Rates of weight change for black and white Americans over a twenty year period

Reported theory use in electronic health weight management interventions targeting young adults: a systematic review

This review assesses the extent of reported theory use in electronic health weight management interventions targeting young adults aged 18-35 years. Twenty-four eligible studies were identified. Two independent reviewers extracted data and coded for theory use using the Theory Coding Scheme. Overall, the mean total use of theory score was 6/23 (SD = 5; Min. = 0, Max. = 17); 17 studies were classified as having weak application of theory, five as moderate, and two as strong. The majority (N = 18) of studies mentioned theory, however, most (N = 14) did not report how intervention techniques related to theoretical base. No study used theory to select intervention recipients and only four used theory to tailor intervention techniques to recipients. Limited studies reported theory testing (N = 6) and no study used intervention results to build and/or refine theory. Results indicate that weight-related outcomes may be enhanced when at least one or more theoretical constructs are explicitly linked to an intervention technique and when theoretical constructs are included in evaluations. Increases in theory application and reporting are needed to assist the scientific research community in systematically identifying which theories work, for whom, how, why, and when; thereby delivering an advanced understanding of how best to apply theory to enhance intervention outcomes.

Adult weight gain accelerates the onset of breast cancer

PURPOSE

Weight gain in adulthood is a risk factor for breast cancer; however, the impact on age of onset is unknown. The objective of this study was to investigate whether weight gain from early- to mid-adulthood influenced the timing of breast cancer onset.

METHODS

Increase in body mass index (BMI) from lowest adult BMI to BMI at diagnosis and age at which these events occurred were calculated from breast cancer survivors enrolled in a weight loss trial (n = 660). Quartiles (Q) of the average increase in BMI were determined and associations between weight gain and age at disease onset were analyzed using analysis of covariance and spline regression models.

RESULTS

A significant linear trend was observed across the quartiles of BMI change for earlier age at diagnosis [Q1 52.3 (± 0.73), Q2 51.9 (± 0.70), Q3 49.6 (± 0.66), Q4 47.3 (± 0.67), p < 0.0001] after adjusting for potential confounders. In analyses that stratified by tumor subtype and menopausal status, significant linear trends continued to be observed for earlier age at diagnosis across quartiles of BMI for ER ± , PR ± , HER2 + , as well as pre- and postmenopausal status (p-values < 0.001).

CONCLUSIONS

Women who gain excess weight during adulthood are not only at risk for breast cancer, but also may experience earlier onset of disease and reduced cancer-free years.

Metabolic trajectories across early adolescence: differences by sex, weight, pubertal status and race/ethnicity

Background: Biomarkers of cardiovascular and metabolic risk track from adolescence into adulthood, therefore characterising the direction and magnitude of these changes is an important first step to identifying health trajectories that presage future disease risk.Aim: To characterise changes in metabolic biomarkers across early adolescence in a multi-ethnic cohort.Subjects and methods: Among 891 participants in Project Viva we estimated changes in insulin resistance (HOMA-IR), adipokines, lipids, and SBP between ages 6-10 years and 11-16 years. Next, we used multivariable linear regression to examine associations of sex, baseline overweight/obesity, baseline pubertal status and race/ethnicity with change in the biomarkers during follow-up.Results: Boys exhibited a larger decrement in adiponectin (-0.66 [95% CI = -1.14, -0.18)] ng/mL) and a greater increase in SBP (3.20 [2.10, 4.30] mmHg) than girls. Overweight/obese participants experienced larger increases in HOMA-IR, leptin, and triglycerides; and a steeper decrement in HDL. Pubertal youth showed larger decrements in total and LDL cholesterol than their pre-pubertal counterparts. In comparison to White participants, Black youth experienced a larger magnitude of increase in HOMA-IR, and Hispanic youth exhibited larger decrements in adiponectin and HDL.Conclusions: Change in metabolic biomarkers across early adolescence differed by sex, weight status, pubertal status and race/ethnicity. Some of the metabolic changes may reflect normal physiological changes of puberty, while others may presage future disease risk. Future studies are warranted to link metabolic changes during adolescence to long-term health.

Effects of aging, high-fat diet, and testosterone treatment on neural and metabolic outcomes in male brown Norway rats

Risk for Alzheimer's disease (AD) is affected by multiple factors, including aging, obesity, and low testosterone. We previously showed that obesity and low testosterone independently and interactively exacerbate AD-related outcomes in young adult rodents. The goals of the present study are two-fold: to examine whether the effects of an obesogenic diet differ with increasing age and to determine if testosterone treatment in middle-aged and aged animals mitigates negative effects of the diet. Male brown Norway rats were maintained on control or high-fat diets for 12 weeks beginning in young adulthood, middle age, or advanced age. Separate cohorts of middle-aged and aged animals were treated with testosterone during dietary manipulations. Endpoints included metabolic indices, inflammation, cognitive performance, and neural health outcomes. Aging was associated with poorer outcomes that were generally exacerbated by high-fat diet, especially at middle age. Testosterone treatment was largely without benefit, exerting only subtle effects on a select number of measures. Understanding how the deleterious effects of obesity are affected by advancing age and the ability of protective strategies such as testosterone to reduce these effects may provide significant insight into both the development and prevention of age-related cognitive decline and AD.

Dissemination of the Look AHEAD Intensive Lifestyle Intervention in the United States Military: A Randomized Controlled Trial

OBJECTIVE

The purpose of this study, "Fit Blue," was to compare a translation of the Look AHEAD (Action for Heath in Diabetes) intensive lifestyle intervention with a self-paced version of the same intervention among active duty military personnel.

METHODS

Active duty military personnel (N = 248; 49% male, 34% racial minority) with overweight or obesity were randomized to 12-month distance-based (i.e., phone and email) parallel programs, counselor-initiated (CI) condition or self-paced (SP) condition, from 2014 to 2016. Trained lay interventionists were retired military personnel or had extensive familiarity with the military.

RESULTS

The CI condition had greater weight loss at 4 months (CI: mean ± SD = -3.2 ± 3.4 kg; SP: -0.6 ± 2.9 kg; P < 0.0001) and at 12 months (CI: mean ± SD = -1.9 ± 4.1 kg; SP: -0.1 ± 3.8 kg; P < 0.001). Participants in the CI condition also had a greater percent weight loss at both 4 months (CI: 3.5% ± 3.8, SP: 0.6% ± 3.1; P < 0.0001) and 12 months (CI: 2.1% ± 4.7, SP: 0.0% ± 4.0; P < 0.001). In addition, a greater proportion of CI participants lost 5% or more at 4 months (CI: 29.8%, SP: 10.5%; P < 0.001) and at 12 months (CI: 29.5%, SP: 15.6%; P < 0.05).

CONCLUSIONS

The CI behavioral weight loss intervention translated from Look AHEAD was well received and is a promising approach for managing weight in an active duty military population.

Metabolic Effects of Preexposure Prophylaxis With Coformulated Tenofovir Disoproxil Fumarate and Emtricitabine

Background

Antiretroviral drugs have been associated with changes in lipids, fat mass and dat distribution. Tenofovir disoproxil fumarate (TDF) has been shown to have a more favorable metabolic profile than other drugs in its class. However, the metabolic effects of TDF in preexposure prophylaxis (PrEP) are unknown.

Methods

We evaluated the effects of TDF/emtricitabine (FTC) on lipids and body composition in a blinded, placebo-controlled PrEP trial. Participants enrolled in a metabolic subcohort (N = 251, TDF/FTC; N = 247, placebo) consented to fasting lipid panels, dual-energy X-ray absorptiometry scans for body composition, and pharmacologic testing of drug metabolites at baseline and every 24 weeks thereafter.

Results

Lean body mass was stable and unaffected by TDF/FTC. Body weight increased in both groups but was lower on TDF/FTC through week 72. This difference was explained by lower fat accumulation on TDF/FTC. The net median percent difference (standard error, P value) for TDF/FTC vs placebo at week 24 was -0.8% (0.4%, P = .02), +0.3% (0.4%, P = .46), and -3.8% (1.4%, P = .009) for total, lean, and fat mass, respectively. There was no apparent differential regional fat accumulation on TDF/FTC. Decreases in cholesterol, but not triglycerides, were seen in TDF/FTC participants, with detectable drug levels compared to placebo.

Conclusions

TDF/FTC for PrEP showed cholesterol reductions and appeared to transiently suppress the accumulation of weight and body fat compared to placebo. There was no evidence of altered fat distribution or lipodystrophy during daily oral TDF/FTC PrEP.

Clinical Trials Registration

NCT00458393.

Adverse effects of long-term weight gain on microvascular endothelial function

BACKGROUND

Endothelial dysfunction is the first stage of the atherosclerotic cascade, and independently associated with cardiovascular events. We evaluated the associations of longitudinal changes in weight, waist circumference, body fat percentage and lean mass index with changes in endothelial function.

METHODS

521 community-based subjects who belonged to hypertensive sibships and had no history of myocardial infarction or stroke had their anthropometric measures and endothelial function assessed a mean of 8.5 years apart. Endothelial function was assessed with brachial artery ultrasound, yielding measures of flow-mediated dilation and reactive hyperemia. We used multivariable linear regression with generalised estimating equations to assess the associations of longitudinal changes (Δ) in anthropometric measures with Δ flow-mediated dilation and reactive hyperemia, adjusting for potential confounders.

RESULTS

Mean±standard deviation age was 57.6±8.7years, 58% were women, and 72% were hypertensive. Most (84%) were overweight or obese at baseline. At end of follow-up, flow-mediated dilation and reactive hyperemia increased by 1.9±7.6% and 51.2±605.8% on average, respectively. In multivariable linear regression, changes in anthropometric measures were not associated with changes in flow-mediated dilation. However, Δ weight (β±SE: -9.00±2.35), Δ waist circumference (-6.78±2.21) and Δ body fat percentage (-19.72±5.62, P<0.0001 for each) were inversely associated with Δ reactive hyperemia. Δ lean mass index was not associated with Δ reactive hyperemia.

CONCLUSIONS

Long-term increases in weight, waist circumference and body fat percentage are associated with progressive worsening of microvascular endothelial function, but not conduit vessel endothelial function, in subjects without a history of cardiovascular events, independently of risk factors.

Weight Changes After Thyroid Surgery for Patients with Benign Thyroid Nodules and Thyroid Cancer: Population-Based Study and Systematic Review and Meta-Analysis

BACKGROUND

A key concern among patients who undergo thyroid surgery is postoperative weight gain. Yet, the impact of thyroid surgery on weight is unclear.

METHODS

The population-based Rochester Epidemiology Project was used to examine weight and body mass index (BMI) changes at one, two, and three years of follow-up in (i) patients with thyroid cancer and benign thyroid nodules after thyroid surgery, and (ii) patients with thyroid nodules who did not have surgery. A comprehensive systematic review of the published literature from inception to February 2016 was also conducted. The results were pooled across studies using a random effects model.

RESULTS

A total of 435 patients were identified: 181 patients with thyroid cancer who underwent surgery (group A), 226 patients with benign thyroid nodules without surgery (group B), and 28 patients with benign thyroid nodules undergoing surgery (group C). Small changes in mean weight, BMI, and the number of patients whose weight increased between 5 and 10 kg were similar during each year of follow-up between patients in groups A and B. Furthermore, age >50 years, female sex, baseline BMI >25 kg/m², and thyrotropin value at one to two years were not predictors of a 5% weight change. In the meta-analysis, 11 studies were included. One to two years after surgery for thyroid cancer or thyroid nodules, patients gained on average 0.94 kg [confidence interval (CI) 0.58-1.33] and 1.07 kg [CI 0.26-1.87], respectively. Patients with benign thyroid nodules who did not have surgery gained 1.50 kg [CI 0.60-2.4] at the longest follow-up.

CONCLUSIONS

On average, patients receiving care for thyroid nodules or cancer gain weight, but existing evidence suggests that surgery for these conditions does not contribute significantly to further weight gain. Clinicians and patients can use this information to discuss what to expect after thyroid surgery.

Factors Associated with High Weight Gain and Obesity Duration: The Norwegian Women and Cancer (NOWAC) Study

AIM

To identify factors associated with high weight gain and obesity duration in a representative sample of Norwegian women.

METHODS

66,618 Norwegian women aged 34-70 years at baseline were included in the analysis. Baseline and follow-up questionnaires completed in 1991-2011 provided information on height, weight as well as sociodemographic, lifestyle and reproductive factors. We assessed the association with multivariable logistic regression.

RESULTS

Women gained on average 0.5 kg/year (95% CI 0.5-0.5 kg/year) during 6 years of follow-up, and 3.5% maintained in obesity during 13 years of follow-up. The factors with strongest association with high weight gain (≥10 kg) were smoking cessation (cessation vs. no change, OR = 4.39, 95% CI 3.91-4.94) and decreased physical activity level (decrease vs. no change, OR = 2.40, 95% CI 2.21-2.61). Low physical activity level (high vs. low, OR = 0.17, 95% CI 0.14-0.20), higher than median age at menarche (over median vs. median or under median, OR = 0.36, 95% CI 0.31-0.41), and less than 10 years of education (>12 years vs. <10 years, OR = 0.44, 95% CI 0.37-0.51) were strongly associated with obesity duration.

CONCLUSION

The modifiable factor with the strongest association with adverse weight development and potential for prevention was low or decreased physical activity level.

Measures of excess body weight and anthropometry among adult Albertans: cross-sectional results from Alberta's tomorrow project cohort

Background

Excess body weight during adulthood has been consistently associated with all-cause mortality, cardiovascular disease, and cancer at multiple sites among other chronic diseases. We describe the prevalence of excess body weight and abdominal obesity reported by participants enrolled in Alberta’s Tomorrow Project (ATP).

Methods

ATP is a geographically-based cohort study conducted among adults aged 35–69 years from across the province of Alberta. Participants completed anthropometric measures and health and lifestyle questionnaires at enrolment. Overweight and obese were categorized as a body mass index (BMI) of 25.0–29.9 kg/m² and ≥30 kg/m², respectively. Abdominal obesity was categorized using cut-offs of waist circumference of >94 cm for men and >80 cm for women and waist-tp-hip ratio cut-offs of >0.90 for men and >0.85 for women.

Results

BMI and hip and waist circumference data were obtained from 12,062 men and 18,853 women enrolled between 2001 and 2009. Overall, 76.8% of men and 59.5% of women reported a BMI ≥25 kg/m². The proportions of overweight and obese were significantly higher in older age groups (p < 0.001). In addition, the proportion of participants reporting being overweight and obese was higher among lower education (p < 0.001) and lower income groups (p < 0.001). Overall, approximately two thirds of men and women in ATP cohort reported abdominal obesity. Overweight, obesity and abdominal obesity were all associated with a history of several cardiometabolic chronic conditions including hypertension, heart attack, angina, high cholesterol, stroke and diabetes.

Conclusion

A large majority of ATP participants were overweight and carried excess abdominal fat. Strategies to improve energy balance among Albertans are encouraged and may have a notable impact on future chronic disease burden.

Electronic supplementary material

The online version of this article (10.1186/s12889-017-4887-2) contains supplementary material, which is available to authorized users.

Later circadian timing of food intake is associated with increased body fat

Background: Weight gain and obesity have reached alarming levels. Eating at a later clock hour is a newly described risk factor for adverse metabolic health; yet, how eating at a later circadian time influences body composition is unknown. Using clock hour to document eating times may be misleading owing to individual differences in circadian timing relative to clock hour.Objective: This study examined the relations between the timing of food consumption relative to clock hour and endogenous circadian time, content of food intake, and body composition.Design: We enrolled 110 participants, aged 18-22 y, in a 30-d cross-sectional study to document sleep and circadian behaviors within their regular daily routines. We used a time-stamped-picture mobile phone application to record all food intake across 7 consecutive days during a participant's regular daily routines and assessed their body composition and timing of melatonin release during an in-laboratory assessment.Results: Nonlean individuals (high body fat) consumed most of their calories 1.1 h closer to melatonin onset, which heralds the beginning of the biological night, than did lean individuals (low body fat) (log-rank P = 0.009). In contrast, there were no differences between lean and nonlean individuals in the clock hour of food consumption (P = 0.72). Multiple regression analysis showed that the timing of food intake relative to melatonin onset was significantly associated with the percentage of body fat and body mass index (both P < 0.05) while controlling for sex, whereas no relations were found between the clock hour of food intake, caloric amount, meal macronutrient composition, activity or exercise level, or sleep duration and either of these body composition measures (all P > 0.72).Conclusions: These results provide evidence that the consumption of food during the circadian evening and/or night, independent of more traditional risk factors such as amount or content of food intake and activity level, plays an important role in body composition. This trial was registered at clinicaltrials.gov as NCT02846077.

Altered cross-talk between the hypothalamus and non-homeostatic regions linked to obesity and difficulty to lose weight

Interactions between the hypothalamus and non-homeostatic regions may contribute to explain the difficulty to lose weight in obesity, an assumption never tested in human longitudinal studies. We investigated whether the functional connectivity between the medial and lateral hypothalamus (MH and LH) and corticostriatal regions differs between individuals with excess weight (n = 42) and normal weight (n = 39) using a seed-based resting-state approach. In addition, we examined the longitudinal association between functional connectivity and weight loss in a 3-month follow-up diet. Results showed that participants with excess weight had increased connectivity between the MH and the striatum and subgenual anterior cingulate cortex, and decreased connectivity with the middle frontal gyrus, and the bed nucleus of the stria terminalis (BNST), as well as a decreased connectivity between the LH and the cerebellum. Decreased connectivity between the MH and the posterior part of the BNST, and between the LH and the cerebellar cortex, predicted a greater percentage of weight loss. Functional connectivity measures explained 36% of the 3-month weight change among individuals with excess weight. We conclude that altered functional connectivity between homeostatic-hypothalamic regions and non-homeostatic corticostriatal and cerebellar regions is linked to obesity and difficulty to lose weight.

Associations of Weight Gain From Early to Middle Adulthood With Major Health Outcomes Later in Life

IMPORTANCE

Data describing the effects of weight gain across adulthood on overall health are important for weight control.

OBJECTIVE

To examine the association of weight gain from early to middle adulthood with health outcomes later in life.

DESIGN, SETTING, AND PARTICIPANTS

Cohort analysis of US women from the Nurses' Health Study (1976-June 30, 2012) and US men from the Health Professionals Follow-Up Study (1986-January 31, 2012) who recalled weight during early adulthood (at age of 18 years in women; 21 years in men), and reported current weight during middle adulthood (at age of 55 years).

EXPOSURES

Weight change from early to middle adulthood (age of 18 or 21 years to age of 55 years).

MAIN OUTCOMES AND MEASURES

Beginning at the age of 55 years, participants were followed up to the incident disease outcomes. Cardiovascular disease, cancer, and death were confirmed by medical records or the National Death Index. A composite healthy aging outcome was defined as being free of 11 chronic diseases and major cognitive or physical impairment.

RESULTS

A total of 92 837 women (97% white; mean [SD] weight gain: 12.6 kg [12.3 kg] over 37 years) and 25 303 men (97% white; mean [SD] weight gain: 9.7 kg [9.7 kg] over 34 years) were included in the analysis. For type 2 diabetes, the adjusted incidence per 100 000 person-years was 207 among women who gained a moderate amount of weight (≥2.5 kg to <10 kg) vs 110 among women who maintained a stable weight (weight loss ≤2.5 kg or gain <2.5 kg) (absolute rate difference [ARD] per 100 000 person-years, 98; 95% CI, 72 to 127) and 258 vs 147, respectively, among men (ARD, 111; 95% CI, 58 to 179); hypertension: 3415 vs 2754 among women (ARD, 662; 95% CI, 545 to 782) and 2861 vs 2366 among men (ARD, 495; 95% CI, 281 to 726); cardiovascular disease: 309 vs 248 among women (ARD, 61; 95% CI, 38 to 87) and 383 vs 340 among men (ARD, 43; 95% CI, -14 to 109); obesity-related cancer: 452 vs 415 among women (ARD, 37; 95% CI, 4 to 73) and 208 vs 165 among men (ARD, 42; 95% CI, 0.5 to 94). Among those who gained a moderate amount of weight, 3651 women (24%) and 2405 men (37%) achieved the composite healthy aging outcome. Among those who maintained a stable weight, 1528 women (27%) and 989 men (39%) achieved the composite healthy aging outcome. The multivariable-adjusted odds ratio for the composite healthy aging outcome associated with moderate weight gain was 0.78 (95% CI, 0.72 to 0.84) in women and 0.88 (95% CI, 0.79 to 0.97) in men. Higher amounts of weight gain were associated with greater risks of major chronic diseases and lower likelihood of healthy aging.

CONCLUSIONS AND RELEVANCE

In these cohorts of health professionals, weight gain during adulthood was associated with significantly increased risk of major chronic diseases and decreased odds of healthy aging. These findings may help counsel patients regarding the risks of weight gain.

Geography of breast cancer incidence according to age & birth cohorts

PURPOSE

Geographic variation in breast cancer incidence across Connecticut was examined according to age and birth cohort -specific groups.

METHODS

We assigned each of 60,937 incident breast cancer cases diagnosed in Connecticut, 1986-2009, to one of 828 census tracts around the state. Global and local spatial statistics estimated rate variation across the state according to age and birth cohorts.

RESULTS

We found the global distribution of incidence rates across places to be more heterogeneous for younger women and later birth cohorts. Concurrently, the spatial scan identified more locations with significantly high rates that pertained to larger proportions of at-risk women within these groups. Geographic variation by age groups was more pronounced than by birth cohorts.

CONCLUSION

Geographic patterns of cancer incidence exhibit differences within and across age and birth cohorts. With the continued insights from descriptive epidemiology, our capacity to effectively limit spatial disparities in cancer will improve.

The association of change in physical activity and body weight in the regulation of total energy expenditure

BACKGROUND/OBJECTIVES

The limited success in addressing the current obesity epidemic reflects the insufficient understanding of the regulation of energy balance. The present study examines the longitudinal association of body weight with physical activity (PA), total daily energy expenditure (TDEE) and total daily energy intake (TDEI).

SUBJECTS/METHODS

A total of 195 adults (52% male) between 21 and 35 years of age with no intention for weight loss were followed over a 2-year period. Body weight, fat mass and fat-free mass were measured every 3 months. Participants were stratified into three groups based on change in body weight using a 5% cutpoint. TDEE and time spent in different PA intensities were determined via a multisensor device at each measurement time. TDEI was calculated based on change in body composition and TDEE.

RESULTS

At 2-year follow-up, 57% of the participants maintained weight, 14% lost weight and 29% gained weight. Average weight change was -6.9±3.4 and 7.1±3.6 kg in the weight-loss and weight-gain groups, respectively. Average TDEE and TDEI did not change significantly in any weight change group (P>0.16). Moderate-to-vigorous PA, however, increased significantly in the weight-loss group (35±49 min/day; P<0.01) and decreased in the weight-gain group (-35±46 min/day; P<0.01).

CONCLUSIONS

Results of this observational study indicate an inverse association between body weight and PA to maintain a stable TDEE and allow for a stable TDEI over time. Sufficient PA levels, therefore, are an important contributor to weight loss maintenance.

Maintaining a Healthy BMI: Data From a 16-Year Study of Young Australian Women

INTRODUCTION

The aims of this prospective cohort study were to examine 16-year trajectories of weight and BMI in young adult women who had a healthy BMI in 1996 and determinants of remaining in the healthy BMI category.

METHODS

A total of 4,881 women with healthy BMI at baseline and either healthy, overweight, or obese BMI at 16-year follow-up reported their weight, height, health, and health behaviors in six surveys of the Australian Longitudinal Study on Women's Health between 1996 (aged 18-23 years) and 2012 (aged 34-39 years). Determinants of BMI maintenance were estimated using binary logistic regression and generalized estimating equations in 2015.

RESULTS

Almost 60% remained in the healthy BMI category from 1996 to 2012, (mean weight gain, 0.19 kg/year), 29% transitioned to overweight BMI (0.83 kg/year), and 11.6% transitioned to obese (1.73 kg/year). The mean rates of annual weight gain in each group were consistent over time. Only three factors (low alcohol, moderate/high physical activity, having a university degree) were positively associated with maintaining a healthy BMI. Additional behavioral factors (smoking, high sitting time, energy intake, dieting, takeaway food, and use of oral contraceptives), as well as blue collar occupation, separation/divorce/widowhood, and major illness were negatively associated with BMI maintenance.

CONCLUSIONS

To prevent the transition from healthy to overweight/obese BMI, weight gain must be limited to <0.5 kg/year. Women with healthy BMI, but with higher rates of weight gain in their early 20s, could be identified by health professionals for assistance with prevention of becoming overweight/obese.

High respiratory quotient is associated with increases in body weight and fat mass in young adults

BACKGROUND/OBJECTIVES

Metabolic disturbances, such as reduced rates of fat oxidation (high respiratory quotient (RQ)) or low energy expenditure (low resting metabolic rate (RMR)), may contribute to obesity. The objective was to determine the association between a high RQ or a low RMR and changes in body weight and body composition over 1 year.

SUBJECTS/METHODS

We measured RQ and RMR in 341 adults using indirect calorimetry, along with body weight/body composition using dual-energy X-ray absorptiometery, energy expenditure using an arm-based activity monitor and energy intake using dietary recalls. Participants were classified into low, moderate or high RQ and RMR (adjusted for age, sex, race and body composition) groups according to tertiles by sex. Follow-up measurements were completed every 3 months.

RESULTS

Individuals with a high RQ had larger gains in body weight and fat mass compared with individuals with a low/moderate RQ at month 3, and increases in fat mass were more than double among individuals with a high RQ at 12 months (1.3±3.0 vs 0.6±3.7 kg, P=0.03). Individuals with a low RMR did not gain more body weight nor fat mass compared with individuals with a moderate/high RMR.

CONCLUSION

The primary finding is a high RQ is predictive of gains in body weight and fat mass over a 12-month period among young adults, with changes occurring as soon as 3 months. In addition, a low RMR was not associated with gains in body weight or fat mass over the same period.

The effects of the academic performance of college students whose major is sports on body composition and abdominal fat rates

The subjects of this research are 30 students of Dong-Eui Institute of Technology in Busan city, who were grouped into two categories after applying the curriculum of the second semester of the freshman year to their classes: those whose academic performance was at the top 20% (15 students) and those whose academic performance was at the bottom 20% (15 students). For the measurement items, we measured their weight, body fat mass, body fat rates, body mass index, and abdominal fat rates by using a body composition testing machine. We then analyzed the t-test results by using the IBM SPSS ver. 18.0 program. Through this research, we found that there was a significant difference among those in the group of students whose academic performance was at the top 20% in terms of body fat mass and body fat rates, which means that academic performance has relatively little effect on body composition and abdominal fat rates.

25-year weight gain in a racially balanced sample of U.S. adults: The CARDIA study

OBJECTIVE

To examine 25-year trends in weight gain, partitioned by time-related and aging-related changes, during early and middle adulthood.

METHODS

Coronary Artery Risk Development in Young Adults (CARDIA), a prospective, non-nationally representative cohort study conducted at four urban field centers that began in 1985 to 1986 with 5,109 Black (B) and White (W) men (M) and women (W) aged 18 to 30 years, has followed participants for 25 years (aged 43-55 years in 2010-2011). Time-related and aging-related components of weight change were estimated to construct longitudinal models of linear and nonlinear trends.

RESULTS

There were nonlinear trends in time-related weight gain in W, with larger weight gains early that attenuated at subsequent exams. Time-related trends were linear in M. There were nonlinear trends in aging-related weight gain in BM, BW, and WM, with the greatest weight gains at younger ages. Aging-related trends were linear in WW. Participants with overweight or obesity in early adulthood had greater attenuation of aging-related weight gain during middle adulthood.

CONCLUSIONS

These findings partially support recent surveys indicating slower increases in obesity prevalence in recent years. Findings further suggest that aging-related weight gain is greatest in the 20s and may begin attenuating as early as the mid-30s among some groups.

Using social and mobile tools for weight loss in overweight and obese young adults (Project SMART): a 2 year, parallel-group, randomised, controlled trial

BACKGROUND

Few weight loss interventions are evaluated for longer than a year, and even fewer employ social and mobile technologies commonly used among young adults. We assessed the efficacy of a 2 year, theory-based, weight loss intervention that was remotely and adaptively delivered via integrated user experiences with Facebook, mobile apps, text messaging, emails, a website, and technology-mediated communication with a health coach (the SMART intervention).

METHODS

In this parallel-group, randomised, controlled trial, we enrolled overweight or obese college students (aged 18-35 years) from three universities in San Diego, CA, USA. Participants were randomly assigned (1:1) to receive either the intervention (SMART intervention group) or general information about health and wellness (control group). We used computer-based permuted-block randomisation with block sizes of four, stratified by sex, ethnicity, and college. Participants, study staff, and investigators were masked until the intervention was assigned. The primary outcome was objectively measured weight in kg at 24 months. Differences between groups were evaluated using linear mixed-effects regression within an intention-to-treat framework. Objectively measured weight at 6, 12, and 18 months was included as a secondary outcome. The trial is registered with ClinicalTrials.gov, number NCT01200459.

FINDINGS

Between May 18, 2011, and May 17, 2012, 404 individuals were randomly assigned to the intervention (n=202) or control (n=202). Participants' mean (SD) age was 22·7 (3·8) years. 284 (70%) participants were female and 125 (31%) were Hispanic. Mean (SD) body-mass index at baseline was 29·0 (2·8) kg/m(2). At 24 months, weight was assessed in 341 (84%) participants, but all 404 were included in analyses. Weight, adjusted for sex, ethnicity, and college, was not significantly different between the groups at 24 months (-0·79 kg [95% CI -2·02 to 0·43], p=0·204). However, weight was significantly less in the intervention group compared with the control group at 6 months (-1·33 kg [95% CI -2·36 to -0·30], p=0·011) and 12 months (-1·33 kg [-2·30 to -0·35], p=0·008), but not 18 months (-0·67 kg [95% CI -1·69 to 0·35], p=0·200). One serious adverse event in the intervention group (gallstones) could be attributable to rapid and excessive weight loss.

INTERPRETATION

Social and mobile technologies did not facilitate sustained reductions in weight among young adults, although these approaches might facilitate limited short-term weight loss.

FUNDING

The National Heart, Lung, and Blood Institute of the National Institutes of Health (U01 HL096715).

The association between sedentary behaviors during weekdays and weekend with change in body composition in young adults

BACKGROUND

High sedentary time has been considered an important chronic disease risk factor but there is only limited information on the association of specific sedentary behaviors on weekdays and weekend-days with body composition. The present study examines the prospective association of total sedentary time and specific sedentary behaviors during weekdays and the weekend with body composition in young adults.

METHODS

A total of 332 adults (50% male; 27.7 ± 3.7 years) were followed over a period of 1 year. Time spent sedentary, excluding sleep (SED), and in physical activity (PA) during weekdays and weekend-days was objectively assessed every 3 months with a multi-sensor device over a period of at least 8 days. In addition, participants reported sitting time, TV time and non-work related time spent at the computer separately for weekdays and the weekend. Fat mass and fat free mass were assessed via dual x-ray absorptiometry and used to calculate percent body fat (%BF). Energy intake was estimated based on TDEE and change in body composition.

RESULTS

Cross-sectional analyses showed a significant correlation between SED and body composition (0.18 ≤ r ≤ 0.34). Associations between body weight and specific sedentary behaviors were less pronounced and significant during weekdays only (r ≤ 0.16). Nevertheless, decrease in SED during weekends, rather than during weekdays, was significantly associated with subsequent decrease in %BF (β = 0.06, p <0.01). After adjusting for PA and energy intake, results for SED were no longer significant. Only the association between change in sitting time during weekends and subsequent %BF was independent from change in PA or energy intake (β%BF = 0.04, p = 0.01), while there was no significant association between TV or computer time and subsequent body composition.

CONCLUSIONS

The stronger prospective association between sedentary behavior during weekends with subsequent body composition emphasizes the importance of leisure time behavior in weight management.

Iatrogenic Subclinical Hyperthyroidism Does Not Promote Weight Loss

OBJECTIVES

Among patients who have undergone total thyroidectomy, do those with thyroid cancer being kept iatrogenically subclinical hyperthyroid (SCH) differ from euthyroid patients in long-term weight change?

METHODS

In a retrospective study, medical records identified 291 patients who had undergone a thyroidectomy for differentiated thyroid cancer or benign thyroid disease. Weight, thyroid-stimulating hormone, and levothyroxine dose were measured presurgery and 1, 2, and 3 years postsurgery.

RESULTS

Of 291 patients, 147 were in the SCH group and 144 were in the euthyroid group. At all 3 years both groups gained weight from baseline, but the two groups did not differ in weight change from baseline at any time period: year 1 (SCH mean 0.4% ± 6.2% weight gain vs euthyroid group mean 2.2% ± 6.6% weight gain; P = 0.12), year 2 (SCH mean 1.1% ± 9.1% weight gain vs euthyroid mean 2.9% ± 7.8% weight gain; P = 0.22), and year 3 (SCH mean 2.6% ± 9.2% weight gain vs euthyroid mean 3.1% ± 11.1% weight gain; P = 0.49).

CONCLUSIONS

Among total thyroidectomy patients, weight change did not differ between SCH patients and euthyroid patients at years 1 through 3. As such, the use of levothyroxine to induce SCH did not lead to long-term weight change when compared with euthyroid patients.

The Association of Physical Activity during Weekdays and Weekend with Body Composition in Young Adults

Physical activity (PA) is a key contributor in long-term weight management but there remains limited research on the association between weekly PA patterns and weight change. The purpose of the present study was to examine the prospective association between weekly PA patterns and weight change in generally healthy young adults. Anthropometric measurements, including dual X-ray absorptiometry, were obtained every 3 months over a period of one year in 338 adults (53% male). At each measurement time, participants wore a multisensor device for a minimum of 10 days to determine total daily energy expenditure and time spent sleeping, sedentary, in light PA (LPA), in moderate PA (MPA), and in vigorous PA (VPA). PA did not differ between weekdays and the weekend at baseline. Twenty-four-hour sleep time, however, was significantly longer during weekends compared to weekdays, which was associated with less time spent sedentary. Weight loss was associated with a significant increase in LPA at the expense of sedentary time during the weekend but not during weekdays. Regression analyses further revealed an inverse association between change in VPA during the weekend and body composition at 12-month follow-up. Taken together, these results suggest that weekend PA plays an important role in long-term weight management.

Body Mass Index Trajectories and Healthcare Utilization in Young and Middle-aged Adults

The obesity epidemic is a significant public health issue with adverse impact on health and costs. Applying a life-course perspective to obesity may advance our understanding of the influence of obesity over time on patterns of healthcare utilization in young and middle-aged United States (US) adults.We identified baseline body mass index (BMI) and BMI trajectories, and assessed their association with outpatient visits, emergency department (ED) visits, and hospitalizations in a well-defined population of young and middle-aged US adults.Using the Rochester Epidemiology Project resources, we conducted a retrospective cohort study of adults (N = 23,254) aged 18 to 44 years, with at least 3 BMI measurements, residing in Olmsted County, MN from January 1, 2005 through December 31, 2012.We observed that 27.5% of the population was obese. Four BMI trajectories were identified. Compared to under/normal weight, obese class III adults had higher risk of outpatient visits (adjusted rate ratio [RR], 1.86; 95% confidence intervals [CIs], 1.67-2,08), ED visits (adjusted RR, 3.02; 95% CI, 2.74-3.34), and hospitalizations (adjusted RR, 1.67; 95% CI, 1.59-1.75). BMI trajectory was positively associated with ED visits after adjustment for age, sex, race, and Charlson Comorbidity Index (P < 0.001 for trend).Among young and middle-aged US adults, baseline BMI is positively associated with outpatient visits, ED visits, and hospitalizations, while BMI trajectory is positively associated with ED visits. These findings extend our understanding of the longitudinal influence of obesity on healthcare utilization in early to mid-adulthood.

Trajectories of Body Mass Index from Young Adulthood to Middle Age among Canadian Men and Women

Knowledge regarding the heterogeneity of BMI trajectories is limited for the Canadian population. Using latent class growth modelling, four distinct BMI trajectories of individuals from young adulthood to middle age were identified for both women and men from the longitudinal data of the National Population Health Survey. The associations between BMI trajectories and the individuals’ sociodemographic characteristics and behavioural factors were also examined. Aboriginal women were found more likely to be in the long-term overweight or obese groups. It reveals that increased years of smoking, drinking, and being physically active were associated with lowering the BMI trajectory in all groups for both women and men, with some exceptions in the long-term normal weight group for men. Increased years of rural living, being employed, and living with low income were associated with raising the BMI trajectory in all groups for women and in some groups for men. Food insecurity was associated with raising the BMI trajectory in each group for both women and men.

Changes in body weight and obesity status in German adults: results of seven population-based prospective studies

BACKGROUND/OBJECTIVES

The objective of this study was to quantify body weight changes in German adult populations during the past decades.

SUBJECTS/METHODS

Longitudinal analysis of seven cohort studies covering different age ranges between 18 and 83 years. Baseline examinations were between 1994 and 2007 and follow-up durations between 4.0 and 11.9 years. For each study, mean change in body weight per year and 10-year change in body mass index (BMI) classification were analyzed. For the middle age group of 45-64 years, meta-analysis was conducted to obtain an overall estimate for Germany.

RESULTS

Among men weight gain was highest in the youngest participants and decreased with advancing age. Among women weight gain was on a stable high level among those younger than 45 years and decreased at older age. Within 10 years, 30-40% of middle-aged participants with normal baseline weight became pre-obese or obese and 20-25% of those with pre-obesity at baseline became obese, whereas >80% of persons who were obese at baseline remained obese over time. The estimated average weight change in adults aged 45-64 years was 0.25 (95% confidence interval (CI): 0.18-0.33) kg/year among men and 0.24 (0.17-0.30) kg/year among women.

CONCLUSIONS

We could observe a moderate weight gain over the past years in German middle-aged populations of 0.25 kg/year. Obesity prevention needs to be targeted to specific subgroups in the population, especially to younger adults, who seem to be most vulnerable for gaining weight. Obesity intervention needs to be improved, as the majority of obese adults remained obese over time.

Overweight and obese midlife women in Israel: cultural differences in perceived weight status

OBJECTIVES

To examine cultural differences in Weight status misperception (WSMP) and identify associations between weight perception and weight control efforts among overweight/obese midlife women in Israel.

METHODS

Data from the nationally representative Women's-Health-in-Midlife-National-Study were used. Participants included overweight (25 ≤ BMI < 30) and obese (BMI ≥ 30) midlife women (45-64 years) from three cultural groups: Long-Term Jewish Residents (LTJR), Immigrants from the former USSR, and Arabs. Interviews included measures of BMI, weight perception, lifestyle, and socio-demographics.

RESULTS

Most overweight/obese women (88 %) perceived their weight status correctly. No significant differences were found in overall WSMP rates across cultural groups. Overweight women of Arab origin were significantly more likely (p < 0.001) to perceive their weight as "about right" relative to LTJR and Immigrants. WSMP was associated with several unhealthy eating patterns [eating red meat (OR = 2.1, 95 % CI = 1.13-3.97), white bread (OR = 2.4, 95 % CI = 1.26-4.58)] and with more perceived barriers to exercising (OR = 1.8, 95 % CI = 1.00-3.42).

CONCLUSIONS

Health care providers are encouraged to pay attention to overweight/obese women who misperceive their weight status. These women are more likely to consume unhealthy foods and to be at higher risks of suffering from medical complications associated with obesity.

Job-loss and weight gain in British adults: Evidence from two longitudinal studies

Overweight and obesity have been associated with unemployment but less is known about changes in weight associated with changes in employment. We examined weight changes associated with job-loss, retirement and maintaining employment in two samples of working adults in the United Kingdom. This was a prospective study of 7201 adults in the European Prospective Investigation of Cancer (EPIC)-Norfolk study (aged 39–76 years) and 4539 adults in the British Household Panel Survey (BHPS) who were followed up over 43 months and 26 months, respectively. In both samples, changes in measured (EPIC) and self-reported (BHPS) weight were computed for each participant and assessed in relation to three employment transitions: maintaining paid employment, retirement and job-loss. Regression models adjusted for potential confounders. Further analyses evaluated the contribution of diet, physical activity and smoking to weight gain. In EPIC-Norfolk, weight change differed across the three employment transitions for women but not men. The mean (95% CI) annualised change in weight for women who became unemployed over the follow-up period was 0.70 (0.55, 0.85) kg/y while those who maintained employment gained 0.49 (0.43, 0.55) kg/y (P = 0.007). Accounting for changes in smoking, diet and physical activity did not substantially alter the difference in weight gain among groups. In BHPS, job-loss was associated with weight gain of 1.56 (0.89, 2.23) kg/y, while those who maintained employment 0.60 (0.53, 0.68) kg/y (P < 0.001). In both samples, weight changes associated with retirement were similar to those staying in work. In BHPS, job-loss was also associated with significant declines in self-reported well-being and increases in sleep-loss.

Two UK-based samples of working adults reveal strong associations between job-loss and excess weight gain. The mediating behaviours are so far unclear but psychosocial mechanisms and sleep-loss may contribute to the excess weight gain among individuals who become unemployed.

•

Job-loss is associated with a more weight gain in working UK adults.

•

The association between job-loss and weight may be stronger for women.

•

Changes in smoking, diet and physical activity did not explain weight gain.

•

Job-loss is associated with loss of sleep due to worry.

•

Behavioural and psychosocial impacts of job-loss need further elucidation.

Prospective association between body composition, physical activity and energy intake in young adults

BACKGROUND/OBJECTIVES

Despite considerable research on the association between physical activity (PA) and body composition, there remains limited information on the directionality of the relationship. The present study examined the prospective associations among objectively measured PA, energy intake (EI) and body composition.

SUBJECTS/METHODS

A convenience sample of 430 adults (49% male) between 21 and 35 years of age was followed over 1 year with repeated measurements taken every 3 months. BMI (kg/m(2)) and percent body fat (%BF) were calculated based on anthropometric measurements and dual energy X-ray absorptiometry. A multi-sensor device was worn over a period of 10 days to estimate total daily energy expenditure and time spent in different intensities. EI was calculated based on change in body composition and total daily energy expenditure.

RESULTS

A total of 379 participants provided valid data. On average, participants experienced a significant weight gain of 1.2±4.3 kg during the 12-month observation period, which was associated with an increase in %BF (0.8±3.2 %). Average time spent in moderate-to-vigorous PA (MVPA) decreased significantly, whereas EI remained constant. Optimal linear mixed models, adjusting for age and sex, showed an inverse effect of MVPA on BMI and %BF, whereas EI only directly affected BMI (P<0.001). There was also a significant inverse effect of BMI and %BF on MVPA (P<0.001).

CONCLUSIONS

Results of this study indicate an inverse reciprocal association between MVPA and measures of adiposity. Thus, primary preventive actions are warranted to avoid excess weight gain, which may result in a vicious cycle of weight gain and low PA.

Value of lifestyle intervention to prevent diabetes and sequelae

BACKGROUND

The Community Preventive Services Task Force recommends combined diet and physical activity promotion programs for people at increased risk of type 2 diabetes, as evidence continues to show that intensive lifestyle interventions are effective for overweight individuals with prediabetes.

PURPOSE

To illustrate the potential clinical and economic benefits of treating prediabetes with lifestyle intervention to prevent or delay onset of type 2 diabetes and sequelae.

METHODS

This 2014 analysis used a Markov model to simulate disease onset, medical expenditures, economic outcomes, mortality, and quality of life for a nationally representative sample with prediabetes from the 2003-2010 National Health and Nutrition Examination Survey. Modeled scenarios used 10-year follow-up results from the lifestyle arm of the Diabetes Prevention Program and Outcomes Study versus simulated natural history of disease.

RESULTS

Over 10 years, estimated average cumulative gross economic benefits of treating patients who met diabetes screening criteria recommended by the ADA ($26,800) or USPSTF ($24,700) exceeded average benefits from treating the entire prediabetes population ($17,800). Estimated cumulative, gross medical savings for these three populations averaged $10,400, $11,200, and $6,300, respectively. Published estimates suggest that opportunistic screening for prediabetes is inexpensive, and lifestyle intervention similar to the Diabetes Prevention Program can be achieved for ≤$2,300 over 10 years.

CONCLUSIONS

Lifestyle intervention among people with prediabetes produces long-term societal benefits that exceed anticipated intervention costs, especially among prediabetes patients that meet the ADA and USPSTF screening guidelines.

Body Image in Adult Women: Moving Beyond the Younger Years

In spite of copious literature investigating body dissatisfaction and its correlates in adolescents and young adult women, exploration of body image disturbances in adult women remains an underrepresented domain in the literature. Yet, there are many reasons to suspect that body image in adult women both may differ from and possibly be more complex than that of younger women. Adult women face myriad factors influencing body image beyond those delineated in the body image literature on adolescents and young adult women. For instance, aging-related physiological changes shift the female body further away from the thin-young-ideal, which is the societal standard of female beauty. Further, life priorities and psychological factors evolve with age as well. As such, adult women encounter changes that may differentially affect body image across the lifespan. This paper aims to provide an up-to-date review of the current literature on the relationship between body image and associated mental and physical health problems and behaviors in adult women. In addition, we explore factors that may influence body image in adult women. Lastly, we use this review to identify significant gaps in the existing literature with the aim of identifying critical targets for future research.

Socio-demographic and behavioural determinants of weight gain in the Swiss population

Background

In Switzerland, socio-demographic and behavioural factors are associated with obesity, but no study ever assessed their impact on weight gain using prospective data.

Methods

Data from 4,469 participants (53.0% women), aged 35 to 75 years at baseline and followed for 5.5 years. Weight gain was considered as a rate (kg/year) or as gaining ≥5 kg during the study period.

Results

Rate of weight gain was lower among participants who were older (mean ± standard deviation: 0.46 ± 0.92, 0.33 ± 0.88, 0.21 ± 0.86 and 0.06 ± 0.74 kg/year in participants aged [35-45], [45-55], [55–65] and [65+] years, respectively, P<0.001); physically active (0.27 ± 0.82 vs. 0.35 ± 0.95 kg/year for sedentary, P < 0.005) or living in couple (0.29 ± 0.84 vs. 0.35 ± 0.96 kg/year for living single, P < 0.05), and higher among current smokers (0.41 ± 0.97, 0.26 ± 0.84 and 0.29±0.85 kg/year for current, former and never smokers, respectively, p<0.001). These findings were further confirmed by multivariable analysis. Multivariable logistic regression showed that receiving social help, being a current smoker or obese increased the likelihood of gaining ≥5 Kg: Odds ratio (OR) and 95% confidence interval (CI) 1.43 (1.16-1.77); 1.63 (1.35-1.95) and 1.95 (1.57-2.43), respectively, while living in couple or being physically active decreased the risk: 0.73 (0.62-0.86) and 0.72 (0.62-0.83), respectively. No association was found between weight gain and gender, being born in Switzerland or education.

Conclusions

In Switzerland, financial difficulties (indicated by receiving social help) and current smoking were associated with increases in body weight over a 5 years follow-up. Living in couple, being older or physically active were protective against weight gain.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1451-9) contains supplementary material, which is available to authorized users.

Modeling the clinical and economic implications of obesity using microsimulation

OBJECTIVES

The obesity epidemic has raised considerable public health concerns, but there are few validated longitudinal simulation models examining the human and economic cost of obesity. This paper describes a microsimulation model as a comprehensive tool to understand the relationship between body weight, health, and economic outcomes.

METHODS

Patient health and economic outcomes were simulated annually over 10 years using a Markov-based microsimulation model. The obese population examined is nationally representative of obese adults in the US from the 2005-2012 National Health and Nutrition Examination Surveys, while a matched normal weight population was constructed to have similar demographics as the obese population during the same period. Prediction equations for onset of obesity-related comorbidities, medical expenditures, economic outcomes, mortality, and quality-of-life came from published trials and studies supplemented with original research. Model validation followed International Society for Pharmacoeconomics and Outcomes Research practice guidelines.

RESULTS

Among surviving adults, relative to a matched normal weight population, obese adults averaged $3900 higher medical expenditures in the initial year, growing to $4600 higher expenditures in year 10. Obese adults had higher initial prevalence and higher simulated onset of comorbidities as they aged. Over 10 years, excess medical expenditures attributed to obesity averaged $4280 annually-ranging from $2820 for obese category I to $5100 for obese category II, and $8710 for obese category III. Each excess kilogram of weight contributed to $140 higher annual costs, on average, ranging from $136 (obese I) to $152 (obese III). Poor health associated with obesity increased work absenteeism and mortality, and lowered employment probability, personal income, and quality-of-life.

CONCLUSIONS

This validated model helps illustrate why obese adults have higher medical and indirect costs relative to normal weight adults, and shows that medical costs for obese adults rise more rapidly with aging relative to normal weight adults.

Association of the degree of adiposity and duration of obesity with measures of cardiac structure and function: the CARDIA study

OBJECTIVE

Examine whether there are independent influences of a greater degree of adiposity and longer duration of obesity on cardiac structure and function.

METHODS

Participants of CARDIA were 18-30 years when they underwent a baseline examination in 1985-86. Seven follow-up examinations were conducted every 2-5 years.

RESULTS

Among 2,547 participants who underwent an echocardiogram at the year 25 examination and were not obese at baseline, 34.4 and 35.5% were overall (BMI ≥ 30 kg m(-2) ) and abdominally obese (waist circumference: men: >102 cm; women: >88 cm) at year 25, respectively. A greater degree of overall and abdominal adiposity at year 25 were each associated with a greater left ventricular (LV) mass (P < 0.001), LV volume (P < 0.001), LV mass-to-volume ratio (P < 0.001), left atrial dimension (P < 0.001), and ejection fraction (P < 0.05) after adjustment for duration of obesity and other risk factors. In contrast, a longer duration of overall obesity was associated with a greater LV mass (P = 0.003) and a trend for a lower ejection fraction (P = 0.07).

CONCLUSIONS

A greater degree of adiposity is strongly associated with concentric LV remodeling in midlife, while the cumulative effects of a longer duration of overall obesity during young adulthood contribute to concentric remodeling predominantly by increasing LV mass.

Body mass index and all-cause mortality in a large prospective cohort of white and black U.S. Adults

Remaining controversies on the association between body mass index (BMI) and mortality include the effects of smoking and prevalent disease on the association, whether overweight is associated with higher mortality rates, differences in associations by race and the optimal age at which BMI predicts mortality. To assess the relative risk (RR) of mortality by BMI in Whites and Blacks among subgroups defined by smoking, prevalent disease, and age, 891,572 White and 38,119 Black men and women provided height, weight and other information when enrolled in the Cancer Prevention Study II in 1982. Over 28 years of follow-up, there were 434,400 deaths in Whites and 18,702 deaths in Blacks. Cox proportional-hazards regression was used to estimate multivariable-adjusted relative risks (RR) and 95% confidence intervals (CI). Smoking and prevalent disease status significantly modified the BMI-mortality relationship in Whites and Blacks; higher BMI was most strongly associated with higher risk of mortality among never smokers without prevalent disease. All levels of overweight and obesity were associated with a statistically significantly higher risk of mortality compared to the reference category (BMI 22.5-24.9 kg/m2), except among Black women where risk was elevated but not statistically significant in the lower end of overweight. Although absolute mortality rates were higher in Blacks than Whites within each BMI category, relative risks (RRs) were similar between race groups for both men and women (p-heterogeneity by race  = 0.20 for men and 0.23 for women). BMI was most strongly associated with mortality when reported before age 70 years. Results from this study demonstrate for the first time that the BMI-mortality relationship differs for men and women who smoke or have prevalent disease compared to healthy never-smokers. These findings further support recommendations for maintaining a BMI between 20-25 kg/m2 for optimal health and longevity.

Persistence or change in leisure-time physical activity habits and waist gain during early adulthood: a twin-study

OBJECTIVE

To determine the relationship between persistence or change in leisure-time physical activity habits and waist gain among young adults.

METHODS

Population-based cohort study among 3383 Finnish twin individuals (1578 men) from five birth cohorts (1975-1979), who answered questionnaires at mean ages of 24.4 y (SD 0.9) and 33.9 y (SD 1.2), with reported self-measured waist circumference. Persistence or change in leisure-time physical activity habits was defined based on thirds of activity metabolic equivalent h/day during follow-up (mean 9.5 y; SD 0.7).

RESULTS

Decreased activity was linked to greater waist gain compared to increased activity (3.6 cm, P < 0.001 for men; 3.1 cm, P < 0.001 for women). Among same-sex activity discordant twin pairs, twins who decreased activity gained an average 2.8 cm (95%CI 0.4 to 5.1, P = 0.009) more waist than their co-twins who increased activity (n = 85 pairs); among MZ twin pairs (n = 43), the difference was 4.2 cm (95%CI 1.2 to 7.2, P = 0.008).

CONCLUSIONS

Among young adults, an increase in leisure-time physical activity or staying active during a decade of follow-up was associated with less waist gain, but any decrease in activity level, regardless baseline activity, led to waist gain that was similar to that associated with being persistently inactive.

Diet behaviour among young people in transition to adulthood (18-25 year olds): a mixed method study

Background: Young people (18-25 years) during the adolescence/adulthood transition are vulnerable to weight gain and notoriously hard to reach. Despite increased levels of overweight/obesity in this age group, diet behaviour, a major contributor to obesity, is poorly understood. The purpose of this study was to explore diet behaviour among 18-25 year olds with influential factors including attitudes, motivators and barriers. Methods: An explanatory mixed method study design, based on health Behaviour Change Theories was used. Those at University/college and in the community, including those Not in Education, Employment or Training (NEET) were included. An initial quantitative questionnaire survey underpinned by the Theory of Planned Behaviour and Social Cognitive Theory was conducted and the results from this were incorporated into the qualitative phase. Seven focus groups were conducted among similar young people, varying in education and socioeconomic status. Exploratory univariate analysis was followed by multi-staged modelling to analyse the quantitative data. 'Framework Analysis' was used to analyse the focus groups. Results: 1313 questionnaires were analysed. Self-reported overweight/obesity prevalence was 22%, increasing with age, particularly in males. Based on the survey, 40% of young people reported eating an adequate amount of fruits and vegetables and 59% eating regular meals, but 32% reported unhealthy snacking. Based on the statistical modelling, positive attitudes towards diet and high intention (89%), did not translate into healthy diet behaviour. From the focus group discussions, the main motivators for diet behaviour were 'self-appearance' and having 'variety of food'. There were mixed opinions on 'cost' of food and 'taste'. Conclusion: Elements deemed really important to young people have been identified. This mixed method study is the largest in this vulnerable and neglected group covering a wide spectrum of the community. It provides evidence base to inform tailored interventions for a healthy diet within this age group.

Racism, segregation, and risk of obesity in the Black Women's Health Study

We assessed the relation of experiences of racism to the incidence of obesity and the modifying impact of residential racial segregation in the Black Women's Health Study, a follow-up study of US black women. Racism scores were created from 8 questions asked in 1997 and 2009 about the frequency of "everyday" racism (e.g., "people act as if you are dishonest") and of "lifetime" racism (e.g., unfair treatment on the job). Residential segregation was measured by linking participant addresses to 2000 and 2010 US Census block group data on the percent of black residents. We used Cox proportional hazard models to estimate incidence rate ratios and 95% confidence intervals. Based on 4,315 incident cases of obesity identified from 1997 through 2009, both everyday racism and lifetime racism were positively associated with increased incidence. The incidence rate ratios for women who were in the highest category of everyday racism or lifetime racism in both 1997 and 2009, relative to those in the lowest category, were 1.69 (95% confidence interval: 1.45, 1.96; Ptrend < 0.01) and 1.38 (95% confidence interval: 1.15, 1.66; Ptrend < 0.01), respectively. These associations were not modified by residential segregation. These results suggest that racism contributes to the higher incidence of obesity among African American women.

Exploratory and confirmatory factor analyses and demographic correlate models of the strategies for weight management measure for overweight or obese adults

PURPOSE

There is a need for a self-report measure that assesses use of recommended strategies related to weight management.

DESIGN

Cross-sectional analysis.

SETTING

Universities, community.

SUBJECTS

Exploratory factor analysis (EFA) involved data from 404 overweight/obese young adults (mean age = 22 years, 48% non-Hispanic white, 68% ethnic minority). Confirmatory factor analysis (CFA) involved data from 236 overweight/obese adults (mean age = 42 years, 63% non-Hispanic white, 84% ethnic minority).

MEASURES

The Strategies for Weight Management (SWM) measure is a 35-item questionnaire that assesses use of recommended behavioral strategies for reducing energy intake and increasing energy expenditure in overweight/obese adults.

ANALYSIS

EFA and CFA were conducted on the SWM. Correlate models assessed the associations between SWM factor/total scores and demographics by using linear regressions.

RESULTS

EFA suggested a four-factor model: strategies categorized as targeting (1) energy intake, (2) energy expenditure, (3) self-monitoring, and (4) self-regulation. CFA indicated good model fit (χ(2)/df = 2.0, comparative fit index = .90, standardized root mean square residual = .06, and root mean square error of approximation = .07, confidence interval = .06-.08, R(2) = .11-.74). The fourth factor had the lowest loadings, possibly because the items cover a wide domain. The final model included 20 items. Correlate models revealed weak associations between the SWM scores and age, gender, Hispanic ethnicity, and relationship status in both samples, with the models explaining only 1% to 8% of the variance (betas = -.04 to .29, p < .05).

CONCLUSION

The SWM has promising psychometric qualities in two diverse samples.

Age and obesity alter the relationship between femoral articular cartilage thickness and ambulatory loads in individuals without osteoarthritis

Articular cartilage is sensitive to mechanical loading, so increased risk of osteoarthritis in older or obese individuals may be linked to changes in the relationship between cartilage properties and extrinsic joint loads. A positive relationship has been reported between ambulatory loads and cartilage thickness in young individuals, but whether this relationship exists in individuals who are older or obese is unknown. This study examined the relationship between femoral cartilage thickness and load, measured by weight × height and the peak adduction moment, in young normal-weight (28 subjects, age: 28.0 ± 3.8 years, BMI: 21.9 ± 1.9 kg/m(2)), middle-aged normal-weight (27 subjects, 47.0 ± 6.5 years, 22.7 ± 1.7 kg/m(2)), young overweight/obese (27 subjects, 28.4 ± 3.6 years, 33.3 ± 4.6 kg/m(2)), and middle-aged overweight/obese (27 subjects, 45.8 ± 7.2 years, 31.9 ± 4.4 kg/m(2)) individuals. On the lateral condyle, cartilage thickness was positively correlated with weight × height for all groups (R(2)  = 0.26-0.20) except the middle-aged overweight/obese. On the medial condyle, weight × height was significantly correlated only in young normal-weight subjects (R(2)  = 0.19), as was the case for the correlation between adduction moment and medial-lateral thickness ratio (R(2)  = 0.20). These results suggest that aging and obesity are both associated with a loss of the positive relationship between cartilage thickness and ambulatory loads, and that the relationship is dependent on the compartment and whether the load is generated by body size or subject-specific gait mechanics.

Patterns of obesity development before the diagnosis of type 2 diabetes: the Whitehall II cohort study

BACKGROUND

Patients with type 2 diabetes vary greatly with respect to degree of obesity at time of diagnosis. To address the heterogeneity of type 2 diabetes, we characterised patterns of change in body mass index (BMI) and other cardiometabolic risk factors before type 2 diabetes diagnosis.

METHODS AND FINDINGS

We studied 6,705 participants from the Whitehall II study, an observational prospective cohort study of civil servants based in London. White men and women, initially free of diabetes, were followed with 5-yearly clinical examinations from 1991-2009 for a median of 14.1 years (interquartile range [IQR]: 8.7-16.2 years). Type 2 diabetes developed in 645 (1,209 person-examinations) and 6,060 remained free of diabetes during follow-up (14,060 person-examinations). Latent class trajectory analysis of incident diabetes cases was used to identify patterns of pre-disease BMI. Associated trajectories of cardiometabolic risk factors were studied using adjusted mixed-effects models. Three patterns of BMI changes were identified. Most participants belonged to the "stable overweight" group (n = 604, 94%) with a relatively constant BMI level within the overweight category throughout follow-up. They experienced slightly worsening of beta cell function and insulin sensitivity from 5 years prior to diagnosis. A small group of "progressive weight gainers" (n = 15) exhibited a pattern of consistent weight gain before diagnosis. Linear increases in blood pressure and an exponential increase in insulin resistance a few years before diagnosis accompanied the weight gain. The "persistently obese" (n = 26) were severely obese throughout the whole 18 years before diabetes diagnosis. They experienced an initial beta cell compensation followed by loss of beta cell function, whereas insulin sensitivity was relatively stable. Since the generalizability of these findings is limited, the results need confirmation in other study populations.

CONCLUSIONS

Three patterns of obesity changes prior to diabetes diagnosis were accompanied by distinct trajectories of insulin resistance and other cardiometabolic risk factors in a white, British population. While these results should be verified independently, the great majority of patients had modest weight gain prior to diagnosis. These results suggest that strategies focusing on small weight reductions for the entire population may be more beneficial than predominantly focusing on weight loss for high-risk individuals.

Obesity and late-age survival without major disease or disability in older women

IMPORTANCE

The effect of obesity on late-age survival in women without disease or disability is unknown.

OBJECTIVE

To investigate whether higher baseline body mass index and waist circumference affect women's survival to 85 years of age without major chronic disease (coronary disease, stroke, cancer, diabetes mellitus, or hip fracture) and mobility disability.

DESIGN, SETTING, AND PARTICIPANTS

Examination of 36,611 women from the Women's Health Initiative observational study and clinical trial programs who could have reached 85 years or older if they survived to the last outcomes evaluation on September 17, 2012. Recruitment was from 40 US clinical centers from October 1993 through December 1998. Multinomial logistic regression models were used to estimate odds ratios and 95% CIs for the association of baseline body mass index and waist circumference with the outcomes, adjusting for demographic, behavioral, and health characteristics.

MAIN OUTCOMES AND MEASURES

Mutually exclusive classifications: (1) survived without major chronic disease and without mobility disability (healthy); (2) survived with 1 or more major chronic disease at baseline but without new disease or disability (prevalent diseased); (3) survived and developed 1 or more major chronic disease but not disability during study follow-up (incident diseased); (4) survived and developed mobility disability with or without disease (disabled); and (5) did not survive (died).

RESULTS

Mean (SD) baseline age was 72.4 (3.0) years (range, 66-81 years). The distribution of women classified as healthy, prevalent diseased, incident diseased, disabled, and died was 19.0%, 14.7%, 23.2%, 18.3%, and 24.8%, respectively. Compared with healthy-weight women, underweight and obese women were more likely to die before 85 years of age. Overweight and obese women had higher risks of incident disease and mobility disability. Disability risks were striking. Relative to healthy-weight women, adjusted odds ratios (95% CIs) of mobility disability were 1.6 (1.5-1.8) for overweight women and 3.2 (2.9-3.6), 6.6 (5.4-8.1), and 6.7 (4.8-9.2) for class I, II, and III obesity, respectively. Waist circumference greater than 88 cm was also associated with higher risk of earlier death, incident disease, and mobility disability.

CONCLUSIONS AND RELEVANCE

Overall and abdominal obesity were important and potentially modifiable factors associated with dying or developing mobility disability and major chronic disease before 85 years of age in older women.

Physical activity and the incidence of obesity in young African-American women

BACKGROUND

Obesity occurs more commonly among African-American women than among other racial/ethnic groups, and most weight gain occurs before middle age.

PURPOSE

The study prospectively investigated the relationship of vigorous exercise and brisk walking to the incidence of obesity (BMI ≥ 30) among African-American women aged <40 years.

METHODS

During 1995-2009 in the Black Women's Health Study, the current authors followed 20,259 African-American women who were aged <40 years and not obese at baseline. BMI, exercise, and walking were assessed at baseline and on biennial follow-up questionnaires. Data for BMI were collected through 2009. Data for exercise and walking were collected through 2007. Validation and reproducibility data indicated that reporting was more accurate for vigorous exercise than for brisk walking. Cox proportional hazards models estimated incidence rate ratios (IRRs) and 95% CIs of incident obesity for hours/week of vigorous exercise and walking relative to "little or no exercise" (<1 hour/week of vigorous exercise and <1 hour/week of brisk walking). The analyses were conducted in 2012.

RESULTS

The incidence of obesity decreased with increasing vigorous exercise; the IRR was 0.77 (95% CI=0.69, 0.85) for ≥ 7 hours/week relative to little or no exercise; the IRRs were reduced both among women with a healthy weight (BMI <25) at baseline and among women who were overweight (BMI 25-<30) at baseline. The IRRs for brisk walking for exercise and walking for transport were <1.0 for most levels of walking, but without clear trends of decreasing risk with increasing time spent walking.

CONCLUSIONS

The results suggest that vigorous exercise may reduce the incidence of obesity among young African-American women. Results for brisk walking were inconclusive.

The energy balance study: the design and baseline results for a longitudinal study of energy balance

PURPOSE

The Energy Balance Study (EBS) was a comprehensive study designed to determine over a period of 12 months the associations of caloric intake and energy expenditure on changes in body weight and composition in a population of healthy men and women.

METHOD

EBS recruited men and women aged 21 to 35 years with a body mass index between 20 and 35 kg/m2. Measurements of energy intake and multiple objective measures of energy expenditure, as well as other physiological, anthropomorphic and psychosocial measurements, were made quarterly. Resting metabolic rate and blood chemistry were measured at baseline, 6 and 12 months.

RESULTS

Four hundred and thirty (218 women and 212 men) completed all baseline measurements. There were statistically significant differences by sex uncovered for most anthropomorphic, physiological and behavioral variables. Only percent of kcals from fat and alcohol intake, as well as energy expenditure in light activity and very vigorous activity were not different. Self-reported weight change (mean +/- SD) over the previous year were 0.92 +/- 5.24 kg for women and--1.32 +/- 6.1 kg for men. Resting metabolic rate averages by sex were 2.88 +/- 0.35 ml/kg/min for women and 3.05 +/- 0.33 ml/kg/min for men.

CONCLUSION

Results from EBS will inform our understanding of the impact of energy balance components as they relate to changes in body weight and composition. Initial findings suggest a satisfactory distribution of weight change to allow for robust statistical analyses. Resting metabolic rates well below the standard estimate suggest that the evaluation of the components of total energy expenditure will be impactful for our understanding of the roles of energy intake and expenditure on changes in energy utilization and storage.