Despite achieving significant improvements in blood pressure and cholesterol levels, obese Americans continue to grow fatter, with worsening blood glucose and an increasing incidence of diabetes.
From 1998 to 2014, national health data showed that mean diastolic and systolic blood pressures decreased in obese men and women in all racial and ethnic groups. Mean lipid measurements improved as well, including a “marked” 21-mg/dL decrease in total cholesterol and a significant increase in HDL cholesterol.
Dr. W. Timothy Garvey
But markers of blood glucose health continued to decline over the same period, contributing to an overall worsening of metabolic health and a increase from 11% to 19% in the rate of diabetes, Fangjian Guo, MD, and W. Timothy Garvey, MD, reported in July 13 issue of the Journal of the American Heart Association (J Am Heart Assoc. 2016 Jul 13. 5:e003619 doi: 10.1161/JAHA.116.003619).
The rate of obese adults free of these three cardiovascular disease risk factors – diabetes, elevated cholesterol, and blood pressure – remained stable over the study period at about 15%. But the rate of obese adults with all three risk factors increased by 37% over the same period. By 2014, 22% reported having all three of those risk factors.
“The deteriorated blood glucose health among obese adults in the United States calls for lifestyle interventions (diet and exercise) on a national scale,” wrote Dr. Garvey, chair of nutrition science at the University of Alabama, Birmingham. “Community-based public health intervention programs may help increase physical activity and diet quality to alleviate the problem.”
The investigators examined trends in cardiometabolic health among 18,626 obese adults who participated in National Health and Nutrition Examination Surveys from 1988 to 2014. Over this period, mean body mass index increased significantly, from 34.7 to 36 kg/m2. Waist circumference increased as well, from 110 to 114.8 cm.
The picture was much better for blood pressure. Mean systolic pressures decreased about 2 points – from 126.1 to 124.4 mm Hg – in all age, racial and ethnic groups, and in both sexes. Mean diastolic blood pressure also decreased, dropping from 76.6 to 72.5 mm Hg. By 2014, 44% of the men and 51% of the women were below the blood pressure risk threshold.
Lipids also improved over the years, the investigators noted, with significant decreases in mean total cholesterol, from 214.5 to 193.7 mg/dL, and increases in HDL cholesterol, from 45.4 to 47.4 mg/dL.
Blood glucose worsened significantly, however. The mean hemoglobin A1c increased from 5.7% to 5.9%. The measurement rose in all ages, both sexes, and in all racial and ethnic groups except for non-Hispanic blacks.
Perhaps not surprisingly, the incidence of diabetes (a self-reported HbA1c of 6.5% or more) increased from 11% to 19% from 1988 to 2014. The increase occurred in all age groups and both sexes except for young adults aged 20-39 years. No racial or ethnic group was exempt from the increase.
The number of people having all three risk factors (hypertension, hypercholesterolemia, and hyperglycemia) increased from 16% in 1988 to 22% in 2014.
“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 investigators said.
Only 15% of the study population was free from all of these risk factors – a percentage that remained unchanged during 1988-2014.
The findings should be a wake-up call for physicians and their patients, and a national call for action to improve cardiovascular health among obese adults, the team wrote.
“The increasing trend of obese people with all three cardiovascular risk factors, commensurate with a decline in those with one or two risk factors, suggests an overall deterioration in health among people with obesity. ... These patterns of worsening metabolic health constitute an increase in risk of type 2 diabetes mellitus and underlie increasing prevalence rates for diabetes mellitus,” the investigators wrote.
Aggressive treatment will be necessary to reverse these trends. This might include treatment with weight-loss medications in conjunction with lifestyle interventions, which should be especially targeted at obese individuals who are already metabolically unhealthy and in those who have complications or are at risk for developing them.
“In the context of the current data, those obese adults who are metabolically unhealthy or perhaps those with suboptimal metabolic health represent patients who will benefit most from intensive obesity management … coordinated efforts aligning cardiovascular disease prevention and control activities across the public and private sectors in the United States are needed reduce the burden of cardiovascular disease among the obese population,” Dr. Garvey concluded.