NHANES: HbA1c increasing among adults with obesity
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Adults with obesity have experienced a steady increase in mean HbA1c during the past 3 decades, which indicates a rising risk for type 2 diabetes, despite an overall reduction in blood pressure and cholesterol levels, according to an analysis of National Health and Nutrition Examination Survey data.
“The adverse impact of obesity on blood sugar status appears to develop over a longer period of time, and the population is still experiencing progressive worsening of glycemic status,” Fangjian Guo, MD, PhD, assistant professor of obstetrics and gynecology at the University of Texas in Galveston, said in a press release. “If blood sugar goes high too often, it can overwork the body’s ability to keep blood sugar in healthy ranges, increasing the risk for developing diabetes complications.”
Fangjian Guo
Guo and W. Timothy Garvey, MD, professor of medicine and chair of the department of nutrition sciences at the University of Alabama in Birmingham, analyzed data from 18,626 adults with obesity (BMI at least 30 kg/m²) participating in NHANES III and NHANES 1999-2014. Researchers measured BP, blood glucose and lipid profiles, and used data to determine secular trends in the prevalence of cardiovascular disease risk factors and CV health status in the United States during the past 3 decades.
Within the cohort, mean systolic BP decreased from 126.1 mm Hg in 1988-1992 to 124.4 mm Hg in 2011-2014 (P < .001 for trend); diastolic BP also decreased, from a mean of 76.6 mm Hg to 72.5 mm Hg from 1988 to 2014. The reductions were observed across age and racial and ethnic groups and in both sexes.
W. Timothy Garvey
Mean total cholesterol also decreased among all subgroups from a mean of 214.5 mg/dL in 1988-1992 to 193.7 mg/dL in 2011-2014, for a mean decrease of 20.8 mg/dL (P < .001); mean HDL increased from 45.4 mg/dL to 47.4 mg/dL between 1988 and 2014 (P < .001).
Mean HbA1c increased from 5.7% in 1988-1992 to 5.9% in 2011-2014 (P < .001 for trend). Researchers observed increases across all age, sex and racial groups except among black adults. The researchers noted that an increase in the prevalence of self-reported diabetes contributed to declining glycemic health; diabetes prevalence increased from 11.3% to 19% from 1988 to 2014 across all subgroups except among young adults.
The number of adults with obesity who had all three CVD risk factors increased by 37% across all subgroups during the study period, from 16.4% to 22.4%.
“The increase occurred in parallel with a decline in the prevalence of healthy blood glucose, which is the predominant explanation accounting for the rise in the prevalence of presence of all three risk factors,” the researchers wrote.
The prevalence of adults free from all three risk factors remained stable at about 15% during the study period, with adults aged 20 to 39 years most likely to fall into this category. Very few adults with obesity met the criteria for ideal CV health; prevalence remained stable at about 2% during the study period, according to researchers.
“Diabetes places patients at very high risk for heart attack and coronary death,” Garvey said in the release. “Obese adults at high risk for diabetes and heart disease may require more intense approaches to control blood sugar and achieve weight loss, such as healthy meal plans and physical activity.” – by Regina Schaffer
Disclosure: Garvey reports serving as an adviser, a stock holder or receiving research support from AstraZeneca, Boehringer Ingelheim, Bristol-Myers Squibb, Daiichi-Sanyo, Eisai, Eli Lilly and Co., Ionis/Genzyme, Janssen Pharmaceuticals, Lexicon, LipoScience, Merck, Novartis, Novo Nordisk, Pfizer, Sanofi, Takeda, Vivus and Weight Watchers International. Guo reports no relevant financial disclosures.