Obesity is a rapidly increasing public health problem, with surveillance most often based on self-reported values of height and weight. We conducted a systematic review to determine what empirical evidence exists regarding the agreement between objective (measured) and subjective (reported) measures in assessing height, weight and body mass index (BMI). Five electronic databases were searched to identify observational and experimental studies on adult populations over the age of 18. Searching identified 64 citations that met the eligibility criteria and examined the relationship between self-reported and directly measured height or weight. Overall, the data show trends of under-reporting for weight and BMI and over-reporting for height, although the degree of the trend varies for men and women and the characteristics of the population being examined. Standard deviations were large indicating that there is a great deal of individual variability in reporting of results. Combining the results quantitatively was not possible because of the poor reporting of outcomes of interest. Accurate estimation of these variables is important as data from population studies such as those included in this review are often used to generate regional and national estimates of overweight and obesity and are in turn used by decision makers to allocate resources and set priorities in health.
In this paper, we consider the concept of food addiction from a clinical and neuroscientific perspective. Food addiction has an established and growing currency in the context of models of overeating and obesity, and its acceptance shapes debate and research. However, we argue that the evidence for its existence in humans is actually rather limited and, in addition, there are fundamental theoretical difficulties that require consideration. We therefore review food addiction as a phenotypic description, one that is based on overlap between certain eating behaviours and substance dependence. To begin, we consider limitations in the general application of this concept to obesity. We share the widely held view that such a broad perspective is not sustainable and consider a more focused view: that it underlies particular eating patterns, notably binge eating. However, even with this more specific focus, there are still problems. Validation of food addiction at the neurobiological level is absolutely critical, but there are inconsistencies in the evidence from humans suggesting that caution should be exercised in accepting food addiction as a valid concept. We argue the current evidence is preliminary and suggest directions for future work that may provide more useful tests of the concept.
Obesity is rising in the obstetric population, yet there is an absence of services and guidance for the management of maternal obesity. This systematic review aimed to investigate relationships between obesity and impact on obstetric care. Literature was systematically searched for cohort studies of pregnant women with anthropometric measurements recorded within 16‐weeks gestation, followed up for the term of the pregnancy, with at least one obese and one comparison group. Two researchers independently data‐extracted and quality‐assessed each included study. Outcome measures were those that directly or indirectly impacted on maternity resources. Primary outcomes included instrumental delivery, caesarean delivery, duration of hospital stay, neonatal intensive care, neonatal trauma, haemorrhage, infection and 3rd/4th degree tears. Meta‐analysis shows a significant relationship between obesity and increased odds of caesarean and instrumental deliveries, haemorrhage, infection, longer duration of hospital stay and increased neonatal intensive care requirement. Maternal obesity significantly contributes to a poorer prognosis for mother and baby during delivery and in the immediate post‐partum period. National clinical guidelines for management of obese pregnant women, and public health interventions to help safeguard the health of mothers and their babies are urgently required.
We provide arguments to the debate question and update a previous meta‐analysis with recently published studies on effects of sugar‐sweetened beverages ( SSBs ) on body weight/composition indices ( BWIs ). We abstracted data from randomized controlled trials examining effects of consumption of SSBs on BWIs . Six new studies met these criteria: (i) human trials, (ii) ≥ 3 weeks duration, (iii) random assignment to conditions differing only in consumption of SSBs and (iv) including a BWI outcome. Updated meta‐analysis of a total of seven studies that added SSBs to persons’ diets showed dose‐dependent increases in weight. Updated meta‐analysis of eight studies attempting to reduce SSB consumption showed an equivocal effect on BWIs in all randomized subjects. When limited to subjects overweight at baseline, meta‐analysis showed a significant effect of roughly 0.25 standard deviations (more weight loss/less weight gain) relative to controls. Evidence to date is equivocal in showing that decreasing SSB consumption will reduce the prevalence of obesity. Although new evidence suggests that an effect may yet be demonstrable in some populations, the integrated effect size estimate remains very small and of equivocal statistical significance. Problems in this research area and suggestions for future research are highlighted.
Few studies have examined both the relative magnitude of association and the discriminative capability of multiple indicators of obesity with cardiovascular disease (CVD) mortality risk. We conducted an individual-participant meta-analysis of nine cohort studies of men and women drawn from the British general population resulting in sample of 82864 individuals. Body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) were measured directly. There were 6641 deaths (1998 CVD) during a mean of 8.1 years of follow-up. After adjustment, a one SD higher in WHR and WC was related to a higher risk of CVD mortality (hazard ratio [95% CI]): 1.15 (1.05-1.25) and 1.15 (1.04-1.27), respectively. The risk of CVD mortality also increased linearly across quintiles of both these abdominal obesity markers with a 66% increased risk in the highest quintile of WHR. In age- and sex-adjusted models only, BMI was related to CVD mortality but not in any other analyses. No major differences were revealed in the discrimination capabilities of models with BMI, WC or WHR for cardiovascular or total mortality outcomes. In conclusion, measures of abdominal adiposity, but not BMI, were related to an increased risk of CVD mortality. No difference was observed in discrimination capacities between adiposity markers.
Few studies have examined both the relative magnitude of association and the discriminative capability of multiple indicators of obesity with cardiovascular disease (CVD) mortality risk. We conducted an individual‐participant meta‐analysis of nine cohort studies of men and women drawn from the British general population resulting in sample of 82 864 individuals. Body mass index (BMI), waist circumference (WC) and waist‐to‐hip ratio (WHR) were measured directly. There were 6641 deaths (1998 CVD) during a mean of 8.1 years of follow‐up. After adjustment, a one SD higher in WHR and WC was related to a higher risk of CVD mortality (hazard ratio [95% CI]): 1.15 (1.05–1.25) and 1.15 (1.04–1.27), respectively. The risk of CVD mortality also increased linearly across quintiles of both these abdominal obesity markers with a 66% increased risk in the highest quintile of WHR. In age‐ and sex‐adjusted models only, BMI was related to CVD mortality but not in any other analyses. No major differences were revealed in the discrimination capabilities of models with BMI, WC or WHR for cardiovascular or total mortality outcomes. In conclusion, measures of abdominal adiposity, but not BMI, were related to an increased risk of CVD mortality. No difference was observed in discrimination capacities between adiposity markers.
China faces a major increase in cardiovascular disease, yet there is limited population‐based data on risk factors, particularly in children. Fasting blood samples, anthropometry and blood pressure were collected on 9,244 children and adults aged ≥7 years in late 2009 as part of the national China Health and Nutrition Survey. Prevalent overweight, elevated blood pressure, and cardiometabolic risk factors: glucose, HbA1c, triglycerides (TG), total cholesterol (TC), high‐ and low‐density lipoprotein cholesterol (HDL‐C and LDL‐C), and C‐reactive protein (CRP) are presented. We found that 11% of Chinese children and 30% of Chinese adults are overweight. Rates of diabetes, dyslipidaemia, hypertension and inflammation are high and increased with age and were associated with urbanization. Approximately 42% of children have at least one of the following: pre‐diabetes or diabetes, hypertension, high TC, LDL‐C, TG, and CRP and low HDL‐C, as do 70% men and 60% women aged 18–40 years and >90% of men and women ≥60 years. In sum, the HbA1c findings suggest that as many as 27.7 million Chinese children and 334 million Chinese adults may be pre‐diabetic or diabetic. The high prevalence in less urban areas and across all income levels suggests that cardiometabolic risk is pervasive across rural and urban China.
This study aims to quantitatively summarize the association between night shift work and the risk of metabolic syndrome ( MetS ), with special reference to the dose–response relationship with years of night shift work. We systematically searched all observational studies published in E nglish on P ub M ed and E mbase from 1971 to 2013. We extracted effect measures (relative risk, RR ; or odd ratio, OR ) with 95% confidence interval ( CI ) from individual studies to generate pooled results using meta‐analysis approach. Pooled RR was calculated using random‐ or fixed‐effect model. D owns and B lack scale was applied to assess the methodological quality of included studies. A total of 13 studies were included. The pooled RR for the association between ‘ever exposed to night shift work’ and MetS risk was 1.57 (95% CI = 1.24–1.98, p heterogeneity = 0.001), while a higher risk was indicated in workers with longer exposure to night shifts ( RR = 1.77, 95% CI = 1.32–2.36, p heterogeneity = 0.936). Further stratification analysis demonstrated a higher pooled effect of 1.84 (95% CI = 1.45–2.34) for studies using the NCEP ‐ ATPIII criteria, among female workers ( RR = 1.61, 95% CI = 1.10–2.34) and the countries other than A sia ( RR = 1.65, 95% CI = 1.39–1.95). Sensitivity analysis confirmed the robustness of the results. No evidence of publication bias was detected. The present meta‐analysis suggested that night shift work is significantly associated with the risk of MetS , and a positive dose–response relationship with duration of exposure was indicated.
Personality is thought to affect obesity risk but before such information can be incorporated into prevention and intervention plans, robust and converging evidence concerning the most relevant personality traits is needed. We performed a meta-analysis based on individualparticipant data from nine cohort studies to examine whether broad-level personality traits predict the development and persistence of obesity (n=78,931 men and women; mean age 50 years). Personality was assessed using inventories of the Five-Factor Model (extraversion, neuroticism, agreeableness, conscientiousness and openness to experience). High conscientiousness reflecting high self-control, orderliness and adherence to social norms was associated with lower obesity risk across studies (pooled odds ratio [OR]=0.84; 95% confidence interval [CI]=0.800.88 per 1 standard deviation increment in conscientiousness). Over a mean follow-up of 5.4 years, conscientiousness predicted lower obesity risk in initially non-obese individuals (OR=0.88, 95% CI=0.850.92; n=33,981) and was associated with greater likelihood of reversion to non-obese among initially obese individuals (OR=1.08, 95% CI=1.011.14; n=9,657). Other personality traits were not associated with obesity in the pooled analysis, and there was substantial heterogeneity in the associations between studies. The findings indicate that conscientiousness may be the only broad-level personality trait of the Five-Factor Model that is consistently associated with obesity across populations.
This meta‐analysis synthesizes current literature concerning the effects of active video games ( AVGs ) on children/adolescents’ health‐related outcomes. A total of 512 published studies on AVGs were located, and 35 articles were included based on the following criteria: (i) data‐based research articles published in English between 1985 and 2015; (ii) studied some types of AVGs and related outcomes among children/adolescents and (iii) had at least one comparison within each study. Data were extracted to conduct comparisons for outcome measures in three separate categories: AVGs and sedentary behaviours, AVGs and laboratory‐based exercise, and AVGs and field‐based physical activity. Effect size for each entry was calculated with the Comprehensive Meta‐Analysis software in 2015. Mean effect size ( H edge's g) and standard deviation were calculated for each comparison. Compared with sedentary behaviours, AVGs had a large effect on health outcomes. The effect sizes for physiological outcomes were marginal when comparing AVGs with laboratory‐based exercises. The comparison between AVGs and field‐based physical activity had null to moderate effect sizes. AVGs could yield equivalent health benefits to children/adolescents as laboratory‐based exercise or field‐based physical activity. Therefore, AVGs can be a good alternative for sedentary behaviour and addition to traditional physical activity and sports in children/adolescents.
Recent epidemiological and ecological trends in humans indicate a possible causal relationship between sleep duration and energy balance. We aimed to find experimental evidence that has tested this relationship between sleep duration and measures of body composition, food intake or biomarkers related to food intake. We conducted a systematic literature review using six databases throughout 7 A ugust 2014. We sought reports of randomized controlled trials where sleep duration was manipulated and measured outcomes were body weight or other body composition metrics, food intake, and/or biomarkers related to eating. We found 18 unique studies meeting all criteria: eight studies with an outcome of body weight (4 – increased sleep, 4 – reduced sleep); four studies on food intake; four studies of sleep restriction on total energy expenditure and three of respiratory quotient; and four studies on leptin and/or ghrelin. Few controlled experimental studies have addressed the question of the effect of sleep on body weight/composition and eating. The available experimental literature suggests that sleep restriction increases food intake and total energy expenditure with inconsistent effects on integrated energy balance as operationalized by weight change. Future controlled trials that examine the impact of increased sleep on body weight/energy balance factors are warranted.
There is currently no consensus regarding the optimal protocol for measurement of waist circumference (WC), and no scientific rationale is provided for any of the WC protocols recommended by leading health authorities. A panel of experts conducted a systematic review of 120 studies (236 samples) to determine whether measurement protocol influenced the relationship of WC with morbidity of cardiovascular disease (CVD) and diabetes and with mortality from all causes and from CVD. Statistically significant associations with WC were reported for 65% (152) of the samples across all outcomes combined. Common WC protocols performed measurement at the minimal waist (33%), midpoint (26%) and umbilicus (27%). Non‐significant associations were reported for 27% (64) of the samples. Most of these protocols measured WC at the midpoint (36%), umbilicus (28%) or minimal waist (25%). Significant associations were observed for 17 of the remaining 20 samples, but these were not significant when adjustment was made for covariates. For these samples, the most common WC protocols were the midpoint (35%) and umbilicus (30%). Similar patterns of association between the outcomes and all WC protocols were observed across sample size, sex, age, race and ethnicity. Our findings suggest that WC measurement protocol has no substantial influence on the association between WC, all‐cause and CVD mortality, CVD and diabetes.
Increased energy intakes are contributing to overweight and obesity. Growing evidence supports the role of protein appetite in driving excess intake when dietary protein is diluted (the protein leverage hypothesis). Understanding the interactions between dietary macronutrient balance and nutrient‐specific appetite systems will be required for designing dietary interventions that work with, rather than against, basic regulatory physiology. Data were collected from 38 published experimental trials measuring ad libitum intake in subjects confined to menus differing in macronutrient composition. Collectively, these trials encompassed considerable variation in percent protein (spanning 8–54% of total energy), carbohydrate (1.6–72%) and fat (11–66%). The data provide an opportunity to describe the individual and interactive effects of dietary protein, carbohydrate and fat on the control of total energy intake. Percent dietary protein was negatively associated with total energy intake (F = 6.9, P < 0.0001) irrespective of whether carbohydrate (F = 0, P = 0.7) or fat (F = 0, P = 0.5) were the diluents of protein. The analysis strongly supports a role for protein leverage in lean, overweight and obese humans. A better appreciation of the targets and regulatory priorities for protein, carbohydrate and fat intake will inform the design of effective and health‐promoting weight loss diets, food labelling policies, food production systems and regulatory frameworks.
This systematic review and meta‐analysis aimed to quantify weight gain after smoking cessation and the difference in weight gain between quitters and continuing smokers. Five electronic databases were searched before J anuary 2015. Population‐based prospective cohort studies were included if they recorded the weight change of adult smokers from baseline (before smoking cessation) to follow‐up (at least 3 months after cessation). Thirty‐five cohort studies were identified, including 63,403 quitters and 388,432 continuing smokers. The mean weight gain was 4.10 kg (95% confidence interval [ CI ]: 2.69, 5.51) and body mass index ( BMI ) gain was 1.14 kg m −2 (95% CI : 0.50, 1.79) among quitters. Compared with continuing smoking, quitting smoking was significantly associated with absolute weight (adjusted mean difference [ MD ]: 2.61 kg; 95% CI : 1.61, 3.60) and BMI gain (adjusted MD : 0.63 kg m −2 ; 95% CI : 0.46, 0.80). Subgroup analyses using geographic region found that the difference in weight gain was considerably greater in studies from N orth A merica than from A sia. Follow‐up length was identified as a source of heterogeneity, such that studies with longer follow‐up showed greater difference in weight gain. Effective strategies are needed to encourage smokers to quit irrespective of potential weight gain and to help quitters avoid excess weight gain.
A systematic review and meta‐analysis of randomized controlled trials was conducted to examine the effects of probiotic supplementation on body weight, body mass index (BMI), fat mass and fat percentage in subjects with overweight (BMI 25–29.9 kg m −2 ) or obesity (BMI ≥30 kg m −2 ). MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials were searched for studies published between 1946 and September 2016. A meta‐analysis, using a random effects model, was performed to calculate the weighted mean difference between the intervention and control groups. Of 800 studies identified through the literature search, 15 were finally included. The studies comprised a total of 957 subjects (63% women), with the mean BMI being 27.6 kg m −2 and the duration of the interventions ranging from 3 to 12 weeks. Administration of probiotics resulted in a significantly larger reduction in body weight (weighted mean difference [95% confidence interval]; −0.60 [−1.19, −0.01] kg, I 2 = 49%), BMI (−0.27 [−0.45, −0.08] kg m −2 , I 2 = 57%) and fat percentage (−0.60 [−1.20, −0.01] %, I 2 = 19%), compared with placebo; however, the effect sizes were small. The effect of probiotics on fat mass was non‐significant (−0.42 [−1.08, 0.23] kg, I 2 = 84%).
The contribution of rapid weight gain (RWG) during infancy to later adiposity has received considerable investigation. The present systematic review and meta‐analysis aimed to update the literature on association between RWG and subsequent adiposity outcomes. Electronic searches were undertaken in EMBASE, MEDLINE, psycINFO, PubMed and ScienceDirect. Studies that examined the associations between RWG (a change in weight z ‐scores > 0.67) during infancy (from birth to age 2 years) and subsequent adiposity outcomes were included. Random effects meta‐analysis was conducted to obtain the weighted‐pooled estimates of the odds of overweight/obesity for those with RWG. Seventeen studies were eligible for inclusion with the majority of studies (15/17) being of high/acceptable quality and reporting positive associations between RWG during infancy and later adiposity outcomes. RWG in infancy was associated with overweight/obesity from childhood to adulthood (pooled odds ratio = 3.66, 95% confidence interval: 2.59–5.17, I 2 > 75%). Subgroup analyses revealed that RWG during infancy was associated with higher odds of overweight/obesity in childhood than in adulthood, and RWG from birth to 1 year was associated with higher odds of overweight/obesity than RWG from birth to 2 years. The present study supports that RWG during infancy is a significant predictor of adiposity in later life.
This study aims to investigate the impact of gestational diabetes mellitus (GDM) on the long‐term risks of diabetes in women with prior GDM, including the effect at different time periods after GDM. We searched PubMed and other databases to retrieve articles which were published prior to February 28, 2017. Cohort studies which evaluated the risk and time of onset of diabetes postpartum in women with and without GDM were included. Meta‐analysis with random effects models was used to obtain pooled relative risks and 95% confidence intervals for the risk of diabetes. Subgroup analyses were performed to check for different effect sizes as well as consistency across groups. Multivariable logistic regression was used to adjust for confounders. Thirty cohort studies with 2,626,905 pregnant women were included. Women with prior GDM had 7.76‐fold (95% confidence intervals: 5.10–11.81) unadjusted pooled risk of diabetes as compared with women without GDM, whilst the adjusted risk was 17.92‐fold (16.96–18.94). The adjusted ORs of GDM for diabetes among women at <3, ≥3 – <6 and ≥6 – <10 years after GDM were 5.37 (3.51–9.34), 16.55 (16.08–17.04) and 8.20 (4.53–14.86), respectively. Women with prior GDM had substantially increased risk of diabetes, with the risk highest during the 3–6 years after GDM.
There is currently no consensus regarding the optimal protocol for measurement of waist circumference (WC), and no scientific rationale is provided for any of the WC protocols recommended by leading health authorities. A panel of experts conducted a systematic review of 120 studies (236 samples) to determine whether measurement protocol influenced the relationship of WC with morbidity of cardiovascular disease (CVD) and diabetes and with mortality from all causes and from CVD. Statistically significant associations with WC were reported for 65% (152) of the samples across all outcomes combined. Common WC protocols performed measurement at the minimal waist (33%), midpoint (26%) and umbilicus (27%). Non-significant associations were reported for 27% (64) of the samples. Most of these protocols measured WC at the midpoint (36%), umbilicus (28%) or minimal waist (25%). Significant associations were observed for 17 of the remaining 20 samples, but these were not significant when adjustment was made for covariates. For these samples, the most common WC protocols were the midpoint (35%) and umbilicus (30%). Similar patterns of association between the outcomes and all WC protocols were observed across sample size, sex, age, race and ethnicity. Our findings suggest that WC measurement protocol has no substantial influence on the association between WC, all-cause and CVD mortality, CVD and diabetes.
Recent estimates indicate that two billion people are overweight or obese and hence are at increased risk of cardiovascular disease and its comorbidities. However, this may be an underestimate of the true extent of the problem, as the current method used to define overweight may lack sensitivity, particularly in some ethnic groups where there may be an underestimate of risk. Measures of central obesity may be more strongly associated with cardiovascular risk, but there has been no systematic attempt to compare the strength and nature of the associations between different measures of overweight with cardiovascular risk across ethnic groups. Data from the Obesity in Asia Collaboration, comprising 21 cross‐sectional studies in the Asia‐Pacific region with information on more than 263 000 individuals, indicate that measures of central obesity, in particular, waist circumference (WC), are better discriminators of prevalent diabetes and hypertension in Asians and Caucasians, and are more strongly associated with prevalent diabetes (but not hypertension), compared with body mass index (BMI). For any given level of BMI, WC or waist : hip ratio, the absolute risk of diabetes or hypertension tended to be higher among Asians compared with Caucasians, supporting the use of lower anthropometric cut‐points to indicate overweight among Asians.