Association between obesity with disease-free survival and overall survival in triple-negative breast cancer: A meta-analysis
In a systematic review, published in Medicine, the authors sought to investigate whether obesity conveyed a benefit to disease-free survival (DFS) and overall survival (OS) in patients with triple-negative breast cancer. Breast cancer is a complex condition with many different subtypes, which each behave in different ways. Triple negative breast cancer means that there is not enough expression of three receptors, ER, PR and HER-2. It is a rare and often aggressive form of breast cancer, characterised by short recurrence time and greater chance of metastasis via the bloodstream.
The effect of obesity on cancer survival is still contested, and it varies between each type of cancer. The rationale behind it increasing survival is that by having a greater body mass, an obese patient is better able to survive the wasting effects of cancer and its treatment. Conversely, it is argued that many endocrine, metabolic and inflammatory complications that result from a persistent obese state, predispose these patients to cancer and limits there survival ability. This review included data from 9 studies for DFS meta-analysis (4,412 patients) and 8 studies for OS meta-analysis (4,392 patients). It found a number of controversial studies, which suggested obesity conveyed a very significant survival advantage, and others, which concluded that the opposite was true. The result of their analysis is that there was no statistically significant difference between the DFS and OS rates of obese patients compared to normal weight patients in triple negative breast cancer.
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Effects of Physical Activity and Sedentary Behaviour on Brain Response to High‐Calorie Food Cues in Young Adults
Physical activity is known to be an effective method of weight management, due to increased burning of calories. However, this study published in Obesity, found that beyond the calorific effect, there is also a physiological change in the brain in areas associated with reward.
For this study, 22 lean and 18 obese people were selected and their activity levels assessed. Looking at levels of moderate to vigorous physical activity (MVPA), and levels of sedentary behaviour (SB). Next, they ingested some glucose and underwent an fMRI brain scan, and while in the scanner, they were shown images of high-calorie foods, alongside inanimate objects. The researchers looked at 10 regions of the brain known to be responsive to visual food cues. What they found is that those who engaged in MVPA had lower responses to the food cues, and those who engaged in SB, had higher responses. This was true of the healthy weight individuals, and particularly true amongst the obese participants.
The potential mechanism through which physical activity suppresses responses to food cues is still unclear, however what is clear is that reducing SB and increasing MVPA can have positive effects on regions of the brain associated with food perception. Future studies on the underlying mediators of the effects of physical activity on the brain’s response to unhealthy food cues, may provide an interesting new approach to treating obesity.
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Identification of Children’s BMI Trajectories and Prediction from Weight Gain in Infancy
The causes of childhood obesity are not always clear; however, the risk that it poses to adult health outcomes, such as cardiovascular health and premature death, mean that an understanding of common patterns and predictors in infancy are essential. This paper published in Obesity, used data on birthweight and BMI from 1,364 children of ages 24 months to 13 years, to see which patterns are associated with higher risk of becoming overweight or obese.
They found that risk of membership of a high-BMI trajectory could be predicted from as early as 15 months old. Birth weight for gestational age and percent weight increase in the first 15 months are the strongest predictors for following a high-rising trajectory of weight change across childhood. Therefore, high-birth weight should trigger parents and physicians to ensure healthy nutrition. More importantly than that, rapid weight gain in the first 15 months was found to be strongly correlated to high-BMI in later life, meaning that close monitoring of weight-gain in early life, along with intervention, could be a new way of preventing childhood obesity.
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Metabolically Healthy Obesity, Transition to Metabolic Syndrome, and Cardiovascular Risk
This study, published in the Journal of the American College of Cardiology, used data from 6,089 participants of the MESA study to see how having a healthy metabolic profile despite obesity, affects your risk of cardiovascular disease.
The debate over the risk of cardiovascular disease (CVD) associated with the three groups, metabolically healthy normal (MHN), metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO), stems from the apparent contradiction that an individual can be obese (BMI>30 Kg/m2) and yet be free of metabolic syndrome (MetS). This study found that for the vast majority of people, MHO was a transition state towards MUO, and that there was a dosing effect associated with obesity. With the risk of developing MetS being relative to cumulative obesity exposure. They found that almost one-half of those with MHO at baseline, developed MetS during follow-up. Higher MetS duration was also significantly associated with CVD, supporting the theory that risk from obesity is cumulative.
Very few individuals can stay metabolically healthy when continuously exposed to obesity, and the transition to MetS represents a massive increase in risk of CVD. Clinicians should see MHO as an opportunity for early intervention, to prevent later disease, rather than waiting for an unhealthy metabolic profile to develop, by which point, risk has already massively gone up.
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Ectopic fat obesity presents the greatest risk for incident type 2 diabetes: a population-based longitudinal study
Obesity is usually evaluated based on BMI, however more and more research is showing that the distribution of fat within the body is important in determining the harmful metabolic effects of obesity.
In this historical cohort study, conducted in Japan, and published in the international journal of obesity, the authors set out to determine the relationship between different phenotypes of obesity and the onset of type 2 diabetes. The authors used three phenotypes, obesity, visceral fat obesity and ectopic fat obesity; defined as body mass index >25 Kg/m2, waist circumference >90cm in men or >80cm in women, and having fatty liver diagnosed by abdominal ultrasound. Ectopic fat is defined as extra adipose tissue in locations not originally associated with adipose tissue storage. The study included 15,464 participants, who were divided into 8 groups, depending on the absence or presence of each phenotype.
They found that obesity and visceral fat alone had very little effect on the risk of incident type 2 diabetes and that the presence of ectopic fat obesity presented the greatest risk of developing type 2 diabetes. Several studies have shown before that increased adiposity in the liver leads to disrupted metabolic function, including glucose control, however this is the first study to directly compare phenotypes and assess risk. Although there were limitations to this study, the data suggests that body composition analysis should be considered when assessing a patient’s risk of obesity related disease.
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