title: Effect of improved fitness beyond weight loss on cardiovascular risk factors in individuals with type 2 diabetes in the Look AHEAD study.
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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: The Johns Hopkins Bloomberg School of Public Health and School of Medicine, Baltimore, USA.
authors.forename: Bethany Barone
authors.initials: BB
authors.lastname: Gibbs
authors.forename: Frederick L
authors.initials: FL
authors.lastname: Brancati
authors.forename: Haiying
authors.initials: H
authors.lastname: Chen
authors.forename: Mace
authors.initials: M
authors.lastname: Coday
authors.forename: John M
authors.initials: JM
authors.lastname: Jakicic
authors.forename: Cora E
authors.initials: CE
authors.lastname: Lewis
authors.forename: Kerry J
authors.initials: KJ
authors.lastname: Stewart
authors.forename: Jeanne M
authors.initials: JM
authors.lastname: Clark
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000503:physiopathology / Q000517:prevention & control*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D004032:Diet / Q000009:adverse effects; D015444:Exercise; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D016014:Linear Models; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010353:Patient Education as Topic; D010809:Physical Fitness; D018570:Risk Assessment; D012307:Risk Factors; D040242:Risk Reduction Behavior; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States; D015431:Weight Loss
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin; D008055:Lipids; C517652:hemoglobin A1c protein, human