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Research Critique. Hailey Koch September 18, 2013. Dietary protein intake is associated with lean mass change In older community-dwelling adults: the Health, Aging and Body Composition (Health ABC) Study .
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Research Critique Hailey Koch September 18, 2013
Dietary protein intake is associated with lean mass change In older community-dwelling adults: the Health, Aging and Body Composition (Health ABC) Study Denise K Houston, Barbara J Nicklas, Jingzhong Ding, Tamara B Harris, Frances A Tylvasky, Anne B Newman, Jung Sun Lee, Nadine R Sahyoun, Marjolein Visser, and Stephen B Kritchevsky; 2008
Briefly… Outline Objectives • Background • Results • Strengths/Weaknesses • Future Research • Applications to Dietetics • Explore a relevant topic that addresses the increasing elderly population • Discuss validity of findings regarding dietary protein & lean mass • Apply research to dietetics practice
Research Need • Inadequate dietary protein intake may accelerate the process of sarcopenia in aging adults • Few studies of this nature have investigated associations in older adults
Background • Objective • Determine association between dietary protein and changes in lean mass (LM) and appendicular lean mass (aLM) • Secondary Objectives • Research Question • “If older adults consume defined amounts of dietary protein and these amounts correlate with their body composition (specifically LM and aLM), then there must be an association.”
Background • Design • Prospective cohort • Study population (n = 2066) • Age 70-79 y • Medicare-eligible residents in Pittsburg, PA and Memphis, TN metropolitan areas
Exposure • Dietary Protein Intake • Assessment tool: Food Frequency Questionnaire (FFQ) • Individual exposure data measured @ year 2 and 3-year follow-up
Outcome • Lean Mass (LM) and Appendicular Lean Mass (aLM) • Assessment tool: Dual-Energy X-ray Absorptiometry • Measured @ year 2 and 3-year follow-up (year 5)
Results • 28.8% lost >3% of body weight • 21.7% gained >3% of body weight • 49.5% remained weight stable • Participants in highest protein quintile lost significantly less LM and aLM compared to participants in lowest protein quintile • Protein intake was associated with changes in aLM in weight gainers and weight losers • Total protein and animal protein significantly associated with changes in LM
Change in Appendicular Lean Mass by Quintile of Dietary Protein Intake
Appendicular Lean Mass by Quintile of Dietary Protein Intake According to Weight Change Status (P-value < 0.05)
Strengths & Weaknesses • Sample size (n = 2066) • Appropriate inclusion and exclusion criteria • Confounders • Statistical significance • DXA used to measure body composition • Length of study • Sample representative? • FFQ not a primary dietary intake tool • LM changes due to lifestyle? • Protein categories not defined • Reason for weight loss unknown in “weight loser” participants • Observational study cannot make a cause-effect conclusion or association
Future Research • Dietary protein intake as a modifiable risk factor in older adults • Weight loss strategies in obese older adults • Risks for weight losers • Consideration of protein standard for older adults
Applications to Dietetics • Assessment • Evaluation of Intake • Education • Intervention