Do worse baseline risk factors explain the association of healthy obesity with increased mortality risk? Whitehall II Study

Metabolically healthy obesity and risks of cardiovascular disease and all-cause mortality, a matched cohort study: the Shizuoka study

BACKGROUND

Metabolically healthy obesity is not always a benign condition. It is associated with an increased incidence of cardiovascular disease and all-cause mortality. We investigated the prognostic significance of metabolically healthy obesity by comparing clinical profile-matched metabolically healthy obesity and non-obesity groups.

METHODS

We analyzed a health insurance dataset with annual health checkup data from Japan. The analyzed data included 168,699 individuals aged <65 years. Obesity was defined as ≥25 kg/m2 body mass index. Metabolically healthy was defined as ≤1 metabolic risk factor (high blood pressure, low high-density lipoprotein cholesterol, high low-density lipoprotein cholesterol, or high hemoglobin A1c). Incidence rates of stroke, myocardial infarction, and all-cause mortality identified from the insurance data were compared between metabolically healthy obesity and non-obesity groups (n = 8644 each) using a log-rank test.

RESULTS

The stroke (obesity: 9.2 per 10,000 person-years; non-obesity: 10.5; log-rank test p = 0.595), myocardial infarction (obesity: 3.7; non-obesity: 3.1; p = 0.613), and all-cause mortality (obesity: 26.6; non-obesity: 23.2; p = 0.304) incidence rates did not differ significantly between the metabolically healthy obesity and non-obesity groups, even when the abdominal obesity was considered in the analysis. The lack of association was also observed in the comparison between the metabolically unhealthy obesity and non-obesity groups (n = 10,965 each). The population with metabolically healthy obesity reported negligibly worse metabolic profiles than the population with non-obesity at the 5.6-year follow-up.

CONCLUSION

Obesity, when accompanied by a healthy metabolic profile, did not increase the risk of cardiovascular outcomes and all-cause mortality.

Prolonged or Transition to Metabolically Unhealthy Status, Regardless of Obesity Status, Is Associated with Higher Risk of Cardiovascular Disease Incidence and Mortality in Koreans

The risk of chronic disease and mortality may differ by metabolic health and obesity status and its transition. We investigated the risk of cardiovascular disease (CVD) and cancer incidence and mortality according to metabolic health and obesity status and their transition using the nationally representative Korea National Health and Nutrition Examination Survey (KNHANES) and the Ansan-Ansung (ASAS) cohort of the Korean Genome and Epidemiology Study. Participants that agreed to mortality linkage (n = 28,468 in KNHANES and n = 7530 adults in ASAS) were analyzed (mean follow-up: 8.2 and 17.4 years, respectively). Adults with no metabolic risk factors and BMI <25 or ≥25 kg/m2 were categorized as metabolically healthy non-obese (MHN) or metabolically healthy obese (MHO), respectively. Metabolically unhealthy non-obese (MUN) and metabolically unhealthy obese (MUO) adults had ≥1 metabolic risk factor and a BMI < or ≥25 kg/m2, respectively. In KNHANES participants, MUN, and MUO had higher risks for cardiovascular mortality, but not cancer mortality, compared with MHN adults. MHO had 47% and 35% lower risks of cancer mortality and all-cause mortality, respectively, compared to MHN. Similar results were observed in the ASAS participants. Compared to those persistently MHN, the risk of CVD was greater when continuously MUN or MUO. Transitioning from a metabolically healthy state to MUO also increased the risk of CVD. Few associations were found for cancer incidence. Using a nationally representative cohort and an 18-year follow-up cohort, we observed that the risk of CVD incidence and mortality and all-cause mortality, but not cancer incidence or mortality, increases with a continuous or a transition to an unhealthy metabolic status in Koreans.

Pattern of long-term weight and metabolic changes after a first episode of psychosis: Results from a 10-year prospective follow-up of the PAFIP program for early intervention in psychosis cohort

Background

People with psychosis are at higher risk of cardiovascular events, partly explained by a higher predisposition to gain weight. This has been observed in studies on individuals with a first-episode psychosis (FEP) at short and long term (mainly up to 1 year) and transversally at longer term in people with chronic schizophrenia. However, there is scarcity of data regarding longer-term (above 3-year follow-up) weight progression in FEP from longitudinal studies. The aim of this study is to evaluate the longer-term (10 years) progression of weight changes and related metabolic disturbances in people with FEP.

Methods

Two hundred and nine people with FEP and 57 healthy participants (controls) were evaluated at study entry and prospectively at 10-year follow-up. Anthropometric, clinical, and sociodemographic data were collected.

Results

People with FEP presented a significant and rapid increase in mean body weight during the first year of treatment, followed by less pronounced but sustained weight gain over the study period (Δ15.2 kg; SD 12.3 kg). This early increment in weight predicted longer-term changes, which were significantly greater than in healthy controls (Δ2.9 kg; SD 7.3 kg). Weight gain correlated with alterations in lipid and glycemic variables, leading to clinical repercussion such as increments in the rates of obesity and metabolic disturbances. Sex differences were observed, with women presenting higher increments in body mass index than men.

Conclusions

This study confirms that the first year after initiating antipsychotic treatment is the critical one for weight gain in psychosis. Besides, it provides evidence that weight gain keep progressing even in the longer term (10 years), causing relevant metabolic disturbances.

Contribution of 20-year body mass index and waist circumference history to poor cardiometabolic health in overweight/obese and normal weight adults: A cohort study

BACKGROUND AND AIMS

We investigated the associations of 20-year body mass index (BMI) and waist circumference (WC) histories with risk of being 1) metabolically unhealthy overweight/obese (MUOO) vs metabolically healthy overweight/obese (MHOO) and 2) metabolically unhealthy normal weight (MUNW) vs metabolically healthy normal weight (MHNW).

METHODS AND RESULTS

Participants comprised 3018 adults (2280 males; 738 females) with BMI and WC measured, every ~5 years, in 1991-1994, 1997-1999, 2002-2004, 2007-2009, and 2012-2013. Mean age in 2012-2013 was 69.3 years, with a range of 59.7-82.2 years. Duration was defined as the number of times a person was overweight/obese (or centrally obese) across the 5 visits, severity as each person's mean BMI (or WC), and variability as the within-person standard deviation of BMI (or WC). At the 2013-2013 visit, participants were categorised based on their weight (overweight/obese or normal weight; body mass index (BMI) ≥25 kg/m2) and health status (healthy or unhealthy; two or more of hypertension, low high-density lipoprotein cholesterol, high triglycerides, high glucose, and high homeostatic model assessment of insulin resistance). Logistic regression was used to estimate associations with the risk of being MUNW (reference MHNW) and MUOO (reference MHOO) at the last visit. BMI and WC severity were each related to increased risk of being unhealthy, with estimates being stronger among normal weight than overweight/obese adults. The estimates for variability exposures became null upon adjustment for severity. Individuals who were overweight/obese at all 5 time points had a 1.60 (0.96-2.67) times higher risk of being MUOO than MHOO compared to those who were only overweight/obese at one (i.e., the last) time point. The corresponding estimate for central obesity was 4.20 (2.88-6.12). Greater duration was also related to higher risk of MUNW than MHNW.

CONCLUSION

Being overweight/obese yet healthy seems to be partially attributable to lower exposure to adiposity across 20 years of adulthood. The results highlight the importance of maintaining optimum and stable BMI and WC, both in adults who become and do not become overweight/obese.

Weight-Based Teasing and Metabolic Syndrome Components among Adolescent Military Dependents at Risk for Adult Obesity

Background: Among adults, weight stigma is associated with markers of poor cardiometabolic health. Although weight-based teasing (WBT) is common among youth with high body weight, few studies have examined its associations with cardiometabolic markers. Owing to unique stressors (e.g., parental deployment and frequent moves), military-dependent youth may be at particularly high risk for obesity, WBT, and poor cardiometabolic health. We, therefore, assessed associations between WBT and cardiometabolic health markers among adolescent military dependents presenting for a weight gain prevention trial. Methods: Participants underwent fasting phlebotomy; had fasting weight, height, and waist circumference measured; and completed assessments of WBT, anxiety, and loss-of-control eating. Multivariate analysis of covariance, adjusting for relevant covariates including demographics and body composition, was used to examine differences in metabolic syndrome (MetS) components (waist circumference, systolic and diastolic blood pressure, high-density lipoprotein cholesterol, triglycerides, and glucose) between youth reporting WBT and youth reporting no WBT. Bootstrapped models examined whether WBT mediated the relationship between BMIz and MetS components. Results: Data from 142 youth (57.7% female; 14.4 ± 1.6 years; 51.2% non-Hispanic White, 20.9% non-Hispanic Black; BMIz: 1.9 ± 0.4) were analyzed. WBT was not significantly associated with any MetS component. Relationships were observed between BMIz and all MetS components (except systolic blood pressure and glucose), although WBT did not significantly mediate these relationships (p's > 0.05). Conclusions: This study did not find support for a relationship between WBT and MetS components in adolescent military dependents at risk for adult obesity. Prospective research is needed to determine whether associations between WBT and adverse cardiometabolic outcomes emerge primarily in adulthood.

Associations of Metabolic/Obesity Phenotypes with Insulin Resistance and C-Reactive Protein: Results from the CNTR Study

BACKGROUND

Obesity is a heterogeneous condition in terms of metabolic status. Different obesity phenotypes have various health risks. The aim of this work was to define different subtypes of obesity and investigate their relationship with inflammatory-cardiometabolic abnormalities among Chinese adult twins.

METHODS

The analyses used data from 1113 adult twins in 4 provinces (Shandong, Zhejiang, Jiangsu and Sichuan) from Chinese National Twin Registry (CNTR) which collected detailed information. We defined those with 0 or 1 metabolic syndrome (MetS) components excluding waist circumference as metabolically healthy, and those with waist circumference ≥90 cm (for men) and ≥85 cm (for women) as obese. The two-category obesity status and metabolic states are combined to generate four metabolic/obesity phenotypes. High sensitivity C reactive protein (hsCRP) was measured to assess underlying inflammation and homeostasis model assessment of insulin resistance (HOMA-IR) was calculated as surrogate measure of insulin resistance. Mixed-effect linear regression models and fixed-effect linear regression models were used to analyse the correlation between HOMA-IR, hsCRP and different metabolic/obesity phenotypes.

RESULTS

In cross-sectional analyses of 1113 individuals (mean [SD] age, 46.6 [12.9] years; 463 obese [41.6%]), 20.3% obese twins were metabolic healthy and 64.2% non-obese twins were metabolic unhealthy. Serum HOMA-IR level was higher in metabolically unhealthy non-obesity (MUNO) (β=0.42, 95% CI: 0.21-0.64), metabolically healthy obesity (MHO) (β=0.68, 95% CI: 0.36-1.00) and metabolically unhealthy obesity (MUO) (β=0.69, 95% CI: 0.46-0.91) twins, compared with their metabolically healthy non-obesity (MHNO) counterparts. HsCRP was similar between MHO and MUO, which differed significantly to metabolic healthy non-obesity (MHNO).

CONCLUSION

MHO and MUNO phenotypes were common in Chinese twin population. Both phenotypes were associated with elevated IR and hsCRP which may not be benign and need to be concerned.

Metabolically healthy obesity: facts and fantasies

Although obesity is typically associated with metabolic dysfunction and cardiometabolic diseases, some people with obesity are protected from many of the adverse metabolic effects of excess body fat and are considered "metabolically healthy." However, there is no universally accepted definition of metabolically healthy obesity (MHO). Most studies define MHO as having either 0, 1, or 2 metabolic syndrome components, whereas many others define MHO using the homeostasis model assessment of insulin resistance (HOMA-IR). Therefore, numerous people reported as having MHO are not metabolically healthy, but simply have fewer metabolic abnormalities than those with metabolically unhealthy obesity (MUO). Nonetheless, a small subset of people with obesity have a normal HOMA-IR and no metabolic syndrome components. The mechanism(s) responsible for the divergent effects of obesity on metabolic health is not clear, but studies conducted in rodent models suggest that differences in adipose tissue biology in response to weight gain can cause or prevent systemic metabolic dysfunction. In this article, we review the definition, stability over time, and clinical outcomes of MHO, and discuss the potential factors that could explain differences in metabolic health in people with MHO and MUO - specifically, modifiable lifestyle factors and adipose tissue biology. Better understanding of the factors that distinguish people with MHO and MUO can produce new insights into mechanism(s) responsible for obesity-related metabolic dysfunction and disease.

Adipose Tissue Distribution, Inflammation and Its Metabolic Consequences, Including Diabetes and Cardiovascular Disease

Adipose tissue plays essential roles in maintaining lipid and glucose homeostasis. To date several types of adipose tissue have been identified, namely white, brown, and beige, that reside in various specific anatomical locations throughout the body. The cellular composition, secretome, and location of these adipose depots define their function in health and metabolic disease. In obesity, adipose tissue becomes dysfunctional, promoting a pro-inflammatory, hyperlipidemic and insulin resistant environment that contributes to type 2 diabetes mellitus (T2DM). Concurrently, similar features that result from adipose tissue dysfunction also promote cardiovascular disease (CVD) by mechanisms that can be augmented by T2DM. The mechanisms by which dysfunctional adipose tissue simultaneously promote T2DM and CVD, focusing on adipose tissue depot-specific adipokines, inflammatory profiles, and metabolism, will be the focus of this review. The impact that various T2DM and CVD treatment strategies have on adipose tissue function and body weight also will be discussed.

Association of Concurrent Changes in Metabolic Health and Weight on Cardiovascular Disease Risk: A Nationally Representative Cohort Study

Background

The combined effect of transitions of metabolic health and weight on cardiovascular disease (CVD) remains unclear. We aimed to examine the association of concurrent changes of metabolic health and weight on CVD over time.

Methods and Results

The study population consisted of 205 394 from the Korean National Health Insurance Service. Metabolic health was determined by fasting serum glucose, total cholesterol, and blood pressure levels, while obesity was determined by body mass index. All participants were divided into either metabolically healthy nonobese (MHNO), metabolically healthy obese, metabolically unhealthy nonobese, or metabolically unhealthy obese for each of the first (2002–2003) and second (2004–2005) health screening periods, after which participants were followed‐up for CVD from 2006 to 2015. Cox proportional hazards regression was used to determine adjusted hazard ratios (aHRs) and 95% CIs. Among initial MHNO participants, those who became metabolically healthy obese (aHR, 1.25; 95% CI, 1.10–1.41), metabolically unhealthy nonobese (aHR, 1.23; 95% CI, 1.15–1.31), and metabolically unhealthy obese (aHR, 1.34; 95% CI, 1.12–1.61) had elevated risk for CVD compared with those who remained MHNO. Conversely, improving metabolic health and obesity were associated with reduced CVD risk among initially metabolically unhealthy nonobese to secondary MHNO (aHR, 0.79; 95% CI, 0.73–0.84), metabolically unhealthy obese to MHNO (aHR, 0.68; 95% CI, 0.58–0.81), and metabolically unhealthy obese to metabolically healthy obese (aHR, 0.73; 95% CI, 0.66–0.80) participants.

Conclusions

Changes toward metabolically unhealthy or obese states resulted in increased CVD risk. Improving metabolic health along with reducing weight may lead to decreased risk of CVD.

Six Years of Sick Leave Spells in a Group of University Civil Workers. Can Modern Work Bring Them a New Health Problem?

The objective of this study is to analyse sick leave episodes of a university’s collective of statutory workers in the State of São Paulo, between January 2010 and December 2015. For this, a descriptive study analysed 5776 registered spells of sick leave of four university units: agricultural sciences; human health, health and animal reproduction, and biological sciences; an administrative unit; and a university hospital. The medical expert assessment was carried out by general practitioners and psychiatrists who managed sick leave and return to work cases. Around 52% had up to three sick leave episodes, and 10% of the workers had 20 or more episodes. Each spell of sickness absence lasted a median of 30 days (IQR 8–60 days). Among all of sick leaves, 35% had as a primary cause mental or behavioural diseases, of which 30% were depressive disorders, followed by around 18% related to the musculoskeletal system and the connective tissues. In the medical reports, 80% of the workers reported pain and 30% reported psychological symptoms. The collective, seen as privileged by many for their job stability, has a high percentage of sick leave due to mental illness, with extended periods which affect the levels of disability and reduce possibilities of return.

Body size trajectories and cardio-metabolic resilience to obesity

Individuals with obesity do not represent a single homogenous group in terms of cardio‐metabolic health prospects. The concept of metabolically healthy obesity is a crude way of capturing this heterogeneity and has resulted in a plethora of research linking to future outcomes to show that it is not a benign condition. By contrast, very few studies have looked back in time and modelled the life course processes and exposures that explain the heterogeneity in cardio‐metabolic health and morbidity and mortality risk among people with the same body mass index (BMI) (or waist circumference or percentage body fat). The aim of the Medical Research Council New Investigator Research Grant (MR/P023347/1) ‘Body size trajectories and cardio‐metabolic resilience to obesity in three United Kingdom birth cohorts’ is to reveal the body size trajectories, pubertal development patterns and other factors (e.g. early‐life adversity) that might attenuate the positive associations of adulthood obesity makers (e.g. BMI) with cardio‐metabolic disease risk factors and other outcomes, thereby providing some degree of protection against the adverse effects of obesity. This work builds on the Principle Investigator's previous research as part of the Cohort and Longitudinal Studies Enhancement Resources initiative and focuses on secondary data analysis in the nationally representative UK birth cohort studies (initiated in 1946, 1958 and 1970), which have life course body size and exposure data and a biomedical sweep in adulthood. The grant will provide novel evidence on the life course processes and exposures that lead to some people developing a cardio‐metabolic complication or disease or dying while other people with the same BMI do not. This paper details the grant's scientific rationale, research objectives and potential impact.