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Body Mass Index Changes in Prodromal Huntington Disease. Nancy R. Downing, PhD, RN CANS September 13, 2012. Research Team. M. Kathleen Clark, PhD, RN 1 Spencer Lourens 1 Ashwini Rao, EdD, OTR 2 Karen Marder, MD 2 Jeffrey D. Long, PhD 1 James A. Mills, MS 1 Jane S. Paulsen, PhD 1
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Body Mass Index Changes in Prodromal Huntington Disease Nancy R. Downing, PhD, RN CANS September 13, 2012
Research Team • M. Kathleen Clark, PhD, RN1 • Spencer Lourens1 • Ashwini Rao, EdD, OTR2 • Karen Marder, MD2 • Jeffrey D. Long, PhD1 • James A. Mills, MS1 • Jane S. Paulsen, PhD1 1University of Iowa 2Columbia University
Huntington Disease • Progressive neurodegenerative disease • Single genetic mutation—autosomal dominant • Trio of symptom clusters • Motor • Cognitive • Psychiatric/behavioral • Middle age onset • Premature death • No cure
Weight Loss and HD • Weight loss is associated with functional decline in HD • Occurs despite higher caloric intake • In the prodromal period, weight loss may be a harbinger of advancing disease
Purpose • Examine baseline and longitudinal body BMI differences in a large sample of prodromal HD subjects compared with healthy controls • Examine ability of BMI to predict time to Huntington disease diagnosis
Body Weight • A modulator of disease progression in prodromal HD that could be manipulated?
Methods • Participants: Prodromal HD and gene mutation negative controls (N=1026) participants in PREDICT-HD study • Stratified: 3 disease-severity groups (Low, Medium, High) based on age at time of study entrance and length of gene mutation • Linear mixed effects regression: Compare BMI changes among groups over 5 years • Accelerated Failure Time modeling: Calculate odds ratio (OR) for BMI to predict time to diagnosis, controlling for age at baseline, years of education, gender, and motor rater experience
Accelerated Failure Time Modeling Results • Odds Ratio for ability of BMI to predict HD diagnosis given a 2-unit decrease in BMI: • Males = 1.20 (CI 1.006 - 1.432) • Females = 0.98 (CI 0.906 - 1.063)
Working Hypotheses for Current Research • Body composition changes occur prior to HD diagnosis • Weight loss in HD is primarily related to loss of muscle mass • Supported by decreased amount of BCAA in people with HD vs. healthy controls
Significance • Body composition and BCAA changes may be useful biomarkers for clinical trials • May be possible to design interventions to prevent body composition changes and preserve function • Possible interventions include exercise and/or dietary interventions • Weight loss occurs in other neurodegenerative diseases such as Alzheimer and Parkinson • Mechanisms may have relevance to obesity
Acknowledgements • During the time of this data analysis, Nancy Downing was supported by a NINR clinical genetics nursing research T32 grant to the University of Iowa College of Nursing • Jane S. Paulsen’s research is supported by the National Institutes for Health, National Institute of Neurological Disorders and Stroke (5R01NS040068-11) and CHDI Foundation, Inc.