Effect of improved fitness beyond weight loss on cardiovascular risk factors in individuals with type 2 diabetes in the Look AHEAD study

Eur J Prev Cardiol. 2014 May;21(5):608-17. doi: 10.1177/2047487312462823. Epub 2012 Sep 25.

Abstract

Background: Because lifestyle-induced improvements in cardiovascular risk factors vary substantially across individuals with type 2 diabetes, we investigated the extent to which increases in fitness explain cardiovascular risk factor improvements independent of weight loss in a lifestyle intervention.

Methods: We studied 1-year changes in Look AHEAD, a randomized trial comparing an intensive lifestyle intervention (ILI) to a diabetes support and education (DSE) control group in adults with type 2 diabetes. Assessments included weight, fitness, blood pressure (BP), glucose, HbA1c, and lipids. We evaluated the effects of changes in weight and fitness on changes in cardiovascular risk factors by study arm, using R (2) from multiple linear regression.

Results: Analyses included participants with fitness data at baseline and 1-year (n = 4408; 41% male, 36% non-white; mean age 58.7 ± 6.8 years). Weight change alone improved R (2) for explaining changes in risk factors up to 8.2% in ILI and 1.7% in DSE. Fitness change alone improved R (2) up to 3.9% in ILI and 0.8% in DSE. After adjusting for weight change, fitness was independently associated (p < 0.05) with improvements in R (2) for glucose (+0.7%), HbA1c (+1.1%), high-density lipoprotein (HDL) cholesterol (+0.4%), and triglycerides (+0.2%) in ILI and diastolic BP (+0.3%), glucose (+0.3%), HbA1c (+0.4%), and triglycerides (+0.1%) in DSE. Taken together, weight and fitness changes explained from 0.1-9.3% of the variability in cardiovascular risk factor changes.

Conclusion: Increased fitness explained statistically significant but small improvements in several cardiovascular risk factors beyond weight loss. Further research identifying other factors that explain cardiovascular risk factor change is needed.

Trial registration: ClinicalTrials.gov NCT00017953.

Keywords: Cardiovascular risk factor; fitness; lifestyle intervention; obesity.

Publication types

  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Biomarkers / blood
  • Blood Glucose / metabolism
  • Blood Pressure
  • Cardiovascular Diseases / diagnosis
  • Cardiovascular Diseases / physiopathology
  • Cardiovascular Diseases / prevention & control*
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / diagnosis
  • Diabetes Mellitus, Type 2 / physiopathology
  • Diabetes Mellitus, Type 2 / therapy*
  • Diet / adverse effects
  • Exercise
  • Female
  • Glycated Hemoglobin A / metabolism
  • Health Knowledge, Attitudes, Practice
  • Humans
  • Linear Models
  • Lipids / blood
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Patient Education as Topic
  • Physical Fitness*
  • Risk Assessment
  • Risk Factors
  • Risk Reduction Behavior*
  • Time Factors
  • Treatment Outcome
  • United States
  • Weight Loss*

Substances

  • Biomarkers
  • Blood Glucose
  • Glycated Hemoglobin A
  • Lipids
  • hemoglobin A1c protein, human

Associated data

  • ClinicalTrials.gov/NCT00017953

Grant support