Inaccuracies in food and physical activity diaries of obese subjects: complementary evidence from doubly labeled water and co-twin assessments

Resolution of diabetes, gastrointestinal symptoms, and self-reported dietary intake after gastric bypass vs sleeve gastrectomy – a randomized study

BACKGROUND

There is a lack of randomized studies examining diabetes remission and dietary intake between patients undergoing Roux-en-Y gastric bypass (RYGB) versus sleeve gastrectomy (SG).

OBJECTIVE

To examine longitudinal differences in diabetes resolution, dietary intake, and gastrointestinal (GI) symptoms in patients with obesity and type 2 diabetes (T2D) randomized to either RYGB or SG and according to remission of T2D.

SETTING

Four hospitals in Sweden, 2 of which are university hospitals.

METHODS

Dietary intake and GI symptoms were calculated from questionnaires and morphometric differences between surgical methods and T2D remission were compared using the Student t test, effect size (ES) for parametric parameters, and Mann-Whitney U test for nonparametric parameters.

RESULTS

Five years after RYGB or SG there was no significant difference in the rate of remission of T2D between RYGB and SG (43% versus 20%, P = .176). RYGB (n = 19) patients had greater weight loss than SG patients (n = 14) (26.4 [9.5] versus 13.1 [9.6] kg, P < .001), despite reporting higher daily caloric intake (Δ 669 kcal, P = .059, ES .67) and food weight (Δ 1029 g/d, P = .003, ES 1.11). RYGB patients, compared with SG patients, also ate 1 more fruit per day (P = .023). Pooled data showed no differences between patients with and without T2D remission regarding weight loss, but those in remission drank more nonalcoholic drinks and milk.

CONCLUSIONS

Five years postoperatively, patients randomized to RYGB reported considerably higher food intake compared with SG despite lower body weight. The reason and importance of the higher food intake after RYGB compared with SG needs to be further studied.

Trends in spontaneous physical activity and energy expenditure among adults in a respiratory chamber, 1985 to 2005

OBJECTIVE

Fidgeting, a type of spontaneous physical activity (SPA), has substantial thermogenic potential. This research aims to examine secular trends in SPA and energy expenditure (EE) inside a respiratory chamber.

METHODS

From 1985 to 2005, healthy adults (n = 678; mean age: 28.8 years; men: 60%; 522 Indigenous American, 129 White, and 27 Black) had a 24-hour stay in the respiratory chamber equipped with radar sensors. Body composition, glucose tolerance, fasting insulin, insulin action (hyperinsulinemic-euglycemic clamp), and insulin secretion (intravenous glucose tolerance test) were measured as covariates.

RESULTS

SPA, adjusted for age, sex, race, and body composition, declined (r = -0.30, p < 0.0001), with a concomitant rise in the energy cost of SPA (r = 0.30, p < 0.0001). The 24-hour EE adjusted for covariates increased (r = 0.31, p < 0.0001), which was reflected in increases in EE during sleep (r = 0.18, p < 0.0001) and during the awake, fed condition (r = 0.28, p < 0.0001). The secular trends in SPA or 24-hour EE were unchanged with adjustment for measures related to glucose metabolism.

CONCLUSIONS

Secular trend analyses showed a decline in fidgeting. However, this decline in SPA was partially counterbalanced by an increase in energy cost of this activity and a rise in EE. Nevertheless, our results support public health efforts to promote small but sustained changes in these behaviors.

Computational modelling of self-reported dietary carbohydrate intake on glucose concentrations in patients undergoing Roux-en-Y gastric bypass versus one-anastomosis gastric bypass

OBJECTIVES

Our aim was to investigate in a real-life setting the use of machine learning for modelling the postprandial glucose concentrations in morbidly obese patients undergoing Roux-en-Y gastric bypass (RYGB) or one-anastomosis gastric bypass (OAGB).

METHODS

As part of the prospective randomized open-label trial (RYSA), data from obese (BMI ≥35 kg/m2) non-diabetic adult participants were included. Glucose concentrations, measured with FreeStyle Libre, were recorded over 14 preoperative and 14 postoperative days. During these periods, 3-day food intake was self-reported. A machine learning model was applied to estimate glycaemic responses to the reported carbohydrate intakes before and after the bariatric surgeries.

RESULTS

Altogether, 10 participants underwent RYGB and 7 participants OAGB surgeries. The glucose concentrations and carbohydrate intakes were reduced postoperatively in both groups. The relative time spent in hypoglycaemia increased regardless of the operation (RYGB, from 9.2 to 28.2%; OAGB, from 1.8 to 37.7%). Postoperatively, we observed an increase in the height of the fitted response curve and a reduction in its width, suggesting that the same amount of carbohydrates caused a larger increase in the postprandial glucose response and that the clearance of the meal-derived blood glucose was faster, with no clinically meaningful differences between the surgeries.

CONCLUSIONS

A detailed analysis of the glycaemic responses using food diaries has previously been difficult because of the noisy meal data. The utilized machine learning model resolved this by modelling the uncertainty in meal times. Such an approach is likely also applicable in other applications involving dietary data. A marked reduction in overall glycaemia, increase in postprandial glucose response, and rapid glucose clearance from the circulation immediately after surgery are evident after both RYGB and OAGB. Whether nondiabetic individuals would benefit from monitoring the post-surgery hypoglycaemias and the potential to prevent them by dietary means should be investigated.KEY MESSAGESThe use of a novel machine learning model was applicable for combining patient-reported data and time-series data in this clinical study.Marked increase in postprandial glucose concentrations and rapid glucose clearance were observed after both Roux-en-Y gastric bypass and one-anastomosis gastric bypass surgeries.Whether nondiabetic individuals would benefit from monitoring the post-surgery hypoglycaemias and the potential to prevent them by dietary means should be investigated.

Evaluation of the impact of gastric bypass surgery on eating behaviour using objective methodologies under residential conditions: Rationale and study protocol

Gastric bypass surgery leads to significant and sustained weight loss and a reduction in associated health risks in individuals with severe obesity. While reduced energy intake (EI) is the primary driver of weight loss following surgery, the underlying mechanisms accounting for this energy deficit are not well understood. The evidence base has been constrained by a lack of fit-for-purpose methodology in assessing food intake coupled with follow-up studies that are relatively short-term. This paper describes the underlying rationale and protocol for an observational, fully residential study using covert, objective methodology to evaluate changes in 24-hr food intake in patients (n = 31) at 1-month pre-surgery and 3-, 12- and 24-months post-surgery, compared to weight-stable controls (n = 32). The main study endpoints included change in EI, macronutrient intake, food preferences, and eating behaviours (speed, frequency, and duration of eating). Other physiological changes that may influence EI and weight regulation including changes in body composition, circulating appetite hormones, resting metabolic rate, total energy expenditure and gastrointestinal symptoms were also evaluated. Understanding which mechanisms contribute to a reduction in EI and weight loss post-surgery could potentially help to identify those individuals who are most likely to benefit from gastric bypass surgery as well as those that may need more targeted intervention to optimise their weight loss post-surgery. Furthermore, clarification of these mechanisms may also inform targeted approaches for non-surgical treatments of obesity.

The Specific Impact of Nutrition and Physical Activity on Adolescents' Body Composition and Energy Balance

Purpose: The aim of the present study was to identify the contribution of nutrition, physical activity (PA), and total energy intake and expenditure on body weight and composition in adolescents. Methods: Body composition, PA, and dietary intakes from 904 Greek adolescents (446 boys and 458 girls; Age: 14.6 ± 1.5 yrs), were evaluated. All participants were assigned into three groups according to their age-sex adjusted Fat Mass Index: (A) Normal weight (N; N = 503), (B) Overweight (OW; N = 253), and (C) Obese (O; N = 148). Results: Significant differences were found for body weight and composition, basal metabolic rate (BMR) expressed per kg of body mass (normal weight children exhibited the highest values), physical-total energy expenditure, and energy balances between the groups (η²: 0.138 to 0.657; p < .05). In contrast, no differences were found for macronutrients' and total energy intakes, food consumption and quality (η²: 0.002 to 0.099; p > .05) between the three examined groups. Strong, negative correlations were observed between body weight, body fat percentage, PA, and total energy expenditure (r: -0.311 to -0.810; p < .001). Lower, negative correlations were found between body weight, body fat percentage, and macronutrients' daily intakes (r:-0.235 to -0.432; p < .05). BMR and total energy expenditure had strong, negative relative strengths for the determination of body weight and fat percentage. Conclusions: In conclusion, it seems that BMR, PA, and total daily energy expenditure expressed per body weight and not the nutritional and total energy intakes, were the primary determinant parameters of body composition and weight in adolescents.

Associations of obesity, physical activity level, inflammation and cardiometabolic health with COVID-19 mortality: a prospective analysis of the UK Biobank cohort

OBJECTIVES

To investigate the associations of physical activity level with COVID-19 mortality risk across body mass index (BMI) categories, and to determine whether any protective association of a higher physical activity level in individuals with obesity may be explained by favourable levels of cardiometabolic and inflammatory biomarkers.

DESIGN

Prospective cohort study (baseline data collected between 2006 and 2010). Physical activity level was assessed using the International Physical Activity Questionnaire (high: ≥3000 Metabolic Equivalent of Task (MET)-min/week, moderate: ≥600 MET-min/week, low: not meeting either criteria), and biochemical assays were conducted on blood samples to provide biomarker data.

SETTING

UK Biobank.

MAIN OUTCOME MEASURES

Logistic regressions adjusted for potential confounders were performed to determine the associations of exposure variables with COVID-19 mortality risk. Mortality from COVID-19 was ascertained by death certificates through linkage with National Health Service (NHS) Digital.

RESULTS

Within the 259 397 included participants, 397 COVID-19 deaths occurred between 16 March 2020 and 27 February 2021. Compared with highly active individuals with a normal BMI (reference group), the ORs (95% CIs) for COVID-19 mortality were 1.61 (0.98 to 2.64) for highly active individuals with obesity, 2.85 (1.78 to 4.57) for lowly active individuals with obesity and 1.94 (1.04 to 3.61) for lowly active individuals with a normal BMI. Of the included biomarkers, neutrophil count and monocyte count were significantly positively associated with COVID-19 mortality risk. In a subanalysis restricted to individuals with obesity, adjusting for these biomarkers attenuated the higher COVID-19 mortality risk in lowly versus highly active individuals with obesity by 10%.

CONCLUSIONS

This study provides novel evidence suggesting that a high physical activity level may attenuate the COVID-19 mortality risk associated with obesity. Although the protective association may be partly explained by lower neutrophil and monocyte counts, it still remains largely unexplained by the biomarkers included in this analysis.

Maternal prepregnancy BMI and physical activity and type 1 diabetes in the offspring

BACKGROUND

Previous studies showed conflicting results on the association between maternal prepregnancy body mass index (BMI) and type 1 diabetes in the offspring, and the role of maternal prepregnancy physical activity is unclear. We aimed to assess whether maternal prepregnancy BMI and physical activity predict type 1 diabetes in their offspring.

METHODS

Prospective study including women participating in the Nurses' Health Study II with follow-up from 1989 to 2011. Women repeatedly reported their BMI and physical activity, from which prepregnancy exposures were derived; and retrospectively reported their BMI at age 18 and physical activity at ages 18-22, considered early adulthood exposure. We estimated risk ratios (RR) and 95% confidence intervals (95%CI) using generalized estimating equations, adjusted for covariates. Findings at p < 0.05 were considered statistically significant.

RESULTS

We identified 276 cases of type 1 diabetes among offspring (n = 70,168) with maternal prepregnancy information and 448 cases among offspring (n = 111,692) with maternal early adulthood information. Prepregnancy and early adulthood maternal BMI and physical activity were not associated with offspring type 1 diabetes. The RR comparing overweight to normal weight mothers was 1.08 (95%CI: 0.73-1.59) and comparing obese to normal weight was 0.94 (95%CI: 0.49-1.79, p-trend: 0.98). Comparing highest to lowest quartile of maternal physical activity the RR was 0.90 (95%CI: 0.61-1.32; p-trend: 0.73). Maternal type 2 diabetes was associated with an increased risk of type 1 diabetes in the offspring (RR = 1.87; 95%CI: 1.25-2.80).

CONCLUSIONS

Our findings do not support a relationship between maternal prepregnancy BMI or physical activity and the risk of type 1 diabetes in the offspring.

Comparison of total and activity energy expenditure estimates from physical activity questionnaires and doubly labelled water: a systematic review and meta-analysis

Physical activity questionnaires (PAQ) could be suitable tools in free-living people for measures of physical activity, total and activity energy expenditure (TEE and AEE). This meta-analysis was performed to determine valid PAQ for estimating TEE and AEE using doubly labelled water (DLW). We identified data from relevant studies by searching Google Scholar, PubMed and Scopus databases. This revealed thirty-eight studies that had validated PAQ with DLW and reported the mean differences between PAQ and DLW measures of TEE (TEEDLW - TEEPAQ) and AEE (AEEDLW - AEEPAQ). We assessed seventy-eight PAQ consisting of fifty-nine PAQ that assessed TEE and thirty-five PAQ that examined AEE. There was no significant difference between TEEPAQ and TEEDLW with a weighted mean difference of -243·3 and a range of -841·4 to 354·6 kJ/d, and a significant weighted mean difference of AEEDLW - AEE PAQ 414·6 and a range of 78·7-750·5. To determine whether any PAQ was a valid tool for estimating TEE and AEE, we carried out a subgroup analysis by type of PAQ. Only Active-Q, administered in two seasons, and 3-d PA diaries were correlated with TEE by DLW at the population level; however, these two PAQ did not demonstrate an acceptable limit of agreement at individual level. For AEE, no PAQ was correlated with DLW either at the population or at the individual levels. Active-Q and 3-d PA diaries were identified as the only valid PAQ for TEE estimation. Further well-designed studies are needed to verify this result and identify additional valid PAQ.

Obesity and eating behavior from the perspective of twin and genetic research

Obesity has dramatically increased during the last decades and is currently one of the most serious global health problems. We present a hypothesis that obesity is a neuro-behavioral disease having a strong genetic background mediated largely by eating behavior and is sensitive to the macro-environment; we study this hypothesis from the perspective of genetic research. Genetic family and genome-wide-association studies have shown well that body mass index (BMI, kg/m²) is a highly heritable and polygenic trait. New genetic variation of BMI emerges after early childhood. Candidate genes of BMI notably express in brain tissue, supporting that this new variation is related to behavior. Obesogenic environments at both childhood family and societal levels reinforce the genetic susceptibility to obesity. Genetic factors have a clear influence on macro-nutrient intake and appetite-related eating behavior traits. Results on the gene-by-diet interactions in obesity are mixed, but emerging evidence suggests that eating behavior traits partly mediate the effect of genes on BMI. However, more rigorous prospective study designs controlling for measurement bias are still needed.

An integrative machine learning approach to discovering multi-level molecular mechanisms of obesity using data from monozygotic twin pairs

We combined clinical, cytokine, genomic, methylation and dietary data from 43 young adult monozygotic twin pairs (aged 22-36 years, 53% female), where 25 of the twin pairs were substantially weight discordant (delta body mass index > 3 kg m^-2). These measurements were originally taken as part of the TwinFat study, a substudy of The Finnish Twin Cohort study. These five large multivariate datasets (comprising 42, 71, 1587, 1605 and 63 variables, respectively) were jointly analysed using an integrative machine learning method called group factor analysis (GFA) to offer new hypotheses into the multi-molecular-level interactions associated with the development of obesity. New potential links between cytokines and weight gain are identified, as well as associations between dietary, inflammatory and epigenetic factors. This encouraging case study aims to enthuse the research community to boldly attempt new machine learning approaches which have the potential to yield novel and unintuitive hypotheses. The source code of the GFA method is publically available as the R package GFA.

Rural-urban differences in meeting physical activity recommendations and health status in cancer survivors in central Pennsylvania

PURPOSE

This study explored rural-urban differences in meeting physical activity (PA) recommendations and health status in cancer survivors in central Pennsylvania and associations between PA and health status.

METHODS

Cancer survivors (N = 2463) were identified through a state cancer registry and mailed questionnaires assessing PA and health status. Rural-urban residence was based on county of residence at diagnosis. Participants self-reported frequency and duration of leisure-time PA and were classified as meeting: (1) aerobic recommendations (≥ 150 min/week), (2) muscle-strengthening recommendations (≥ 2 times/week), (3) both aerobic and muscle-strengthening recommendations, or (4) neither recommendation. Logistic regression models examined associations between rural-urban residence and meeting PA recommendations and associations between PA and health status, adjusting for age, cancer type, gender, and income.

RESULTS

Nearly 600 (N = 591, 24.0%) cancer survivors returned completed questionnaires (rural 9.5%, urban 90.5%). Half (50.0%) of rural cancer survivors reported no leisure-time PA compared to 35.2% of urban cancer survivors (p = 0.020), and urban cancer survivors were 2.6 times more likely to meet aerobic PA recommendations (95% CI 1.1-6.4). Odds of reporting good physical and mental health were 2.3 times higher among survivors who reported meeting aerobic recommendations compared to those who did not meet PA recommendations (95% CI 1.1-4.5), adjusting for rurality and covariates.

CONCLUSIONS

Results demonstrate persistent rural-urban differences in meeting PA recommendations in cancer survivors and its association with self-reported health.

IMPLICATIONS FOR CANCER SURVIVORS

Findings underscore the need for interventions to increase PA in rural cancer survivors in an effort to improve health status and reduce cancer health disparities.

Do Stairs Inhibit Seniors Who Live on Upper Floors From Going Out?

BACKGROUND

Walk-up buildings are common in China today since they were almost the only type of residential buildings constructed from the 1950s to the 1990s.

OBJECTIVES

This study examined how a vertical mobility obstacle, that is, mandatory stair climbing in walk-up residential buildings, may impact whether seniors go outdoors.

METHODS

We collected and examined 1,608 valid data records from 64 Chinese senior participants in Shanghai wearing Fitbit HR wristbands that tracked their mobility and physical activity for 31 consecutive days. Multilevel mixed-effects logistic regressions were performed on the binary leaving-home-or-not probability by the level of vertical obstacles controlled for physical-demographic factors, socioeconomic factors, outdoor activity habits, and weather.

RESULTS

Our observations revealed that each floor above ground level reduced the likelihood of outdoor trips by approximately one third per floor. After controlling for the physical, demographic, and socioeconomic factors of the participants as well as weather and holidays, we found that significantly fewer going-out incidents were also associated with more frequent outdoor activities within the community, especially in paved areas, but no associations were observed with self-reported visit frequencies to green spaces, senior centers within the community, or other places outside the community.

CONCLUSION

This study offered the in situ observation that seniors' probability of leaving their homes is correlated with the degree of vertical circulation as a mobility barrier (i.e., the number of stairs between their living space and access to the outdoors), which may impact policy making for regulations concerning elevators in residential codes and renovations.

New insights into the association of mid-childhood macronutrient intake to pubertal development in adolescence using nutritional geometry

Nutritional geometry (NG) is a novel dietary analysis approach that considers nutrient balance, rather than single nutrient effects, on health and behaviour. Through NG, recent animal experiments have found that lifespan and reproduction are differentially altered by dietary macronutrient distribution. Epidemiological research using NG reports similar findings for human ageing. Yet, the relation of macronutrient balance to human reproduction, especially reproductive maturation, remains undefined. We studied the impact of childhood macronutrient intake on pubertal maturation, by applying NG to an Australian longitudinal adolescent dataset. Food records, collected at age 8 years from 142 pre-pubertal children (females, 92; males, 50), were analysed for absolute energy, percentage energy and energy-adjusted residuals from protein, carbohydrate and fat. Pubertal stage change (assessed at 8, 13 and 15 years) was modelled to obtain individual mathematical estimates of pubertal timing and tempo. Timing of menarche was recorded. The association of macronutrients to pubertal timing/tempo was assessed via NG, involving generalised additive models and heat maps to aid interpretation. Results showed lower dietary protein (relative to carbohydrate and fat) in girls consistently predicted earlier pubertal timing and menarche, and was related to faster pubertal tempo (all P < 0·05). No significant associations were identified in boys for both timing and tempo. Results suggest a role of non-protein macronutrients in facilitating female maturation; corroborating feeding and reproductive behaviour patterns observed in earlier NG studies of primates. Application of NG to other adolescent datasets is required to confirm the present findings. Such work would advance understanding of how nutrient balance shapes human development and health.

Does Lifestyle Intervention After Gastric Bypass Surgery Prevent Weight Regain? A Randomized Clinical Trial

BACKGROUND

Weight regain after bariatric surgery often starts after 1-2 y, but studies evaluating strategies to prevent weight regain are lacking. The aim of this intervention was to evaluate the efficacy of a 2-y-group-based lifestyle intervention starting approximately 2 y after Roux-en-Y gastric bypass (RYGB) compared with usual care on weight regain and related metabolic risk factors.

METHODS

A total of 165 patients with a mean of 21 months (range 14-32) after RYGB were randomized to a lifestyle intervention group (LIG) or a usual care group (UCG). Of the 165 participants 86% completed the study. The LIG was offered 16 group meetings over 2 y with focus on healthy diet, physical activity, and behavioural strategies to prevent weight regain, in addition to usual care.

RESULTS

Mean (SD) total weight loss at study start was 30.1 ± 8.2%, while weight regain during the intervention was 4.9 ± 7.4 and 4.6 ± 9.2% in the LIG and UCG, respectively (P = 0.84). There were no differences in metabolic risk factors between the groups. The LIG participants attended 8 ± 4 group meetings, with no difference in weight regain between participants with high compared to lower participation. In all the participants, a positive association between weight increase from nadir to study start and weight regain during the intervention was found. Participants who reported physical activity ≥ 150 min/wk had smaller % weight regain compared with less active participants (β = - 5.2 [SE 2.0, 95% CI - 9.1 to - 1.4]).

CONCLUSION

We found no difference in weight regain between LIG and UCG.

Physical activity and breast cancer risk: results from the UK Biobank prospective cohort

BACKGROUND

Previous studies suggest a protective role of physical activity in breast cancer risk, largely based on self-reported activity. We aimed to clarify this association by examining breast cancer risk in relation to self-reported physical activity, informed by accelerometer-based measures in a large subset of participants.

METHODS

We analysed data from 47,456 premenopausal and 126,704 postmenopausal women in UK Biobank followed from 2006 to 2014. Physical activity was self-reported at baseline, and at resurvey in a subsample of 6443 participants. Accelerometer data, measured from 2013 to 2015, were available in 20,785 women. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated by using multivariable-adjusted Cox regression.

RESULTS

A total of 3189 cases were diagnosed during follow-up (mean = 5.7 years). Women in the top compared with the bottom quartile of self-reported physical activity had a reduced risk of both premenopausal (RR 0.75; 95% CI 0.60-0.93) and postmenopausal breast cancer (RR 0.87; 95% CI 0.78-0.98), after adjusting for adiposity. In analyses utilising physical activity values assigned from accelerometer measurements, an increase of 5 milli-gravity was associated with a 21% (RR 0.79; 95% CI 0.66-0.95) reduction in premenopausal and a 16% (RR 0.84; 95% CI 0.73-0.96) reduction in postmenopausal breast cancer risk.

CONCLUSIONS

Greater physical activity is associated with a reduction in breast cancer risk, which appears to be independent of any association it may have on risk through its effects on adiposity.

Eating Behaviors in Healthy Young Adult Twin Pairs Discordant for Body Mass Index

We aimed to study the eating behavioral traits that associate with body mass index (BMI) among BMI-discordant twin pairs. This cross-sectional study examined self-reported eating behaviors in 134 healthy young adult twin pairs (57 monozygotic [MZ] and 77 same-sex dizygotic [DZ]), of whom 29 MZ and 46 DZ pairs were BMI discordant (BMI difference ≥ 3 kg/m2). In both MZ and DZ BMI-discordant pairs, the heavier co-twins reported being less capable of regulating their food intake optimally than their leaner co-twins, mainly due to ‘frequent overeating’. Furthermore, the heavier co-twins reported augmented ‘disinhibited eating’, ‘binge-eating scores’ and ‘body dissatisfaction’. The twins agreed more frequently that the heavier co-twins (rather than the leaner co-twins) ate more food in general, and more fatty food, in particular. No significant behavioral differences emerged in BMI-concordant twin pairs. Overeating — measured by ‘frequent overeating’, ‘disinhibited eating’ and ‘binge-eating score’ — was the main behavioral trait associated with higher BMI, independent of genotype and shared environment.

A within-sibling pair analysis of lifestyle behaviours and BMI z-score in the multi-centre I.Family study

BACKGROUND AND AIMS

By investigating differences in lifestyle behaviours and BMI in sibling pairs, family-level confounding is minimized and causal inference is improved, compared to cross-sectional studies of unrelated children. Thus, we aimed to investigate within-sibling pair differences in different lifestyle behaviours and differences in BMI z-scores in children and adolescents.

METHODS AND RESULTS

We examined three groups of sibling pairs 1) all same-sex sibling pairs with maximum 4 years age difference (n = 1209 pairs from 1072 families in 8 countries, mean age 10.7 years, standard deviation 2.4 years), 2) sibling pairs discordant for overweight (n = 262) and 3) twin pairs (n = 85). Usual dietary intake was estimated by 24-h recalls and time spent in light (LPA) and moderate-to-vigorous physical activity (MVPA) was measured by accelerometers. Screen time, sleep and dieting for weight loss were assessed by questionnaires. Within all 3 groups of sibling pairs, more time in MVPA was associated with lower BMI z-score. Higher energy intake was associated with higher BMI z-score within twin pairs and within all sibling pairs who were not currently dieting for weight loss. Regarding LPA, screen time or sleep duration, no or inconsistent associations were observed for the three groups of sibling pairs.

CONCLUSIONS

MVPA and energy intake were associated with BMI differences within sibling and twin pairs growing up in the same home, thus independent of family-level confounding factors. Future studies should explore whether genetic variants regulating appetite or energy expenditure behaviours account for weight differences in sibling pairs.

Brain reward responses to food stimuli among female monozygotic twins discordant for BMI

Obese individuals are characterized by altered brain reward responses to food. Despite the latest discovery of obesity-associated genes, the contribution of environmental and genetic factors to brain reward responsiveness to food remains largely unclear. Sixteen female monozygotic twin pairs with a mean BMI discordance of 3.96 ± 2.1 kg/m² were selected from the Netherlands Twin Register to undergo functional MRI scanning while watching high- and low-calorie food and non-food pictures and during the anticipation and receipt of chocolate milk. In addition, appetite ratings, eating behavior and food intake were assessed using visual analog scales, validated questionnaires and an ad libitum lunch. In the overall group, visual and taste stimuli elicited significant activation in regions of interest (ROIs) implicated in reward, i.e. amygdala, insula, striatum and orbitofrontal cortex. However, when comparing leaner and heavier co-twins no statistically significant differences in ROI-activations were observed after family wise error correction. Heavier versus leaner co-twins reported higher feelings of hunger (P = 0.02), cravings for sweet food (P = 0.04), body dissatisfaction (P < 0.05) and a trend towards more emotional eating (P = 0.1), whereas caloric intake was not significantly different between groups (P = 0.3). Our results suggest that inherited rather than environmental factors are largely responsible for the obesity-related altered brain responsiveness to food. Future studies should elucidate the genetic variants underlying the susceptibility to reward dysfunction and obesity.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02025595.

Addictive Eating and Its Relation to Physical Activity and Sleep Behavior

The obesity epidemic has led to the exploration of factors contributing to its etiology. Addictive eating, physical activity, and sleep behaviors have all been independently associated with obesity, and recent research suggests plausible interrelationships between food addiction, physical activity, and sleep. This study aims to investigate the relationship between food addiction with physical activity and sleep behavior. Australian adults were invited to complete an online survey which collected information including: demographics, food addiction symptoms, physical activity, sitting time and sleep behavior items. The sample comprised 1344 individuals with a mean age of 39.8 ± 13.1 years (range 18–91), of which 75.7% were female. Twenty-two percent of the sample met the criteria for a diagnosis of food addiction as per the Yale Food Addiction Scale (YFAS 2.0) criteria, consisting of 0.7% with a “mild” addiction, 2.6% “moderate”, and 18.9% classified as having a “severe” food addiction. Food-addicted individuals had significantly less physical activity (1.8 less occasions walking/week, 32 min less walking/week, 58 min less moderate to vigorous physical activity (MVPA)/week; p < 0.05), reported sitting for longer on weekends (83 min more on weekends/week; p < 0.001), and reported significantly more symptoms of poorer-quality sleep (more likely to snore, more likely to have fallen asleep while driving, reported more days of daytime falling asleep; p < 0.05) compared to non-food-addicted individuals. These differences were also observed in those with a “severe” food addiction classification. The present study suggests frequency and duration of physical activity, time spent sitting and sleep duration are associated with food addiction.

The under-reporting of energy intake influences the dietary pattern reported by obese women in the waiting list for bariatric surgery

ABSTRACT Objective To verify the interference of the energy intake under-reporting in the determination of the dietary patterns and nutrient intakes reported by obese women in the waiting list for bariatric surgery. Methods The study included 412 women aged 20 to 45 years with a body mass index ranging from 35 to 60kg/m2 who were on waiting list for bariatric surgery. Data from three reported food intake and physical activity, body weight, and height were used for estimating the reported energy intake, physical activity level, and resting energy expenditure. Subsequently, it was checked the biological plausibility of the reported energy intakes, classifying all participants as plausible reporters or under-reporters. Exploratory factor analysis was used to determine the participants’ dietary patterns. The Mann-Whitney test assessed the reported energy and nutrient intakes between plausible reporters and under-reporters groups. The Z-test assessed the variables of plausible reporters or under-reporters in relation to all participants of the study. Results Six dietary patterns were determined for all participants of study. After excluding information from under-reporting women, only two dietary patterns remained similar to those of all participants, while three other dietary patterns presented different conformations from food subgroups to plausible reporters. The reported energy intake did not present difference for the subgroups of fruits, leaf vegetables and vegetables. However, the energetic value reported for the other food subgroups was higher for the plausible reporters. Conclusion The under-reporting of energy intake influenced the determination of dietary patterns of obese women waiting for bariatric surgery.

The influence of ethnicity and glucose tolerance status on subjective hunger sensations and prospective food intake in overweight and obese Asian and European Australians

AIMS

To examine the influence of ethnicity and glucose tolerance status on subjective sensations and food intake in overweight/obese Asian and European Australians.

METHODS

18 Asians and 26 Europids were classified as normal glucose tolerance (NGT) and impaired glucose tolerance (IGT) based on serial measures of finger-prick glucose following an oral glucose tolerance test (OGTT). Subjective sensations of hunger and satiety were measured before and every 15min after the OGTT using a visual analogue scale (VAS). Food intake was measured covertly from consumption of a buffet style lunch and from self-maintained 24h food records. All serial measurements were converted into total area under the curve (TAUC) and comparisons adjusted for age, fat and fat-free mass.

RESULTS

There was a significant difference interaction between ethnicity (ETH) and glucose tolerance (GTT) for subjective fullness, desire for food and prospective food intake. IGT Asians had significantly greater sensations of fullness, but lesser prospective food and desire to eat, as compared to other groups. However there were no differences in calorie and macronutrient intake at buffet lunch or over 24-h.

CONCLUSION

Interactions between ethnicity and glucose tolerance status in subjective sensations did not transcribe to differences in prospective food intake.

Suitability of random forest analysis for epidemiological research: Exploring sociodemographic and lifestyle-related risk factors of overweight in a cross-sectional design

Aims: Factors that contribute to the development of overweight are numerous and form a complex structure with many unknown interactions and associations. We aimed to explore this structure (i.e. the mutual importance or hierarchy of sociodemographic and lifestyle-related risk factors of being overweight) using a machine-learning technique called random forest (RF). The results were compared with traditional logistic regression (LR) analysis. Methods: The cross-sectional FINRISK 2007 Study included 4757 Finns (aged 25–74 years). Information on participants’ lifestyle and sociodemographic characteristics were collected with questionnaires. Diet was assessed, using a validated food-frequency questionnaire. Height and weight were measured. Participants with a body mass index (BMI) ≥25 kg/m2 were classified as overweight. R-statistical software was used to run RF analysis (‘randomForest’) to derive estimates for variable importance and out-of-bag error, which were compared to a LR model. Results: In total, 704 (32%) men and 1119 (44%) women had normal BMI, whereas 1502 (69%) men and 1432 (57%) women had BMI ≥25. Estimated error rates for the models were similar (RF vs. LR: 42% vs. 40% for men, 38% vs. 35% for women). Both models ranked age, education and physical activity as the most important risk factors for being overweight, but RF ranked macronutrients (carbohydrates and protein) as more important compared to LR. Conclusions: RF did not demonstrate higher power in variable selection compared to LR in our study. The features of RF are more likely to appear beneficial in settings with a larger number of predictors.

Relationship between mean daily energy intake and frequency of consumption of out-of-home meals in the UK National Diet and Nutrition Survey

BACKGROUND

Out-of-home meals have been characterised as delivering excessively large portions that can lead to high energy intake. Regular consumption is linked to weight gain and diet related diseases. Consumption of out-of-home meals is associated with socio-demographic and anthropometric factors, but the relationship between habitual consumption of such meals and mean daily energy intake has not been studied in both adults and children in the UK.

METHODS

We analysed adult and child data from waves 1-4 of the UK National Diet and Nutrition Survey using generalized linear modelling. We investigated whether individuals who report a higher habitual consumption of meals out in a restaurant or café, or takeaway meals at home had a higher mean daily energy intake, as estimated by a four-day food diary, whilst adjusting for key socio-demographic and anthropometric variables.

RESULTS

Adults who ate meals out at least weekly had a higher mean daily energy intake consuming 75-104 kcal more per day than those who ate these meals rarely. The equivalent figures for takeaway meals at home were 63-87 kcal. There was no association between energy intake and frequency of consumption of meals out in children. Children who ate takeaway meals at home at least weekly consumed 55-168 kcal more per day than those who ate these meals rarely. Additionally, in children, there was an interaction with socio-economic position, where greater frequency of consumption of takeaway meals was associated with higher mean daily energy intake in those from less affluent households than those from more affluent households.

CONCLUSIONS

Higher habitual consumption of out-of-home meals is associated with greater mean daily energy intake in the UK. More frequent takeaway meal consumption in adults and children is associated with greater daily energy intake and this effect is greater in children from less affluent households. Interventions seeking to reduce energy content through reformulation or reduction of portion sizes in restaurants, cafés and takeaways could potentially lead to reductions in mean daily energy intake, and may reduce inequalities in health in children.

Does obesity modify the relationship between physical activity and breast cancer risk?

PURPOSE

With only 5-10% of breast cancer cases attributed to genetic inheritance, prevention efforts have focused on modifiable risk factors. Physical activity plays a role in reducing breast cancer risk; however, the interaction between physical activity and other modifiable risk factors, such as obesity, has received little attention.

METHODS

A systematic review and meta-analysis was conducted of studies examining the relationship between physical activity and breast cancer and how it may be modified by body mass index (BMI).

RESULTS

A total of 29 papers were included: 18 were cohort and 11 were case-control studies. Overall, a significant reduction in the relative risk of breast cancer was found in postmenopausal women with high versus low levels of physical activity for women with a BMI <25 kg/m² (RR 0.85, 95% CI 0.79, 0.92) and ≥25 kg/m² (RR 0.87, 95% CI 0.81, 0.93) but not ≥30 kg/m² (RR: 0.93, 95% CI 0.76, 1.13). Physical activity was not associated with a significant reduction in risk of breast cancer in premenopausal women in any BMI group.

CONCLUSION

The results of this meta-analysis suggest that physical activity is associated with a larger breast cancer risk reduction among women who are normal weight or overweight than among women who are obese. Since the included studies used diverse methods for assessment of physical activity and categories of BMI, results should be interpreted with caution and additional work is needed.

People with a body mass index ⩾30 under-report their dietary intake: A systematic review

Under-reporting of total energy intake is a common and well-known source of measurement error in dietary assessment, and evidence suggests that this bias is particularly significant in obese individuals. After a multi-stage selection process of eligible papers, this literature review appraised 34 papers detailing the accuracy of self-reported dietary intake in people with an obese body mass index (BMI ⩾ 30). The available literature to date shows that having a body mass index ⩾30 is associated with significant under-reporting of food intake. Future research should look into identifying effective techniques to reduce this bias in clinical practice.

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.

Leisure-time exercise, physical activity during work and commuting, and risk of metabolic syndrome

Data are limited regarding effect of intensity of leisure-time physical activity on metabolic syndrome. Furthermore, no prospective data are available regarding effect of occupational and commuting physical activity on metabolic syndrome. We compared metabolic syndrome risk by intensity level of leisure-time exercise and by occupational and commuting physical activity in Japanese workers. We followed 22,383 participants, aged 30-64 years, without metabolic syndrome until 2014 March (maximum, 5 years of follow-up). Physical activity was self-reported. Metabolic syndrome was defined by the Joint Statement criteria. We used Cox regression models to estimate the hazard ratios (HRs) and 95 % confidence intervals (CIs) of metabolic syndrome. During a mean follow-up of 4.1 years, 5361 workers developed metabolic syndrome. After adjustment for covariates, compared with engaging in no exercise, the HRs (95 % CIs) for <7.5, 7.5 to <16.5, and ≥16.5 metabolic equivalent hours of exercise per week were 0.99 (0.90, 1.08), 0.99 (0.90, 1.10), and 0.95 (0.83, 1.08), respectively, among individuals engaging in moderate-intensity exercise alone; 0.93 (0.75, 1.14), 0.81 (0.64, 1.02), and 0.84 (0.66, 1.06), among individuals engaging in vigorous-intensity exercise alone; and 0.90 (0.70, 1.17), 0.74 (0.62, 0.89), and 0.81 (0.69, 0.96) among individuals engaging in the two intensities. Higher occupational physical activity was weakly but significantly associated with lower risk of metabolic syndrome. Walking to and from work was not associated with metabolic syndrome. Vigorous-intensity exercise alone or vigorous-intensity combined with moderate-intensity exercise and worksite intervention for physical activity may help prevent metabolic syndrome for Japanese workers.

Intrapair Comparison of Life-Course Appetite and Physical Activity in Elderly Danish Twins: Reliability and Association With Subsequent Survival

Avoiding overeating and being physically active is associated with healthy aging, but methodological issues challenge the quantification of the association. Intrapair comparison of twins is a study design that attempts to minimize social norm-driven biased self-reporting of lifestyle factors. We aimed to investigate the association between self-reported lifestyle factors and subsequent survival in 347 Danish twin pairs aged 70 years and older and, additionally, to investigate the reliability of these self-reports. The twins were interviewed in 2003 and followed for mortality until 2015. They were asked to compare their appetite and physical activity to that of their co-twins in different stages of life. On an individual level, we found a positive association between current self-reported physical activity and late-life survival for elderly twins. This was supported by the intrapair analyses, which revealed a positive association between midlife and current physical activity and late-life survival. A positive association between lower appetite and late-life survival was found generally over the life course in the individual level analyses but not in the intrapair analyses. Kappa values for the inter-twin agreement on who ate the most were 0.16 to 0.34 in different life stages, and for physical activity 0.19 to 0.26, corresponding to a slight-to-fair agreement. Approximately, 50% of the twin pairs were not in agreement regarding physical activity, and of these twins 75% (95% CI: 67-82%) considered themselves the most active twin. These findings indicate a still-existing tendency of answering according to social norms, even in a twin study designed to minimize this.

Improved Physical Activity Screening Enhances Intervention Effectiveness in Ethnic Minority Women

This study identified inconsistencies in physical activity (PA) reported at screening and baseline of a 6-month health promotion intervention and explored how these inconsistencies influenced intervention effectiveness in African American and Hispanic women. Participants completed a telephone screener to determine eligibility for a PA intervention. Inactive participants (≤90 minutes of PA/week) were invited to a baseline assessment, where they completed the International Physical Activity Questionnaire, measuring work, transportation, gardening/housework, and leisure-time PA. Women returned after 6 months to complete an identical post-intervention assessment. Despite being screened as inactive, baseline Questionnaire data indicated that 85.0% of participants (N = 274, M age = 44.6 years, M body mass index = 34.8 kg/m2) were active (>90 minutes of PA/week). Women who reported any work-related PA were 20.9 times more likely to be active at baseline than those who did not (p < .001). Participants who were inactive at both screening and baseline reported greater increases in domestic and gardening PA and total PA from baseline to postintervention (ps < .05). Overweight/obese ethnic minority women may misreport being physically inactive during screening if specific questions about type of PA are not included. Post hoc analyses controlling for screening inaccuracies may improve effectiveness of PA interventions and help intervention programs reach women who may benefit the most.

Physical activity and dietary intake in BMI discordant identical twins

OBJECTIVE

Despite the latest discovery of obesity-associated genes, the rapid rise in global obesity suggests a major role for environmental factors. This study investigated the influence of environmental factors on physical activity and dietary intake independent of genetic effects.

METHODS

Sixteen female monozygotic twins aged 48.8 ± 9.8 years (range 37-70) with a mean BMI discordance of 3.96 ± 2.1 kg/m(2) (range 0.7-8.2) were studied. Physical activity was determined using 7-day accelerometry and dietary intake using 3-day 24-h recalls.

RESULTS

Heavier cotwins were generally less physically active (mean activity counts × 1,000 per day ± SD; 505.5 ± 155.1 vs. 579.6 ± 185.4, P = 0.047) and tended to spend 6.1 min/day less in moderate to vigorous physical activity than leaner cotwins (P = 0.09). Energy intake did not significantly differ within pairs. Total fat intake (en%; P = 0.03), specifically monounsaturated fat (P < 0.01) and polyunsaturated fat (P = 0.08), was higher in the heavier cotwins.

CONCLUSIONS

After eliminating genetic effects, higher BMI is associated with lower overall and moderate to vigorous physical activity and higher intake of total fat, although the direction of causality cannot be determined. Future identification of the environmental factors responsible for these findings might contribute to developing new strategies in managing obesity.

Abdominal obesity and circulating metabolites: A twin study approach

OBJECTIVE

To investigate how obesity, insulin resistance and low-grade inflammation link to circulating metabolites, and whether the connections are due to genetic or environmental factors.

SUBJECTS AND METHODS

Circulating serum metabolites were determined by proton NMR spectroscopy. Data from 1368 (531 monozygotic (MZ) and 837 dizygotic (DZ)) twins were used for bivariate twin modeling to derive the genetic (rg) and environmental (re) correlations between waist circumference (WC) and serum metabolites. Detailed examination of the associations between fat distribution (DEXA) and metabolic health (HOMA-IR, CRP) was performed among 286 twins including 33 BMI-discordant MZ pairs (intrapair BMI difference ≥3 kg/m(2)).

RESULTS

Fat, especially in the abdominal area (i.e. WC, android fat % and android to gynoid fat ratio), together with HOMA-IR and CRP correlated significantly with an atherogenic lipoprotein profile, higher levels of branched-chain (BCAA) and aromatic amino acids, higher levels of glycoprotein, and a more saturated fatty acid profile. In contrast, a higher proportion of gynoid to total fat associated with a favorable metabolite profile. There was a significant genetic overlap between WC and several metabolites, most strongly with phenylalanine (rg=0.40), glycoprotein (rg=0.37), serum triglycerides (rg=0.36), BCAAs (rg=0.30-0.40), HDL particle diameter (rg=-0.33) and HDL cholesterol (rg=-0.30). The effect of acquired obesity within the discordant MZ pairs was particularly strong for atherogenic lipoproteins.

CONCLUSIONS

A wide range of unfavorable alterations in the serum metabolome was associated with abdominal obesity, insulin resistance and low-grade inflammation. Twin modeling and obesity-discordant twin analysis suggest that these associations are partly explained by shared genes but also reflect mechanisms independent of genetic liability.

Great Health Benefits But No Change in Employment or Psychopharmaceutical Drug Use 2 Years After Roux-en-Y Gastric Bypass

BACKGROUND

The aim was to examine health benefits and lifestyle factors after Roux-en-Y gastric bypass (RYGB).

METHODS

Patients (n = 165) were investigated 2 years after RYGB in relation to psychopharmaceutical drugs, employment status, type 2 diabetes mellitus (T2DM), hypertension, metabolic syndrome (MetS), body weight, physical activity (PA), and energy intake.

RESULTS

Excess weight loss (EWL) was 71.4 ± 20.6 %. Prevalence of T2DM, hypertension, and MetS was reduced (P < 0.001 for all). There were no changes in the use of psychopharmaceutical drugs (20.6 vs. 18.8 %, P = 0.549) or in the proportion of unemployed participants (37.7 vs. 33.3 %, P = 0.189) from pre- to post-surgery. Eighty-three percent achieved EWL ≥ 50 %. These subjects had a lower pre-surgery BMI. We found no differences in the prevalence of hypertension, T2DM, and MetS pre-surgery, but the prevalence was lower after surgery compared with subjects with EWL < 50 %.

CONCLUSION

RYGB induced remission of T2DM, hypertension, and MetS 2 years after surgery. The benefit was greatest in the group with EWL ≥ 50 %. Despite excellent weight loss, there was no change in the use of psychopharmaceutical drugs or proportion of unemployed participants.

Physical Activity and Dietary Determinants of Weight Loss Success in the US General Population

OBJECTIVES

I studied lifestyle behaviors of long-term weight losers in a nationally representative sample.

METHODS

I categorized the dietary and physical activity data of 8012 adults from the 2009-2012 National Health and Nutrition Examination Surveys into (1) long-term weight losers (≥ 10% loss for ≥ 1 year), (2) recent weight losers (≥ 10% loss within past year), and (3) overweight or obese individuals who never lost 10% or more of their weight.

RESULTS

Long-term weight losers consumed fewer calories (2072; 95% confidence interval [CI] = 2011, 2134 kcal vs 2211; 95% CI = 2173, 2249 kcal; P < .001) and were more likely to report any vigorous leisure activity (24.5% vs 20.3%; P = .027) than did overweight or obese individuals. Among those engaging in vigorous leisure activity, long-term weight losers reported a greater quantity (188; 95% CI = 159, 223 min × wk(-1) vs 156; 95% CI = 142, 172 min × wk(-1); P = .047). Recent weight losers did not differ from overweight or obese individuals on absolute calorie intake but reported less fat (79; 95% CI = 75, 83 g vs 84; 95% CI = 82, 86 g; P = .016) and more activity.

CONCLUSIONS

Balanced calorie restriction from all macronutrients and physical activity are important behaviors for successful long-term weight loss in the general population.

Longitudinal weight differences, gene expression and blood biomarkers in BMI-discordant identical twins

Background

BMI discordant monozygotic (MZ) twins allows an examination of the causes and consequences of adiposity in a genetically controlled design. Few studies have examined longitudinal BMI discordance in MZ pairs.

Objectives

To study the development over time of BMI discordance in adolescent and adult MZ twin pairs, and to examine lifestyle, metabolic, inflammatory, and gene expression differences associated with concurrent and long-term BMI discordance in MZ pairs.

Subjects/Methods

BMI data from 2775 MZ twin pairs, collected in eight longitudinal surveys and a biobank project between 1991 and 2011, were analyzed to characterize longitudinal discordance. Lifestyle characteristics were compared within discordant pairs (ΔBMI ≥ 3 kg/m²) and biomarkers (lipids, glucose, insulin, CRP, fibrinogen, IL-6, TNF-α and sIL-6R and liver enzymes AST, ALT and GGT) and gene expression were compared in peripheral blood from discordant pairs who participated in the NTR biobank project.

Results

The prevalence of discordance ranged from 3.2% in 1991 (mean age=17, SD=2.4) to 17.4% (N=202 pairs) in 2009 (mean age=35, SD=15), and was 16.5% (N=174) among pairs participating in the biobank project (mean age=35, SD=12). Of 699 MZ with BMI data from 3-5 time points, 17 pairs (2.4%) were long-term discordant (at all available time points; mean follow-up range=6.4 years). Concurrently discordant pairs showed significant differences in self-ratings of which twin eats most (p=2.3×10⁻¹³), but not in leisure time exercise activity (p=0.28) and smoking (p>0.05). Ten out of 14 biomarkers showed significantly more unfavorable levels in the heavier of twin of the discordant pairs (p-values < 0.001); most of these biomarker differences were largest in longitudinally discordant pairs. No significant gene expression differences were identified, although high ranking genes were enriched for Gene Ontology (GO) terms highlighting metabolic gene regulation and inflammation pathways.

Conclusions

BMI discordance is uncommon in adolescent identical pairs but increases with higher pair-mean of BMI at older ages, although long-term BMI discordance is rare. In discordant pairs, the heavier twin had a more unfavorable blood biomarker profile than the genetically matched leaner twin, in support of causal effects of obesity.

Comparative analysis of approaches for assessing energy intake underreporting by female bariatric surgery candidates

OBJECTIVE

To test six variations in the Goldberg equation for evaluating the underreporting of energy intake (EI) among obese women on the waiting list for bariatric surgery, considering variations in resting metabolic rate (RMR), physical activity, and food intake levels in group and individual approaches.

METHODS

One hundred obese women aged 20 to 45 years (33.3 ± 6.08) recruited from a bariatric surgery waiting list participated in the study. Underreporting assessment was based on the difference between reported energy intake, indirect calorimetry measurements and RMR (rEI:RMR), which is compatible with the predicted physical activity level (PAL). Six approaches were used for defining the cutoff points. The approaches took into account variances in the components of the rEI:RMR = PAL equation as a function of the assumed PAL, sample size (n), and measured or estimated RMR.

RESULTS

The underreporting percentage varied from 55% to 97%, depending on the approach used for generating the cutoff points. The ratio rEI:RMR and estimated PAL of the sample were significantly different (p = 0.001). Sixty-one percent of the women reported an EI lower than their RMR. The PAL variable significantly affected the cutoff point, leading to different proportions of underreporting. The RMR measured or estimated in the equation did not result in differences in the proportion of underreporting. The individual approach was less sensitive than the group approach.

CONCLUSION

RMR did not interfere in underreporting estimates. However, PAL variations were responsible for significant differences in cutoff point. Thus, PAL should be considered when estimating underreporting, and even though the individual approach is less sensitive than the group approach, it may be a useful tool for clinical practice.

A break in the obesity epidemic? Explained by biases or misinterpretation of the data?

Recent epidemiologic papers are presenting prevalence data suggesting breaks and decreases in obesity rates. However, before concluding that the obesity epidemic is not increasing anymore, the validity of the presented data should be discussed more thoroughly. We had a closer look into the literature presented in recent reviews to address the major potential biases and distortions, and to develop insights about how to interpret the presented suggestions for a potential break in the obesity epidemic. Decreasing participation rates, the use of reported rather than measured data and small sample sizes, or lack of representativeness, did not seem to explain presented breaks in the obesity epidemic. Further, available evidence does not suggest that stabilization of obesity rates is seen in higher socioeconomic groups only, or that urbanization could explain a potential break in the obesity epidemic. However, follow-ups of short duration may, in part, explain the apparent break or decrease in the obesity epidemic. On the other hand, a single focus on body mass index (BMI) ⩾25 or ⩾30 kg m(-)(2) is likely to mask a real increase in the obesity epidemic. And, in both children and adults, trends in waist circumferences were generally suggesting an increase, and were stronger than those reported for trends in BMI. Studies concluding that there is a recent break in the obesity epidemic need to be interpreted with caution. Reported studies presenting a break were mostly of short duration. Further, focusing on trends in waist circumference rather than BMI leads to a less optimistic conclusion: the public health problem of obesity is still increasing.

In an urban neighborhood, who is physically active and where?

Previous research has shown differences in adult physical activity (PA) levels within urban population, in what types of activities they participated, and where they were active. A sample of 514 urban Philadelphia adult residents was surveyed about level and location of PA. A majority (55.6%) of survey participants reported being vigorously or moderately active or walking enough to meet PA guidelines. A significantly higher proportion of men (vs. women), younger (vs. older) adults and people who were employed (vs. unemployed) met the PA guidelines. Most participants (87.5%) reported walking at least once within the previous week, while 79.3% reported engaging in moderate or vigorous activity. Of the participants who reported being moderately or vigorously active, 64.0% were physically active in indoors only, 22.6% were active in outdoors only, and 13.4% were active in both indoors and outdoors. Significantly fewer black women were active outdoors, compared to all other race/sex combinations (odds ratio = 0.43, p-value < 0.01). In this diverse sample of urban residents, outdoor PA was significantly less frequently reported than indoor PA, particularly for Black women. These findings could help inform urban PA interventions.

The Association Between Diet and Obesity in Specific European Cohorts: DiOGenes and EPIC-PANACEA

This review summarizes evidence from two projects embedded within the European Prospective Investigation into Cancer and Nutrition (EPIC) on the association between dietary factors and obesity risk, in particular change in weight and waist circumference. A total of 12 publications from DiOGenes and six from EPIC-PANACEA were reviewed. The results show that dietary fiber, especially cereal fiber, was inversely associated with weight or waist change, as well as fruit/vegetable intake and the Mediterranean dietary pattern. Energy density and meat consumption were positively associated with the anthropometric changes, as was glycemic index with waist change. Clear associations with macronutrient composition were not observed. In additional studies, interactions with genetic polymorphism were investigated and shown to be present for protein intake and GI, although effect estimates were small. These interactions require replication. These results show that in European populations dietary factors are independently associated with weight/waist change. The findings provide further clues for the prevention of obesity.

Neuroendocrine mechanisms in athletes

Athletic activity may be associated with alterations in various neuroendocrine axes depending on the state of energy availability. In addition, genetic factors and an underlying predilection for polycystic ovarian syndrome (PCOS) may predispose some athletes to develop functional hypothalamic amenorrhea earlier than other athletes. In conditions of low energy availability associated with athletic activity, changes that occur in various neuroendocrine axes are primarily adaptive, and aim to either conserve energy for the most essential functions, or allow the body to draw on its reserves to meet energy needs. These hormonal changes, however, then lead to changes in body composition and bone metabolism. Impaired bone accrual in younger athletes and low bone density in older athletes constitutes the major pathologic consequence of neuroendocrine changes associated with low energy availability. The female athlete triad of low energy availability, menstrual dysfunction, and low bone density is prevalent in certain kinds of sports and activities, particularly endurance sports, gymnastics, and ballet. It is essential to screen for this condition in athletes at every preparticipation physical and during office visits, and to put in place an effective treatment team to manage the triad early, in order to optimize outcomes.

Dysmetabolic signals in "metabolically healthy" obesity

SUMMARY

BACKGROUND

Obesity is associated with decreased insulin sensitivity, atherogenic dyslipidemia and hypertension, but clinical studies have also identified a "metabolically healthy" obese phenotype.

OBJECTIVE

To compare the characteristics of so-called "metabolically healthy" obese (MHO), normal weight subjects (MHNW) and obese with insulin resistance in the United States National Health and Nutrition Examination Survey, 1999-2004 (NHANES).

DESIGN, SETTING AND PARTICIPANTS

Insulin resistance was defined by a homeostatic model assessment (HOMA) value in the upper tertile for the entire NHANES cohort. "Metabolic health" was defined as the absence of diabetes, insulin resistance, metabolic syndrome, and lipid-lowering therapy. The study evaluated the 314 MHO, 1173 MHNW and 843 insulin-resistant obese from among the 6485 non-diabetic, non-pregnant adults aged 20-79 years.

MAIN OUTCOME MEASURES

Demographic, metabolic, nutrition and physical activity features.

RESULTS

MHO and MHNW groups were similar regarding age, and fasting glucose and triglyceride levels. MHO had higher insulin (P < 0.0001), insulin resistance as measured with the homeostatic model (P < 0.0001), non-HDL cholesterol (P = 0.002 in females and P = 0.049 in males) and C-reactive protein levels (P < 0.0001 in females and P = 0.038 in males), and lower high-density lipoprotein cholesterol (HDL) levels (P < 0.002). In addition, MHO females had higher low-density lipoprotein (LDL) cholesterol levels (P = 0.012) and systolic blood pressure (P = 0.02), and lower intake of dietary fiber (P = 0.0009) and levels of physical activity (P = 0.002). Triglycerides levels were normal in the MHO group.

CONCLUSIONS

"Metabolically healthy" obese people have multiple dysmetabolic changes that may signal increased risk for coronary artery disease.

The role of metabonomics as a tool for augmenting nutritional information in epidemiological studies

Most chronic diseases have been demonstrated to have a link to nutrition. Within food and nutritional research there is a major driver to understand the relationship between diet and disease in order to improve health of individuals. However, the lack of accurate dietary intake assessment in free-living populations, makes accurate estimation of how diet is associated with disease risk difficulty. Thus, there is a pressing need to find solutions to the inaccuracy of dietary reporting. Metabolic profiling of urine or plasma can provide an unbiased approach to characterizing dietary intake and various high-throughput analytical platforms have been used in order to implement targeted and nontargeted assays in nutritional clinical trials and nutritional epidemiology studies. This review describes first the challenges presented in interpreting the relationship between diet and health within individual and epidemiological frameworks. Second, we aim to explore how metabonomics can benefit different types of nutritional studies and discuss the critical importance of selecting appropriate analytical techniques in these studies. Third, we propose a strategy capable of providing accurate assessment of food intake within an epidemiological framework in order establish accurate associations between diet and health.

Sedentary behaviours and obesity in adults: the Cardiovascular Risk in Young Finns Study

OBJECTIVE

Sedentary behaviour may contribute to the development of obesity. We investigated the relations between different types of sedentary behaviour and adiposity markers in a well-characterised adult population after controlling for a wide range of potential confounders.

DESIGN

Cross-sectional study.

SETTING

The Cardiovascular Risk in Young Finns Multicenter Study. Participants Sedentary time (TV viewing, computer time, reading, music/radio listening and other relaxation) was assessed with a questionnaire for 1084 women and 909 men aged 30-45 years. Other study variables included occupational and leisure-time physical activity, sleep duration, socioeconomic status, smoking, alcohol consumption, energy intake, adherence to the recommended diet, multiple individual food items, age and genetic variants associated with body mass index (BMI). Primary outcome measures BMI in kg/m(2) and waist circumference (WC in cm).

RESULTS

Of the different sedentary behaviour types, TV viewing was most consistently related to higher BMI and WC, both in men and women. One additional daily TV hour was associated with a 1.81±0.44 cm larger WC in women and 2 cm±0.44 cm in men (both p<0.0001). The association with TV was diluted, but remained highly significant after adjustments with all measured covariates, including several potentially obesogenic food items associated with TV viewing. The intakes of food items such as sausage, beer and soft drinks were directly associated with TV viewing, while the intakes of oat and barley, fish, and fruits and berries were associated indirectly. After these adjustments, non-TV sedentary behaviour remained associated with adiposity indices only in women.

CONCLUSIONS

Out of the different types of sedentary behaviour, TV viewing was most consistently associated with adiposity markers in adults. Partial dilution of these associations after adjustments for covariates suggests that the obesogenic effects of TV viewing are partly mediated by other lifestyle factors.

Examination of the association of diet and persistent cancer-related fatigue: a pilot study

PURPOSE/OBJECTIVES

To examine associations between diet and persistent cancer-related fatigue (PCRF) in cancer survivors.

DESIGN

A cross-sectional pilot study.

SETTING

A university cancer center in Michigan.

SAMPLE

40 adult cancer survivors who were recruited from July 2007 to August 2008 and had completed all cancer treatments at least 12 weeks prior to recording their dietary intakes and fatigue severity.

METHODS

Participants' fatigue was assessed with the Brief Fatigue Inventory (BFI). Based on the BFI score, participants were placed into one of three fatigue levels: no fatigue, moderate fatigue, or severe fatigue. Dietary data were collected using a four-day food diary and analyzed using Nutrition Data System for Research software. Diet data were collected during the same week that fatigue was measured.

MAIN RESEARCH VARIABLES

Fatigue and dietary intake.

FINDINGS

Mean daily intake of whole grains, vegetables, and, in particular, green leafy vegetables and tomatoes were significantly higher in the nonfatigued group compared to fatigued cancer survivors. Also, cancer survivors reporting no fatigue had significantly higher intakes of certain anti-inflammatory and antioxidant nutrients.

CONCLUSIONS

Increased consumption of whole grains, vegetables, and foods rich in certain anti-inflammatory nutrients was associated with decreased levels of PCRF. Additional rigorous studies are required to investigate possible mechanisms and causal relationships regarding the benefits of particular diets on PCRF.

IMPLICATIONS FOR NURSING

Nurses, as one of the main providers of care to cancer survivors, should continue to follow National Comprehensive Cancer Network recommendations until additional data on diet and fatigue are evaluated.

KNOWLEDGE TRANSLATION

Nurses should be aware of national guidelines for nutritional recommendations for treating cancer-related fatigue. In addition, nurses should ask about and record the cancer survivor's typical dietary intake. Referrals to registered dietitians, in accordance with national guidelines for cancer survivors, should be considered when advising a fatigued patient.

Hip structural analysis in adolescent and young adult oligoamenorrheic and eumenorrheic athletes and nonathletes

CONTEXT

Stress fractures are common in endurance athletes. Whereas studies have described distal tibia bone structure in athletes, there are few data regarding hip geometric parameters. Hip structural analysis (HSA) using dual-energy x-ray absorptiometry is a validated technique to assess hip bone structure.

OBJECTIVES

The purpose of this study was to compare hip geometry in young oligoamenorrheic athletes (AAs), eumenorrheic athletes (EAs), and nonathletes using HSA. We hypothesized that AAs would have impaired bone structure compared with that of EAs.

DESIGN

This was a cross-sectional study.

SETTING

The setting was a clinical research center.

SUBJECTS

We enrolled 55 AAs, 24 EAs, and 23 nonathletes of normal weight who were 14 to 22 years old. Athletes ran ≥20 miles/wk or were engaged in weight-bearing sports for ≥4 hours/wk.

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry was used for HSA and hip areal bone mineral density (aBMD).

RESULTS

Hip aBMD Z-scores were lower in AAs and in nonathletes than in EAs (P = .002). A larger proportion of AAs than EAs and nonathletes had hip Z-scores <-1 (30.9, 4.2, 17.4%, P = .01). At the narrow neck, trochanteric region, and femoral shaft, subperiosteal width, cross-sectional moment of inertia, and section modulus were higher in EAs than in nonathletes; values in AAs did not differ from those of nonathletes. Cross-sectional area was lower in AAs and in nonathletes than in EAs. Groups did not differ for cortical thickness or buckling ratio. Group differences were lost after adjustment for lean mass but not aBMD.

CONCLUSIONS

In an eugonadal state, athletic activity confers benefits for hip structure independent of aBMD. This advantage is lost in AAs, who do not differ from nonathletes for most parameters and fare worse than EAs for cross-sectional area.