Tiffany N. Hilton
Duke University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Tiffany N. Hilton.
The New England Journal of Medicine | 2011
Dennis T. Villareal; Suresh Chode; Nehu Parimi; David R. Sinacore; Tiffany N. Hilton; Reina Armamento-Villareal; Nicola Napoli; Clifford Qualls; Krupa Shah
BACKGROUND Obesity exacerbates the age-related decline in physical function and causes frailty in older adults; however, the appropriate treatment for obese older adults is controversial. METHODS In this 1-year, randomized, controlled trial, we evaluated the independent and combined effects of weight loss and exercise in 107 adults who were 65 years of age or older and obese. Participants were randomly assigned to a control group, a weight-management (diet) group, an exercise group, or a weight-management-plus-exercise (diet-exercise) group. The primary outcome was the change in score on the modified Physical Performance Test. Secondary outcomes included other measures of frailty, body composition, bone mineral density, specific physical functions, and quality of life. RESULTS A total of 93 participants (87%) completed the study. In the intention-to-treat analysis, the score on the Physical Performance Test, in which higher scores indicate better physical status, increased more in the diet-exercise group than in the diet group or the exercise group (increases from baseline of 21% vs. 12% and 15%, respectively); the scores in all three of those groups increased more than the scores in the control group (in which the score increased by 1%) (P<0.001 for the between-group differences). Moreover, the peak oxygen consumption improved more in the diet-exercise group than in the diet group or the exercise group (increases of 17% vs. 10% and 8%, respectively; P<0.001); the score on the Functional Status Questionnaire, in which higher scores indicate better physical function, increased more in the diet-exercise group than in the diet group (increase of 10% vs. 4%, P<0.001). Body weight decreased by 10% in the diet group and by 9% in the diet-exercise group, but did not decrease in the exercise group or the control group (P<0.001). Lean body mass and bone mineral density at the hip decreased less in the diet-exercise group than in the diet group (reductions of 3% and 1%, respectively, in the diet-exercise group vs. reductions of 5% and 3%, respectively, in the diet group; P<0.05 for both comparisons). Strength, balance, and gait improved consistently in the diet-exercise group (P<0.05 for all comparisons). Adverse events included a small number of exercise-associated musculoskeletal injuries. CONCLUSIONS These findings suggest that a combination of weight loss and exercise provides greater improvement in physical function than either intervention alone. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00146107.).
Physical Therapy | 2008
Tiffany N. Hilton; Lori J. Tuttle; Kathryn L. Bohnert; Michael J. Mueller; David R. Sinacore
Background and Purpose: The primary purpose of this study was to report differences in calf intermuscular adipose tissue (IMAT), muscle strength (peak torque), power, and physical function in individuals with obesity, diabetes mellitus (DM), and peripheral neuropathy (PN) compared with those without these impairments. A secondary purpose was to assess the relationship between IMAT and muscle strength, power, and physical function. Subjects and Methods: Six participants with obesity, DM, and PN (2 women, 4 men; mean age=58 years, SD=10; mean body mass index=36.3, SD=5; mean modified Physical Performance Test [PPT] score=22, SD=3) and 6 age- and sex-matched control subjects without these impairments were assessed and compared in muscle strength, muscle power, physical functioning, and muscle and fat volume, including IMAT in the calf muscles. Muscle, adipose tissue, and IMAT volumes of each calf were quantified by noninvasive magnetic resonance imaging. Muscle strength and power of the plantar-flexor and dorsiflexor muscles were quantified using isokinetic dynamometry. The modified PPT was used to assess physical function. Results: Leg muscle and fat volumes were similar between groups, although IMAT volumes were 2.2-fold higher in the subjects with obesity, DM, and PN (X̄=120 cm3, SD=47) than in the control subjects (X̄=54 cm3, SD=41). Muscle strength, muscle power, ratio of leg muscle power to leg muscle volume, and modified PPT scores were lower in subjects with obesity, DM, and PN compared with the control subjects. Discussion and Conclusion: The data indicate that excess fat infiltration in leg skeletal muscles is associated with low calf muscle strength, low calf muscle power, and impaired physical function in individuals who are obese with DM and PN.
Obesity | 2009
Krupa Shah; Abby Stufflebam; Tiffany N. Hilton; David R. Sinacore; Samuel Klein; Dennis T. Villareal
Both obesity and aging increase intrahepatic fat (IHF) content, which leads to nonalcoholic fatty liver disease (NAFLD) and metabolic abnormalities such as insulin resistance. We evaluated the effects of diet and diet in conjunction with exercise on IHF content and associated metabolic abnormalities in obese older adults. Eighteen obese (BMI ≥30 kg/m2) older (≥65 years old) adults completed a 6‐month clinical trial. Participants were randomized to diet (D group; n = 9) or diet + exercise (D+E group; n = 9). Primary outcome was IHF quantified by magnetic resonance spectroscopy (MRS). Secondary outcomes included insulin sensitivity (assessed by oral glucose tolerance), body composition (assessed by dual‐energy X‐ray absorptiometry), physical function (VO2peak and strength), glucose, lipids, and blood pressure (BP). Body weight (D: −9 ± 1%, D+E: −10 ± 2%, both P < 0.05) and fat mass (D: −13 ± 3%, D+E −16 ± 3%, both P < 0.05) decreased in both groups but there was no difference between groups. IHF decreased to a similar extent in both groups (D: −46 ± 11%, D+E: −45 ± 8%, both P < 0.05), which was accompanied by comparable improvements in insulin sensitivity (D: 66 ± 25%, D+E: 68 ± 28%, both P < 0.05). The relative decreases in IHF correlated directly with relative increases in insulin sensitivity index (ISI) (r = −0.52; P < 0.05). Improvements in VO2peak, strength, plasma triglyceride (TG), and low‐density lipoprotein–cholesterol concentration, and diastolic BP occurred in the D+E group (all P < 0.05) but not in the D group. Diet with or without exercise results in significant decreases in IHF content accompanied by considerable improvements in insulin sensitivity in obese older adults. The addition of exercise to diet therapy improves physical function and other obesity‐ and aging‐related metabolic abnormalities.
Journal of Bone and Mineral Research | 2011
Krupa Shah; Reina Armamento-Villareal; Nehu Parimi; Suresh Chode; David R. Sinacore; Tiffany N. Hilton; Nicola Napoli; Clifford Qualls; Dennis T. Villareal
Weight loss therapy to improve health in obese older adults is controversial because it causes further bone loss. Therefore, it is recommended that weight loss therapy should include an intervention such as exercise training (ET) to minimize bone loss. The purpose of this study was to determine the independent and combined effects of weight loss and ET on bone metabolism in relation to bone mineral density (BMD) in obese older adults. One‐hundred‐seven older (age >65 years) obese (body mass index [BMI] ≥30 kg/m2) adults were randomly assigned to a control group, diet group, exercise group, and diet‐exercise group for 1 year. Body weight decreased in the diet (−9.6%) and diet‐exercise (−9.4%) groups, not in the exercise (−1%) and control (−0.2%) groups (between‐group p < 0.001). However, despite comparable weight loss, bone loss at the total hip was relatively less in the diet‐exercise group (−1.1%) than in the diet group (−2.6%), whereas BMD increased in the exercise group (1.5%) (between‐group p < 0.001). Serum C‐terminal telopeptide (CTX) and osteocalcin concentrations increased in the diet group (31% and 24%, respectively), whereas they decreased in the exercise group (−13% and −15%, respectively) (between‐group p < 0.001). In contrast, similar to the control group, serum CTX and osteocalcin concentrations did not change in the diet‐exercise group. Serum procollagen propeptide concentrations decreased in the exercise group (−15%) compared with the diet group (9%) (p = 0.04). Serum leptin and estradiol concentrations decreased in the diet (−25% and −15%, respectively) and diet‐exercise (−38% and −13%, respectively) groups, not in the exercise and control groups (between‐group p = 0.001). Multivariate analyses revealed that changes in lean body mass (β = 0.33), serum osteocalcin (β = −0.24), and one‐repetition maximum (1‐RM) strength (β = 0.23) were independent predictors of changes in hip BMD (all p < 0.05). In conclusion, the addition of ET to weight loss therapy among obese older adults prevents weight loss–induced increase in bone turnover and attenuates weight loss–induced reduction in hip BMD despite weight loss–induced decrease in bone‐active hormones.
Journal of the American Geriatrics Society | 2012
Krupa Shah; Tiffany N. Hilton; Lauren Myers; Jonathan F. Pinto; Amneris E. Luque; William J. Hall
To evaluate the relationships between body composition and physical frailty in community‐dwelling older adults with the human immunodeficiency virus (HIV) (HOA).
Aging and Disease | 2013
Mark Mapstone; Tiffany N. Hilton; Hongmei Yang; Joseph J. Guido; Amneris E. Luque; William J. Hall; Stephen Dewhurst; Krupa Shah
The HIV-infected older adult (HOA) community is particularly vulnerable to cognitive impairment. Previous studies in the general older adult population have reported that lower scores on tests of cognitive function often correlate negatively with aerobic fitness [5-7]. HIV-infected individuals have significantly reduced aerobic fitness and physical function compared to HIV-uninfected individuals. Determining important correlates of cognitive ability may be beneficial in not only detecting precursors to future cognitive impairments, but also target areas for interventions. The purpose of this study was to investigate the relationship between cognitive ability and aerobic fitness in HIV-infected older adults. We conducted a cross-sectional study of HOA on antiretroviral therapy (ART) >50 years of age. Domain specific cognitive function was assessed by means of a neuropsychological battery. Aerobic fitness (VO2peak) was assessed using a graded, progressive treadmill test. Thirty-seven HOA on ART (mean±SD: age 59±6 years, BMI 28±5, CD4 663±337 cells/ml, duration since HIV diagnosis 17±7 years; 81% males) completed the cognitive tests. Several domains of cognition were significantly associated with VO2peak by Spearman correlation analysis (p<0.05). By step-wise adjusted regression VO2peak was most frequently and significantly related to many cognitive domains such as verbal and visual memory, visual perception, and language (p<0.05). We found that participants with higher Vo2peak were less likely to have more severe forms of HIV-associated neurocognitive disorders (HAND) such as mild neurocognitive disorder (OR=0.65; p=0.01) and HIV-associated dementia (OR=0.64; p=0.0006). In HOA and in conclusion, aerobic fitness is related to cognitive performance on various tasks. The likelihood of cognitive impairment increased with lower fitness levels. Therefore, increased fitness may serve an important factor in maintenance of cognition and neural integrity for aging HIV-infected individuals. Future prospective and large scale studies are needed to evaluate the effect of fitness and vascular stiffness and function on cognition and brain structure among HOA.
Health Psychology | 2016
Krupa Shah; Zahraa Majeed; Yilmaz B. Yoruk; Hongmei Yang; Tiffany N. Hilton; James M. McMahon; William J. Hall; Donna Walck; Amneris E. Luque; Richard M. Ryan
OBJECTIVE HIV-infected older adults (HOA) are at risk of functional decline. Interventions promoting physical activity that can attenuate functional decline and are easily translated into the HOA community are of high priority. We conducted a randomized, controlled clinical trial to evaluate whether a physical activity counseling intervention based on self-determination theory (SDT) improves physical function, autonomous motivation, depression and the quality of life (QOL) in HOA. METHOD In total, 67 community-dwelling HOA with mild-to-moderate functional limitations were randomized to 1 of 2 groups: a physical activity counseling group or the usual care control group. We used SDT to guide the development of the experimental intervention. Outcome measures that were collected at baseline and final study visits included a battery of physical function tests, levels of physical activity, autonomous motivation, depression, and QOL. RESULTS The study participants were similar in their demographic and clinical characteristics in both the treatment and control groups. Overall physical performance, gait speed, measures of endurance and strength, and levels of physical activity improved in the treatment group compared to the control group (p < .05). Measures of autonomous regulation such as identified regulation, and measures of depression and QOL improved significantly in the treatment group compared with the control group (p < .05). Across the groups, improvement in intrinsic regulation and QOL correlated with an improvement in physical function (p < .05). CONCLUSION Our findings suggest that a physical activity counseling program grounded in SDT can improve physical function, autonomous motivation, depression, and QOL in HOA with functional limitations. (PsycINFO Database Record
Journal of Educational Evaluation for Health Professions | 2016
Christian Jaeger Cook; Chad Cook; Tiffany N. Hilton
Purpose It aimed at determining whether emotional intelligence is a predictor for success in a medical school program and whether the emotional intelligence construct correlated with other markers for admission into medical school. Methods Three databases (PubMed, CINAHL, and ERIC) were searched up to and including July 2016, using relevant terms. Studies written in English were selected if they included emotional intelligence as a predictor for success in medical school, markers of success such as examination scores and grade point average and association with success defined through traditional medical school admission criteria and failures, and details about the sample. Data extraction included the study authors and year, population description, emotional intelligence I tool, outcome variables, and results. Associations between emotional intelligence scores and reported data were extracted and recorded. Results Six manuscripts were included. Overall, study quality was high. Four of the manuscripts examined emotional intelligence as a predictor for success while in medical school. Three of these four studies supported a weak positive relationship between emotional intelligence scores and success during matriculation. Two of manuscripts examined the relationship of emotional intelligence to medical school admissions. There were no significant relevant correlations between emotional intelligence and medical school admission selection. Conclusion Emotional intelligence was correlated with some, but not all, measures of success during medical school matriculation and none of the measures associated with medical school admissions. Variability in success measures across studies likely explains the variable findings.
Clinical Biomechanics | 2015
Janet A. Kneiss; Tiffany N. Hilton; Josh Tome; Jeff Houck
BACKGROUND Individuals post hip fracture decrease force on the involved limb during sit to stand tasks, creating an asymmetry in vertical ground reaction force. Joint specific differences that underlie asymmetry of the vertical ground reaction force are unknown. The purpose of this study was to compare differences in vertical ground reaction force variables and joint kinetics at the hip and knee in participants post-hip fracture, who were recently discharged from homecare physical therapy to controls. METHODS Forty-four community-dwelling older adults, 29 who had a hip fracture and 15 elderly control participants completed the sit to stand task on an instrumented chair with 3 force plates. T-tests were used to compare clinical tests (Berg Balance Scale, activity balance confidence and gait speed, isokinetic knee strength) and vertical ground reaction force variables. Two-way analyses of variance compared vertical ground reaction force variables and kinetics at the hip and knee between hip fracture and elderly control groups. Pearson correlation coefficients were used to determine correlations between clinical and vertical ground reaction force variables. FINDINGS Vertical ground reaction force variables were significantly lower on the involved side for the hip fracture group compared to the uninvolved side and controls. Lower involved side hip and knee moments and power contributed to lower involved side vertical ground reaction force. Vertical ground reaction force variables and strength had moderate to high correlations with clinical measures. INTERPRETATION Uninvolved side knee moments and powers were the largest contributors to asymmetrical vertical ground reaction force in participants post-hip fracture. The association of vertical ground reaction force variables and clinical measures of function suggesting reducing vertical ground reaction force asymmetry may contribute to higher levels of function post-hip fracture. Functional and strength training should target the involved knee to reduce vertical ground reaction force asymmetry.
Osteoporosis International | 2014
Reina Armamento-Villareal; Lina E. Aguirre; Nicola Napoli; Krupa Shah; Tiffany N. Hilton; David R. Sinacore; Clifford Qualls; Dennis T. Villareal