Gastric banding achieved more weight loss in obese teens

According to a study published in the February 10 issue of JAMA, gastric banding achieved significant weight loss than lifestyle intervention in severely obese adolescents.


Australian researchers conducted a randomised controlled trial to compare the outcomes of gastric banding with a lifestyle program on adolescent obesity including 50 people aged between 14 and 18 with a BMI >35. The study, carried out between 2005 and 2008, was followed up for 2 years.


The researchers found that more than 50% weight loss was achieved by 84% in the gastric banding group compared with just 12% in the lifestyle group. The average weight loss was about 34 kg in the gastric banding group and only 3 kg in the lifestyle group. The differences between the 2 groups were significant for all weight measures at 24 months with 24 in the gastric banding group and 18 in the lifestyle group completed the study.


The authors concluded that "Among obese adolescent participants, use of gastric banding compared with lifestyle intervention resulted in a greater percentage achieving a loss of 50% of excess weight" and "There were associated benefits to health and quality of life".


Critics say there are limitations to the study including recruitment bias, small number of participants and short follow-up period. An accompanying editorial "Surgical Treatment of Obesity in Adolescence" notes that this study provides important evidence about the bebefits and risks of bariatric surgery.


Source:"Laparoscopic Adjustable Gastric Banding in Severely Obese Adolescents : A Randomized Trial" JAMA. 2010;303(6):519-526 (f/t via Athens)

Higher antibiotic doses to bigger people

Two doctors said in The Lancet Viewpoint, although drug treatments are tailored for individual patients, most dosing regimens, do not take patient's body size into consideration.

They argued that with increasing level of obesity worldwide, the standard dose of antibiotics for all adults is outdated because it may not be strong enough to clear the infection in taller and larger adults and resistance may be developed. Likewise, smaller patients may get too much drug, and suffer greater side-effects as a result.

They said that a patient's bodyweight should be taken into account when calculating their dose of antibiotics to achieve effectivenesss and safety.

Critics say that this review is based on authors' views and experience and is a valuable discussion. Changes to current prescribing would be costly and complicated, therfore further research and follow-up of previous study data would be needed.

Source:
"Adjustment of dosing of antimicrobial agents for bodyweight in adults". The Lancet, 375(9710):248-251

Editorial: "Prescribing medicines: size matters". The Lancet 2010; 375(9710): 172

Obesity shortens life

Oxford researchers carried out a meta-analysis 0f 57 cohort studies with a total of 894,576 people to examine the relationship between MBI and mortality. Most of the participants were recruited during 1970s and 80s with an average of 8 years further follow up. They were aged 46 in average at enrollment with BMI 24.8kg/sq m ( BMI>30kg/sq m were considered obese).

Researchers found that people with a normal BMI (22.5 - 25kg/sq m) had the lowest overall mortality. Every 5kg/sq m rise in BMI above 25 increased the risk of death by 30% compared with people having normal BMI. They estimated that average lifespan is reduced by 8 - 10 year for people with BMI above 35kg/sq m. The greatest increase in death risk was associated with diabetes, kidney or liver disease, followed by vascular mortality. They concluded that BMI itself is a strong predictor of overall mortality.

Critics say that this research gives actual figures on mortality risk associated with obesity but they argue that the increased death rate cannot be attributed to obesity alone, diabetes, high blood pressure and bad cholesterol are associated particularly with increased risk of cardiovascular mortality with high BMI, also the effects of diet, exercise and socioeconomic status were not taken into acount.

Source: "Body-mass index and cause-specific mortality in 900,000 adults: collaborative analyses of 57 prospective studies". The Lancet 2009; early online publication, March 18

Obesity increases dementia risk

Multiple news sources reported a systematic review of 10 published studies in 5 different countries that found obesity increases the risk of dementia in general by 42% and Alzheimer's by 80%. Researchers also found that people who are underweight have an elevated risk of dementia and its subtype. The study also included a meta-analysis of 7 stuides with at least 5 years followed up.

The senior author said that preventing obesity at a younger age could reduce the number of dementia patients in the US.

Source: "Obesity and central obesity as risk factors for incident dementia and its subtypes: a systematic review and meta-analysis". Obesity Reviews 9(3):204-218, May 2008

Childhood obesity has lifelong effects

According to 2 studies published in this week's NEJM, children worldwide are gaining excessive weight that causes serious health problems in their adulthood.

The studies found that high body mass index in childhood increases the risk of coronary heart disease in adulthood. The authors said that healthy food and physical activities are the keys to prevent this health problem, but a national strategy involving parents to help these children to maintain an appropraite weight to reduce the future risk of heart disease is urgently needed.

Source:"Childhood Body-Mass Index and the Risk of Coronary Heart Disease in Adulthood" NEJM 357(23):2329-2337 (free full text)


"Adolescent Overweight and Future Adult Coronary Heart Disease" NEJM 357(23):2371-2379
(free full text)

Prostate cancer may be missed in obese men

A new study found dcotors may be missing a large number of cancer in obese men because the test for prostate-specific antigen (PSA) is unreliable. It may explain why obese men tend to have more aggressive cancer.

Researchers said doctors must take body weight into account when reading test results for prostate cancer because higher body mass index (BMI) is linked to higher plama volume that can lead to dilution of PSA.

Source: "Obesity-Related Plasma Hemodilution and PSA Concentration Among Men With Prostate Cancer" JAMA. 2007;298(19):2275-2280

Being overweight does not increase death risk from cancer or heart disease

A new American federal report found that overweight increase the risks of dying from diabetes and kidney disease but not cancer or heart disease. The findings are based on decades of cause-of-death data collected by federal scientists. They also found a protective effect against all other causes of death.

Some dismissed the findings as fundamentally flawed while others saw that the dangers of being fat have been exaggerated. The author said the findings does not mean being overweight is good, but is associated with less mortality than expected.

Source : "Cause-Specific Excess Deaths Associated With Underweight, Overweight, and Obesity" JAMA. 2007;298(17):2028-2037

Hungry hormone and over-eating

British scientists discovered that the hormone Leptin, made by fat cells, is responsible for reducing hunger and increasing the feeling of fullness hunger, it also controls the fondness for food.The findings could lead to new insights into obesity and how to treat the condition.

They studied two teenagers with a rare genetic disorder that do not produce any leptin. They eat excessively and are severely obese. However, when they were treated with leptin, they became more choosey about food, ate less and lost weight.

Their brain activities in response to different food and non-food pictures were recorded using fMRI. The scientists found that the pictures stimulated activity in the area called striatal regions that are associated with pleasant emotions and desires. When the patients were treated with leptin, responses to food pictures in these area were reduced and were activated mostly by foods the patients liked and only when they were hungry.

The researchers said that the findings should "encourage a more sympathetic attitude to people with weight problems" and "will be a key step in the prevention and treatment of obesity". Some experts said such a small study cannot provide conclusive evidence. Read the press release.


The article "Leptin regulates striatal regions and human eating behaviour" is published online in the journal Science, 9 August 2007 (subscription required)

Obesity is socially contagious

A new study that looked at data collected over 32 years from the Framingham Heart Study, an ongoing cardiovascular study begun in 1948, found that when an individual became obese, the chance that a friend will become obese increased by 57 % even if they were geographically distant.

Researchers said that obesity spread through social ties (see diagram in the article), particularly close friendship. Some experts said the results suggested that people influence one another's behavior and share the ideas about what an acceptable weight is, so it might be more effective to treat obese people in groups than individuals to slow this worldwide epidemic. Read the press release.

The study "The Spread of Obesity in a Large Social Network over 32 Years" is published in NEJM, July 26, Volume 357:370-379. Free full text.

"A medical student grows and learns"

This is an interesting blog post about the learning experience of a Harvard medical student with the bariatric surgery group in a medical centre : posted by a hospital blog on Tuesday 26 June 2007 :

The student wrote in his journal:

"Like most people, I think that obesity is a lifestyle issue -- it is a reflection of our society with gluttony of unhealthy food and paucity of exercise. And like most people, I feel uneasy about "fixing" obesity by reducing the size of the stomach to give the "artificial" feeling of safety and/or to curb the caloric intake by shortening the length of the digested food transit. Is this an appropriate and responsible medical approach? Is obesity a condition indicating for surgical procedure? What kind of people would allow, or even demand, to have one's body altered in such unnatural ways to escape from obesity?"

"Having spent almost one year with my patient, I am beginning to realize some answers.... ......................" Read more at Running a Hospital.

The student concluded that candid conversations with the patient have taught him to "relinquish assumptions, to empathize and above all, to never forget to listen to my patients so that I can offer them what they really need."

What is your view on this?

Obesity drug Rimonabant questioned

Rimonabant (Acomplia) by Sanofi-Aventis, was licensed for use in the UK since June 2006 for the treatment of obesity.


However, adverts have claimed the drug can cut levels of potentially harmful cholesterol, fats and sugars in the blood to a greater extent than would be expected by weight loss alone. In theory, this should help to reduce the risk of developing type 2 diabetes and heart disease.

A report published in The Drug and Therapeutics Bulletin (DTB) on 30 May 2007 said there was no proof that the drug had any beneficial effects outside those expected by weight loss. The drug had not been effectively compared with other less expensive drug treatment for obesity.

The DTB authors said Orlistat (Xenical), costs less and approved for use in the NHS is the drug for obesity with the most evidence for efficacy and safety to date, and they have previously concluded that it is a reasonable option for obese patients where diet and exercise and/or behavioural measures alone have failed.