Weight-I (BMI 18.5-22.9; HR = 3.41, p = 0.0149), and Overweight-Obese (BMI>30.0; HR = 4.05,p = 0.0423). Among the old (≥65 years), however, Overweight and Obese categories were not significantly associated with increased all-cause mortality (HR from 0.98 to 1.29), but Overweight-Obese was associated with increased CVD and stroke mortality (HR = 10.0, p = 0.0086).

CONCLUSION

BMI showed a U-shaped relationship with mortality. Among older persons aged 65 and above, the overweight-or-obese category of BMI was not associated with excess all-cause mortality.

Relation of binge eating disorder with impulsiveness in obese individuals

AIM

To investigate the levels of impulsiveness, and the relationship between the binge eating disorder (BED) and the levels of impulsiveness in obese individuals.

METHODS

Two hundred and forty-one obese patients who were included in the study and candidate for bariatric surgery (weight loss surgery) were clinically interviewed to identify the BED group, and patients were divided into two groups: Those with BED and those without BED. The comorbidity rate of groups was determined by using structured clinical interview for DSM-IV (SCID-I). A sociodemographic data form including the story of previous psychiatric treatment, structured clinical interview for DSM-IV (SCID-I), Beck Anxiety Inventory, Beck Depression Inventory (BDI) and Barratt Impulsiveness Scale-11 were applied to both of the groups.

RESULTS

In regard to 241 obese individuals included in the study, total score and score of attention subscale for BED (+) group were significantly high (P < 0.05). In addition, suicide attempt, story of psychiatric consultation, and score for BDI were again significantly high in the BED (+) group (P < 0.05).

CONCLUSION

In assessment of obese individuals, assessment of associated psychopathology such as impulsive characteristics and suicide attempt in addition to disrupted eating behaviors will allow to have a more extensive view.

Comparative effects of the restriction method in two large observational studies of body mass index and mortality among adults

BACKGROUND

A method applied in some large studies of weight and mortality is to begin with a well-defined analytic cohort and use successive restrictions to control for methodologic bias and arrive at final analytic results.

MATERIALS AND METHODS

Two observational studies of body mass index and mortality allow a comparative assessment of these restrictions in very large data sets. One was a meta-analysis of individual participant data with a sample size of 8 million. The second was a study of a South Korean cohort with a sample size of 12 million. Both presented results for participants without pre-existing disease before and after restricting the sample to never-smokers and deleting the first 5 years of follow-up.

RESULTS

Initial results from both studies were generally similar, with hazard ratios (HRs) below 1 for overweight and above 1 for underweight and obesity. The meta-analysis showed higher HRs for overweight and obesity after the restrictions, including a change in the direction of the HR for overweight from 0·99 (95% CI: 0·98-1·01) to 1·11 (95% CI: 1·10, 1·11). The South Korean data showed little effect of the restrictions and the HR for overweight changed from 0·85 (95% CI: 0·84-0·86) to 0·91 (95% CI: 0·90, 0·91). The summary effect size for overweight was 0·90 (95% CI: 0·89-0·91) before restrictions and 1·02 (95% CI: 1·02, 1·03) after restrictions.

CONCLUSIONS

The effect of the restrictions is not consistent across studies, weakening the argument that analyses without such restrictions lack validity.

Sources of heterogeneity in studies of the BMI-mortality association

Background

To date, the amount of heterogeneity among studies of the body mass index-mortality association attributable to differences in the age distribution and length of follow-up has not been quantified. Therefore, we wanted to quantify the amount of heterogeneity attributable to age and follow-up in results of studies on the body mass index-mortality relation.

Methods

We used optima of the body mass index mortality association reported for 30 populations and performed meta-regression to estimate the amount of heterogeneity attributable to sex, ethnicity, mean age at baseline, percentage smokers, and length of follow-up.

Results

Ethnicity as single factor accounted for 36% (95% CI, 11–56%) of heterogeneity. Mean age and length of follow-up had an interactive effect and together accounted for 56% (95% CI, 24–74%) of the remaining heterogeneity. Sex did not significantly contribute to the heterogeneity, after controlling for ethnicity, age, and length of follow-up.

Conclusions

A considerable amount of heterogeneity in studies of the body mass index-mortality association is attributable to ethnicity, age, and length of follow-up.

•

The BMI-mortality association varies considerably between study cohorts.

•

We found ethnicity alone to account for 36% of the heterogeneity.

•

Age and length of follow-up accounted for 56% of the remaining heterogeneity.

Is Childhood Socioeconomic Status Independently Associated with Adult BMI after Accounting for Adult and Neighborhood Socioeconomic Status?

Childhood socioeconomic status (SES) is inversely associated with adult weight in high income countries. Whether the influence of childhood SES on adult weight is best described using a critical period model or an accumulation of risk model is not yet settled. This research tests whether childhood SES is associated with adult BMI and likelihood of obesity independent of adult socioeconomic status and neighborhood characteristics. Data on individual childhood and adult characteristics come from the Health and Retirement Study (N = 13,545). Data on neighborhood characteristics come from the 2000 Decennial Census and American Community Survey (2005-2009). In the fully adjusted models, perceived financial hardship before the age of sixteen and having a father who was unemployed are associated with higher BMI among males and, among females, paternal education remains associated with adult BMI. However, childhood SES is not associated with likelihood of obesity after fully adjusting for adult SES and neighborhood characteristics, suggesting that the direct effects of early childhood SES on BMI are small relative to the other factors associated with obesity in adulthood.

Association of BMI with risk of CVD mortality and all-cause mortality

OBJECTIVE

To determine the relationship between BMI and risk of CVD mortality and all-cause mortality among Malaysian adults.

DESIGN

Population-based, retrospective cohort study. Participants were followed up for 5 years from 2006 to 2010. Mortality data were obtained via record linkages with the Malaysian National Registration Department. Multiple Cox regression was applied to compare risk of CVD and all-cause mortality between BMI categories adjusting for age, gender and ethnicity. Models were generated for all participants, all participants the first 2 years of follow-up, healthy participants, healthy never smokers, never smokers, current smokers and former smokers.

SETTING

All fourteen states in Malaysia.

SUBJECTS

Malaysian adults (n 32 839) aged 18 years or above from the third National Health and Morbidity Survey.

RESULTS

Total follow-up time was 153 814 person-years with 1035 deaths from all causes and 225 deaths from CVD. Underweight (BMI<18·5 kg/m2) was associated with a significantly increased risk of all-cause mortality, while obesity (BMI ≥30·0 kg/m2) was associated with a heightened risk of CVD mortality. Overweight (BMI=25·0-29·9 kg/m2) was inversely associated with risk of all-cause mortality. Underweight was significantly associated with all-cause mortality in all models except for current smokers. Overweight was inversely associated with all-cause mortality in all participants. Although a positive trend was observed between BMI and CVD mortality in all participants, a significant association was observed only for severe obesity (BMI≥35·0 kg/m2).

CONCLUSIONS

Underweight was associated with increased risk of all-cause mortality and obesity with increased risk of CVD mortality. Therefore, maintaining a normal BMI through leading an active lifestyle and healthy dietary habits should continue to be promoted.

BMI and all cause mortality: systematic review and non-linear dose-response meta-analysis of 230 cohort studies with 3.74 million deaths among 30.3 million participants

OBJECTIVE

To conduct a systematic review and meta-analysis of cohort studies of body mass index (BMI) and the risk of all cause mortality, and to clarify the shape and the nadir of the dose-response curve, and the influence on the results of confounding from smoking, weight loss associated with disease, and preclinical disease.

DATA SOURCES

PubMed and Embase databases searched up to 23 September 2015.

STUDY SELECTION

Cohort studies that reported adjusted risk estimates for at least three categories of BMI in relation to all cause mortality.

DATA SYNTHESIS

Summary relative risks were calculated with random effects models. Non-linear associations were explored with fractional polynomial models.

RESULTS

230 cohort studies (207 publications) were included. The analysis of never smokers included 53 cohort studies (44 risk estimates) with >738 144 deaths and >9 976 077 participants. The analysis of all participants included 228 cohort studies (198 risk estimates) with >3 744 722 deaths among 30 233 329 participants. The summary relative risk for a 5 unit increment in BMI was 1.18 (95% confidence interval 1.15 to 1.21; I(2)=95%, n=44) among never smokers, 1.21 (1.18 to 1.25; I(2)=93%, n=25) among healthy never smokers, 1.27 (1.21 to 1.33; I(2)=89%, n=11) among healthy never smokers with exclusion of early follow-up, and 1.05 (1.04 to 1.07; I(2)=97%, n=198) among all participants. There was a J shaped dose-response relation in never smokers (Pnon-linearity <0.001), and the lowest risk was observed at BMI 23-24 in never smokers, 22-23 in healthy never smokers, and 20-22 in studies of never smokers with ≥20 years' follow-up. In contrast there was a U shaped association between BMI and mortality in analyses with a greater potential for bias including all participants, current, former, or ever smokers, and in studies with a short duration of follow-up (<5 years or <10 years), or with moderate study quality scores.

CONCLUSION

Overweight and obesity is associated with increased risk of all cause mortality and the nadir of the curve was observed at BMI 23-24 among never smokers, 22-23 among healthy never smokers, and 20-22 with longer durations of follow-up. The increased risk of mortality observed in underweight people could at least partly be caused by residual confounding from prediagnostic disease. Lack of exclusion of ever smokers, people with prevalent and preclinical disease, and early follow-up could bias the results towards a more U shaped association.

Obesity and the microbiome

Obesity constitutes a significant and rapidly increasing public health challenge and is associated with significant co-morbidities and healthcare costs. Although undoubtedly multifactorial, research over the last decade has demonstrated that the microbes that colonize the human gut may contribute to the development of obesity through roles in polysaccharide breakdown, nutrient absorption, inflammatory responses and gut permeability. Studies have consistently shown that the Firmicutes to Bacteroidetes ratio, in particular, is increased in obesity and reduces with weight loss. In addition, we and others have shown that the methanogenic Archaea may also contribute to altered metabolism and weight gain in the host. However, much remains to be learned about the roles of different gut microbial populations in weight gain and obesity and the underlying mechanisms before we can begin to approach targeted treatments.

Effects of dietary protein intake on body composition changes after weight loss in older adults: a systematic review and meta-analysis

CONTEXT

The impact of dietary protein on body composition changes after older adults purposefully lose weight requires systematic evaluation

OBJECTIVE

: This systematic review and meta-analysis assessed the effects of protein intake (< 25% vs ≥ 25% of energy intake or 1.0 g/kg/d) on energy restriction-induced changes in body mass, lean mass, and fat mass in adults older than 50 years.

DATA SOURCES

PubMed, Cochrane, Scopus, and Google Scholar were searched using the keywords "dietary proteins," "body composition," "skeletal muscle," and "muscle strength."

STUDY SELECTION

Two researchers independently screened 1542 abstracts.

DATA EXTRACTION

Information was extracted from 24 articles.

DATA SYNTHESIS

Twenty randomized control trials met the inclusion criteria.

CONCLUSION

Older adults retained more lean mass and lost more fat mass during weight loss when consuming higher protein diets.

How well does the standard body mass index or variations with a different exponent predict human lifespan?

OBJECTIVE

The objective was twofold: (1) to estimate for each individual the body mass index (BMI) which is associated with the lowest risk of death, and (2) to study variants of the BMI formula to determine which gives the best predictions of death.

METHODS

Treating BMI = mass/height(2) as a continuous variable and estimating its interaction effects with several other variables, this study analyzed the NIH-AARP study data set of approximately 566,000 individuals and fit Cox proportional hazards models to the survival times.

RESULTS

For each individual, a "personalized optimal BMI," the BMI for that individual which, according to the model, is associated with the lowest risk of death, is estimated. The average personalized optimal BMI is approximately 26, which is in the current "overweight" category. In fact, mass/height is a better predictor of death on the data set than BMI itself.

CONCLUSIONS

The model suggests that an individual's "optimal" BMI depends on his or her features; "one-size-fits-all" recommendations may be not best.

Lower Mortality Associated With Overweight in the U.S. National Health Interview Survey: Is Overweight Protective?

It is still debatable whether overweight has protective or detrimental effects on survival. The focus of the ongoing debate is on possible confounding bias due to factors such as preexisting illness and smoking. We aimed to assess the association between overweight and mortality and to examine confounding effects of various factors including smoking and preexisting cancer, cardiovascular disease (CVD), diabetes, asthma, bronchitis, and kidney disease on the overweight-mortality association in adults.The data were extracted from the public-use National Health Interview Survey (NHIS) 1997 to 2009. Mortality data up to December 31, 2011 were linked to 131,813 with normal weight and 120,217 overweight adults. We assessed the association between overweight and mortality using Cox proportional hazard model with adjustments for various sets of confounding factors-age, sex, smoking, race, survey year, diabetes, CVD, cancer, asthma, bronchitis, and kidney disease.During the period from the original surveys to December 31, 2011, 22,513 (11,815 normal weight and 10,698 overweight) adults died. Normal weight and overweight groups differed in the characteristics of age, sex, smoking, and preexisting diseases. After adjusting for age and sex, the risk of dying was lower for overweight than normal weight adults (hazard ratio [HR], 0.82; 95% confidence interval [CI]: 0.80-0.85). Lower mortality risk associated with overweight remained after further adjusting for smoking and preexisting diseases such as diabetes, CVD, cancer, asthma, bronchitis, and kidney disease (HR, 0.80; 95% CI: 0.78-0.82). We observed a similar pattern for men and women, and for those free from preexisting diabetes, hypertension, and CVD.In conclusion, overweight adults have a lower mortality risk than normal weight adults. Our findings do not support that the lower mortality in overweight adults is due to confounding effects of smoking and preexisting diseases.

Neighbourhood urban form and individual-level correlates of leisure-based screen time in Canadian adults

OBJECTIVES

Despite evidence for an association between the built environment and physical activity, less evidence exists regarding relations between the built environment and sedentary behaviour. This study investigated the extent to which objectively assessed and self-reported neighbourhood walkability, in addition to individual-level characteristics, were associated with leisure-based screen time in adults. We hypothesised that leisure-based screen time would be lower among adults residing in objectively assessed and self-reported 'high walkable' versus 'low walkable' neighbourhoods.

SETTING

The study was undertaken in Calgary, Alberta, Canada in 2007/2008.

PARTICIPANTS

A random cross-section of adults who provided complete telephone interview and postal survey data (n=1906) was included. Captured information included leisure-based screen time, moderate-intensity and vigorous-intensity physical activity, perceived neighbourhood walkability, sociodemographic characteristics, self-reported health status, and self-reported height and weight. Based on objectively assessed built characteristics, participant's neighbourhoods were identified as being low, medium or high walkable.

PRIMARY AND SECONDARY OUTCOME MEASURES

Using multiple linear regression, hours of leisure-based screen time per day was regressed on self-reported and objectively assessed walkability adjusting for sociodemographic and health-related covariates.

RESULTS

Compared to others, residing in an objectively assessed high walkable neighbourhood, women, having a college education, at least one child at home, a household income ≥$120 000/year, and a registered motor vehicle at home, reporting very good-to-excellent health and healthy weight, and achieving 60 min/week of vigorous-intensity physical activity were associated (p<0.05) with less leisure-based screen time. Marital status, dog ownership, season, self-reported walkability and achieving 210 min of moderate-intensity physical activity were not significantly associated with leisure-based screen time.

CONCLUSIONS

Improving neighbourhood walkability could decrease leisure-based television and computer screen time. Programmes aimed at reducing sedentary behaviour may want to consider an individual's sociodemographic characteristics, physical activity level, health status and weight status, in addition to the walkability of their neighbourhood as these factors were found to be important independent correlates of leisure-based screen time.

Role of the Gut Microbiome in Obesity and Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) and obesity represent two of the biggest global health challenges of this century and are associated with significant comorbidities and healthcare costs. Although multiple factors undoubtedly contribute to the development and progression of DM and obesity, research over the last decade has demonstrated that the microbes that colonize the human gut may play key contributory roles. Gut microbes are now known to codevelop with the human host and are strongly influenced by mode of birth and early diet and nutrition, as well as environmental and other factors including antibiotic exposure. Gut microbes contribute to human health through roles in polysaccharide breakdown, nutrient absorption, inflammatory responses, gut permeability, and bile acid modification. Numerous studies have suggested that disruptions in the relative proportions of gut microbial populations may contribute to weight gain and insulin resistance, including alterations in Gammaproteobacteria and Verrucomicrobia and the ratios of Firmicutes to Bacteroidetes in weight gain and possible alterations in butyrate-producing bacteria such as Faecalibacterium prausnitzii in DM. In addition, it has been shown that the methanogenic Archaea may contribute to altered metabolism and weight gain in the host. However, the majority of studies are performed with stool or colonic samples and may not be representative of the metabolically active small intestine. Studies predominantly in rodent models are beginning to elucidate the mechanisms by which gut microbes contribute to DM and obesity, but much remains to be learned before we can begin to approach targeted treatments.