Duration of obesity increases the incidence of NIDDM

The association of female reproductive factors with risk of metabolic syndrome in women from NHANES 1999-2018

BACKGROUND

Female reproductive factors such as age at first birth (AFB), age at last birth (ALB), number of pregnancies and live births play an essential role in women's health. However, few epidemiological studies have evaluated the association between female reproductive factors and metabolic syndrome (MetS). We therefore conducted a cross-sectional study to investigate the association between MetS risk and female reproductive factors.

METHODS

We investigated the relationship between AFB, ALB, number of pregnancies and live births and the incidence of MetS using publicly available data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. Weighted multivariable logistic regression analysis, restricted cubic spline (RCS) model, and subgroup analysis were used to evaluate the association between AFB and ALB and the risk of MetS in women. In addition, the relationship between the number of pregnancies, live births and MetS risk was also explored.

RESULTS

A total of 15,404 women were included in the study, and 5,983 (38.8%) had MetS. RCS models showed an N-shaped relationship between AFB and MetS risk, whereas ALB, number of pregnancies, and live births were linearly associated with MetS. Weighted multivariable logistic regression analysis showed that the number of live births was associated with MetS risk, with ORs of 1.18 (95% CI: 1.04, 1.35) for women with ≥ 5 deliveries compared to women with ≤ 2 births.

CONCLUSIONS

AFB was associated with the risk of MetS in an N-shaped curve in women. In addition, women with high live births have a higher incidence of MetS.

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.

Pediatric Obesity: Complications and Current Day Management

Obesity affects approximately 1 in 5 youth globally and increases the risk of complications during adolescence and young adulthood, including type 2 diabetes, dyslipidemia, hypertension, non-alcoholic fatty liver disease, obstructive sleep apnea, and polycystic ovary syndrome. Children and adolescents with obesity frequently experience weight stigma and have an impaired quality of life, which may exacerbate weight gain. Pediatric obesity is typically defined using sex-, age-, and population-specific body mass index percentiles. Once identified, pediatric obesity should always be managed with lifestyle modification. However, adolescents with obesity may also benefit from anti-obesity medications (AOM), several of which have been approved for use in adolescents by the US Food and Drug Administration, including liraglutide, phentermine/topiramate, and semaglutide. For children with specific, rare monogenic obesity disorders, setmelanotide is available and may lead to significant weight loss. Metabolic and bariatric surgery may be used for the management of severe obesity in youth; though highly effective, it is limited to specialized centers and has had relatively low pediatric uptake. In this narrative review using pediatric-focused data from original research, reviews, clinical practice guidelines, governmental agencies, and pharmaceutical companies, we review obesity-related metabolic complications in youth and management strategies, including AOM and bariatric surgery.

Youth-Onset Type 2 Diabetes: The Epidemiology of an Awakening Epidemic

In this narrative review, we describe the epidemiology (prevalence, incidence, temporal trends, and projections) of type 2 diabetes among children and adolescents (<20 years), focusing on data from the U.S. and reporting global estimates where available. Secondarily, we discuss the clinical course of youth-onset type 2 diabetes, from prediabetes to complications and comorbidities, drawing comparisons with youth type 1 diabetes to highlight the aggressive course of this condition, which, only recently, has become recognized as a pediatric disease by health care providers. Finally, we end with an overview of emerging topics in type 2 diabetes research that have potential to inform strategies for effective preventive action at the community and individual levels.

Life-long body mass index trajectories and mortality in two generations

PURPOSE

To identify life-long body mass index (BMI) trajectories across two related generations and estimate their associated mortality risks and population attributable deaths.

METHODS

We use prospective cohort data from the Framingham Heart Study (1948-2011) original (4576 individuals, 3913 deaths) and offspring (3753 individuals, 967 deaths) cohorts and latent trajectory models to model BMI trajectories from age 31 to 80 years. Survival models are used to estimate trajectory-specific mortality risk.

RESULTS

We define seven BMI trajectories among original cohort and six among offspring cohort. Among original cohort, people who are normal weight at age 31 years and gradually move to overweight status in middle or later adulthood have the lowest mortality risk even compared to those who maintain normal weight throughout adulthood, followed by overweight stable, lower level of normal weight, overweight downward, class I obese upward, and class II/III upward trajectories. Mortality risks associated with obesity trajectories have declined across cohorts, while the prevalence of high-risk trajectories has increased.

CONCLUSIONS

The mortality impact of weight gain depends on an individual's BMI trajectory. Population attributable deaths associated with unhealthy weight trajectories have grown over generations because the prevalence has increased, offsetting the decline in trajectory-specific mortality risks.

Concentration/activity of superoxide dismutase isozymes and the pro-/antioxidative status, in context of type 2 diabetes and selected single nucleotide polymorphisms (genes: INS, SOD1, SOD2, SOD3) - Preliminary findings

The alterations in concentration/activity of superoxide dismutase isozymes in the context of type 2 diabetes or obesity are well-described. Moreover, many hereditary factors, including single-nucleotide polymorphisms (SNPs) of genes for coding insulin, insulin receptors, or insulin receptor substrates (INS, INSR, IRS1, IRS2) or superoxide dismutase isozymes (SOD1, SOD2, SOD3), have been linked with the incidence of obesity and diabetes. However, the underlying changes in the plasma concentration/activity of superoxide dismutase isozymes and their potential connection with the said hereditary factors remain unexplored. Previously, we have observed that the plasma concentration/activity of superoxide dismutase isozymes differs in the context of obesity and/or rs2234694 (SOD1) and rs4880 (SOD2) and that the concentrations of SOD1, SOD2, SOD3 are correlated with each other. Intersexual variability of SOD1 concentration was detected regardless of obesity. In this study, the variability of concentration/activity of superoxide dismutase isozymes in plasma is considered in the context of type 2 diabetes and/or SNPs: rs2234694 (SOD1), rs5746105 (SOD2), rs4880 (SOD2), rs927450 (SOD2), rs8192287 (SOD3). Genotypic variability of SNP rs3842729 (INS), previously studied in the context of insulin-dependent diabetes, is investigated in terms of selected clinical parameters associated with type 2 diabetes. This study revealed higher SOD1 concentration in diabetic men compared to women, and extremely high SOD1 concentration, higher total superoxide dismutase, and copper-zinc superoxide dismutase activity, and lower superoxide dismutase and copper-zinc superoxide dismutase activity (when adjusted for the concentration of SODs) in the diabetic group regardless of sex. Multiple logistic regression, applied to explore possible links between the studied SNPs and other factors with the odds of type 2 diabetes or obesity, revealed that the genotypic variability of rs4880 (SOD2) could affect these odds, supporting the findings of several other studies.

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.

Dynamic Models Supporting Personalised Chronic Disease Management through Healthcare Sensors with Interactive Process Mining

Rich streams of continuous data are available through Smart Sensors representing a unique opportunity to develop and analyse risk models in healthcare and extract knowledge from data. There is a niche for developing new algorithms, and visualisation and decision support tools to assist health professionals in chronic disease management incorporating data generated through smart sensors in a more precise and personalised manner. However, current understanding of risk models relies on static snapshots of health variables or measures, rather than ongoing and dynamic feedback loops of behaviour, considering changes and different states of patients and diseases. The rationale of this work is to introduce a new method for discovering dynamic risk models for chronic diseases, based on patients' dynamic behaviour provided by health sensors, using Process Mining techniques. Results show the viability of this method, three dynamic models have been discovered for the chronic diseases hypertension, obesity, and diabetes, based on the dynamic behaviour of metabolic risk factors associated. This information would support health professionals to translate a one-fits-all current approach to treatments and care, to a personalised medicine strategy, that fits treatments built on patients' unique behaviour thanks to dynamic risk modelling taking advantage of the amount data generated by smart sensors.

Weight tracking in childhood and adolescence and type 2 diabetes risk

AIMS/HYPOTHESIS

The aim of this work was to examine the associations of average weight and weight velocity in three growth periods from birth through adolescence with type 2 diabetes incidence.

METHODS

Child participants were selected from a 43 year longitudinal study of American Indians to represent three growth periods: pre-adolescence (birth to ~8 years); early adolescence (~8 to ~13 years); and late adolescence (~13 to ~18 years). Age-, sex- and height-standardised weight z score mean and weight z score velocity (change/year) were computed for each period. Participants were followed for up to 25 years from the end of each growth period until they developed diabetes. Associations of weight z score mean or weight z score velocity with diabetes incidence were determined with sex-, birth date- and maternal diabetes-adjusted Poisson regression models.

RESULTS

Among 2100 participants representing the pre-adolescence growth period, 1558 representing the early adolescence period and 1418 representing the late adolescence period, there were 290, 315 and 380 incident diabetes cases, respectively. During the first 10 years of follow-up, the diabetes incidence rate ratio (95% CI) was 1.72 (1.40, 2.11)/SD of log₁₀ weight z score mean in pre-adolescence, 2.09 (1.68, 2.60)/SD of log₁₀ weight z score mean in early adolescence and 1.85 (1.58, 2.17)/SD of log₁₀ weight z score mean in late adolescence. The diabetes incidence rate ratio (95% CI) was 1.79 (1.49, 2.17)/SD of log₁₀ weight z score velocity in pre-adolescence, 1.13 (0.91, 1.41)/SD of log₁₀ weight z score velocity in early adolescence and 1.29 (1.09, 1.51)/SD of log₁₀ weight z score velocity in late adolescence. There were strong correlations in the weight z score means and weak correlations in the weight z score velocities between successive periods.

CONCLUSIONS/INTERPRETATION

Higher weight and accelerated weight gain in all growth periods associate with increased type 2 diabetes risk. Importantly, higher weight and greater weight velocity during pre-adolescence jointly associate with the highest type 2 diabetes risk. Graphical abstract.

Association of Weight Loss Between Early Adulthood and Midlife With All-Cause Mortality Risk in the US

IMPORTANCE

Describing potential mortality risk reduction associated with weight loss between early adulthood and midlife is important for informing primary and secondary prevention efforts for obesity.

OBJECTIVE

To examine the risk of all-cause mortality among adults who lost weight between early adulthood and midlife compared with adults who were persistently obese over the same period.

DESIGN, SETTING, AND PARTICIPANTS

Combined repeated cross-sectional analysis was conducted using data from the National Health and Nutrition Examination Survey III (1988-1994) and continuous waves collected in 2-year cycles between 1999 and 2014. The data analysis was conducted from February 10, 2019, to April 20, 2020. Individuals aged 40 to 74 years at the time of survey (baseline) were included in the analyses (n = 24 205).

EXPOSURES

Weight history was assessed by self-reported weight at age 25 years, at 10 years before baseline (midlife: mean age, 44 years; interquartile range, 37-55), and measured weight at baseline. Body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) at each time was categorized as normal (18.5-24.9), overweight (25.0-29.9), and obese (≥30.0). Weight change patterns were assessed from age 25 years (early adulthood) to 10 years before baseline (midlife).

MAIN OUTCOMES AND MEASURES

Incident all-cause mortality using linked data from the National Death Index.

RESULTS

Of the 24 205 participants, 11 617 were women (49.0%) and 11 567 were non-Hispanic White (76.9%). The mean (SD) BMI was 29.0 (6.1) at baseline. During a mean (SD) follow-up of 10.7 (7.2) years, 5846 deaths occurred. Weight loss from obese to overweight was associated with a 54% (hazard ratio, 0.46; 95% CI, 0.27-0.77) reduction in mortality risk compared with individuals with stable obesity between early adulthood and midlife. An estimated 3.2% (95% CI, 1.6%-4.9%) of early deaths could have been avoided if those who maintained an obese BMI instead lost weight to an overweight BMI by midlife. Overall, an estimated 12.4% (95% CI, 8.1%-16.5%) of early deaths may be attributable to having weight in excess of the normal BMI range at any point between early and mid-adulthood.

CONCLUSIONS AND RELEVANCE

In this study, weight loss from obesity to overweight between early adulthood through midlife appeared to be associated with a mortality risk reduction compared with persistent obesity. These findings support the importance of population-based approaches to preventing weight gain across the life course and a need for greater emphasis on treating obesity early in life.

Obesity-mortality link over the life course: the contribution of population compositional changes

A key uncertainty in the obesity-mortality association continues to be how this association changes over the life course. Prior studies tend to rely on cross-sectional design with static weight status taken at the time of the survey. This study tracks a cohort of individuals and employs lifelong body mass index information from the Framingham Heart Study original cohort (1948-2010). We focus on respondents who were younger than age 45 at time of their first survey (n = 2,176) and evaluate how the mortality risk associated with obesity changes over three age groups (below 45, 45-59, and 60 and above) and how population compositions may contribute to this pattern. We find the hazard ratio associated with obesity compared to normal weight decreases over three age groups, but this pattern is influenced by different ages of onset of obesity, inconsistency in the reference group (normal weight) over ages, and mortality selection effects. These factors explain away the decreasing effect of obesity (with onset before age 45) on mortality up to age 60; after age 60, the detrimental effect still declines, but to a much less degree. Later onset of obesity, however, is not significantly associated with excess mortality risks after age 60.

Life-course trajectories of body mass index and subsequent cardiovascular risk among Chinese population

BACKGROUND

Examining body mass index (BMI) change over life course is crucial for cardiovascular health promotion and prevention. So far, there is very few evidence on the long-term change of BMI from childhood to late life. This study aimed to examine the life-course trajectory patterns of BMI and then to link the trajectory patterns to cardiovascular risk factors in adulthood.

METHODS

Based on longitudinal data from the China Health and Nutrition Survey, 5276 participants (aged 6-60) at baseline (in 1989) with up to 7 measurements of BMI during 1989-2009 were selected in this study. Cardiovascular risk factors including high blood pressure, high blood glucose and high blood lipids were assessed in 2411 participants in 2009. Latent growth curve modelling was used to analyse the BMI trajectories, and logistic regression was used to examine the associations between trajectory patterns and cardiovascular risk factors.

RESULTS

Four trajectories patterns of BMI over life course (age 6-80) were identified: Normal-Stable (22.4% of the total participants), Low normal-Normal-Stable (44.1%), Low normal-Normal-Overweight (27.2%), and Overweight-Obese (4.3%). Compared to those with Normal-Stable pattern, those with Low normal-Normal-Stable pattern, Low normal-Normal-Overweight pattern and Overweight-Obese pattern had higher risk of high blood pressure (odds ratio range = 1.6-6.6), high blood glucose (1.7-9.1), dyslipidemia (2.6-5.9) and having at least two of the three cardiovascular risk factors (3.9-30.9).

CONCLUSIONS

Having a stable BMI within normal range over life course is associated with the lowest cardiovascular risk, whereas remaining overweight and obese over life course is associated with the highest cardiovascular risk.

Prediction of adult class II/III obesity from childhood BMI: the i3C consortium

Background and Objectives:

Adult class II/III obesity (BMI ≥ 35 kg/m²) has significant adverse health outcomes. Early prevention and treatment are critical, but prospective childhood risk estimates are lacking. This study aimed to define the prospective risk of adult class II/III obesity, using childhood BMI.

Methods:

Children ages 3–19 years enrolled in cohorts of The International Childhood Cardiovascular Cohort (i3C) Consortium with measured BMI assessments in childhood and adulthood were included. Prospective risk of adult class II/III obesity was modeled based on childhood age, sex, race and BMI.

Results:

12 142 individuals (44% male, 85% white) were assessed at median age 14 [Interquartile range, IQR: 11, 16] and 33 [28, 39] years. Class II/III adult obesity developed in 6% of children with normal weight; 29% of children with overweight; 56% of children with obesity; and 80% of children with severe obesity. However, 38% of the 1 440 adults with class II/III obesity (553/1440) were normal weight as children. Prospective risk of adult class II/III obesity varied by age, sex and race within childhood weight status classifications, and is notably higher for girls, black participants, and those in the United States. The risk of class II/III obesity increased with older adult age.

Conclusions:

Children with obesity or severe obesity have a substantial risk of adult class II/III obesity, and observed prospective risk estimates are now presented by age, sex, race and childhood BMI. Clinical monitoring of children’s BMI for adult class II/III obesity risk may be especially important for females and black Americans.

This study developed prospective risk estimates of adult class II/III obesity using childhood BMI, childhood age, sex and race, using longitudinal international data.

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

OBJECTIVE

Limited research has assessed the association between patterns of body mass index (BMI) change across adulthood and mortality. We aimed to identify groups of individuals who followed specific group-based BMI trajectories across adulthood, using weight collected on three occasions and recalled data from early adulthood, and to examine associations with all-cause and cause-specific mortality.

DESIGN

Prospective cohort study.

SETTING

Melbourne, Australia.

PARTICIPANTS

Adults (n=29 881) enrolled in the Melbourne Collaborative Cohort Study, who were aged from 40 to 70 years between 1990 and 1994, and had BMI data for at least three time points.

OUTCOME

Deaths from any cause before 31 March 2017 and deaths from obesity-related cancers, cardiovascular diseases (CVDs) and other causes before 31 December 2013.

RESULTS

We identified six group-based BMI trajectories: lower-normal stable (TR1), higher-normal stable (TR2), normal to overweight (TR3), chronic borderline obesity (TR4), normal to class I obesity (TR5) and overweight to class II obesity (TR6). Generally, compared with maintaining lower-normal BMI throughout adulthood, the lowest mortality was experienced by participants who maintained higher-normal BMI (HR 0.90; 95% CI 0.84 to 0.97); obesity during midlife was associated with higher all-cause mortality even when BMI was normal in early adulthood (HR 1.09; 95% CI 0.98 to 1.21) and prolonged borderline obesity from early adulthood was also associated with elevated mortality (HR 1.16; 95% CI 1.01 to 1.33). These associations were stronger for never-smokers and for death due to obesity-related cancers. Being overweight in early adulthood and becoming class II obese was associated with higher CVD mortality relative to maintaining lower-normal BMI (HR 2.27; 95% CI 1.34 to 3.87).

CONCLUSION

Our findings highlight the importance of weight management throughout adulthood to reduce mortality.

Long-term Body Weight Gain After Maturity is Associated With the Incidence of Chronic Kidney Disease (CKD), Independent of Current Body Weight, in Middle-aged and Older Men

BACKGROUND

This study investigated the relationship between long-term body weight gain after maturity and the incidence of chronic kidney disease (CKD).

METHODS

The participants were 303 men without a history of cardiovascular and cerebrovascular diseases, kidney dysfunction, or dialysis treatment. Their body weight gain after maturity was examined using a standardized self-administered questionnaire. The participants were divided into two groups based on the presence/absence of a body weight gain of ≥10 kg since 20 years of age.

RESULTS

After a 6-year follow-up, the cumulative incidence of CKD was significantly higher in participants with a body weight gain of ≥10 kg than in participants without body weight a body weight gain of ≥10 kg since 20 years of age (log-rank test: P = 0.041). After adjusting for the age, body mass index, estimated glomerular filtration rate levels, smoking and drinking habits, and the presence of hypertension, dyslipidemia, and hyperglycemia at baseline, the normal body weight participants with a body weight gain of ≥10 kg since 20 years of age was significantly related to the incidence of CKD (hazard ratio 2.47; 95% confidence of interval, 1.02-6.01, P = 0.045).

CONCLUSIONS

These results suggest that long-term body weight gain after maturity in normal body weight participants may be associated with the incidence of CKD, independent of current body weight.

Genistein increases the thermogenic program of subcutaneous WAT and increases energy expenditure in mice

White adipose tissue (WAT) can differentiate into beige adipose tissue by the browning process. Some polyphenols, including isoflavones, particularly genistein, are suggested to increase the expression of browning markers. There is evidence that consumption of genistein can attenuate body weight gain and improve glucose tolerance and blood lipid levels. The aim of the present study was to investigate the potential mechanisms of stimulation by which genistein activates the browning of WAT. We studied the stimulation of the expression of browning markers in the following models: mice fed genistein; preadipocytes from 3 T3-L1 cells; and the stromal vascular fraction (SVF) from the inguinal adipose tissue of mice. The results indicated that genistein can stimulate the browning process by at least two mechanisms. An indirect mechanism was involved in the induction of PGC-1α/FNDC5 in skeletal muscle leading to an increase in the myokine irisin. In preadipocytes, irisin was able to increase the expression of Ucp1 and Tmem26, markers of browning, to increase energy expenditure. Interestingly, genistein was also able to activate browning by a direct mechanism. Incubation of preadipocytes with genistein increased UCP1 expression as well as some biomarkers of browning in a concentration-dependent manner, possibly via phosphorylation of AMPK. The effect of genistein was accompanied by an increase in the number of mitochondria as well as in the maximum respiration rate of the adipocytes. In conclusion, this study indicated that genistein can increase energy expenditure by stimulating the browning process directly in preadipocytes and indirectly by increasing the circulating levels of irisin.

Cohort trends in duration of obesity in the United States, 1925-89: Estimates from cross-sectional data

This paper introduces the metric 'mean duration of obesity' to measure the average number of years lived with obesity in a population. A procedure was developed to estimate duration from periodic cross-sectional surveys. For annual cohorts born in the United States between 1925 and 1989, I estimated a logit model to derive age-cohort-specific probabilities of overweight and obesity (body mass index 25 to <30 and [Formula: see text]30, respectively), and applied life table techniques to convert these into person-years. Duration of obesity by age 50 increased fourfold from 3.58 to 14.35 years. The rate of increase was stronger across the 1945-79 and 1980-89 cohorts than the 1925-44 cohorts. The trend was driven by increased risks of obesity among children: age groups under 20 were responsible for 31 per cent of the duration increase between the 1930 and 1960 cohorts, but 72 per cent between the 1960 and 1985 cohorts.

Recovery Responses to Maximal Exercise in Healthy-Weight Children and Children With Obesity

PURPOSE

The purpose of this study was to examine differences in heart rate recovery (HRRec) and oxygen consumption recovery (VO₂ recovery) between young healthy-weight children and children with obesity following a maximal volitional graded exercise test (GXTmax).

METHOD

Twenty healthy-weight children and 13 children with obesity completed body composition testing and performed a GXTmax. Immediately after the GXTmax, HRRec and VO₂ recovery were measured each minute for 5 consecutive minutes.

RESULTS

There were no statistically significant group differences in HRRec for the 5 min following maximal exercise, Wilks's Lambda = .885, F(4, 28) = 0.911, p = .471, between the healthy-weight children and children with obesity despite statistically significant differences in body fat percentage (BF%; healthy-weight children, 18.5 ± 6.1%; children with obesity, 41.1 ± 6.9%, p < .001) and aerobic capacity relative to body mass (VO₂ peak; healthy-weight children, 46.8 ± 8.2 mL/kg/min; children with obesity, 31.9 ± 4.7 mL/kg/min, p < .001). There were statistically significant differences in VO₂ recovery for the 5 min following exercise, Wilks's Lambda = .676, F(4, 26) = 3.117, p = .032. There were no statistically significant correlations between HRRec and body mass index (BMI), BF%, VO₂peak, or physical activity.

CONCLUSIONS

In a healthy pediatric population, obesity alone does not seem to significantly impact HRRec, and because HRRec was not related to obesity status, BMI, or BF%, it should not be used as the sole indicator of aerobic capacity or health status in children. Using more than one recovery variable (i.e., HRRec and VO₂ recovery) may provide greater insight into cardiorespiratory fitness in this population.

Targeting self-regulation to promote health behaviors in children

Poor self-regulation (i.e., inability to harness cognitive, emotional, motivational resources to achieve goals) is hypothesized to contribute to unhealthy behaviors across the lifespan. Enhancing early self-regulation may increase positive health outcomes. Obesity is a major public health concern with early-emerging precursors related to self-regulation; it is therefore a good model for understanding self-regulation and health behavior. Preadolescence is a transition when children increase autonomy in health behaviors (e.g., eating, exercise habits), many of which involve self-regulation. This paper presents the scientific rationale for examining self-regulation mechanisms that are hypothesized to relate to health behaviors, specifically obesogenic eating, that have not been examined in children. We describe novel intervention protocols designed to enhance self-regulation skills, specifically executive functioning, emotion regulation, future-oriented thinking, and approach bias. Interventions are delivered via home visits. Assays of self-regulation and obesogenic eating behaviors using behavioral tasks and self-reports are implemented and evaluated to determine feasibility and psychometrics and to test intervention effects. Participants are low-income 9-12 year-old children who have been phenotyped for self-regulation, stress, eating behavior and adiposity through early childhood. Study goals are to examine intervention effects on self-regulation and whether change in self-regulation improves obesogenic eating.

Low Birth Weight, Cumulative Obesity Dose, and the Risk of Incident Type 2 Diabetes

BACKGROUND

Obesity history may provide a better understanding of the contribution of obesity to T2DM risk.

METHODS

17,634 participants from the 1958 National Child Development Study were followed from birth to 50 years. Cumulative obesity dose, a measure of obesity history, was calculated by subtracting the upper cut-off of the normal BMI from the actual BMI at each follow-up and summing the areas under the obesity dose curve. Hazard ratios (HRs) for diabetes were calculated using Cox regression analysis. Three separate models compared the predictive ability of cumulative obesity dose on diabetes risk with the time-varying BMI and last BMI.

RESULTS

In final models, 341 of 15,043 (2.27%) participants developed diabetes; male sex and low birth weight were significant confounding variables. Adjusted HRs were 1.080 (95% CI: 1.071, 1.088) per 10-unit cumulative obesity dose, 1.098 (95% CI: 1.080, 1.117) per unit of the time-varying BMI, and 1.146 (95% CI: 1.084, 1.212) per unit of the last BMI. Cumulative obesity dose provided the best predictive ability for diabetes.

CONCLUSIONS

Cumulative obesity dose is an improved method for evaluating the impact of obesity history on diabetes risk. The link between low birth weight and T2DM is strengthened by adjusting for cumulative obesity dose.

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.

Evidence for Association between SH2B1 Gene Variants and Glycated Hemoglobin in Nondiabetic European American Young Adults: The Add Health Study

Glycated hemoglobin (HbA1c) is used to classify glycaemia and type 2 diabetes (T2D). Body mass index (BMI) is a predictor of HbA1c levels and T2D. We tested 43 established BMI and obesity loci for association with HbA1c in a nationally representative multiethnic sample of young adults from the National Longitudinal Study of Adolescent to Adult Health [Add Health: age 24-34 years; n = 5641 European Americans (EA); 1740 African Americans (AA); 1444 Hispanic Americans (HA)] without T2D, using two levels of covariate adjustment (Model 1: age, sex, smoking, and geographic region; Model 2: Model 1 covariates plus BMI). Bonferroni adjustment was made for 43 SNPs and we considered P < 0.0011 statistically significant. Means (SD) for HbA1c were 5.4% (0.3) in EA, 5.7% (0.4) in AA, and 5.5% (0.3) in HA. We observed significant evidence for association with HbA1c for two variants near SH2B1 in EA (rs4788102, P = 2.2 × 10(-4) ; rs7359397, P = 9.8 × 10(-4) ) for Model 1. Both results were attenuated after adjustment for BMI (rs4788102, P = 1.7 × 10(-3) ; rs7359397, P = 4.6 × 10(-3) ). No variant reached Bonferroni-corrected significance in AA or HA. These results suggest that SH2B1 polymorphisms are associated with HbA1c, largely independent of BMI, in EA young adults.

Unstable bodyweight and incident type 2 diabetes mellitus: A meta-analysis

AIMS/INTRODUCTION

The present meta-analysis aimed to clarify the association of unstable bodyweight with the risk of type 2 diabetes mellitus, an association that has been controversial among longitudinal studies.

MATERIALS AND METHODS

An electronic literature search using EMBASE and MEDLINE was followed up to 31 August 2016. The relative risks (RRs) of type 2 diabetes mellitus in individuals with unstable bodyweight were pooled using the inverse variance method.

RESULTS

Eight studies were eligible for the meta-analysis. The median duration of measurements of weight change and follow-up years for ascertaining type 2 diabetes mellitus were 13.5 and 9.4 years, respectively. The pooled RR for the least vs most stable category was 1.33 (95% confidence interval 1.12-1.57). Between-study heterogeneity was statistically significant (P = 0.048). Whether type 2 diabetes mellitus was ascertained by blood testing explained 66.0% of the variance in the logarithm of RR (P = 0.02). In three studies in which blood testing was carried out, type 2 diabetes mellitus risk was not significant (RR 1.06, 95% confidence interval 0.91-1.25). Furthermore, publication bias that inflated type 2 diabetes mellitus risk was statistically detected by Egger's test (P = 0.09).

CONCLUSIONS

Unstable bodyweight might be modestly associated with the elevated risk of type 2 diabetes mellitus; although serious biases, such as diagnostic suspicion bias and publication bias, made it difficult to assess this association.

Determinants of Health-Related Quality of Life Among Older American Indians and Alaska Natives

During the past decade, health-related quality of life (HRQoL) has been recognized in both clinical and community health research as an important health outcome and a needed supplement to conventional health outcomes. The authors provide a profile of HRQoL and examine its determinants among American Indians and Alaska Natives aged 50 or older. Multivariate analyses of cross-sectional survey data from the 1996-1998 Centers for Disease Control Behavioral Risk Factor Surveillance System were conducted. Thirty-four percent of the sample reported fair or poor self-rated health. The mean number of poor health days in the past month ranged from 4 to 6 on different measures. Age, sex, education, annual household income, employment status, hypertension, and obesity were associated with aspects of HRQoL. Further research aimed at eliminating health disparities among this population should focus on identifying additional indicators of poor HRQoL and on understanding variables that mediate the relationship between disease and HRQoL.

Diabetes incidence and projections from prevalence surveys in Fiji

Background

Type 2 diabetes mellitus (T2DM) incidence is traditionally derived from cohort studies that are not always feasible, representative, or available. The present study estimates T2DM incidence in Fijian adults from T2DM prevalence estimates assembled from surveys of 25–64 year old adults conducted over 30 years (n = 14,288).

Methods

T2DM prevalence by five-year age group from five population-based risk factor surveys conducted over 1980–2011 were variously adjusted for urban-rural residency, ethnicity, and sex to previous censuses (1976, 1986, 1996, 2009) to improve representativeness. Prevalence estimates were then used to calculate T2DM incidence based on birth cohorts from the age-period (Lexis) matrix following the Styblo technique, first used to estimate annual risk of tuberculosis infection (incidence) from sequential Mantoux population surveys. Poisson regression of year, age, sex, and ethnicity strata (n = 160) was used to develop projections of T2DM prevalence and incidence to 2020 based on various scenarios of population weight measured by body mass index (BMI) change.

Results

T2DM prevalence and annual incidence increased in Fiji over 1980–2011. Prevalence was higher in Indians and men than i-Taukei and women. Incidence was higher in Indians and women. From regression analyses, absolute reductions of 2.6 to 5.1% in T2DM prevalence (13–26% lower), and 0.5–0.9 per 1000 person-years in incidence (8–14% lower), could be expected in 2020 in adults if mean population weight could be reduced by 1–4 kg, compared to the current period trend in weight gain.

Conclusions

This is the first application of the Styblo technique to calculate T2DM incidence from population-based prevalence surveys over time. Reductions in population BMI are predicted to reduce T2DM incidence and prevalence in Fiji among adults aged 25–64 years.

Electronic supplementary material

The online version of this article (doi:10.1186/s12963-016-0114-0) contains supplementary material, which is available to authorized users.

The Evidence Is In: Lifestyle Interventions Can Prevent Diabetes

Early epidemiological and clinical trials suggested that type 2 diabetes could be prevented or delayed by lifestyle modifications. The Finnish Diabetes Prevention Study and the Diabetes Prevention Programs provided conclusive evidence that type 2 diabetes could be prevented or delayed with modest lifestyle changes—5% to 7% loss of body weight and 150 min/week of physical activity. Both used intensive intervention strategies and continued support and follow-up to achieve study goals. Other smaller studies made similar observations. Various medications—metformin, acarbose, troglitazone and pioglitazone, orlistat, and rosiglitazone—and bariatric surgery have also been effective for the prevention or delay of diabetes. Nutrient factors studied include the contribution of a high dietary fat intake, especially saturated fat, to the development of diabetes and increased intake of fiber, whole grains, and alcohol to decreased risk. A review of the evidence led the American Diabetes Association to conclude that lifestyle interventions should be the first choice for prevention or delay of diabetes and that drug therapy should not be a substitute for lifestyle interventions—healthy and appropriate food choices and physical activity.

Cumulative Exposure to Ideal Cardiovascular Health and Incident Diabetes in a Chinese Population: The Kailuan Study

Background

It is unclear whether ideal cardiovascular health (CVH), and particularly cumulative exposure to ideal CVH (cumCVH), is associated with incident diabetes. We aimed to fill this research gap.

Methods and Results

The Kailuan Study is a prospective cohort of 101 510 adults aged 18 to 98 years recruited in 2006–2007 and who were subsequently followed up at 2‐ (Exam 2), 4‐ (Exam 3), and 6 (Exam 4)‐year intervals after baseline. The main analysis is restricted to those individuals with complete follow‐up at all 4 examinations and who had no history of diabetes until Exam 3. Cumulative exposure to ideal CVH (cumCVH) was calculated as the summed CVH score for each examination multiplied by the time between the 2 examinations (score×year). Logistic regression models were used to assess the association between cumCVH and incident diabetes. In fully adjusted models, compared with the lowest quintile of cumCVH, individuals in the highest quintile had ~68% (95% confidence interval [CI] 60‐75) lower risk for incident diabetes (compared with 61% [95% CI 52‐69] lower risk when using baseline CVH). Every additional year lived with a 1‐unit increase in ideal CVH was associated with a 24% (95% CI 21‐28) reduction in incident diabetes.

Conclusions

Ideal CVH is associated with a reduced incidence of diabetes, but the association is likely to be underestimated if baseline measures of CVH exposure are used. Measures of cumulative exposure to ideal CVH are more likely to reflect lifetime risk of diabetes and possibly other health outcomes.

Clinical Trial Registration

URL: https://www.chictr.org. Unique identifier: ChiCTRTNC‐11001489.

Longitudinal Trends in the Prevalence of Diabetes Mellitus in an Urban Emergency Department

OBJECTIVE

The objective of this study was to examine the longitudinal trends in diabetes mellitus (DM) in emergency department (ED) patients and evaluate the factors associated with those trends.

METHODS

We conducted a retrospective analysis of all patients who presented to the ED from 2006 to 2011. The presence of DM, height, and weight were recorded prospectively. The study was conducted in the ED of an urban, academic hospital with an average yearly volume of approximately 62,000 patients. Inclusion criteria were age 16 years and older; presentation to the ED for any reason; and documentation of height, weight, and history of DM. Data were analyzed in 1-year blocks, then examined for trends using linear regression analysis. Data also were examined by obesity class: normal (body mass index [BMI] 20-24.9 kg/m(2)), overweight (BMI 25-29.9 kg/m(2)), obese (BMI 30-39.9 kg/m(2)), and extreme obesity (BMI >40 kg/m(2)).

RESULTS

There was a statistically significant increase in the prevalence of type 2 DM during the study period. The percentage of type 2 DM for all patient visits increased progressively from 10.7% to 16.1% (r(2) 0.97). Progressive increases in yearly type 2 DM prevalence were observed for all BMI classes. The rate of change in the increase of DM was related directly to the degree of obesity. For the normal weight category, the percentage of patients with DM increased 0.5%/year (r(2) 0.92), overweight 0.7%/year (r(2) 0.88), obesity 1.0%/year (r(2) 0.90), and extreme obesity 1.4%/year (r(2) 0.94). Patient age increased slightly for all obesity groups, accounting for a 0.2% to 0.4%/year increase in the prevalence of DM in the population.

CONCLUSIONS

In this longitudinal analysis, we found an increase in the prevalence of patients with DM and an increase in ED visits by patients with DM. Our results indicate that these increases are influenced most significantly by the obesity level of the patient.

CB1 receptor blockade counters age-induced insulin resistance and metabolic dysfunction

The endocannabinoid system can modulate energy homeostasis by regulating feeding behaviour as well as peripheral energy storage and utilization. Importantly, many of its metabolic actions are mediated through the cannabinoid type 1 receptor (CB1R), whose hyperactivation is associated with obesity and impaired metabolic function. Herein, we explored the effects of administering rimonabant, a selective CB1R inverse agonist, upon key metabolic parameters in young (4 month old) and aged (17 month old) adult male C57BL/6 mice. Daily treatment with rimonabant for 14 days transiently reduced food intake in young and aged mice; however, the anorectic response was more profound in aged animals, coinciding with a substantive loss in body fat mass. Notably, reduced insulin sensitivity in aged skeletal muscle and liver concurred with increased CB1R mRNA abundance. Strikingly, rimonabant was shown to improve glucose tolerance and enhance skeletal muscle and liver insulin sensitivity in aged, but not young, adult mice. Moreover, rimonabant‐mediated insulin sensitization in aged adipose tissue coincided with amelioration of low‐grade inflammation and repressed lipogenic gene expression. Collectively, our findings indicate a key role for CB1R in aging‐related insulin resistance and metabolic dysfunction and highlight CB1R blockade as a potential strategy for combating metabolic disorders associated with aging.

Duration and Degree of Weight Gain and Incident Diabetes in Younger Versus Middle-Aged Black and White Adults: ARIC, CARDIA, and the Framingham Heart Study

OBJECTIVE

To determine whether duration and degree of weight gain are differentially associated with diabetes risk in younger versus middle-aged black and white adults.

RESEARCH DESIGN AND METHODS

We combined data from three cohort studies: Atherosclerosis Risk in Communities (ARIC), Coronary Artery Risk Development in Young Adults (CARDIA), and the Framingham Heart Study. A total of 17,404 participants (56% women; 21% black) were stratified by baseline age (younger: ≥30 and <45 years; middle-aged: ≥45 and <60 years) and examined for incident diabetes (median follow-up 9 years). Duration and degree of gain in BMI were calculated as "BMI-years" above one's baseline BMI.

RESULTS

Diabetes incidence per 1,000 person-years in the younger and middle-aged groups was 7.2 (95% CI 5.7, 8.7) and 24.4 (22.0, 26.8) in blacks, respectively, and 3.4 (2.8, 4.0) and 10.5 (9.9, 11.2) in whites, respectively. After adjusting for sex, baseline BMI and other cardiometabolic factors, and age and race interaction terms, gains in BMI-years were associated with higher risk of diabetes in the younger compared with middle-aged groups: hazard ratios for 1-unit increase in log BMI-years in younger versus middle-aged blacks were 1.18 (P = 0.02) and 1.02 (P = 0.39), respectively (P for interaction by age-group = 0.047), and in whites were 1.35 (P < 0.001) and 1.11 (P < 0.001), respectively (P for interaction by age-group = 0.008).

CONCLUSIONS

Although middle-aged adults have higher rates of diabetes, younger adults are at greater relative risk of developing diabetes for a given level of duration and degree of weight gain.

The effect of differing patterns of childhood body mass index gain on adult physiology in American Indians

OBJECTIVE

Identifying groups of individuals with similar patterns of body mass index (BMI) change during childhood may increase understanding of the relationship between childhood BMI and adult health.

METHODS

Discrete classes of BMI z-score change were determined in 1,920 American Indian children with at least four non diabetic health examinations between the ages of 2 and 18 years using latent class trajectory analysis. In subsets of subjects, data were available for melanocortin-4 receptor (MC4R) sequencing; in utero exposure to type 2 diabetes (T2D); or, as adults, oral glucose tolerance tests, onset of T2D, or body composition.

RESULTS

Six separate groups were identified. Individuals with a more modern birth year, an MC4R mutation, or in utero exposure to T2D were clustered in the two groups with high increasing and chronic overweight z-scores (P < 0.0001). The z-score classes predicted adult percent fat (P < 0.0001, partial r(2)  = 0.18 adjusted for covariates). There was a greater risk for T2D, independent from adult BMI, in three classes (lean increasing to overweight, high increasing, and chronic overweight z-scores) compared to the two leanest groups (respectively: HRR= 3.2, P = 0.01; 6.0, P = 0.0003; 11.6, P < 0.0001).

CONCLUSIONS

Distinct patterns of childhood BMI z-score change associate with adult adiposity and may impact risk of T2D.

Effect of maternal age at childbirth on insulin resistance: the 2010 Korean National Health and Nutrition Examination Survey

OBJECTIVE

This study aimed to assess insulin resistance according to maternal age at childbirth.

PATIENTS AND METHODS

The data used in this study were obtained from the 2010 Korean National Health and Nutrition Examination Survey. This study included a total of 2233 nondiabetic female subjects ≥30 years of age that were subdivided into groups according to their obesity and abdominal obesity (AOB) statuses. The homoeostasis model assessment of insulin resistance (HOMA-IR) was used to quantify the insulin resistance according to age at first childbirth and last childbirth.

RESULTS

Age at first childbirth showed a negative relationship with HOMA-IR in both the nonobese and non-AOB groups, while age at last childbirth showed a positive relationship with HOMA-IR in both the nonobese and non-AOB groups. A multivariate logistic regression analysis revealed that ages at first and last childbirth were significantly associated with the highest HOMA-IR quartile. The odds ratio was 0·9 (95% confidence interval: 0·82-0·98) for age at first childbirth, and 1·07 (95% confidence interval: 1·01-1·14) for age at last childbirth in the nonobese and non-AOB groups.

CONCLUSION

In conclusion, this study suggests that insulin resistance is increased in females who experienced their first childbirth at a younger age or their last childbirth at a later age, particularly in nonobese individuals. Because these data suggest that childbearing age could be an independent risk factor for diabetes, a high-quality prospective study assessing the relationship between childbearing age and insulin resistance should be performed.

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.

Trajectory of body mass index before the development of type 2 diabetes in Japanese men: Toranomon Hospital Health Management Center Study 15

Aims/Introduction

We aimed to investigate the long-term trajectory of general adiposity assessed by the body mass index (BMI) before the onset of type 2 diabetes in Japanese individuals.

Materials and Methods

We retrospectively examined data on 1,553 Japanese men without diabetes. Mean BMI and incident cases of diabetes (diabetes indicated by fasting glucose concentrations ≥7.0 mmol/L, a self-reported history of clinician-diagnosed diabetes, or glycated hemoglobin ≥6.5% (≥48 mmol/mol) were assessed on an annual basis over a 10-year period after the baseline examination.

Results

Mean (standard deviation) BMI at the time of diagnosis was 24.4 kg/m² (3.1 kg/m²) among cases of diabetes (n = 191). An increasingly high BMI was associated with the early stage of the disease development, such as an 8- to 10-year prediagnosis period; individuals who developed diabetes experienced a prolonged and stable elevated BMI of ≥24.4 kg/m² over the 8 years before the diagnosis of diabetes. The mean BMI among the non-cases of diabetes did not exceed 23.2 kg/m² throughout the period.

Conclusions

These results suggested that Japanese men who eventually developed diabetes during the 10-year observation period were not characterized as obese, but had stable high-normal BMIs before the onset of diabetes. Previous evidence showed that values for glycemic markers rapidly increased before the development of diabetes; however, the present study showed a slight gain in BMI in the earlier stage of the natural history of diabetes followed by a prolonged period of overweight.

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.

Quantitative relationship between body weight gain in adulthood and incident type 2 diabetes: a meta-analysis

This meta-analysis quantified the risk of type 2 diabetes mellitus (T2DM) preceded by body weight (BW) gain in the general population. Systematic literature searches retrieved 15 eligible studies. The BW gain was divided into early weight-gain, which was defined as BW gain from early adulthood (18-24 years of age) to cohort entry (≥25 years of age), and late weight-gain, which was defined as BW gain from cohort entry. The pooled relative risk (RR; 95% confidence interval [CI]) of T2DM for an increment of BW gain standardized into a 5-kg m(-2) increment in the body mass index (BMI) was 3.07 (2.49-2.79) for early weight-gain and 2.12 (1.74-2.58) for late weight-gain. When limiting analysis to studies that concurrently examined T2DM risk for current BMI (defined in both groups as BMI at cohort entry), a larger magnitude of T2DM risk was revealed for early weight-gain compared with current BMI (RR [95% CI], 3.38 [2.20-5.18] vs. 2.39 [1.58-3.62]), while there was little difference between late weight-gain (RR [95% CI], 2.21 [1.91-2.56]) and current BMI (RR [95% CI], 2.47 [1.97-3.30]). The meta-analysis suggested that BW gain was a quantifiable predictor of T2DM, as well as current obesity in adults. Particularly, BW gain in early rather than middle-to-late adulthood played an important role in developing T2DM.

Dietary risk factors for the development of insulin resistance in adolescent girls: a 3-year prospective study

OBJECTIVE

Identifying risk factors for insulin resistance in adolescence could provide valuable information for early prevention. The study sought to identify risk factors for changes in insulin resistance and fasting blood glucose levels.

DESIGN

Prospective cohort of girls participating in the National Heart, Lung, and Blood Institute Growth and Health Study.

SETTING USA SUBJECTS

Adolescent girls (n 774) assessed at the ages of 16-17 and 18-19 years. Over a 3-year period, measurements of fasting blood glucose and insulin and serum cotinine were taken, and dietary intake (3 d food diary), smoking status and physical activity levels were self-reported.

RESULTS

Improvements in homeostasis model assessment of insulin resistance (HOMA-IR) were associated with increases in the percentage of energy intake from polyunsaturated fats (β = -3·33, 95% CI -6·28, -0·39, P = 0·03) and grams of soluble fibre (β = -5·20, 95% CI -9·81, -0·59, P = 0·03) between the ages of 16-17 and 18-19 years; with similar findings for insulin. Transitioning into obesity was associated with an increase in insulin (β = 6·34, 95% CI 2·78, 9·91, P < 0·001) and HOMA-IR (β = 28·77, 95% CI 8·13, 49·40, P = 0·006). Serum cotinine concentrations at 16-17 years, indicating exposure to tobacco, were associated with large increases (β = 15·43, 95% CI 6·09, 24·77, P < 0·001) in fasting blood glucose concentrations.

CONCLUSIONS

Increases in the percentage of energy from polyunsaturated fat and fibre, and avoidance of excess weight gain and tobacco exposure, could substantially reduce the risk of insulin resistance in late adolescence.

Impact of age at first childbirth on glucose tolerance status in postmenopausal women: the 2008-2011 Korean National Health and Nutrition Examination Survey

OBJECTIVE

The objective of the current study was to determine whether there was an association between age at first childbirth and glucose tolerance status in postmenopausal women.

RESEARCH DESIGN AND METHODS

This study was based on the data from the Korean National Health and Nutrition Examination Survey, conducted by the Korean Ministry of Health and Welfare from 2008-2011. Of 37,753 participants, data for 4,965 postmenopausal women were included in the analysis. Subjects were subdivided according to the age at first childbirth as follows: ≤19, 20-24, 25-29, and ≥30 years. Multivariate logistic regression analyses were used to identify whether there was an independent association between age at first childbirth and glucose tolerance status by adjusting for potential confounding factors.

RESULTS

The prevalence of impaired fasting glucose (IFG) and diabetes was 21.8% (1.066 of 4.965) and 15.3% (774 of 4,965), respectively. Diabetes prevalence differed significantly between the subgroups and was higher with earlier age at first childbirth: it was 10.9% in subjects aged ≥30 years and 23.8% in subjects aged ≤19 years at first childbirth. After fully adjusting for potential confounding factors, including lifestyle, sociodemographic factors, known diabetes risk factors, and reproductive factors, age at first childbirth ≤19 years was significantly associated with diabetes (odds ratio 1.492 [95% CI 1.005-2.215]). No significant associations were found between age at first childbirth and IFG.

CONCLUSIONS

Age at first childbirth influenced diabetes risk in postmenopausal women, and adolescent pregnancy was independently associated with a higher risk of diabetes in postmenopausal women.

Obesity persistence and duration dependence: evidence from a cohort of US adults (1985-2010)

This study investigates dynamic patterns of obesity persistence and identifies the determinants of obesity-spell exits and re-entries. We utilize longitudinal data from the NLSY79 covering the period 1985-2010. Non-parametric techniques are applied to investigate the relationship between exit from obesity and spell duration. Multivariate discrete hazard models are also estimated, taking into account duration dependence and observed and time-invariant unobserved heterogeneity. In all cases, the probability of exiting obesity is inversely related to the duration of the obesity spell. Without controlling for unobserved heterogeneity, the probability of exit after one wave in obesity is 31.5 per cent; it is reduced to 3.8 per cent after seven or more waves. When time-invariant unobserved heterogeneity is taken into account, the estimated probabilities are slightly larger and broadly similar (36.8 and 10.3, respectively), which suggests that the identified negative duration dependence is not primarily due to composition effects. The obtained results indicate that public health interventions targeting the newly obese may be particularly effective at reducing incidence of long durations of obesity.

The effect of obesity in adolescence on adult health status

OBJECTIVE

To test the hypothesis that adolescent obesity would be associated with greater risks of adverse health in severely obese adults.

METHODS

Before weight loss surgery, adult participants in the Longitudinal Assessment of Bariatric Surgery-2 underwent detailed anthropometric and comorbidity assessment. Weight status at age 18 was retrospectively determined. Participants who were ≥80% certain of recalled height and weight at age 18 (1502 of 2308) were included. Log binomial regression was used to evaluate whether weight status at age 18 was independently associated with risk of comorbid conditions at time of surgery controlling for potential confounders.

RESULTS

Median age and adult body mass index (BMI) were 47 years and 46, respectively. At age 18, 42% of subjects were healthy weight, 29% overweight, 16% class 1 obese, and 13% class ≥2 obese. Compared with healthy weight at age 18, class ≥2 obesity at age 18 independently increased the risk of lower-extremity venous edema with skin manifestations by 435% (P < .0001), severe walking limitation by 321% (P < .0001), abnormal kidney function by 302% (P < .0001), polycystic ovary syndrome by 74% (P = .03), asthma by 48% (P = .01), diabetes by 42% (P < .01), obstructive sleep apnea by 25% (P < .01), and hypertension (by varying degrees based on age and gender). Conversely, the associated risk of hyperlipidemia was reduced by 61% (P < .01).

CONCLUSIONS

Severe obesity at age 18 was independently associated with increased risk of several comorbid conditions in adults undergoing bariatric surgery.

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.

Modeling obesity histories in cohort analyses of health and mortality

There is great interest in understanding the role of weight dynamics over the life cycle in predicting the incidence of disease and death. Beginning with a Medline search, we identify, classify, and evaluate the major approaches that have been used to study these dynamics. We identify four types of models: additive models, duration-of-obesity models, additive-weight-change models, and interactive models. We develop a framework that integrates the major approaches and shows that they are often nested in one another, a property that facilitates statistical comparisons. Our criteria for evaluating models are two-fold: the model's interpretability and its ability to account for observed variation in health outcomes. We apply two sets of nested models to data on adults age 50-74 years at baseline in two national probability samples drawn from National Health and Nutrition Examination Survey. One set of models treats obesity as a dichotomous variable and the other treats it as a continuous variable. In three of four applications, a fully interactive model does not add significant explanatory power to the simple additive model. In all four applications, little explanatory power is lost by simplifying the additive model to a duration model in which the coefficients of weight at different ages are set equal to one another. Other versions of a duration-of-obesity model also perform well, underscoring the importance of obesity at early adult ages for mortality at older ages.

Risk of type 2 diabetes and cumulative excess weight exposure in the Framingham Offspring Study

AIM

Mid-life obesity is associated with T2D risk. However, less is known about the cumulative effect of obesity during adulthood.

METHODS

Framingham Offspring Study participants who had an examination at 35±2 years and were initially free of T2D were included in this study (N=1026). A cumulative excess weight (CEW) score (year*kg/m²) was calculated until T2D diagnostic or the end of follow-up.

RESULTS

Eighty-four individuals (8.2%) developed T2D over 20±6 years. Mean CEW scores were 118.0±114.6 year*kg/m² in individuals who developed T2D and 30.2±91.4 year*kg/m² in those who did not develop T2D (P<0.01). T2D risk was doubled for each standard deviation increase in the CEW score (OR=1.99 [1.64-2.40]; P<0.001). However, CEW score was only significantly associated with T2D incidence for participants with a baseline BMI <25 kg/m² (OR =2.13 [1.36-3.36]; P<0.001).

CONCLUSIONS

Accumulating weight between the mid-thirties to the mid-fifties increases the risk of developing T2D. However, BMI in mid-thirties remains a stronger predictor of T2D risk.

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.

Comparison of BMI and physical activity between old order Amish children and non-Amish children

OBJECTIVE

The Old Order Amish (OOA) is a conservative Christian sect of European origin living in Pennsylvania. Diabetes is rare in adult OOA despite a mean BMI rivaling that in the general U.S. non-Hispanic white population. The current study examines childhood factors that may contribute to the low prevalence of diabetes in the OOA by comparing OOA children aged 8-19 years with National Health and Nutrition Examination Survey (NHANES) data and children from Maryland's Eastern Shore (ES), a nearby, non-Amish, rural community. We hypothesized that pediatric overweight is less common in OOA children, that physical activity (PA) and BMI are inversely correlated, and that OOA children are more physically active than ES children.

RESEARCH DESIGN AND METHODS

We obtained anthropometric data in 270 OOA children and 229 ES children (166 non-Hispanic white, 60 non-Hispanic black, 3 Hispanic). PA was measured by hip-worn accelerometers in all ES children and in 198 OOA children. Instrumentation in 43 OOA children was identical to ES children.

RESULTS

OOA children were approximately 3.3 times less likely than non-Hispanic white ES children and NHANES estimates to be overweight (BMI ≥85th percentile, Centers for Disease Control and Prevention). Time spent in moderate/vigorous PA (MVPA) was inversely correlated to BMI z-score (r = -0.24, P = 0.0006). PA levels did not differ by ethnicity within the ES group, but OOA children spent an additional 34 min/day in light activity (442 ± 56 vs. 408 ± 75, P = 0.005) and, impressively, an additional 53 min/day in MVPA (106 ± 54 vs. 53 ± 32, P < 0.0001) compared with ES children. In both groups, boys were more active than girls but OOA girls were easily more active than ES boys.

CONCLUSIONS

We confirmed all three hypotheses. Together with our previous data, the study implies that the OOA tend to gain their excess weight relatively late in life and that OOA children are very physically active, both of which may provide some long-term protection against diabetes.

Etiology of insulin resistance in youth with type 2 diabetes

Type 2 diabetes (T2DM), historically an adult disease, is now increasingly prevalent in obese youth. Poor diet and increased sedentary behavior contribute to the increasing rates of obesity in youth, yet not all obese children develop T2DM. In general, T2DM is characterized by both insulin resistance (IR) and pancreatic beta-cell insufficiency. In children, IR is related to elevated body mass index (BMI) and pubertal hormones, along with abnormal fat partitioning, elevated free fatty acids, inflammation, and/or mitochondrial dysfunction. Hyperglycemia and T2DM develop when the pancreas cannot match the increased insulin demands resulting from IR. Unique to youth, IR varies with stage of pubertal development, and some children may have resolution of hyperglycemia post-puberty once the IR of puberty resolves. Further understanding of IR, the progression to T2DM in youth, and later outcomes as adults will help direct future therapies and interventions for youth at risk.

Contribution of modifiable risk factors to social inequalities in type 2 diabetes: prospective Whitehall II cohort study

OBJECTIVE

To assess the contribution of modifiable risk factors to social inequalities in the incidence of type 2 diabetes when these factors are measured at study baseline or repeatedly over follow-up and when long term exposure is accounted for.

DESIGN

Prospective cohort study with risk factors (health behaviours (smoking, alcohol consumption, diet, and physical activity), body mass index, and biological risk markers (systolic blood pressure, triglycerides and high density lipoprotein cholesterol)) measured four times and diabetes status assessed seven times between 1991-93 and 2007-09.

SETTING

Civil service departments in London (Whitehall II study).

PARTICIPANTS

7237 adults without diabetes (mean age 49.4 years; 2196 women).

MAIN OUTCOME MEASURES

Incidence of type 2 diabetes and contribution of risk factors to its association with socioeconomic status.

RESULTS

Over a mean follow-up of 14.2 years, 818 incident cases of diabetes were identified. Participants in the lowest occupational category had a 1.86-fold (hazard ratio 1.86, 95% confidence interval 1.48 to 2.32) greater risk of developing diabetes relative to those in the highest occupational category. Health behaviours and body mass index explained 33% (-1% to 78%) of this socioeconomic differential when risk factors were assessed at study baseline (attenuation of hazard ratio from 1.86 to 1.51), 36% (22% to 66%) when they were assessed repeatedly over the follow-up (attenuated hazard ratio 1.48), and 45% (28% to 75%) when long term exposure over the follow-up was accounted for (attenuated hazard ratio 1.41). With additional adjustment for biological risk markers, a total of 53% (29% to 88%) of the socioeconomic differential was explained (attenuated hazard ratio 1.35, 1.05 to 1.72).

CONCLUSIONS

Modifiable risk factors such as health behaviours and obesity, when measured repeatedly over time, explain almost half of the social inequalities in incidence of type 2 diabetes. This is more than was seen in previous studies based on single measurement of risk factors.