Metabolically healthy obese do not remain so for long
medwireNews: Findings from the ARIC cohort show that people who are metabolically healthy but obese are at an increased risk for developing metabolic abnormalities, particularly dysglycemia.
The ARIC cohort includes nearly 16,000 people, aged 45 to 64 years at baseline, among whom the researchers identified 3969 who were initially free of all cardiometabolic abnormalities, disregarding their weight.
A total of 458 of these participants were obese, and over the next 9 years they were a significant 45% more likely to develop any additional metabolic syndrome component than the 2062 participants who were of normal weight.
The highest risk increase, of 2.33-fold, was for elevated glucose levels, followed by low levels of high-density lipoprotein (HDL) cholesterol, at 1.68-fold; elevated triglycerides, at 1.63-fold; and high blood pressure, at 1.54-fold. These associations were independent of age, sex, race, study center, alcohol consumption, smoking, education, and physical activity.
Overweight participants – of whom there were 1449 – had an intermediate risk, with, for example, a 23% increased risk for any metabolic syndrome component relative to participants with a normal weight, and a 69% increased risk for elevated glucose.
“Our results add to the evidence that these factors are strongly associated with excess adiposity among U.S. adults, even among those who may appear initially free from these conditions,” say Patrick Bradshaw (University of California, Berkeley, USA) and study co-authors.
They note that the participants were assessed every 3 years, and any who developed a metabolic abnormality were removed from further analysis “to maintain a consistent definition of metabolic health across all of the follow-up periods.”
Despite there being a higher proportion of African–American than White participants in the overweight and obese groups at baseline, White participants were more prone to developing elevated fasting glucose and low HDL cholesterol.
“These differences are consistent with previous observations that at a given BMI white individuals carry more visceral adipose tissue than blacks and that visceral adiposity may be more relevant for identifying individuals in these race groups who are at high risk for developing metabolic abnormalities,” write the researchers in the International Journal of Obesity.
In line with previous studies, increased waist circumference had a particularly powerful effect on participants’ metabolic risk. Obese people with a waist circumference of at least 102 cm in men and 88 cm in women had a significantly increased risk for all metabolic syndrome components, whereas those with a smaller waist circumference did not.
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