medwireNews: People with body mass index (BMI) values considered to be within the normal range in their late teens have an increased risk of diabetes-related mortality later in life, a large study shows.
Gilad Twig (Sheba Medical Center, Tel Hashomer, Israel) and colleagues found that risk started to increase from the 25th centile – or from a BMI of 20.0–22.4 kg/m2 – among 2,454,693 Israeli people who underwent a medical examination between the ages of 16 to 19 years.
As anticipated, people who were obese had a large increased risk of diabetes-related mortality during the median follow-up of 18.4 years. There were more than 32,000 deaths, of which 481 (1.5%) were attributed to diabetes, and the risk of diabetes-linked death was increased 20.38-fold among obese people (BMI ≥30 kg/m2) relative to those in the reference BMI range of 17.5–19.9 kg/m2.
Similarly, people in the overweight categories of 25.0–27.4 and 27.5–29.9 kg/m2 had 6.94- and 9.81-fold increased risks of diabetes mortality after accounting for age, gender, socioeconomic status, education, country of origin and height.
But the increased risk extended right down to the 20.0–22.4 kg/m2 BMI category; people within this range had a slight but statistically significant increased risk of 1.37-fold, while the risk increase was a highly significant 2.68-fold for those in the 22.5–24.9 kg/m2 BMI category.
The researchers note in Diabetes Care that using the standard “normal” BMI range as a reference category would therefore underestimate the associated risk, because of the increased risk seen at the high end of the normal range.
Twig et al calculated a population-attributable fraction (PAF) for diabetes mortality of 31.2% based on people examined in 1967–1977 who had an overweight/obesity prevalence of 8.7%. But people examined in 2012–2014 had a prevalence of 20.8%, they note, giving a projected PAF of 52.1% and highlighting the “substantial population impact and public health importance” of overweight/obesity.
They add that diabetes is likely to be an underlying cause of many deaths attributed to conditions such as coronary heart disease or stroke.
“The increasing prevalence of overweight and obesity, and of adolescents in the mid- and high-normal range, are likely to account for a large and increasing proportion of [diabetes mellitus] incidence, its related microvascular and macrovascular complications, and [diabetes mellitus] mortality”, the team concludes.
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