Below is a list of currently published peer-reviewed journal articles, and professional publications. Conference abstracts and presentations are listed on my CV.
Effectively preventing and treating chronic diseases through health behavior changes often require intensive theory- and evidence-based intervention including long-term maintenance components. We assessed the efficacy of theory-based maintenance approaches varying by dose for persistently performing resistance training (RT) with the hypothesis that a higher-dose social cognitive theory (SCT) approach would produce greater RT adherence than lower-dose Standard. The Resist-Diabetes study first established 2×/week resistance training (RT) in a 3-month supervised intervention in older (50-69 years, N = 170), overweight to obese (BMI 25-39.9 kg/m(2)) previously inactive adults who fit prediabetes criteria (fasting glucose concentration = 95-125 mg/dl; oral glucose tolerance test 2-h glucose concentration = 140-199 mg/dl or both). After the supervised phase, participants (N = 159) were then randomly assigned to one of two conditions for transition (3 weeks) and then RT alone in community settings for extended contact, maintenance (6 months), and then no contact (6 months). SCT featured continued tailored, interactive personal, and web-based check-ups focused on RT, self-regulation, and a barrier/strategies approach. Standard involved low-dose, generic personal, and web-based check-ups within the same theoretical approach. SCT and Standard both resulted in similar RT, 2×/week adherence during maintenance (74.4 %) and no-contact phases (53.1 %). Cost analysis indicated the Standard intervention for transition and maintenance was inexpensive ($160). Standard can be translated into practice with the potential for continuous contact and persistence in RT beyond the typical program maintenance phase.
Prediabetes is associated with low-grade chronic inflammation that increases the risk for developing type 2 diabetes (T2D) and cardiovascular disease (CVD). An elevated lipopolysaccharide concentration, associated with dysbiosis of the intestinal microbiota, has been implicated in the development of both T2D and CVD. Selective modulation of the intestinal microbiota with prebiotics reduces intestinal permeability and endotoxin concentrations, inflammation, and metabolic dysfunction in rodents. The effect of prebiotic supplementation on cardio-metabolic function in humans at risk for T2D is not known. The primary aim of this trial is to determine the influence of prebiotic supplementation with inulin on insulin sensitivity and skeletal muscle metabolic flexibility in adults at risk for T2D. We hypothesize that prebiotic supplementation with inulin will improve insulin sensitivity and skeletal muscle metabolic flexibility. We will randomize 48 adults (40–75 yrs) with prediabetes or a score ≥5 on the American Diabetes Association (ADA) risk screener to 6 weeks of prebiotic supplementation with inulin (10 g/day) or placebo. Subjects will be provided with all food for the duration of the study, to avoid potential confounding through differences in dietary intake between individuals. Intestinal permeability, serum endotoxin concentrations, insulin sensitivity, skeletal muscle metabolic flexibility, endothelial function, arterial stiffness, and fecal bacterial composition will be measured at baseline and following treatment. The identification of prebiotic supplementation with inulin as an efficacious strategy for reducing cardio-metabolic risk in individuals at risk of T2D could impact clinical practice by informing dietary recommendations and increasing acceptance of prebiotics by the scientific and medical community.
Challenges inherent with the transition to college are often accompanied by weight gain among college freshmen. Weight gain and duration of obesity increase metabolic syndrome and cardiovascular disease risk in young adulthood, which supports the need for weight loss interventions tailored to college students. The purpose of this investigation was to conduct a mixed methods pilot trial to determine the efficacy and acceptability of a semester long Internet-and incentive-based weight loss intervention for overweight/obese college freshmen. Participants (n = 27, aged >18 yrs, BMI >25) were randomly assigned to a 12-week social cognitive theory (SCT)-based intervention (Fit Freshmen [FF]) or a health information control group. The FF intervention also included modest financial incentives for weight loss. Primary outcomes included body weight/composition, dietary and physical activity (PA) behaviors, and psychosocial measures (i.e. self-efficacy, self-regulation) associated with diet, PA, and weight loss. Students in the FF intervention participated in focus groups to provide qualitative feedback on program structure and design. FF participants demonstrated significant reductions (all group differences p < 0.10) in body weight (﹣1.2 kg), fat mass (﹣0.6 kg), dietary energy (﹣673 kcal/d), fat (﹣37 g/d) and added sugar intake (﹣41 g/d), and increases in diet and PA-related self-regulatory skills at week 12 compared to control participants (+1.0 kg, +1.1 kg, ﹣334 kcal/d, ﹣15 g/d, ﹣13 g/d, respectively). No changes in PA were noted, but FF participants demonstrated increases in self-efficacy to overcome barriers to PA relative to control participants. Themes for content improvement from focus groups included reducing email contact and increasing in-person interacttions. Program characteristics that were positively evaluated included incentives for weight loss and access to an onsite weigh station kiosk. Overall, this efficacious SCT Internet-and incentive-based weight loss intervention was well received and can be adapted for larger-scale use in the college population.
Objective: A high intake of sugar-sweetened beverages (SSB) has been suggested as a contributor to childhood obesity. Our purpose was to assess beverage consumption habits of elementary school-aged children from a rural, health disparate region (the Mississippi Delta) and to compare their intake habits with national averages and the 2010 Dietary Guidelines for Americans (DGA).
Methods: In this cross-sectional research study, demographic, anthropometric and dietary intake data were assessed in children (n=141, age=9±2 years, 36% male) using a 24-hr dietary recall and a beverage intake questionnaire (BEVQ-15).
Results: Daily beverage intake was 757±45 kcal, representing ~45% of total energy.
Daily SSB intake was 431±37 kcal or ~25% of total energy, which is greater than national data in children (~ 8% of total calories). Intake from SSB exceeded the DGA, which recommend a total added sugar intake in this age group of <80 kcal/day. Daily water intake was 503±42 grams (17 fl oz.), which is comparable to national intake data of 6-11 year olds (~16 fl oz.).Total daily fluid intake was 2269±125 grams (76 fl oz.), which meets national recommendations of 7-8 cups/day (56-64 fl oz.) for children in this age group.
Conclusion: Energy-containing beverage and SSB intake exceeded both national intake data and the 2010 DGA. Consistent with the DGA, children should be encouraged to drink water instead of SSB, particularly those who live in rural, health disparate regions.
Vitamin D deficiency is endemic in the general population; however, there is much to be learned about the vitamin D status of athletes.
The purposes of this study were to assess the prevalence of vitamin D insufficiency in collegiate athletes and to determine whether 25(OH)D concentrations are related to vitamin D intake, sun exposure, body composition, and risk for illness or athletic injury.
25(OH) vitamin D concentrations were measured in 41 athletes (18 men/23 women, 12 indoor/29 outdoor athletes) throughout the academic year. Dietary intake and lifestyle habits were assessed via questionnaire, bone density was measured by dual energy x-ray absorptiometry, and injury and illness were documented as part of routine care.
The 25(OH)D concentrations changed across time (P = 0.001) and averaged 49.0 ± 16.6, 30.5 ± 9.4, and 41.9 ± 14.6 ng·mL (mean ± SD) in the fall, winter, and spring, respectively, and were higher in outdoor versus indoor athletes in the fall (P < 0.05). Using 40 ng·mL as the cutoff for optimal status, 75.6%, 15.2%, and 36.0% of athletes had optimal status in the fall, winter, and spring, respectively. 25(OH)D concentrations were significantly (P < 0.05) correlated with multivitamin intake in the winter (r = 0.39) and tanning bed use in the spring (r = 0.48); however, status was otherwise not related to intake, lifestyle factors, or body composition. 25(OH)D concentrations in the spring (r = -0.40, P = 0.048) was correlated with frequency of illness.
Our results suggest that collegiate athletes can maintain sufficient status during the fall and spring but would benefit from supplementation during the winter to prevent seasonal decreases in 25(OH)D concentrations. Results further suggest that insufficient vitamin D status may increase risk for frequent illness. Future research is needed to identify whether vitamin D status influences injury risk during athletic training or competition.