Published: Dec 19, 2013 | Updated: Dec 19, 2013
By Elizabeth DeVita Raeburn, Contributing Writer, MedPage Today

Overweight and obese women who lost a modest amount of weight and kept it off for 2 years saw improvement in almost every measure of cardiometabolic health, a study reported.

After 24 months of a diet intervention, LDL cholesterol, C-reactive protein (CRP), insulin and triglycerides (TG) were reduced in women who lost ≥ 10% of body weight.

“Mean total cholesterol and non-HDL cholesterol were reduced regardless of the amount of weight lost,” wrote Cynthia A. Thomson, PhD, RD, of the University of Arizona and her co-authors in the Journal of the American Heart Association.

“Generally, the higher the baseline biomarker values, the greater was the reduction with weight loss,” the authors said.

Step-test performance, a secondary outcome, also improved in women who lost ≥ 10% of their starting body weight, though this change was not associated with a change in cardiometabolic risk factors.

The study included 417 women over 18 who had a BMI between 25 and 40 kg/m² and were at least 15 kg above their ideal body weight as defined by the 1983 Metropolitan Life tables.

The women were allocated to a center-based, telephone-based or usual care diet intervention. Study subjects provided fasting blood samples at baseline and at 12 and 24 months for evaluation of cardiometabolic risk factors.

In all, 70% of women had sustained weight loss at 24 months, the authors said. Women assigned to the two structured weight loss arms had greater reductions in body weight, BMI, and waist circumference over the course of the study, than those in the usual care group.

“The variance in weight loss afforded us an opportunity to evaluate the relationship between weight loss and modification of cardiometabolic risk factors,” the authors wrote.

Prior weight loss studies have suggested that a 10% reduction in body weight in obese individuals can lead to significant reductions in metabolic risk factors. But few studies have evaluated this relationship for longer than 12 months.

“Our data extend the results from short-term weight loss trials and suggest that the magnitude of weight loss and baseline values for risk factors are associated with improvements in cardiometabolic risk factors even after 24 months,” the authors wrote.

Among other notable findings was a significant reduction in insulin levels and homeostatic model assessment of insulin resistance (HOMA-IR) values, at 12 months, in women who lost ≥10% of their body weight.

Earlier studies suggest that physical activity is necessary to reduce insulin resistance. In this study, the cause of the reduction is difficult to ascertain, because, while exercise was advised, diet was the major intervention, the authors said.

The authors also noted that waist-to-height ratio (WHtR), an adiposity index that may more accurately predict cardiometabolic risk than BMI or waist circumference, was reduced, regardless of how much weight was lost — though the effect was greatest in those who lost 10% or more of their starting body weight.

Additionally, levels of non-HDL cholesterol may, according to recent evidence, more accurately predict risk of heart disease than LDL-C, “as it encompasses all cholesterol-containing atherogenic particles including LDL-C and very-low-density lipoprotein-cholesterol,” the authors said.

In this study, on average, women who had an elevated baseline level of non-HDL-cholesterol (≥ 160 mg/dL) achieved levels within a normal range after 24 months regardless of how much weight they lost, the authors said. “Our findings suggest that any amount of weight loss may reduce non-HDL levels,” they wrote.

There were limitations to the study, including the lack of evaluation of lipoprotein particle size “known to be associated with cardiovascular risk and responsive to dietary intervention,” the authors said.

The authors also did not conduct hemodynamic measures such as blood pressure during the 3-minute step test, nor did they collect specific information regarding diet and physical activity.

Finally, the results of this study might not be representative of weight loss on cardiometabolic risk factors in people under the care of a doctor, and who might be taking medication.

From the American Heart Association:

• 2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults
• Effectiveness-Based Guidelines for the Prevention of Cardiovascular Disease in Women—2011 Update

Primary source: Journal of the American Heart Association