JAMA have published an obesity themed issue featuring approaches to the prevention and treatment of obesity.
Although the current obesity epidemic has been well documented in children and adults, less is known about long-term risks of adult obesity for a given child at his or her present age and weight. We developed a simulation model to estimate the risk of adult obesity at the age of 35 years for the current population of children in the United States.
We pooled height and weight data from five nationally representative longitudinal studies totaling 176,720 observations from 41,567 children and adults. We simulated growth trajectories across the life course and adjusted for secular trends. We created 1000 virtual populations of 1 million children through the age of 19 years that were representative of the 2016 population of the United States and projected their trajectories in height and weight up to the age of 35 years. Severe obesity was defined as a body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) of 35 or higher in adults and 120% or more of the 95th percentile in children.
Given the current level of childhood obesity, the models predicted that a majority of today’s children (57.3%; 95% uncertainly interval [UI], 55.2 to 60.0) will be obese at the age of 35 years, and roughly half of the projected prevalence will occur during childhood. Our simulations indicated that the relative risk of adult obesity increased with age and BMI, from 1.17 (95% UI, 1.09 to 1.29) for overweight 2-year-olds to 3.10 (95% UI, 2.43 to 3.65) for 19-year-olds with severe obesity. For children with severe obesity, the chance they will no longer be obese at the age of 35 years fell from 21.0% (95% UI, 7.3 to 47.3) at the age of 2 years to 6.1% (95% UI, 2.1 to 9.9) at the age of 19 years.
On the basis of our simulation models, childhood obesity and overweight will continue to be a major health problem in the United States. Early development of obesity predicted obesity in adulthood, especially for children who were severely obese. (Funded by the JPB Foundation and others.)
Objective To assess whether weight loss interventions for adults with obesity affect all cause, cardiovascular, and cancer mortality, cardiovascular disease, cancer, and body weight.
Design Systematic review and meta-analysis of randomised controlled trials (RCTs) using random effects, estimating risk ratios, and mean differences. Heterogeneity investigated using Cochran’s Q and I2 statistics. Quality of evidence assessed by GRADE criteria.
Data sources Medline, Embase, the Cochrane Central Register of Controlled Trials, and full texts in our trials’ registry for data not evident in databases. Authors were contacted for unpublished data.
Eligibility criteria for selecting studies RCTs of dietary interventions targeting weight loss, with or without exercise advice or programmes, for adults with obesity and follow-up ≥1 year.
Results 54 RCTs with 30 206 participants were identified. All but one trial evaluated low fat, weight reducing diets. For the primary outcome, high quality evidence showed that weight loss interventions decrease all cause mortality (34 trials, 685 events; risk ratio 0.82, 95% confidence interval 0.71 to 0.95), with six fewer deaths per 1000 participants (95% confidence interval two to 10). For other primary outcomes moderate quality evidence showed an effect on cardiovascular mortality (eight trials, 134 events; risk ratio 0.93, 95% confidence interval 0.67 to 1.31), and very low quality evidence showed an effect on cancer mortality (eight trials, 34 events; risk ratio 0.58, 95% confidence interval 0.30 to 1.11). Twenty four trials (15 176 participants) reported high quality evidence on participants developing new cardiovascular events (1043 events; risk ratio 0.93, 95% confidence interval 0.83 to 1.04). Nineteen trials (6330 participants) provided very low quality evidence on participants developing new cancers (103 events; risk ratio 0.92, 95% confidence interval 0.63 to 1.36).
Conclusions Weight reducing diets, usually low in fat and saturated fat, with or without exercise advice or programmes, may reduce premature all cause mortality in adults with obesity.
Systematic review registration PROSPERO CRD42016033217.
Reference: BMJ 2017;359:j4849
Importance Obesity is common in children and adolescents in the United States, is associated with negative health effects, and increases the likelihood of obesity in adulthood.
Objective To systematically review the benefits and harms of screening and treatment for obesity and overweight in children and adolescents to inform the US Preventive Services Task Force.
Data Sources MEDLINE, PubMed, PsycINFO, Cochrane Collaboration Registry of Controlled Trials, and the Education Resources Information Center through January 22, 2016; references of relevant publications; government websites. Surveillance continued through December 5, 2016.
Study Selection English-language trials of benefits or harms of screening or treatment (behavior-based, orlistat, metformin) for overweight or obesity in children aged 2 through 18 years, conducted in or recruited from health care settings.
Data Extraction and Synthesis Two investigators independently reviewed abstracts and full-text articles, then extracted data from fair- and good-quality trials. Random-effects meta-analysis was used to estimate the benefits of lifestyle-based programs and metformin.
Main Outcomes and Measures Weight or excess weight (eg, body mass index [BMI]; BMI zscore, measuring the number of standard deviations from the median BMI for age and sex), cardiometabolic outcomes, quality of life, other health outcomes, harms.
Results There was no direct evidence on the benefits or harms of screening children and adolescents for excess weight. Among 42 trials of lifestyle-based interventions to reduce excess weight (N = 6956), those with an estimated 26 hours or more of contact consistently demonstrated mean reductions in excess weight compared with usual care or other control groups after 6 to 12 months, with no evidence of causing harm. Generally, intervention groups showed absolute reductions in BMI z score of 0.20 or more and maintained their baseline weight within a mean of approximately 5 lb, while control groups showed small increases or no change in BMI z score, typically gaining a mean of 5 to 17 lb. Only 3 of 26 interventions with fewer contact hours showed a benefit in weight reduction. Use of metformin (8 studies, n = 616) and orlistat (3 studies, n = 779) were associated with greater BMI reductions compared with placebo: −0.86 (95% CI, −1.44 to −0.29; 6 studies; I2 = 0%) for metformin and −0.50 to −0.94 for orlistat. Groups receiving lifestyle-based interventions offering 52 or more hours of contact showed greater improvements in blood pressure than control groups: −6.4 mm Hg (95% CI, −8.6 to −4.2; 6 studies; I2 = 51%) for systolic blood pressure and −4.0 mm Hg (95% CI, −5.6 to −2.5; 6 studies; I2 = 17%) for diastolic blood pressure. There were mixed findings for insulin or glucose measures and no benefit for lipids. Medications showed small or no benefit for cardiometabolic outcomes, including fasting glucose level. Nonserious harms were common with medication use, although discontinuation due to adverse effects was usually less than 5%.
Conclusions and Relevance Lifestyle-based weight loss interventions with 26 or more hours of intervention contact are likely to help reduce excess weight in children and adolescents. The clinical significance of the small benefit of medication use is unclear.
Objective To estimate the risks of major congenital malformations in the offspring of mothers who are underweight (body mass index (BMI) <18.5), overweight (BMI 25 to <30), or in obesity classes I (BMI 30 to <35), II (35 to <40), or III (≥40) compared with offspring of normal weight mothers (BMI 18.5 to <25) in early pregnancy.
Design Population based cohort study.
Setting Nationwide Swedish registries.
Participants 1 243 957 liveborn singleton infants from 2001 to 2014 in Sweden. Data on maternal and pregnancy characteristics were obtained by individual record linkages.
Exposure Maternal BMI at the first prenatal visit.
Main outcome measures Offspring with any major congenital malformation, and subgroups of organ specific malformations diagnosed during the first year of life. Risk ratios were estimated using generalised linear models adjusted for maternal factors, sex of offspring, and birth year.
Results A total of 43 550 (3.5%) offspring had any major congenital malformation, and the most common subgroup was for congenital heart defects (n=20 074; 1.6%). Compared with offspring of normal weight mothers (risk of malformations 3.4%), the proportions and adjusted risk ratios of any major congenital malformation among the offspring of mothers with higher BMI were: overweight, 3.5% and 1.05 (95% confidence interval 1.02 to 1.07); obesity class I, 3.8% and 1.12 (1.08 to 1.15), obesity class II, 4.2% and 1.23 (1.17 to 1.30), and obesity class III, 4.7% and 1.37 (1.26 to 1.49). The risks of congenital heart defects, malformations of the nervous system, and limb defects also progressively increased with BMI from overweight to obesity class III. The largest organ specific relative risks related to maternal overweight and increasing obesity were observed for malformations of the nervous system. Malformations of the genital and digestive systems were also increased in offspring of obese mothers.
Conclusions Risks of any major congenital malformation and several subgroups of organ specific malformations progressively increased with maternal overweight and increasing severity of obesity. For women who are planning pregnancy, efforts should be encouraged to reduce adiposity in those with a BMI above the normal range.
Reference: BMJ 2017;357:j2563
Obesity causes frailty in older adults; however, weight loss might accelerate age-related loss of muscle and bone mass and resultant sarcopenia and osteopenia.
In this clinical trial involving 160 obese older adults, we evaluated the effectiveness of several exercise modes in reversing frailty and preventing reduction in muscle and bone mass induced by weight loss. Participants were randomly assigned to a weight-management program plus one of three exercise programs — aerobic training, resistance training, or combined aerobic and resistance training — or to a control group (no weight-management or exercise program). The primary outcome was the change in Physical Performance Test score from baseline to 6 months (scores range from 0 to 36 points; higher scores indicate better performance). Secondary outcomes included changes in other frailty measures, body composition, bone mineral density, and physical functions.
A total of 141 participants completed the study. The Physical Performance Test score increased more in the combination group than in the aerobic and resistance groups (27.9 to 33.4 points [21% increase] vs. 29.3 to 33.2 points [14% increase] and 28.8 to 32.7 points [14% increase], respectively; P=0.01 and P=0.02 after Bonferroni correction); the scores increased more in all exercise groups than in the control group (P<0.001 for between-group comparisons). Peak oxygen consumption (milliliters per kilogram of body weight per minute) increased more in the combination and aerobic groups (17.2 to 20.3 [17% increase] and 17.6 to 20.9 [18% increase], respectively) than in the resistance group (17.0 to 18.3 [8% increase]) (P<0.001 for both comparisons). Strength increased more in the combination and resistance groups (272 to 320 kg [18% increase] and 288 to 337 kg [19% increase], respectively) than in the aerobic group (265 to 270 kg [4% increase]) (P<0.001 for both comparisons). Body weight decreased by 9% in all exercise groups but did not change significantly in the control group. Lean mass decreased less in the combination and resistance groups than in the aerobic group (56.5 to 54.8 kg [3% decrease] and 58.1 to 57.1 kg [2% decrease], respectively, vs. 55.0 to 52.3 kg [5% decrease]), as did bone mineral density at the total hip (grams per square centimeter; 1.010 to 0.996 [1% decrease] and 1.047 to 1.041 [0.5% decrease], respectively, vs. 1.018 to 0.991 [3% decrease]) (P<0.05 for all comparisons). Exercise-related adverse events included musculoskeletal injuries.
Of the methods tested, weight loss plus combined aerobic and resistance exercise was the most effective in improving functional status of obese older adults. (Funded by the National Institutes of Health; LITOE ClinicalTrials.gov number, NCT01065636.)
Obesity is a common cause of non-communicable disease. Guidelines recommend that physicians screen and offer brief advice to motivate weight loss through referral to behavioural weight loss programmes. However, physicians rarely intervene and no trials have been done on the subject. We did this trial to establish whether physician brief intervention is acceptable and effective for reducing bodyweight in patients with obesity.
In this parallel, two-arm, randomised trial, patients who consulted 137 primary care physicians in England were screened for obesity. Individuals could be enrolled if they were aged at least 18 years, had a body-mass index of at least 30 kg/m2 (or at least 25 kg/m2 if of Asian ethnicity), and had a raised body fat percentage. At the end of the consultation, the physician randomly assigned participants (1:1) to one of two 30 s interventions. Randomisation was done via preprepared randomisation cards labelled with a code representing the allocation, which were placed in opaque sealed envelopes and given to physicians to open at the time of treatment assignment. In the active intervention, the physician offered referral to a weight management group (12 sessions of 1 h each, once per week) and, if the referral was accepted, the physician ensured the patient made an appointment and offered follow-up. In the control intervention, the physician advised the patient that their health would benefit from weight loss. The primary outcome was weight change at 12 months in the intention-to-treat population, which was assessed blinded to treatment allocation. We also assessed asked patients’ about their feelings on discussing their weight when they have visited their general practitioner for other reasons. Given the nature of the intervention, we did not anticipate any adverse events in the usual sense, so safety outcomes were not assessed. This trial is registered with the ISRCTN Registry, number ISRCTN26563137.
Between June 4, 2013, and Dec 23, 2014, we screened 8403 patients, of whom 2728 (32%) were obese. Of these obese patients, 2256 (83%) agreed to participate and 1882 were eligible, enrolled, and included in the intention-to-treat analysis, with 940 individuals in the support group and 942 individuals in the advice group. 722 (77%) individuals assigned to the support intervention agreed to attend the weight management group and 379 (40%) of these individuals attended, compared with 82 (9%) participants who were allocated the advice intervention. In the entire study population, mean weight change at 12 months was 2·43 kg with the support intervention and 1·04 kg with the advice intervention, giving an adjusted difference of 1·43 kg (95% CI 0·89–1·97). The reactions of the patients to the general practitioners’ brief interventions did not differ significantly between the study groups in terms of appropriateness (adjusted odds ratio 0·89, 95% CI 0·75–1·07, p=0·21) or helpfulness (1·05, 0·89–1·26, p=0·54); overall, four (<1%) patients thought their intervention was inappropriate and unhelpful and 1530 (81%) patients thought it was appropriate and helpful.
A behaviourally-informed, very brief, physician-delivered opportunistic intervention is acceptable to patients and an effective way to reduce population mean weight.
The UK National Prevention Research Initiative.