Prevalence of Obesity Increasing Among US Adults with Diabetes, According to NHANES Analysis

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Among US adults with diabetes, the prevalence of obesity increased from 1999 to 2020, according to a new study published in the journal Obesity. During the same period, however, the prevalence of blood pressure control and lipid control increased.

An analysis of data from the National Health and Nutrition Examination Survey (NHANES) showed that the prevalence of overall obesity, obesity class II, and obesity class III have all increased among adults with diabetes since 1999. In addition, fewer adults with diabetes achieved glycemic control with an HbA1c of <7% between 2015 and 2020 compared with 1999 to 2010. Data did not distinguish between type 1 and type 2 diabetes.

“The impact of worsening obesity profiles in patients with diabetes is concerning because of lack of optimal cardiometabolic risk factor control. This supports recommendations for more weight-centric diabetes management in people with obesity and diabetes,” wrote researchers from the Pennington Biomedical Research Center in Baton Rouge, Louisiana.

Only a few studies have analyzed trends in prevalence of overweight and obesity among patients with diabetes, according to investigators. Moreover, the team found no studies that examined the more severe degrees of obesity in adults with diabetes and the association between classes of obesity and control of cardiometabolic risk factors.

To fill this gap in medical literature, researchers analyzed US trends in obesity prevalence as well as trends in control of cardiometabolic risk factors among patients with diabetes from 1999 to 2020.

The research team collected NHANES data from every cycle beginning in 1999-2000 and ending in 2017-2020. The survey years were pooled into four 4-year intervals and one 6-year interval: 1999-2002, 2003-2006, 2007-2010, 2011-2014 and 2015-2020.

The study included 6605 adults aged ≥20 years who reported receiving a diagnosis of diabetes from a physician. Body mass index (BMI), waist circumference, HbA1c, blood pressure (BP), cholesterol, and triglycerides were measured. All participants completed self-administered questionnaires on their age, sex, ethnicity, education level, smoking status, and whether they had taken prescription medication in the past 30 days. Medication usage was broken down into 3 categories: glucose-lowering, BP-lowering, and lipid-lowering.

Participants were classified in 5 BMI categories:

• Normal weight: <25.0 kg/m²
• Overweight: 25.0-29.9 kg/m²
• Obesity class I: 30.0-34.9 kg/m²
• Obesity class II: 35.0-39.9 kg/m²
• Obesity class III: ≥40.0 kg/m²

Findings

Among all participants, the mean BMI increased from 31 kg/m² in 1999-2002 to 32.6 kg/m² in 2015-2020. The percentage of participants with obesity class I (22.5% to 26.5%), obesity class II (14.1% to 16.6%), and obesity class III (10.3% to 14.8%) increased from 1999-2002 to 2015-2020, respectively, whereas the proportion of adults with normal weight (17.1% to 12.7%) and overweight (35.9% to 29.2%) decreased during the same time periods.

The prevalence of central obesity—defined for the purposes of the study as a waist circumference of at least 102 cm for men and 88 cm for women—increased from 72.9% in 1999-2002 to 79.1% in 2015-2020.

The average levels of HbA1c and diastolic BPamong all participants decreased from 1999-2002 to the 2007-2010 period, after which each showed increases, according to authors. Among participants with normal weight, HbA1c decreased across the entire study from 7.85% in 1999-2002 to 7.26% in 2015-2020. Systolic BP was stable throughout the study for adults with normal weight, while those with overweight and obesity had a decrease from 1999-2002 to 2015-2020. Non-HDL cholesterol decreased consistently across all BMI categories.

According to the results, the proportion of participants who achieved glycemic control (HbA1c <7%) increased from 42.5% in the 1999-2002 timeframe to 51.8% in the 2007-2010 period, then decreased to 48.0% in the 2015-2020 period.

The proportion of participants who achieved BP control (<140/90 mm Hg) increased from 1999-2002 (53.2%) to 2011–2014 (69.3%) and then decreased in 2015–2020 (65.9%). “This trend was found in participants with overweight and all different classes of obesity,” wrote researchers. The prevalence of participants who achieved non-HDL cholesterol control (<130 mg/dL) increased throughout the study periods for all BMI categories.

Participants with obesity demonstrated worsening glycemic control (46.7%–47.5% vs 55.2%–55.8%, p<.05) and lipid control (52.4%–58.7% vs 63.7%–66.5%, p<.05) compared to those with normal weight between 2011 and 2020.

“Large increases in trends of use of medication from 1999–2002 to 2015–2020, especially the use of blood pressure-lowering and lipid-lowering medication, explain some of the improving trends in blood pressure control and lipid control,” added the research team.

The prevalence of participants who achieved all 3 goals (glycemic control, BP control, and non-HDL cholesterol control) increased from 1999-2002 (8.3%) to 2011-2014 (21.2%) and then decreased in 2015-2020 (18.5%), according to the results.

“Addressing weight management in persons with diabetes should be given priority if cardiometabolic risk factor control is to improve in the population with diabetes,” concluded authors.

Reference: Hu G, Ding J, Ryan DH. Trends in obesity prevalence and cardiometabolic risk factor control in US adults with diabetes, 1999-2020. Obesity. Published online January 25, 2023. doi:10.1002/oby.23652.