Duration of overweight and metabolic health risk in American men and women

Joint effect of BMI and metabolic status on mortality among adults: a population-based longitudinal study in United States

We explored the joint effects of different metabolic obesity phenotypes on all-cause and disease-specific mortality risk among the American population. Data were obtained from the National Health and Nutrition Examination Survey (NHANES) 1999-2018. Mortality outcome data were from mortality files linked to National Death Index record and follow-up information was up to December 31, 2019. 50,013 participants were finally included. Four metabolic obesity phenotypes were defined based on obesity and metabolic status: metabolically healthy obese (MHO), metabolically unhealthy obese (MUO), metabolically healthy non-obese (MHNO), and metabolically unhealthy non-obese (MUNO). Population-weighted Cox proportional hazards models were used to explore the all-cause and disease-specific mortality risk of metabolic obesity phenotypes. The all-cause mortality risk of MUO and MUNO was significantly higher than MHNO. MUNO was associated with a significantly increased risk of death from heart disease (HR: 1.40, 95% CI 1.16-1.70), hypertension (HR: 1.68, 95% CI 1.34-2.12), diabetes (HR: 2.29, 95% CI 1.67-3.15), and malignant neoplasms (HR:1.29, 95% CI 1.09-1.53). Metabolic unhealth significantly increased the risk of all-cause mortality, regardless of obesity status. Among individuals with metabolic unhealthy status, obesity significantly reduced the risk of all-cause mortality (HR: 0.91, 95% CI 0.85-0.98). Our study highlights the importance of identifying and characterizing metabolic obesity phenotypes in obese and metabolically abnormal patients, as well as healthy adults. Comprehensive evaluation of obesity and metabolic status is necessary to adopt appropriate interventions and treatment measures and maximize patient benefit.

Obesity is the main driver of altered gut microbiome functions in the metabolically unhealthy

Obesity (OB) and cardiometabolic disease are major public health issues linked to changes in the gut microbiome. OB and poor cardiometabolic health status (CHS) are often comorbid, which hinders efforts to identify components of the microbiome uniquely linked to either one. Here, we used a deeply phenotyped cohort of 408 adults from Colombia, including subjects with OB, unhealthy CHS, or both, to validate previously reported features of gut microbiome function and diversity independently correlated with OB or CHS using fecal metagenomes. OB was defined by body mass index, waist circumference, and body fat; CHS as healthy or unhealthy according to blood biochemistry and anthropometric data. We found that OB, more so than metabolic status, drove associations with gut microbiome structure and functions. The microbiome of obese individuals with and without co-existing unhealthy CHS was characterized by reduced metagenomic diversity, reduced fermentative potential and elevated capacity to respond to oxidative stress and produce bacterial antigens. Disease-linked features were correlated with increased host blood pressure and inflammatory markers, and were mainly contributed by members of the family Enterobacteriaceae. Our results link OB with a microbiome able to tolerate an inflammatory and oxygenated gut state, and suggest that OB is the main driver of microbiome functional differences when poor CHS is a comorbidity.

Influence of body composition and cardiorespiratory fitness on plasma HSP72, norepinephrine, insulin, and glucose responses to an acute aerobic exercise bout performed in the fed state

Being overweight is already considered a metabolic risk factor, which can be overcome by increasing cardiorespiratory fitness (CRF). Acute exercise is known to induce changes in plasma hormones and heat shock proteins release. However, there is a lack of studies investigating the impact of body composition and CRF on these variables following acute aerobic exercise. To assess the influence of body composition and cardiorespiratory fitness on plasma heat shock protein 72 kDa (HSP72), norepinephrine (NE), insulin, and glucose responses to an acute aerobic exercise bout in the fed state. Twenty-four healthy male adults were recruited and allocated into three groups: overweight sedentary (n = 8), normal weight sedentary (n = 8), and normal weight active (n = 8). The volunteers performed an acute moderate exercise session on a treadmill at 70% of VO2 peak. Blood samples were drawn at baseline, immediately post-exercise, and at 1-h post-exercise. The exercise session did not induce changes in HSP72 nor NE but changes in glucose and insulin were affected by body mass index. Also, subjects with elevated CRF maintain reduced NE through exercise. At baseline, the overweight sedentary group showed elevated NE, insulin, and glucose; these last two impacting the HOMA-IR index. Thirty minutes of aerobic exercise at 70% VO2 peak, in the fed state, did not change the levels of plasma NE and HSP72. Elevated body composition seems to impact metabolic profile and increase sympathetic activity. Conversely, subjects with increased cardiorespiratory fitness seem to have attenuated sympathetic activity.

Obesity Duration and Cardiometabolic Disease

Cardiovascular disease risk is known to be influenced by both the severity of a risk factor and the duration of exposure (eg, LDL [low-density lipoprotein] cholesterol, tobacco smoke). However, this concept has been largely neglected within the obesity literature. While obesity severity has been closely linked with cardiometabolic diseases, the risk of developing these conditions among those with obesity may be augmented by greater obesity duration over the life span. Few longitudinal or contemporary studies have investigated the influence of both factors in combination-cumulative obesity exposure-instead generally focusing on obesity severity, often at a single time point, given ease of use and lack of established methods to encapsulate duration. Our review focuses on what is known about the influence of the duration of exposure to excess adiposity within the obesity-associated cardiometabolic disease risk equation by means of summarizing the hypothesized mechanisms for and evidence surrounding the relationships of obesity duration with diverse cardiovascular and metabolic disease. Through the synthesis of the currently available data, we aim to highlight the importance of a better understanding of the influence of obesity duration in cardiovascular and metabolic disease pathogenesis. We underscore the clinical importance of aggressive early attention to obesity identification and intervention to prevent the development of chronic diseases that arise from exposure to excess body weight.

An Index to Assess Overwork-Related Adverse Effects on Employees Under the Occupational Safety and Health Act in Taiwan

Background

The present study aimed to digitally evaluate the risk of overwork-related adverse effects (OrAEs) among employees from various occupational categories in Taiwan.

Methods

Anonymous data of employees from seven companies/factories providing occupational health services were analyzed. The studied population comprised 5505 employees, and the data analyzed included employment duration, working hours, shift work schedules, and health checkup results. The risk for OrAEs was assessed by an index, Karo index (0-4, the larger the value, the higher the risk for OrAEs) obtained using a risk matrix made up of cardiocerebral and occupational risk factors. Karo index values of 3 and 4 were categorized as at high risk for OrAEs (h-OrAEs).

Results

The 5505 employees had an average employment duration of 8.5 years and a mean age of 39.4 years. The prevalence rates for h-OrAEs of the seven companies/factories ranged from 3.9% to 34.2%. There were significant differences in prevalence rates for h-OrAEs between employees of retail stores and high-tech manufacturing factories. Multivariate analysis results indicated that workers of high-tech manufacturing factories had significantly higher risk for h-OrAEs compared with retail store workers.

Conclusion

In terms of satisfying health risk management and legal requirements in Taiwan, the newly issued Karo index, which covers a wide range of occupational risk factors, can serve as an assessment and a warning tool for managing the risk of OrAEs in workplaces. To reduce risks for h-OrAEs, active and prudent control of cerebrocardiovascular risks and working hours is recommended.

Association between self-reported body mass index and active life expectancy in a large community-dwelling sample of older U.S. adults

Background

Obesity may have a protective effect (greater survival) in older adults, a finding known as the “obesity paradox.” This study examined the association between self-reported body mass index (BMI) and active life expectancy (ALE) among older U.S. adults.

Methods

Using the Medicare Health Outcomes Survey Cohort 15 (2012 baseline, 2014 follow-up), we estimated life expectancy and ALE by participants’ baseline BMI and age using multi-state models. A participant was classified as in an active state if this person reported having no difficulty for any of these six activities of daily living (ADLs).

Results

Small differences in life expectancy were noted among persons in normal weight (BMI 18.5–24.9 kg/m²), overweight (BMI 25–29.9 kg/m²), and obesity ranges (BMI 30 kg/m² and higher). However, persons with obesity had a significantly lower ALE. ALE at age 65 was 11.1 (11.0–11.2) years for persons with obesity, 1.2 (1.1–1.3) years less than that for the normal weight and overweight persons (12.3 years for both, 12.2–12.4). Persons with class III obesity had a significantly lower life expectancy and ALE than normal weight persons. Although persons with class I or II obesity had a similar life expectancy as normal weight persons, they have a shorter ALE.

Conclusions

Although older adults with obesity have a similar life expectancy as normal weight persons, they have a significantly shorter ALE. Given the complex relationship of BMI and ALE, a “one size fits all” approach to weight management is not advisable.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03021-7.

Factors Associated with Body Weight Gain among Korean Adults during the COVID-19 Pandemic

Background

Obesity is of grave concern as a comorbidity of coronavirus disease 2019 (COVID-19). We examined the factors associated with weight gain among Korean adults during the COVID-19 pandemic.

Methods

We conducted an online survey of 1,000 adults (515 men and 485 women aged 20-59 years) in March 2021. Multivariable logistic regression analysis was performed to evaluate the factors associated with weight gain. The analysis was adjusted for sex, age, region, depressive mood, anxiety, eating out, late-night meals, alcohol consumption, exercise, sleep disturbance, meal pattern, subjective body image, comorbidities, marital status, living alone, and income.

Results

After adjusting for confounding variables, the odds for weight gain increased in the group aged 20-34 years compared with the group aged 50-59 years (1.82; 95% confidence interval [CI], 1.01-3.32). Women were more associated with the risk of weight gain compared with men. The odds for weight gain increased in the lack of exercise group compared with the exercise group (4.89; 95% CI, 3.09-7.88). The odds for weight gain increased in the eating-out and late-night meal groups compared with that in the groups not eating out and not having late-night meals. Individuals watching a screen for 3-6 hr/day were more associated with the risk of weight gain compared with those who rarely watched a screen. The odds for weight gain increased in participants who considered themselves obese compared with those who did not consider themselves obese.

Conclusion

A healthy diet and regular physical activity tend to be the best approach to reduce obesity, a risk factor for COVID-19.

Metabolic phenotypes and risk of colorectal cancer: a systematic review and meta-analysis of cohort studies

BACKGROUND

The association of obesity with colorectal cancer (CRC) may vary depending on metabolic status.

OBJECTIVE

This meta-analysis aimed to investigate the combined impacts of obesity and metabolic status on CRC risk.

METHODS

The Scopus, PubMed, and web of sciences databases were systematically searched up to Jun 2021 to find all eligible publications examining CRC risk in individuals with metabolically unhealthy normal-weight (MUHNW), metabolically healthy obesity (MHO), and metabolically unhealthy obesity (MUHO) phenotypes.

RESULTS

A total of 7 cohort studies with a total of 759,066 participants were included in this meta-analysis. Compared with healthy normal-weight people, MUHNW, MHO, and MUHO individuals indicated an increased risk for CRC with a pooled odds ratio of 1.19 (95% CI = 1.09-1.31) in MUHNW, 1.14 (95% CI = 1.06-1.22) in MHO, and 1.24 (95% CI = 1.19-1.29) in MUHO subjects. When analyses were stratified based on gender, associations remained significant for males. However, the elevated risk of CRC associated with MHO and MUHO was not significant in female participants.

CONCLUSIONS

The individuals with metabolic abnormality, although at a normal weight, have an increased risk for CRC. Moreover, obesity is associated with CRC irrespective of metabolic status.

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.

Long-term body mass trajectories and hypertension by sex among Chinese adults: a 24-year open cohort study

Evidence was limited on trajectory of body mass index (BMI) through adulthood and its association with hypertension. We aimed to evaluate their association by sex in large-scale study. Data were obtained from the China Health and Nutrition Survey (CHNS) from 1991 to 2015. Latent class trajectory analysis (LCTA) was used to capture BMI change trajectories. Hazard risks (HRs) were estimated from Cox proportion hazard regression. Among 14,262 participants (mean age, 38.8; 47.8% men), 5138 hypertension occurred (2687 men and 2451 women) occurred during a mean follow-up 9.6 years. Four body mass trajectory groups were identified as BMI loss, stable, moderate and substantial gain. Appropriately half of participants (48.0%) followed 1 of the 2 BMI gain trajectories, where BMI increased at least 3 kg/m2 overtime. Compared with participants with stable BMI, those gaining BMI substantially had higher risk of hypertension by 65% (HR 1.65, 95% CI 1.45-1.86) in male and 83% (HR 1.83, 95% CI 1.58-2.12) in female. The HRs in BMI loss patterns were 0.74 (0.62-0.89) in men and 0.87 (0.75-1.00) in women. Our findings imply that majority of Chinese adults transited up to a higher BMI level during follow-up. Avoiding excessive weight gain and maintaining stable weight might be important for hypertension prevention.

Duration of obesity exposure between ages 10 and 40 years and its relationship with cardiometabolic disease risk factors: A cohort study

BACKGROUND

Individuals with obesity do not represent a homogeneous group in terms of cardiometabolic risk. Using 3 nationally representative British birth cohorts, we investigated whether the duration of obesity was related to heterogeneity in cardiometabolic risk.

METHODS AND FINDINGS

We used harmonised body mass index (BMI) and cardiometabolic disease risk factor data from 20,746 participants (49.1% male and 97.2% white British) enrolled in 3 British birth cohort studies: the 1946 National Survey of Health and Development (NSHD), the 1958 National Child Development Study (NCDS), and the 1970 British Cohort Study (BCS70). Within each cohort, individual life course BMI trajectories were created between 10 and 40 years of age, and from these, age of obesity onset, duration spent obese (range 0 to 30 years), and cumulative obesity severity were derived. Obesity duration was examined in relation to a number of cardiometabolic disease risk factors collected in mid-adulthood: systolic (SBP) and diastolic blood pressure (DBP), high-density-lipoprotein cholesterol (HDL-C), and glycated haemoglobin (HbA1c). A greater obesity duration was associated with worse values for all cardiometabolic disease risk factors. The strongest association with obesity duration was for HbA1c: HbA1c levels in those with obesity for <5 years were relatively higher by 5% (95% CI: 4, 6), compared with never obese, increasing to 20% (95% CI: 17, 23) higher in those with obesity for 20 to 30 years. When adjustment was made for obesity severity, the association with obesity duration was largely attenuated for SBP, DBP, and HDL-C. For HbA1c, however, the association with obesity duration persisted, independent of obesity severity. Due to pooling of 3 cohorts and thus the availability of only a limited number harmonised variables across cohorts, our models included adjustment for only a small number of potential confounding variables, meaning there is a possibility of residual confounding.

CONCLUSIONS

Given that the obesity epidemic is characterised by a much earlier onset of obesity and consequently a greater lifetime exposure, our findings suggest that health policy recommendations aimed at preventing early obesity onset, and therefore reducing lifetime exposure, may help reduce the risk of diabetes, independently of obesity severity. However, to test the robustness of our observed associations, triangulation of evidence from different epidemiological approaches (e.g., mendelian randomization and negative control studies) should be obtained.

Total Knee Arthroplasty: Fitness, Heart Disease Risk, and Quality of Life

Total knee arthroplasty (TKA) may decrease coronary heart disease (CHD) risk in patients with advanced osteoarthritis by reducing pain and allowing for a more active lifestyle. We examined cardiovascular fitness, CHD risk factors, and quality of life in patients for 1 year after TKA compared with matched controls who did not undergo surgery. A total of 14 patients, 7 surgery patients and 7 matched controls, were tested for measurements of body composition, knee range of motion, resting blood pressure, strength testing, a maximal exercise test, quality-of-life questionnaires (Medical Outcomes Study Short Form-36 and Knee Osteoarthritis Outcome Score [KOOS]), and activity monitoring, fasting blood glucose, and lipids at 0, 3, 6, and 12 months after surgery or baseline testing. Comparison between the two groups was analyzed. Twelve months after surgery, patients with TKA had significantly (p < 0.05) lower pain scores, increased fat free mass, lower resting mean arterial pressure, and improved scores on the KOOS for pain, symptoms, activities of daily living, and quality of life. Initially, total cholesterol, high-density lipoprotein cholesterol, triglycerides, and body fat percentage were reduced in the TKA group but returned to baseline at 12 months. The results of this study indicate that there are immediate and long-term improvements in pain and quality of life in patients with TKA, but physical function, exercise capacity, leg strength, and some lipid profiles may take longer than 12 months to improve. This is a level II, prospective, Therapeutic study, comparative study.

Association of obesity status and metabolic syndrome with site-specific cancers: a population-based cohort study

Background

Obesity and metabolic syndrome (MetS) appear in clusters and are both associated with an increased risk of cancer. However, it remains unknown whether obesity status with or without MetS increases the risk of site-specific cancers.

Methods

We used data derived from 390,575 individuals (37–73 years old) from the UK Biobank who were enrolled from 2006–2016 with a median of 7.8 years of follow-up. Obesity was defined by BMI ≥ 30 kg/m² and MetS was defined by the criteria of the Adult Treatment Panel-III (ATP-III). Cox proportional hazards models were used to investigate the associations of BMI and MetS with 22 cancers.

Results

Metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) phenotypes represented 6.7% and 17.9% of the total analytic samples and 27.1% and 72.9% of the included subpopulation with obesity, respectively. Obesity was independently associated with higher risks of 10 of 22 cancers. Stratified by metabolic status, the MUO phenotype was consistently associated with 10 obesity-related cancers. In contrast, the MHO phenotype was only associated with increased risks of five cancers: endometrium, oesophagus, kidney, pancreas and postmenopausal breast cancers.

Conclusion

Even in metabolically healthy individuals, obesity was associated with increased risks of five cancers, whereas we did not find that these individuals were associated with increased risks of several other obesity-related cancers.

Novel Insights into the Pathogenesis and Management of the Metabolic Syndrome

The metabolic syndrome, by definition, is not a disease but is a clustering of individual metabolic risk factors including abdominal obesity, hyperglycemia, hypertriglyceridemia, hypertension, and low high-density lipoprotein cholesterol levels. These risk factors could dramatically increase the prevalence of type 2 diabetes and cardiovascular disease. The reported prevalence of the metabolic syndrome varies, greatly depending on the definition used, gender, age, socioeconomic status, and the ethnic background of study cohorts. Clinical and epidemiological studies have clearly demonstrated that the metabolic syndrome starts with central obesity. Because the prevalence of obesity has doubly increased worldwide over the past 30 years, the prevalence of the metabolic syndrome has markedly boosted in parallel. Therefore, obesity has been recognized as the leading cause for the metabolic syndrome since it is strongly associated with all metabolic risk factors. High prevalence of the metabolic syndrome is not unique to the USA and Europe and it is also increasing in most Asian countries. Insulin resistance has elucidated most, if not all, of the pathophysiology of the metabolic syndrome because it contributes to hyperglycemia. Furthermore, a major contributor to the development of insulin resistance is an overabundance of circulating fatty acids. Plasma fatty acids are derived mainly from the triglycerides stored in adipose tissues, which are released through the action of the cyclic AMP-dependent enzyme, hormone sensitive lipase. This review summarizes the latest concepts in the definition, pathogenesis, pathophysiology, and diagnosis of the metabolic syndrome, as well as its preventive measures and therapeutic strategies in children and adolescents.

Metabolically healthy obesity reduces the risk of Alzheimer's disease in elders: a longitudinal study

A subgroup of overweight/obese individuals, who had favorable metabolic profiles, was termed as metabolically healthy overweight/obese (MHO). Several studies suggested that MHO individuals were not at increased risk of cardiovascular disease and all-course mortality. However, whether MHO is associated with excess risk of Alzheimer’s disease (AD) in elders remains unclear. To explore the risk of AD among MHO phenotype and investigate whether MHO associates with neurodegenerative biomarkers of AD, we assessed body mass index-metabolic status phenotypes of 1199 longitudinal elders from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort using the Adult Treatment Panel-III (ATP- III) criteria. MHO subjects were at a significantly decreased risk for AD (adjusted HR=0.73, 95% CI: 0.54-0.97) compared with metabolically healthy normal weight (MHNW) subjects. In multivariable linear regression models, the cross-sectional associations of MHO with cerebrospinal fluid (CSF) biomarkers, brain Aβ load, and cortical structure were explored. MHO was positively correlated with CSF-Aβ (β=0.746, P=0.015), hippocampal volume (β=0.181, P=0.011), and whole brain volume (β=0.133, P=0.004). The MHO phenotype of the elder conferred a decreased risk of AD and its role may be driven by Aβ.

Duration and stability of metabolically healthy obesity over 30 years

BACKGROUND

Obese adults who are free from metabolic risk factors may develop risk factors over time. Our objective was to characterize development of obesity and duration of metabolically healthy obese (MHO) over 30 years.

METHODS

Participants in CARDIA who developed obesity (BMI ≥ 30 kg/m2) at follow-up exams during years 7, 10, 15, 20, 25, and 30 were analyzed. MHO was defined as obese and having 0 or 1 risk factor: ≥SBP/DBP 130/85 mmHg; fasting glucose ≥100 mg/dL/5.55 mmol/L; fasting triglycerides (≥150 mg/dL/1.69 mmol/L); and HDL-C (men <40 mg/dL/1.036 mmol/L, women <50 mg/dL/1.295 mmol/L) or on any medication(s) for these conditions. MHO duration (years) and obesity duration (years) were estimated for each subsequent time-point; and an overall cumulative duration was also calculated over available follow-up. MHO duration (%) was approximated as MHO duration ÷ obesity duration. Stable MHO was defined as 100% MHO duration over follow-up, while transient MHO was defined as <1-99%. Chi-squared tests were used to compare proportions by sex and race across obesity phenotypes. Multivariable-adjusted ANCOVA, adjusting for baseline BMI, age, race, and sex, was used to analyze obesity duration in all individuals who developed obesity, and also compare MHO duration (%) across race and sex in transient MHO individuals.

RESULTS

Of the 987 eligible participants who developed obesity, 51% were African American (AA), 56% were women. Higher percentages of AA were classified as transient MHO, and higher proportions of females were MHO (both p < 0.0001). Obesity duration (years) was higher in transient MHO compared with stable MHO (mean difference: 6.2 ± 0.5 years, p < 0.0001). Of those with transient MHO, African Americans (51.4 ± 1.6%) were more likely to have longer MHO duration compared to Caucasians (44.4 ± 1.9%, p = 0.005).

CONCLUSION

MHO status can be a transient phenotype which differs by sex and race. Future studies are needed to explore modifiable lifestyle/behavioral predictors associated with longer MHO duration.

Long-term changes in body weight and physical activity in relation to all-cause and cardiovascular mortality: the HUNT study

BACKGROUND

Most previous studies have relied on single measurements of body weight and physical activity and have not considered the interplay between long-term changes in body weight and physical activity in relation to mortality. The aim of the current study was therefore to examine the joint effect of changes in body weight and leisure-time physical activity over a period of ~ 10 years on all-cause and cardiovascular mortality.

METHODS

The study population comprised 34,257 individuals who participated in the first (1984-86) and second (1995-97) waves of the HUNT Study, and were followed up through the Norwegian Cause of Death Registry until December 31st, 2013. We used Cox regression to estimate hazard ratios (HR) with 95% confidence intervals (CI) of death associated with changes in body weight and leisure-time physical activity.

RESULTS

Compared to the reference group with stable weight who were long-term physically active, people who gained ≥5% of their weight had a HR for all-cause mortality of 1.54 (95% CI: 1.28-1.85) if they were long-term physically inactive; a HR of 1.23 (1.09-1.40) if they became physically active, and a HR of 1.00 (95% CI 0.94-1.06) if they were long-term physically active. The corresponding HRs for cardiovascular mortality were 1.57 (95% CI 1.17-2.12), 1.28 (95% CI 1.04-1.58) and 1.06 (95% CI 0.96-1.16), respectively. Long-term physical inactivity was associated with increased all-cause (HR 1.29; 95% CI 1.08-1.53) and cardiovascular (HR 1.37; 95% CI 1.05-1.79) mortality among those who were weight stable.

CONCLUSIONS

The risk of all-cause and cardiovascular mortality is particularly evident among people who gain weight while remaining inactive during a ~ 10 year period. However, participants who remained physically active had the lowest risk of premature mortality, regardless of maintenance or increase in weight. These findings suggest that there is an interplay between long-term changes in body weight and physical activity that should receive particular attention in the prevention of premature mortality.

Lifetime predictors of stroke in subjects without a diagnosis of hypertension: the aerobics center longitudinal study

BACKGROUND AND PURPOSE

Although several studies have assessed the importance of traditional risk factors in predicting stroke, none have concurrently addressed the stroke-predicting ability of these risk factors across the lifespan of subjects without a hypertension (HTN) diagnosis. Thus, this study aimed to assess the importance of blood-pressure-related risk indicators, cardiorespiratory fitness (CRF), weight status, diabetes mellitus (DM), and lifestyle factors as predictors of stroke in different stages of life among non-hypertensive subjects.

MATERIALS AND METHODS

This study was a long-term follow-up study including 33,254 men and 10,598 women from the Aerobics Center Longitudinal Study (ACLS) who were 18-100 years old and did not have a HTN diagnosis at baseline. Logistic regression models were constructed using forward selection procedures for each age category, with stroke occurrence as the dependent variable, and pulse pressure (PP), mean arterial pressure (MAP), systolic blood pressure (SBP), smoking status, CRF, drinking behavior, DM status, and weight status as potential predictors.

RESULTS

In total, 507 subjects had a stroke during an average follow-up period of 17 years (range=1-34 years). Logistic regression models showed that MAP values (P=0.043) in those aged 19-39 years; SBP (P<0.001), CRF (P=0.001), weight status (P=0.005), and alcohol consumption (P=0.001) in those 40-60 years old; and CRF (P=0.002), weight status (P=0.005), and DM status (P=0.037) in those over 60 years old were predictors of stroke.

CONCLUSION

These findings suggest that, among individuals without a baseline HTN diagnosis, classic modifiable risk factors for stroke change across different stages of life.

From Sea to Shining Sea and the Great Plains to Patagonia: A Review on Current Knowledge of Diabetes Mellitus in Hispanics/Latinos in the US and Latin America

The past two decades have witnessed many advances in the prevention, treatment, and control of diabetes mellitus (DM) and its complications. Increased screening has led to a greater recognition of type 2 diabetes mellitus (type 2 DM) and prediabetes; however, Hispanics/Latinos, the largest minority group in the US, have not fully benefited from these advances. The Hispanic/Latino population is highly diverse in ancestries, birth places, cultures, languages, and socioeconomic backgrounds, and it populates most of the Western Hemisphere. In the US, the prevalence of DM varies among Hispanic/Latino heritage groups, being higher among Mexicans, Puerto Ricans, and Dominicans, and lower among South Americans. The risk and prevalence of diabetes among Hispanics/Latinos are significantly higher than in non-Hispanic Whites, and nearly 40% of Hispanics/Latinos with diabetes have not been formally diagnosed. Despite these striking facts, the representation of Hispanics/Latinos in pharmacological and non-pharmacological clinical trials has been suboptimal, while the prevalence of diabetes in these populations continues to rise. This review will focus on the epidemiology, etiology and prevention of type 2 DM in populations of Latin American origin. We will set the stage by defining the terms Hispanic, Latino, and Latin American, explaining the challenges identifying Hispanics/Latinos in the scientific literature and databases, describing the epidemiology of diabetes-including type 2 DM and gestational diabetes mellitus (GDM)-and cardiovascular risk factors in Hispanics/Latinos in the US and Latin America, and discussing trends, and commonalities and differences across studies and populations, including methodology to ascertain diabetes. We will discuss studies on mechanisms of disease, and research on prevention of type 2 DM in Hispanics/Latinos, including women with GDM, youth and adults; and finalize with a discussion on lessons learned and opportunities to enhance research, and, consequently, clinical care oriented toward preventing type 2 DM in Hispanics/Latinos in the US and Latin America.

Risk of all-cause mortality in abdominal obesity phenotypes: Tehran Lipid and Glucose Study

BACKGROUND AND AIM

Long-term health risks in the so-called "healthy obesity" phenotypes remain controversial. Also it is unknown if "metabolically healthy abdominal obese" (MHAO) phenotype is at increased risk of all-cause mortality compared to their non-abdominally obese counterparts. In this study we assessed the risk of all-cause mortality in different abdominal obesity phenotypes.

METHODS AND RESULTS

In this large population-based cohort, 8804 participants (aged ≥ 30 years), from the Tehran Lipid and Glucose Study (TLGS) were enrolled and followed for a median of 12.0 (8.7-12.5) years. Abdominal obesity was defined using national waist circumference (WC) cut-off points of ≥89 cm for men and ≥91 cm for women. Metabolic health was defined as ≤1 components of metabolic syndrome (excluding WC), using the Joint Interim Statement (JIS) definition. Baseline prevalence of MHAO phenotype was 12.8% in the whole population and 23.4% in those with abdominal obesity. A total of 540 all-cause death occurred during the follow-up. After multivariate adjustment, all-cause mortality risk in MHAO phenotype was not significantly increased compared to "metabolically healthy non abdominal obese" (MHNAO) as the reference group (HR: 1.35, CI: 0.89-2.03).

CONCLUSION

Our results indicate that MHAO individuals were not at higher risk for all-cause mortality over a median of 12 years follow-up. However, considering inadequate power of our analysis for fully adjusted model, larger studies with more follow-ups are needed.

Health Outcomes in Relation to Physical Activity Status, Overweight/Obesity, and History of Overweight/Obesity: A Review of the WATCH Paradigm

Previous research has shown that physical activity may mitigate the association between overweight/obesity and a number of negative health outcomes; however, less is known on how the duration of overweight/obesity alters this association. Therefore, the purpose of this leading article was to synthesize recent studies from our research group examining how physical activity, overweight/obesity classification, and importantly, overweight/obesity duration impact the association with a variety of different health outcomes. Five studies were analyzed, each of which used data from the National Health and Nutrition Examination Survey to analyze six mutually exclusive groups and their respective association with cardiovascular disease risk, all-cause mortality, multi-morbidity, health-related quality of life, and mild depressive symptoms. These studies detailed that physical inactivity, overweight/obesity classification, and overweight/obesity duration were each independently associated with cardiovascular disease risk and multi-morbidity. Additionally, physical activity reduced the risk of all-cause mortality across all weight classifications/durations, and also reduced the association with depressive symptoms and poor health-related quality of life among those overweight/obese for longer durations. These results illustrate that, while physical activity may reduce the association with negative health outcomes, overweight/obesity appears to increase this association independent of physical activity level, with this further exacerbated by the duration of overweight/obesity. Therefore, the emerging studies examining the importance of physical activity among overweight/obese individuals should also consider the duration of overweight/obesity as this will likely alter the associations present.

"Metabolically healthy" obesity: Prevalence, clinical features and association with myocardial ischaemia

OBJECTIVE

To evaluate the prevalence of the "metabolically healthy" (MH) or "metabolically unhealthy" (MU) obesity phenotypes and their association with cardiorespiratory fitness and inducible myocardial ischaemia.

METHODS

Individuals without known coronary artery disease undergoing myocardial perfusion single-photon emission computed tomography (MPS) were studied. Those without dyslipidemia, hypertension, or diabetes were considered MH, and when ≥1 of these was present, MU status was considered present. Summed stress and difference perfusion scores (SSS and SDS, respectively) were calculated; a SDS >1 defined ischaemic MPS.

RESULTS

MH patients were 35.0% of the nonobese population and 23.5% of the obese (p<0.001). The prevalence of ischaemia was not significantly different between MH patients with obesity or MH patients without obesity (10.9% vs 9.1%, p=0.3), except for patients with body mass index ≥40kg/m² (21.9%). MH obese patients were less frequently able to exercise and had lower exercise capacity than the nonobese patients.

CONCLUSIONS

The prevalence of myocardial ischaemia was not significantly different between MH obese or nonobese individuals, supporting the concept of the "metabolically healthy obesity". However, there are other factors involved, such as the ability to exercise, that influence the risk of myocardial ischaemia, limiting the "safety" of that obesity phenotype.

Metabolically Healthy Obesity and the Risk of Cardiovascular Disease in the Elderly Population

Background

Whether being metabolically healthy obese (MHO)—defined by the presence of obesity in the absence of metabolic syndrome—is associated with subsequent cardiovascular disease (CVD) remains unclear and may depend on the participants’ age. We examined the association of being MHO with CVD risk in the elderly.

Methods and Findings

This study included 5,314 individuals (mean age 68 years) from the prospective population-based Rotterdam Study. We categorized our population in groups according to body mass index (BMI) and presence and absence of metabolic syndrome, and estimated the hazard ratio (HR) and 95% confidence interval (95%CI) for every group by using Cox proportional hazard models. Among 1048 (19.7%) obese individuals we identified 260 (24.8%) MHO subjects. Over 14 years of follow-up there were 861 incident CVD cases. In the multivariable adjusted analysis, we did not observe an increased CVD risk in MHO individuals (HR 1.07, 95%CI 0.75–1.53), compared to normal weight individuals without metabolic syndrome. CVD risk was increased by the presence of metabolic syndrome in normal weight (HR 1.35, 95%CI 1.02–1.80), overweight (HR 1.32, 95%CI 1.09–1.60) and obese (HR 1.33, 95%CI 1.07–1.66) individuals, compared to those with normal weight without metabolic syndrome. In a mediation analysis, 71.3% of the association between BMI and CVD was explained by the presence of metabolic syndrome.

Conclusions

In our elderly population, we found that the presence of obesity without metabolic syndrome did not confer a higher CVD risk. However, metabolic syndrome was strongly associated with CVD risk, and was associated with an increased risk in all BMI categories. Therefore, preventive interventions targeting cardiometabolic risk factors could be considered in elderly, regardless of weight status.

Differences in physical activity domains, guideline adherence, and weight history between metabolically healthy and metabolically abnormal obese adults: a cross-sectional study

BACKGROUND

Despite the accepted health consequences of obesity, emerging research suggests that a significant segment of adults with obesity are metabolically healthy (MHO). To date, MHO individuals have been shown to have higher levels of physical activity (PA), but little is known about the importance of PA domains or the influence of weight history compared to their metabolically abnormal (MAO) counterpart.

OBJECTIVE

To evaluate the relationship between PA domains, PA guideline adherence, and weight history on MHO.

METHODS

Pooled cycles of the National Health and Nutritional Examination Survey (NHANES) 1999-2006 (≥20 y; BMI ≥ 30 kg/m(2); N = 2,753) and harmonized criteria for metabolic syndrome (MetS) were used. Participants were categorized as "inactive" (no reported PA), "somewhat active" (>0 to < 500 metabolic equivalent (MET) min/week), and "active" (PA guideline adherence, ≥ 500 MET min/week) according to each domain of PA (total, recreational, transportation and household). Logistic and multinomial regressions were modelled for MHO and analyses were adjusted for age, sex, education, ethnicity, income, smoking and alcohol intake.

RESULTS

Compared to MAO, MHO participants were younger, had lower BMI, and were more likely to be classified as active according to their total and recreational PA level. Based on total PA levels, individuals who were active had a 70% greater likelihood of having the MHO phenotype (OR = 1.70, 95% CI: 1.19-2.43); however, once stratified by age (20-44 y; 45-59 y; and; ≥60 y), the association remained significant only amongst those aged 45-59 y. Although moderate and vigorous PA were inconsistently related to MHO following adjustment for covariates, losing ≥30 kg in the last 10 y and not gaining ≥10 kg since age 25 y were significant predictors of MHO phenotype for all PA domains, even if adherence to the PA guidelines were not met.

CONCLUSION

Although PA is associated with MHO, the beneficial effects of PA may be moderated by longer-term changes in weight. Longitudinal analysis of physical activity and weight change trajectories are necessary to isolate the contribution of duration of obesity, PA behaviours, and longer-term outcomes amongst MHO individuals.

Weight histories and mortality among finnish adults: the role of duration and peak body mass index

BACKGROUND

Many studies use information on weight histories to examine the association between body weight and mortality. A recent paper in Epidemiology (2013;25:707-710) developed a typology of the most common weight-history specifications.

METHODS

We use data from a sample of Finnish adults to explore the associations of body weight and mortality, using existing specifications and also peak body mass index (BMI), a new specification.

RESULTS

We confirm earlier findings that longer time in a high BMI state is predictive of mortality. Peak BMI (the highest BMI attained in life or available in the data) is also positively associated with mortality.

CONCLUSIONS

The specifications of duration in a high BMI state and peak BMI are both valuable for understanding the relationship between lifetime weight dynamics and mortality. The collection of information on peak body weight may be useful when collection of more detailed weight histories is not feasible.

Duration of obesity and overweight and risk of type 2 diabetes among US women

OBJECTIVE

The purpose of this study was to examine the association between duration of adiposity and risk of type 2 diabetes (T2D) in US women.

METHODS

Nearly 61,821 participants were prospectively followed from the Nurses' Health Study (1984-2008) and 63,653 participants from Nurses' Health Study II (1991-2011). Participants were considered overweight (BMI 25-30 kg m(-2) ) or obese (BMI ≥ 30 kg m(-2) ) if their BMI was above the cutoffs for two successive assessments. The time-dependent Cox proportional hazard models were used to assess associations between excess weight duration and T2D risk.

RESULTS

In pooled multivariable analyses of the two cohorts, each two extra years of being overweight was associated with 9% (RR = 1.09, 95% CI 1.08-1.09) increased risk of developing T2D. For each 2-year increment in obesity duration, the risk of T2D was increased by 14% (RR = 1.14, 95% CI 1.14-1.15). Adjustment for current BMI greatly attenuated the association for obesity duration (RR = 1.02, 95% CI 1.01-1.03), although the attenuation was less for overweight duration (RR = 1.04, 95% CI 1.04-1.05).

CONCLUSIONS

Both overweight and obesity duration were associated with a significantly higher risk of T2D, and these associations were mainly explained by current BMI, especially for obesity duration.

Eighteen year weight trajectories and metabolic markers of diabetes in modernising China

AIMS/HYPOTHESIS

Although obesity is a major risk factor for diabetes, little is known about weight gain trajectories across adulthood, and whether they are differentially associated with metabolic markers of diabetes.

METHODS

We used fasting blood samples and longitudinal weight data for 5,436 adults (5,734 observations, aged 18-66 years) from the China Health and Nutrition Survey (1991-2009). Using latent class trajectory analysis, we identified different weight gain trajectories in six age and sex strata, and used multivariable general linear mixed effects models to assess elevated metabolic markers of diabetes (fasting glucose, HbA1c, HOMA-IR, insulin) across weight trajectory classes. Models were fitted within age and sex strata, and controlled for baseline weight (or baseline weight by weight trajectory interaction terms), height, and smoking habit, with random intercepts to control for community-level correlations.

RESULTS

Compared with weight gain, classes with weight maintenance, weight loss, or a switch from weight gain to loss had lower values for metabolic markers of diabetes. These associations were stronger among younger women (aged 18-29 and 30-39 years) and men (18-29 years) than in older (40-66 years) men and women. An exception was HOMA-IR, which showed class differences across all ages (at least p < 0.004).

CONCLUSION

Trajectory analysis identified heterogeneity in adult weight gain associated with diabetes-related metabolic markers, independent of baseline weight. Our findings suggest that variation in metabolic markers of diabetes across patterns of weight gain is masked by a homogeneous classification of weight gain.

Misperception of body weight among overweight Danish adults: trends from 1995 to 2008

OBJECTIVE

To examine changes in the prevalence of overweight and weight misperception among overweight Danes from 1995 to 2008, and to identify factors associated with weight misperception.

DESIGN

Cross-sectional studies, in which data on self-reported weight, height and self-perception of overweight status were obtained through face-to-face interviews. 'Overweight' includes obesity. Weight misperception was defined as overweight individuals who did not perceive themselves as overweight. The χ 2 test was used to analyse changes over time and multiple logistic regression analysis was applied to identify factors associated with weight misperception.

SETTING

The Danish National Survey of Diet and Physical Activity in three periods: 1995, 2000-2004 and 2005-2008.

SUBJECTS

A random sample of 9623 Danes aged 15-75 years.

RESULTS

The prevalence of overweight increased in men and women from 1995 to 2005-2008 (from 35·1 % to 43·0 %, P < 0·001). Concurrently, there was a reduction in the proportion of overweight men (from 77·5 % to 71·4 %, P = 0·001) and women (from 54·8 % to 51·9 %, P = 0·24) who misperceived their weight. Factors associated with weight misperception were 'never intend to eat healthily' (men), high levels of leisure-time physical activity, 'very good/excellent' self-rated health and survey year (higher misperception in 2000-2004 than 2005-2008; P < 0·05).

CONCLUSIONS

The increase in overweight from 1995 to 2005-2008 was accompanied by a reduction in the proportion of overweight men misperceiving their weight. This may indicate that more men see overweight as a personally relevant health problem. Our findings also suggest that overweight individuals who are more physically active and have better self-rated health may not consider their excess weight a health problem.

Progression from metabolically benign to at-risk obesity in perimenopausal women: a longitudinal analysis of study of women across the nation (SWAN)

BACKGROUND

Little is known about the natural history of progression from a metabolically benign overweight/obese (MBO) to at-risk overweight/obese (ARO) phenotype. Improved understanding would help clinicians focus on controlling risk factors that predispose an obese individual to progression.

METHODS

Using discrete-time proportional hazard modeling on data from the Study of Women's Health Across the Nation (SWAN), we examined the incident progression from MBO (less than two metabolic syndrome abnormalities) to ARO (two or more metabolic syndrome abnormalities) and factors associated with progression over a 7-year period.

RESULTS

Of 866 MBO women at baseline, 43% progressed to the ARO phenotype. Compared with those who remained MBO, those who progressed had higher baseline BMI and a higher prevalence of cardiometabolic abnormalities (elevated glucose, triglycerides, blood pressure and low high-density lipoprotein cholesterol). In multivariable analyses, an increase in body mass index was associated with a modest increase in the risk of progression. Although all cardiometabolic abnormalities were associated with an increased risk, the baseline impaired fasting glucose showed the strongest association with the risk of progression [hazard ratio 3.24; 95% confidence interval 2.10, 4.92; P < .001]. Physical activity played a protective role in decreasing the risk of progression [hazard ratio 0.86; 95% confidence interval 0.80, 0.92; P < .001].

CONCLUSIONS

Increasing obesity and the presence of cardiometabolic abnormalities increase the risk of progression, whereas physical activity is the only lifestyle factor protective against progression from metabolically benign to the at-risk overweight/obese phenotype, a state that is unanimously associated with an elevated risk of cardiovascular morbidity and mortality.

Long-term obesity and cardiovascular, inflammatory, and metabolic risk in U.S. adults

BACKGROUND

People worldwide are becoming obese at earlier ages, increasing exposure to long-term obesity.

PURPOSE

To examine how BMI at age 25 years predicts later obesity and test the importance of long-term obesity beyond obesity severity for adult cardiovascular, inflammatory, and metabolic risk.

METHODS

Data from adults aged 35-64 years from the 1999-2010 U.S. National Health and Nutrition Examination Survey were analyzed in 2013 to test how BMI at age 25 years predicts later adult BMI. Next, logistic regression models predicted the odds of elevated risk for blood pressure (BP); high-density lipoprotein cholesterol; total cholesterol; triglycerides; C-reactive protein (CRP); and glycosylated hemoglobin (HbA1c) by BMI at age 25 years and current BMI.

RESULTS

Men obese at age 25 years had a 23.1% estimated probability of Class III obesity after age 35 years, compared to a 1.1% probability for men of normal weight at this age. For women, these probabilities were 46.9% and 4.8%, respectively. Those obese in both periods had higher odds of elevated BP, CRP, and HbA1c compared to those of normal weight at age 25 years, with no effects for lipids. After adjustment for current BMI, these associations were either eliminated (for BP and CRP) or greatly reduced (HbA1c).

CONCLUSIONS

The biological risks of long-term obesity are primarily due to the risk of more severe obesity later in life among those obese early in life, rather than obesity duration. Current body weight rather than duration may be the best reflection of clinical cardiovascular and metabolic risk.

Metabolically healthy obesity and the risk of cardiovascular disease and type 2 diabetes: the Whitehall II cohort study

AIM

The metabolically healthy obese (MHO) phenotype refers to obese individuals with a favourable metabolic profile. Its prognostic value is unclear and may depend on the health outcome being examined. We examined the association of MHO phenotype with incident cardiovascular disease (CVD) and type 2 diabetes.

METHODS AND RESULTS

Body mass index and metabolic health, assessed using the Adult Treatment Panel-III (ATP-III) criteria, were assessed on 7122 participants (69.7% men) from the Whitehall II study, aged 39-63 years in 1991-93. Incident CVD (coronary heart disease or stroke) and type 2 diabetes were ascertained from medical screenings (every 5 years), hospital data, and registry linkage until 2009. A total of 657 individuals (9.2% of the cohort) were obese and 42.5% of these were classified as MHO in 1991-93. Over the median follow-up of 17.4 years, there were 828 incident cases of CVD and 798 incident cases of type 2 diabetes. Compared with metabolically healthy normal weight individuals, MHO subjects were at increased risk for CVD (HR = 1.97, 95% CI: 1.38-2.80) and type 2 diabetes (3.25, 95% CI: 2.32-4.54). There was excess risk in metabolically unhealthy obese compared with MHO for type 2 diabetes (1.98, 95% CI: 1.39-2.83) but not CVD (1.23, 95% CI: 0.81-1.87). Treating all measures as time varying covariates produced similar findings.

CONCLUSION

For type 2 diabetes, the MHO phenotype is associated with lower risk than the metabolically unhealthy obese, but for CVD the risk is as elevated in both obesity phenotypes.

The impact of pre-operative weight loss on incidence of surgical site infection and readmission rates after total joint arthroplasty

This study characterized a cohort of obese total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients (1/1/2008-12/31/2010) and evaluated whether a clinically significant amount of pre-operative weight loss (5% decrease in body weight) is associated with a decreased risk of surgical site infections (SSI) and readmissions post-surgery. 10,718 TKAs and 4066 THAs were identified. During the one year pre-TKA 7.6% of patients gained weight, 12.4% lost weight, and 79.9% remained the same. In the one year pre-THA, 6.3% of patients gained weight, 18.0% lost weight, and 75.7% remained the same. In TKAs and THAs, after adjusting for covariates, the risk of SSI and readmission was not significantly different in the patients who gained or lost weight pre-operatively compared to those who remained the same.

All-cause mortality risk of metabolically healthy abdominal obese individuals: the EPIC-MORGEN study

OBJECTIVE

It appears that a certain proportion of obese individuals have a normal metabolic profile despite having excess weight. Whether these so-called "metabolically healthy" obese express lower disease and mortality risks than "metabolically unhealthy" obese is still unclear. The mortality risk of "metabolically healthy" abdominal obese (MHAO) individuals was investigated.

DESIGN AND METHODS

Prospective cohort study (EPIC-MORGEN) among 22,654 individuals aged 20-59 years followed for an average of 13.4 years (SD 2.3). MHAO was assessed at baseline (1993-1997) and defined as abdominal obesity (waist circumference ≥102 cm/≥88 cm (men/women)) with normal glucose, blood pressure, and plasma lipids. All-cause mortality risks adjusted for age and sex were estimated using Cox proportional hazards models.

RESULTS

Individuals who were "metabolically healthy" nonabdominal obese (MHNAO) comprised the reference group. As compared to MHNAO, mortality risk for MHAO was around 40% higher (Hazard ratio (HR) 1.43; 95% confidence interval (CI): 1.00-2.04) and of the same magnitude as that for "metabolically unhealthy" nonabdominal obese (MUNAO) (HR 1.31; 95% CI: 1.08-1.59). The HR for MUAO was 1.99 (95% CI: 1.62-2.43).

CONCLUSIONS

Mortality risk of MHAO individuals was significantly higher than that of MHNAO individuals and lower than, but not statistically significantly different from, that of MUAO individuals.

Longitudinal trajectories of BMI and cardiovascular disease risk: the national longitudinal study of adolescent health

OBJECTIVE

In adulthood, excess BMI is associated with cardiovascular disease (CVD); it is unknown whether risk differs by BMI trajectories from adolescence to adulthood.

DESIGN AND METHODS

The National Longitudinal Study of Adolescent Health, a nationally representative, longitudinal adolescent cohort (mean age: 16.9 years) followed into adulthood (mean age: 28.8 years) [n = 13,984 individuals (41,982 observations)] was examined. Separate logistic regression models for diabetes, hypertension, and inflammation were used to examine odds of risk factors at given adult BMI according to varying BMI trajectories from adolescence to adulthood.

RESULTS

CVD risk factor prevalence at follow-up ranged from 5.5% (diabetes) to 26.4% (hypertension) and 31.3% (inflammation); risk differed across BMI trajectories. For example, relative to men aged 27 years (BMI = 23 kg/m(2) maintained over full study period), odds for diabetes were comparatively higher for men of the same age and BMI ≈ 30 kg/m(2) with ≈8 BMI unit gain between 15 and 20 years (OR = 2.35; 95% CI, 1.51, 3.66) or in those who maintained BMI ≈ 30 kg/m(2) across the study period (OR = 2.33; 1.92, 2.83) relative to the same ≈8 BMI unit gain, but between 20 and 27 years (OR = 1.44; 1.10, 1.87).

CONCLUSIONS

Specific periods and patterns of weight gain in the transition from adolescence to adulthood might be critical for CVD preventive efforts.

Association between duration of overall and abdominal obesity beginning in young adulthood and coronary artery calcification in middle age

IMPORTANCE

Younger individuals are experiencing a greater cumulative exposure to excess adiposity over their lifetime. However, few studies have determined the consequences of long-term obesity.

OBJECTIVE

To examine whether the duration of overall and abdominal obesity was associated with the presence and 10-year progression of coronary artery calcification (CAC), a subclinical predictor of coronary heart disease.

DESIGN, SETTING, AND PARTICIPANTS

Prospective study of 3275 white and black adults aged 18 to 30 years at baseline in 1985-1986 who did not initially have overall obesity (body mass index [BMI] ≥30) or abdominal obesity (men: waist circumference [WC] >102 cm; women: >88 cm) in the multicenter, community-based Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants completed computed tomography scanning for the presence of CAC during the 15-, 20-, or 25-year follow-up examinations. Duration of overall and abdominal obesity was calculated using repeat measurements of BMI and WC, respectively, performed 2, 5, 7, 10, 15, 20, and 25 years after baseline.

MAIN OUTCOMES AND MEASURES

Presence of CAC was measured by computed tomography at the year 15 (2000-2001), year 20 (2005-2006), or year 25 (2010-2011) follow-up examinations. Ten-year progression of CAC (2000-2001 to 2010-2011) was defined as incident CAC in 2010-2011 or an increase in CAC score of 20 Agatston units or greater.

RESULTS

During follow-up, 40.4% and 41.0% developed overall and abdominal obesity, respectively. Rates of CAC per 1000 person-years were higher for those who experienced more than 20 years vs 0 years of overall obesity (16.0 vs 11.0, respectively) and abdominal obesity (16.7 vs 11.0). Approximately 25.2% and 27.7% of those with more than 20 years of overall and abdominal obesity, respectively, experienced progression of CAC vs 20.2% and 19.5% of those with 0 years. After adjustment for BMI or WC and potential confounders, the hazard ratios for CAC for each additional year of overall or abdominal obesity were 1.02 (95% CI, 1.01-1.03) and 1.03 (95% CI, 1.02-1.05), respectively. The adjusted odds ratios for CAC progression were 1.04 (95% CI, 1.01-1.06) and 1.04 (95% CI, 1.01-1.07), respectively. Associations were attenuated but largely persisted following additional adjustment for potential intermediate metabolic factors during follow-up.

CONCLUSIONS AND RELEVANCE

Longer duration of overall and abdominal obesity was associated with subclinical coronary heart disease and its progression through midlife independent of the degree of adiposity. Preventing or at least delaying the onset of obesity in young adulthood may lower the risk of developing atherosclerosis through middle age.

Duration of abdominal obesity beginning in young adulthood and incident diabetes through middle age: the CARDIA study

OBJECTIVE

To examine whether the duration of abdominal obesity determined prospectively using measured waist circumference (WC) is associated with the development of new-onset diabetes independent of the degree of abdominal adiposity.

RESEARCH DESIGN AND METHODS

The Coronary Artery Risk Development in Young Adults Study is a multicenter, community-based, longitudinal cohort study of 5,115 white and black adults aged 18-30 years in 1985 to 1986. Years spent abdominally obese were calculated for participants without abdominal obesity (WC >102 cm in men and >88 cm in women) or diabetes at baseline (n = 4,092) and was based upon repeat measurements conducted 2, 5, 7, 10, 15, 20, and 25 years later.

RESULTS

Over 25 years, 392 participants developed incident diabetes. Overall, following adjustment for demographics, family history of diabetes, study center, and time varying WC, energy intake, physical activity, smoking, and alcohol, each additional year of abdominal obesity was associated with a 4% higher risk of developing diabetes [hazard ratio (HR) 1.04 (95% CI 1.02-1.07)]. However, a quadratic model best represented the data. HRs for 0, 1-5, 6-10, 11-15, 16-20, and >20 years of abdominal obesity were 1.00 (referent), 2.06 (1.43-2.98), 3.45 (2.28-5.22), 3.43 (2.28-5.22), 2.80 (1.73-4.54), and 2.91 (1.60-5.29), respectively; P-quadratic < 0.001.

CONCLUSIONS

Longer duration of abdominal obesity was associated with substantially higher risk for diabetes independent of the degree of abdominal adiposity. Preventing or at least delaying the onset of abdominal obesity in young adulthood may lower the risk of developing diabetes through middle age.

Timing and duration of obesity in relation to diabetes: findings from an ethnically diverse, nationally representative sample

OBJECTIVE

The influence on diabetes of the timing and duration of obesity across the high-risk period of adolescence to young adulthood has not been investigated in a population-based, ethnically diverse sample.

RESEARCH DESIGN AND METHODS

A cohort of 10,481 individuals aged 12-21 years enrolled in the U.S. National Longitudinal Study of Adolescent Health (1996) was followed over two visits during young adulthood (18-27 years, 2001-2002; 24-33 years, 2007-2009). Separate logistic regression models were used to examine the associations of diabetes (A1C ≥6.5% or diagnosis by a health care provider) in young adulthood with 1) obesity timing (never obese, onset <16 years, onset 16 to <18 years, onset ≥18 years) and 2) obesity duration over time (never obese, incident obesity, fluctuating obesity, and persistent obesity), testing differences by sex and race/ethnicity.

RESULTS

Among 24- to 33-year-old participants, 4.4% had diabetes (approximately half were undiagnosed), with a higher prevalence in blacks and Hispanics than whites. In multivariable analyses, women who became obese before age 16 were more likely to have diabetes than women who became obese at or after age 18 (odds ratio 2.77 [95% CI 1.39-5.52]), even after accounting for current BMI, waist circumference, and age at menarche. Persistent (vs. adult onset) obesity was associated with increased likelihood of diabetes in men (2.27 [1.41-3.64]) and women (2.08 [1.34-3.24]).

CONCLUSIONS

Diabetes risk is particularly high in individuals who were obese as adolescents relative to those with adult-onset obesity, thus highlighting the need for diabetes prevention efforts to address pediatric obesity.

The intriguing metabolically healthy but obese phenotype: cardiovascular prognosis and role of fitness

AIMS

Current knowledge on the prognosis of metabolically healthy but obese phenotype is limited due to the exclusive use of the body mass index to define obesity and the lack of information on cardiorespiratory fitness. We aimed to test the following hypotheses: (i) metabolically healthy but obese individuals have a higher fitness level than their metabolically abnormal and obese peers; (ii) after accounting for fitness, metabolically healthy but obese phenotype is a benign condition, in terms of cardiovascular disease and mortality.

METHODS AND RESULTS

Fitness was assessed by a maximal exercise test on a treadmill and body fat per cent (BF%) by hydrostatic weighing or skinfolds (obesity = BF% ≥ 25 or ≥ 30%, men or women, respectively) in 43 265 adults (24.3% women). Metabolically healthy was considered if meeting 0 or 1 of the criteria for metabolic syndrome. Metabolically healthy but obese participants (46% of the obese subsample) had a better fitness than metabolically abnormal obese participants (P < 0.001). When adjusting for fitness and other confounders, metabolically healthy but obese individuals had lower risk (30-50%, estimated by hazard ratios) of all-cause mortality, non-fatal and fatal cardiovascular disease, and cancer mortality than their metabolically unhealthy obese peers; while no significant differences were observed between metabolically healthy but obese and metabolically healthy normal-fat participants.

CONCLUSIONS

(i) Higher fitness should be considered a characteristic of metabolically healthy but obese phenotype. (ii) Once fitness is accounted for, the metabolically healthy but obese phenotype is a benign condition, with a better prognosis for mortality and morbidity than metabolically abnormal obese individuals.

Metabolic syndrome in healthy obese, overweight, and normal weight individuals: the Atherosclerosis Risk in Communities Study

OBJECTIVE

There is recent interest in characterizing the subset of obese (OB) individuals who have healthy metabolic profiles yet only two studies have examined this group prospectively but not in racially diverse populations.

DESIGN AND METHODS

We analyzed factors associated with the prevalence and incidence of metabolic syndrome (MetSyn) among individuals grouped by BMI categories in a multi-center, community-based cohort of 14,663 African-American and white men and women aged 45-64 years at recruitment in 1987-1989, the Atherosclerosis Risk in Communities (ARIC) Study. Logistic and proportional hazards regression were utilized to estimate odds ratios (ORs) for the prevalence and hazard ratios (HRs) for incidence of MetSyn with 95% confidence intervals (CIs).

RESULTS

At visit 1, MetSyn was positively associated with age, female gender, African-American race, and inversely related to education, associations being more pronounced among normal weight (NW) subjects. Among those without MetSyn at visit 1, OB subjects were more likely to develop MetSyn compared with NW (HR (95% CI): 4.53 (4.09-5.01)). Several factors were associated with incident MetSyn among NW, including older age (per year: 1.05 (1.03-1.06)), female gender (vs. male: 1.29 (1.10-1.52)), heavy alcohol intake (vs. never: 0.75 (0.59-0.94)), and physical activity (tertile 3 vs. tertile 1: 0.71 (0.58-0.86)) but not OB. Weight gain (>5%) was also more highly associated with MetSyn in NW (1.61 (1.28-2.02)) compared with OB (1.01 (0.85-1.20)).

CONCLUSIONS

We conclude that lifestyle factors may play a stronger role in the development of MetSyn in NW individuals compared with OB and that metabolically healthy obesity may not be a stable condition.

Life course body mass index, birthweight and lipid levels in mid-adulthood: a nationwide birth cohort study

AIMS

Improvement in lipid profiles is an important public health and clinical goal for which a better understanding is needed of biological pathways and influences. Evidence is scant on the role of growth, including trajectories of body mass index (BMI), so we aimed to determine whether particular life stages from birth to adulthood are important for lipid levels in mid-adulthood (45 years).

METHODS AND RESULTS

In the 1958 British birth cohort (n = 3927 men; 3897 women), weight and height were recorded at: birth (weight only), 7, 11, 16, 23, 33, and 45 years. Birthweight was inversely associated with triglycerides and in women with total- and non-high-density lipoprotein cholesterol; associations were little affected by adjustment for 7-year BMI. Associations between lipids and BMI strengthened with age, e.g. in women, adult (45-year) triglycerides were elevated by 1.54% (95% confidence interval: 0.87-2.21%) and 3.57% (3.29-3.86%), respectively, per kg/m² higher BMI at 11 and 45 years. Body mass index gain was related to lipids, with strongest associations for the interval between 33 and 45 years, where a kg/m² gain in BMI was associated with ~0.6% higher total cholesterol and ~5.3% higher triglycerides. Associations between 45-year BMI and lipids were stronger for those with lowest than highest BMI at younger ages (P for interaction ≤0.05). A long duration of obesity and obesity in childhood but not thereafter were unrelated to adult lipid levels.

CONCLUSIONS

Our findings from a large population-based cohort highlight detrimental consequences of high adult BMI for lipids as most pronounced for those with a lower BMI at earlier life stages.

Indirect calorimetry in obese female subjects: Factors influencing the resting metabolic rate

AIM: To evaluate selected factors influencing resting energy expenditure (REE) in obese female subjects.

METHODS: Seventy seven 61 obese Caucasian women [mean age of 52.93 ± 13.45 years, and mean body mass index (BMI) of 41.78 ± 11.54 kg/m²] were enrolled; measurements of resting metabolic rate (RMR) by a ventilated, open-circuit system, indirect calorimeter were performed after an overnight fast. Body composition as well as medications, physical parameters, blood samples, disease pattern, and smoking were considered.

RESULTS: RMR was significantly associated with body weight (r = 0.732, P < 0.001), body height (r = 0.401, P = 0.008), BMI (r = 0.504, P < 0.001), waist circumference (r = 0.602, P < 0.001), mid-upper arm circumference (r = 0.417, P = 0.006), mid-upper arm muscle circumference (r = 0.344, P = 0.028), total body water (r = 0.339, P = 0.035), body temperature (r = 0.409, P = 0.007), smoking (P = 0.031), serum T₄ levels (r = 0.331, P = 0.036), obstructive sleep apnoea syndrome (OSAS; P = 0.023), impaired glucose tolerance (IGT; P = 0.017) and impaired glycaemic status, including hyperinsulinism, IGT and diabetes mellitus (P = 0.003).

CONCLUSION: Future research should be prompted to optimize the procedure of indirect calorimetry to achieve clinical benefits in obese subjects.

Effect of the timing of weight cycling during adulthood on mortality risk in overweight and obese postmenopausal women

Inconsistent results exist for whether or not weight cycling (WgtC) and weight variability (WgtV) increase mortality risk. The aim of this study was to examine the effect of WgtC and WgtV during adulthood on mortality risk. Data was obtained from the Women's Health Initiative (WHI) observational study (OS) dataset, acquired from the National Heart, Lung and Blood Institute (N = 47,473 overweight and obese women; age 50-79 years). Women were categorized (stable; WgtV: weight-gainer or loser; or WgtC) based on weight changes during early (18-35 years), mid (35-50 years), and late (50 years to current age) adulthood. Those with weight changes of <5% during all three time-periods were classified as being stable-weight. Weight-gainers were those with at least one period of weight-gain (≥5%) without a period of weight-loss (≥5%), and weight-losers were those with at least one period of loss without a period of gain during all time-periods. Those who experienced both a period of weight-gain and loss (≥5%) were categorized as WgtC. Compared to stable-weight individuals, WgtC and WgtV across adulthood were not significantly associated with mortality risk when the age-period of weight change was not considered. However, when considering the age period, increased mortality risk was observed for every 5 kg of weight-gain during early (hazard ratio (HR) = 1.04 (1.00-1.07)) or mid-adulthood (HR = 1.05 (1.02-1.08)), or for every 5 kg of weight-loss since mid (HR = 1.12 (1.01-1.24)) or late-adulthood (HR = 1.12 (1.04-1.20)). In conclusion, merely investigating WgtC and WgtV by weight changes across adulthood may not be sufficient to fully describe mortality risk, and the age at which the weight change occurred might be as important to consider.

Changes in BMI, duration of overweight and obesity, and glucose metabolism: 45 years of follow-up of a birth cohort

OBJECTIVE

Long-term implications of childhood obesity and BMI change over the life course for risk of type 2 diabetes remain uncertain. The objective was to establish whether there are effects on adult glucose metabolism of 1) sensitive periods of BMI gain or 2) long duration of overweight and obesity.

RESEARCH DESIGN AND METHODS

Participants in the 1958 British birth cohort with child to adult BMI and glycosylated hemoglobin (HbA(1c)) at 45 years (n = 7,855).

RESULTS

Prevalence of type 2 diabetes or HbA(1c) ≥7 was 2%. BMI gains in child- and adulthood were associated with higher HbA(1c): for every SD of 5-year BMI increase from 0 to 7 years, there was a 75% (95% CI 1.42-2.16) increased risk of HbA(1c) ≥7, increasing to a 4.7-fold (3.12-7.00) risk for the interval 23-33 years. Associations for BMI gain in adulthood were related to attained BMI but were independent for the longer period birth (or 7 years) to 45 years. Duration of obesity was also associated with HbA(1c); compared with the never obese, those with childhood onset had a 23.9-fold risk (13.5-42.1) of HbA(1c) ≥7%; odds ratios were 16.0 (10.6-24.2) and 2.99 (1.77-5.03), respectively, for young and midadulthood onset. Similar trends by onset age were found in mean HbA(1c) levels and for onset of overweight. Those with the earliest age of onset had higher BMI and waist circumference at 45 years, which markedly explained the associations for onset age and HbA(1c).

CONCLUSIONS

Excessive BMI gain across the life span and earlier onset of overweight/obesity are associated with impaired glucose metabolism, in part through attained adult BMI.

Edmonton Obesity Staging System: association with weight history and mortality risk

We sought to determine whether the Edmonton Obesity Staging System (EOSS), a newly proposed tool using obesity-related comorbidities, can help identify obese individuals who are at greater mortality risk. Data from the Aerobics Center Longitudinal Study (n = 29 533) were used to assess mortality risk in obese individuals by EOSS stage (follow-up (SD), 16.2 (7.5) years). The effect of weight history and lifestyle factors on EOSS classification was explored. Obese participants were categorized, using a modified EOSS definition, as stages 0 to 3, based on the severity of their risk profile and conditions (stage 0, no risk factors or comorbidities; stage 1, mild conditions; and stages 2 and 3, moderate to severe conditions). Compared with normal-weight individuals, obese individuals in stage 2 or 3 had a greater risk of all-cause mortality (stage 2 hazards ratio (HR) (95% CI), 1.6 (1.3-2.0); stage 3 HR, 1.7 (1.4-2.0)) and cardiovascular-related mortality (stage 2 HR, 2.1 (1.6-2.8); stage 3 HR. 2.1 (1.6-2.8)). Stage 0/1 was not associated with higher mortality risk. Lower self-ascribed preferred weight, weight at age 21, cardiorespiratory fitness, reported dieting, and fruit and vegetable intake were each associated with an elevated risk for stage 2 or 3. Thus, EOSS offers clinicians a useful approach to identify obese individuals at elevated risk of mortality who may benefit from more attention to weight management. Further research is necessary to determine what EOSS factors are most predictive of mortality risk, and whether these findings can be generalized to other obese populations.

Open questions about metabolically normal obesity

Subsets of obese subjects without any cardiometabolic risk factors have been repeatedly described. This raises questions whether obesity 'per se' enhances the risk for cardiovascular or metabolic diseases and whether healthy obese subjects would benefit from a medical treatment. In order to answer these questions, as a first step, an expert consensus should be reached for the definition of metabolic normality. In fact, up to now, different parameters related to the metabolic syndrome and/or to insulin sensitivity have been utilized across studies. Once an agreement is reached, population-based studies should be undertaken to establish the incidence of metabolic normality among obese subjects. Furthermore, many other parameters such as age, sex, race, fat distribution and physical activity should be monitored to obtain results representative of a general population. Longitudinal studies aimed at investigating the evolution of the cardiometabolic profile of healthy obese subjects are also needed. In conclusion, data from the literature strongly suggest that a regular surveillance of the cardiometabolic parameters and a prevention of any further weight gain should be applied to healthy obese individuals, whereas possible benefits of a weight loss treatment are still a matter of debate.

Association between obesity history and hand grip strength in older adults--exploring the roles of inflammation and insulin resistance as mediating factors

BACKGROUND

To examine the association between obesity history and hand grip strength, and whether the association is partly explained by subclinical inflammation and insulin resistance.

METHODS

Data are from 2,021 men and women aged 55 years and older participating in the representative population-based Health 2000 Survey in Finland. Body mass and body height, maximal hand grip strength, C-reactive protein, and insulin resistance based on homeostasis model assessment (HOMA-IR) were measured in a health examination. Recalled weight at 20, 30, 40, and 50 years of age were recorded to obtain a hierarchical classification of obesity history. Obesity was defined as body mass index ≥ 30 kg/m².

RESULTS

Earlier onset of obesity was associated with lower hand grip strength (p < .001) after controlling for age, sex, education, smoking, alcohol use, physical activity, several chronic diseases, and current body weight. Based on adjusted logistic regression models, the odds (95% confidence interval) for very low relative hand grip strength were 2.76 (1.78-4.28) for currently obese, 5.57 (3.02-10.28) for obese since age of 50 years, 6.53 (2.98-14.30) for obese since age of 40 years, and 10.36 (3.55-30.24) for obese since age of 30 years compared with never obese participants. The associations remained highly significant even after adjusting for current C-reactive protein and HOMA-IR, but these variables had only minor role in explaining the association between obesity history and hand grip strength.

CONCLUSIONS

Long-term exposure to obesity is associated with poor hand grip strength later in life. Maintaining healthy body weight throughout the life span may help to maintain adequate muscle strength in old age. Prospective studies with information on prior muscle strength are needed to examine in detail the causal association between obesity history and muscle strength.

Are metabolically normal but obese individuals at lower risk for all-cause mortality?

OBJECTIVE

The clinical relevance of the metabolically normal but obese phenotype for mortality risk is unclear. This study examines the risk for all-cause mortality in metabolically normal and abnormal obese (MNOB and MAOB, respectively) individuals.

RESEARCH DESIGN AND METHODS

The sample included 6,011 men and women from the Third National Health and Nutrition Examination Survey (NHANES III) with public-access mortality data linkage (follow-up = 8.7 +/- 0.2 years; 292 deaths). Metabolically abnormal was defined as insulin resistance (IR) or two or more metabolic syndrome (MetSyn) criteria (excluding waist).

RESULTS

A total of 30% of obese subjects had IR, and 38.4% had two or more MetSyn factors, whereas only 6.0% (or 1.6% of the whole population) were free from both IR and all MetSyn factors. By MetSyn factors or IR alone, MNOB subjects (hazard ratio [HR](MetSyn) 2.80 [1.18-6.65]; HR(IR) 2.58 [1.00-6.65]) and MAOB subjects (HR(MetSyn) 2.74 [1.46-5.15]; HR(IR) 3.09 [1.55-6.15]) had similar elevations in mortality risk compared with metabolically normal, normal weight subjects.

CONCLUSIONS

Although a rare phenotype, obesity, even in the absence of overt metabolic aberrations, is associated with increased all-cause mortality risk.