Source: DGNews  |  Posted 1 year ago

NEW YORK -- May 5, 2010 -- Weight-loss surgery should only be used in the most severely obese of children, and only then with extreme caution, according to a Seminar on childhood obesity published online first and appearing in an upcoming edition of The Lancet.

Lifestyle interventions such as diet and exercise should always be first-line therapy, with drug treatment used rarely and weight-loss surgery a last resort.

The Seminar was written by Sue Y. S. Kimm, MD, University of New Mexico Health Sciences Center, University of New Mexico, Albuquerque, New Mexico; Debbie Lawlor, MD, University of Bristol, Bristol, United Kingdom; and Joan C. Han, MD, National Institutes of Health, Bethesda, Maryland.

Data up to 2006 show that prevalence of childhood obesity doubled or trebled between the early 1970s and late 1990s in Australia, Brazil, Canada, Chile, Finland, France, Germany, Greece, Japan, the UK, and the US. In 2010, more than 40% of children in the North American and eastern Mediterranean World Health Organization (WHO) regions, 38% in Europe, 27% in the western Pacific, and 22% in southeast Asia are predicted to be overweight or obese.

However recent data, which, although still too soon to be certain, suggest that the increase in childhood obesity in the US, the UK, and Sweden might be abating and that childhood obesity rates could be stabilising in these high-income settings. "The obesity epidemic is probably the result of evolutionary legacy interacting with our technologically advanced and consumerist society," the authors wrote.

Taking in more calories than are expended is, the authors estimate, responsible for around 90% of cases of child obesity. Conditions such as endocrine diseases, congenital and acquired hypothalamic defects, genetic syndromes, and use of drugs affecting appetite (though rare) should be also be considered during assessment of child obesity, and the authors estimate these scenarios account for the other 10% of cases. Other drugs such as antipsychotics, anticonvulsants, blood-pressure drugs, and antihistamines can also cause weight gain and should be considered as a possible cause when a child has had recent excessive weight gain.

Childhood obesity can adversely affect almost every organ system and often has serious consequences, including hypertension, abnormal blood fats, insulin resistance or diabetes, fatty liver disease, and psychosocial complications. Results of 1 study showed that being overweight or obese between ages 14 and 19 years was associated with increased adult mortality (from age 30 years) from various systemic diseases. Serious orthopaedic complications of childhood obesity are tibia vara, however, paradoxically, obesity might have some beneficial effect on bone mineral density.

Prevention, especially in the young, is universally viewed as the best approach to reverse the rising global prevalence of obesity. Such measures can be instituted at individual, household, institutional, community, and health-care levels. For very young children, the carer rather than the child should be targeted. At a household or family level, encouragement of parents to offer appropriate food portions, foster physical activity, increase activities of daily living, and keep sedentary behaviours to a minimum are viewed as basic measures of prevention.

One policy that is debated in the US is removal of vending machines from schools to curb availability of energy-dense snack foods. However, a US national survey showed that snack foods from vending machines contributed only 1% to 3% of total daily calories from snacks, whereas snacks at or from home contributed 69.1%. In 2007, the British Government introduced legislation to give parents the results of their child's measurements. Existing evidence is unclear as to whether surveillance or screening of childhood obesity will be valuable for prevention.

For treating children that are already obese, the authors said: "Non-pharmacological approaches should be the foundation of all obesity treatments, especially in children, and should always be considered as first-line therapy." One review concluded that family-based, lifestyle interventions with a behavioural programme aimed at changing diet and physical activity and thinking patterns provide significant and clinically meaningful decreases in overweight in both children and adolescents in the short-term and the long-term. Some guidelines, such as those in the UK, emphasise behavioural strategies that do not specify actual caloric intake. Yet results of a randomised trial of behavioural treatment without specified calorie limits showed no significant effect on body-mass index (BMI)."

Drug treatment has been assessed in obese children, with a several studies on the weight-loss drugs orlistat and sibutramine. Both drugs have a number of side effects. When used with lifestyle interventions, both drugs show slight improvement versus lifestyle alone.

"Although evidence exists for slight effectiveness of orlistat and sibutramine when combined with lifestyle intervention, treatment with these drugs is associated with more adverse effects than is lifestyle intervention alone," the authors wrote.

The authors suggest a very conservative approach to drug therapy, only for children in the highest 5% of BMI who have substantial complications of obesity and have failed on lifestyle interventions. "The risks of bariatric surgery are substantial, and long-term safety and effectiveness in children remain largely unknown," they wrote. "Therefore, surgery should be reserved for only the most severely obese (BMI >=50 kg/m², or >=40 kg/m² with important comorbidities), and even then, considered with extreme caution."

The authors concluded that no evidence-based, clinically meaningful definition of childhood obesity has been established. Calorie intake and activity recommendations need to be reassessed and better quantified at a population level because of the modern sedentary lifestyles of children. For individual treatment, the currently recommended calorie prescriptions might be too conservative in view of evolving insight into the "energy gap".

SOURCE: The Lancet