1 Jan 2013
Higher levels of obesity have been linked to an increased risk of death, according to a large analysis of research.
Scientists investigated the results of nearly 100 studies, which overall included approximately three million adults.
It was found that, compared to normal weight, overall obesity and higher levels of obesity were both linked to a significantly higher all-cause risk of death. In addition, being overweight was found to be linked to significantly lower all-cause mortality, according to the study which was published in JAMA.
According to the paper, it is important to study this subject because estimates of the relative mortality risks associated with being a normal weight, overweight and obese could help to inform decision making in a clinical setting.
Katherine M Flegal, from the National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, and colleagues, compiled and summarised published analyses of body mass index (BMI) and all-cause mortality that provide hazard ratios (HRs) for standard BMI categories.
Researchers identified 97 studies that met inclusion criteria, with regions of origin including the US, Europe, Australia, Japan, Brazil, Israel, India and Mexico. All cause mortality HRs for overweight, obesity, grade one obesity and grades two and three obesity, were calculated relative to normal weight.
Overweight was classed as a BMI of 25 to less than 30, obese was a BMI of 30 or above, with grade one obesity equating to a BMI of 30 to less than 35 while grades two and three obesity were equal to or above 35.
A six per cent lower risk of death was discovered for people in the overweight category, while there was an 18 per cent higher risk of death for obese people in all grades. Furthermore, a five per cent lower risk of death was observed in grade one obesity while a 29 per cent increased risk of death was seen in those classed as grades two and three obesity.
The authors of the paper noted that due to the fact grade one obesity was not linked to higher mortality suggested that the excess mortality in obesity is mainly due to elevated mortality at higher BMI levels.
Researchers added: "Possible explanations have included earlier presentation of heavier patients, greater likelihood of receiving optimal medical treatment, cardioprotective metabolic effects of increased body fat, and benefits of higher metabolic reserves."
This follows news that childhood obesity is increasing in England, with one in three primary school children in their final year weight more than they should based on their age.
Research from the Health and Social Care Information Centre (HSCIC) found that the number of children aged between ten and 11 who are classed as being overweight or obese rose from 33.4 per cent in 2010/11 to 33.9 per cent in 2011/12.
It was found that children who lived in urban areas were more likely to be overweight than those who resided in towns or suburban areas, with obesity also exhibiting a link to poverty.
Posted by Edward Bartel
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