Alyce D. Fly

Predictors of continuation of exclusive breastfeeding for the first six months of life.

This study aimed to investigate the relative importance of the psychosocial factors underlying mother’s decision to continue exclusive breastfeeding (EBF) for 6 months using the theory of planned behavior. A cohort of EBF-mothers (N = 78) completed a questionnaire assessing theoretical constructs at baseline and phone-interviewed at follow-up. Multiple regression analyses were performed to find important predictors of intention, overall and married vs unmarried. Attitude, subjective norm, and perceived behavioral control together explained 50.2% (P < .01) of the variance in mothers’ intention to continue EBF for 6 months. Attitude and subjective norm were better predictors of the intention than perceived behavioral control. The role of subjective norm was greater in married than in unmarried women. A strong, positive correlation (γ = 0.67, P < .01) was found between intended and actual EBF duration. Intervention programs designed to positively influence mother’s attitude and social support may be effective in improving intention, thereby increasing EBF maintenance for 6 months. J Hum Lact. 26(1):26-34.

Normalization of flow-mediated dilation to shear stress area under the curve eliminates the impact of variable hyperemic stimulus

BackgroundNormalization of brachial artery flow-mediated dilation (FMD) to individual shear stress area under the curve (peak FMD:SSAUC ratio) has recently been proposed as an approach to control for the large inter-subject variability in reactive hyperemia-induced shear stress; however, the adoption of this approach among researchers has been slow. The present study was designed to further examine the efficacy of FMD normalization to shear stress in reducing measurement variability.MethodsFive different magnitudes of reactive hyperemia-induced shear stress were applied to 20 healthy, physically active young adults (25.3 ± 0. 6 yrs; 10 men, 10 women) by manipulating forearm cuff occlusion duration: 1, 2, 3, 4, and 5 min, in a randomized order. A venous blood draw was performed for determination of baseline whole blood viscosity and hematocrit. The magnitude of occlusion-induced forearm ischemia was quantified by dual-wavelength near-infrared spectrometry (NIRS). Brachial artery diameters and velocities were obtained via high-resolution ultrasound. The SSAUC was individually calculated for the duration of time-to-peak dilation.ResultsOne-way repeated measures ANOVA demonstrated distinct magnitudes of occlusion-induced ischemia (volume and peak), hyperemic shear stress, and peak FMD responses (all p < 0.0001) across forearm occlusion durations. Differences in peak FMD were abolished when normalizing FMD to SSAUC (p = 0.785).ConclusionOur data confirm that normalization of FMD to SSAUC eliminates the influences of variable shear stress and solidifies the utility of FMD:SSAUC ratio as an index of endothelial function.

Adjusting flow-mediated dilation for shear stress stimulus allows demonstration of endothelial dysfunction in a population with moderate cardiovascular risk

Background/Aims: Although normalization of brachial artery flow-mediated dilation (FMD) to individual shear stress (FMD:shear stress ratio) has been proposed to improve this measure of endothelial function, the clinical utility of FMD normalization has not yet been demonstrated. We tested (1) whether following conventional 5-min forearm occlusion, the FMD:shear stress ratio would discriminate a population with moderate cardiovascular risk (MR) from a low-risk (LR) population, and (2) whether the dose-response profile relating shear stress to FMD would be different between the 2 populations. Methods: Five different magnitudes of reactive hyperemia-induced shear stress were applied to 20 MR and 20 LR subjects by manipulating forearm cuff occlusion duration. Brachial artery diameters and velocities were measured via high-resolution ultrasound. To quantify the hyperemic stimulus, shear stress area under the curve was individually calculated for the duration of time-to-peak dilation. Results: Following 5-min of forearm occlusion, FMD:shear stress ratio (p = 0.041), but not FMD (p = 0.286), discriminated MR from LR. The slope of the shear stress-FMD regression line was lower in MR compared to the LR (p <0.001). Conclusion: The FMD:shear stress ratio distinguished reduced endothelial function in a population with MR. The dose-response profile of the shear stress-FMD relationship appears to differ between populations of distinct cardiovascular risk.

Randomized Controlled Trial of Fish Oil and Montelukast and Their Combination on Airway Inflammation and Hyperpnea-Induced Bronchoconstriction

Background Both fish oil and montelukast have been shown to reduce the severity of exercise-induced bronchoconstriction (EIB). The purpose of this study was to compare the effects of fish oil and montelukast, alone and in combination, on airway inflammation and bronchoconstriction induced by eucapnic voluntary hyperpnea (EVH) in asthmatics. Methods In this model of EIB, twenty asthmatic subjects with documented hyperpnea-induced bronchoconstriction (HIB) entered a randomized double-blind trial. All subjects entered on their usual diet (pre-treatment, n = 20) and then were randomly assigned to receive either one active 10 mg montelukast tablet and 10 placebo fish oil capsules (n = 10) or one placebo montelukast tablet and 10 active fish oil capsules totaling 3.2 g EPA and 2.0 g DHA (n = 10) taken daily for 3-wk. Thereafter, all subjects (combination treatment; n = 20) underwent another 3-wk treatment period consisting of a 10 mg active montelukast tablet or 10 active fish oil capsules taken daily. Results While HIB was significantly inhibited (p<0.05) by montelukast, fish oil and combination treatment compared to pre-treatment, there was no significant difference (p>0.017) between treatment groups; percent fall in forced expiratory volume in 1-sec was −18.4±2.1%, −9.3±2.8%, −11.6±2.8% and −10.8±1.7% on usual diet (pre-treatment), fish oil, montelukast and combination treatment respectively. All three treatments were associated with a significant reduction (p<0.05) in FENO, exhaled breathe condensate pH and cysteinyl-leukotrienes, while the fish oil and combination treatment significantly reduced (p<0.05) urinary 9α, 11β-prostaglandin F2 after EVH compared to the usual diet; however, there was no significant difference (p>0.017) in these biomarkers between treatments. Conclusion While fish oil and montelukast are both effective in attenuating airway inflammation and HIB, combining fish oil with montelukast did not confer a greater protective effect than either intervention alone. Fish oil supplementation should be considered as an alternative treatment for EIB. Trial Registration ClinicalTrials.gov NCT00676468

A comparison between active- and reactive-hyperaemia-induced brachial artery vasodilation

The measurement of brachial artery vasodilation in response to a hyperaemic stimulus has been used extensively to assess changes in endothelial function. However, whether or not similar changes occur in response to an active hyperaemic stimulus is unknown. The purpose of the present study was to compare brachial artery vasodilation in response to an active compared with a reactive hyperaemic stimulus following a known perturbation of endothelial function. Eight apparently healthy adults were assigned to four treatment conditions in a counter-balanced design: (i) low-fat meal with active hyperaemic stimulus (LFM-A), (ii) high-fat meal with active hyperaemic stimulus (HFM-A), (iii) low-fat meal with reactive hyperaemic stimulus (LFM-R), and (iv) high-fat meal with reactive hyperaemic stimulus (HFM-R). Meals were ingested at 08:00 hours on each treatment day. Brachial artery vasodilation was assessed via ultrasound 4 h after ingestion of each meal. The active hyperaemic stimulus was induced by 5 min of rhythmic handgrip exercise, whereas reactive hyperaemia was induced by 5 min of forearm occlusion. Brachial artery vasodilation was expressed as the percentage change in diameter from baseline to post-active/reactive hyperaemia. Using a 2x2 repeated measures ANOVA, a significant stimulusxmeal interaction (P=0.025) was found. Simple main effects revealed no difference (P=0.541) in brachial artery vasodilation between LFM-A (5.75+/-1.64%) and HFM-A (6.39+/-1.45%); however, a significant decrease (P=0.014) in brachial artery vasodilation was found in the HFM-R (4.29+/-1.64%) compared with the LFM-R (7.18+/-1.13%) treatment. In conclusion, the measurement of brachial artery vasodilation in response to active hyperaemia did not detect a change in endothelial function following a single perturbation meal, whereas reactive hyperaemia did.

Dietary magnesium intake and risk of metabolic syndrome: a meta-analysis

To estimate quantitatively the association between dietary magnesium intake and risk of metabolic syndrome by combining the relevant published articles using meta‐analysis.

Determinants of middle-school students asking parents for fruits and vegetables: a theory-based salient belief elicitation

OBJECTIVE Despite the benefits of fruit and vegetable intake, many young Americans do not consume them at adequate levels. The present study sought to determine the beliefs that children have about asking their parents to have fruits and vegetables available at home in order to better understand the role children may play in influencing their own fruit and vegetable consumption. DESIGN An instrument utilizing the Reasoned Action Approach, with closed-ended questions on demographic and behavioural variables and open-ended questions eliciting the belief structure underlying asking parents to make fruits and vegetables available, was distributed. Thematic and frequency analyses were performed for open-ended questions. Statistical analyses were conducted to assess differences between children who had v. had not asked for fruits and vegetables. SETTING Three middle schools in rural Indiana, U.S.A. SUBJECTS A sub-sample of sixty students aged 12–15 years from a larger study of 344 students. RESULTS Qualitative analysis identified benefits (i.e., make me healthier; make parents happy), disadvantages (i.e., will upset my parents) and strategies (i.e., asking when you are at the store) that could be used to improve fruit and vegetable intake. Findings also revealed that students who asked their parents for fruits and vegetables were significantly more likely to perform several healthy eating and physical activity behaviours. CONCLUSIONS Data suggest that young people’s view of parental reactions is critical. While additional research is necessary, the findings support a role for children in shaping their own environment and suggest multilevel interventions that simultaneously address parents and children.

Fish Oil Supplementation and Quality of Life in Stage II Colorectal Cancer Patients: A 24-Month Follow-Up Study

Research suggests that cancer survivors have an interest in lifestyle changes following a diagnosis. However, few studies have prospectively investigated whether these changes result in positive outcomes. The objective of this study was to examine the associations between fish oil supplementation and quality of life (QoL), cancer recurrence, and all-cause mortality in Stage 2 colorectal cancer (CRC) patients following diagnosis. Four hundred fifty-three patients were enrolled from the North Carolina Cancer Registry from 2009 to 2011. Data on demography, treatment, and health behaviors were collected at diagnosis, 12-, and 24 mo postdiagnosis. Generalized estimating equations were performed to examine fish oil supplementation in relation to QoL, recurrence, and all-cause mortality. An increase in fish oil supplementation over 24 mo postdiagnosis was associated with an increase in the physical component score of the 12-item Medical Outcomes Short Form (β = 2.43, 95% CI: 0.10–4.76). Supplementation showed no association with the Functional Assessment of Cancer-Colorectal, cancer recurrence or mortality across the 24-mo follow-up. This study suggests that fish oil supplementation may improve symptom-related QoL (i.e., physical functioning) in Stage 2 CRC patients following diagnosis. Future research should address the dose-dependent effects of this relationship.

Using biological samples for youth ATOD survey validation

Abstract Objective: To identify the conditions under which (1) youth would prefer to participate and (2) parents would allow their child to participate in the collection of biological samples for the purposes of validating a self-report alcohol, tobacco, and other drug (ATOD) survey. Design: Focus groups were held with youth in grades six through 12 and parents of youth entering those grades in the pending academic year. Setting: This study was conducted in Monroe County, Indiana, USA. Method: Six focus groups were held with a total of 23 youth and eight parents in June and July of 2014. Participants were recruited using a tiered convenience sample. All utterances were transcribed verbatim in real time. Content was entered into the DeDoose software package for mixed methods analyses. Results: Significantly more youth respondents would assent to toenail and saliva collection than to urine or venous blood collection. Collection of the latter bio-specimens was perceived to be uncomfortable or was associated with punishment. Parents and youth suggested several ways to lessen concerns, such as adding more participant autonomy to procedures. Conclusion: Input from various stakeholders is important to the implementation of an ATOD bio-validation study in schools to address prevailing concerns and promote participation. Decisions about study procedures should consider the views/suggestions of students, parents, and school personnel, in conjunction with requirements to retain methodological rigor and purpose of the study. The results indicate an inherent tension between a researcher’s ability to simultaneously accommodate requests and adhere to desired methodological precision.

Enhanced vascular function after acute fat-rich snacking in healthy males

Diets high in fat are associated with vascular dysfunction. Frequent snacking may exacerbate this problem by extending the postprandial state. We hypothesized that repeated fat-rich mixed snacks would impair peripheral endothelial function and increase oxidative stress, a purported causal factor. Second, we hypothesized that feeding a quantity of snack based on the subjects body size would not cause different effects from feeding a fixed or constant size snack. A crossover design was used where 10 healthy males followed 2 repeated-snack regimens (fixed and variable based on body surface area), 1 week apart. Each regimen consisted of 2 snacks, fed 4 hours apart (0 and 4 hours). Markers of vascular function (reactive hyperemia index [RHI]), oxidative stress, and antioxidant capacity were measured before and after each snack. Peripheral vascular function improved from fasting to 2 hours after snack 1 (RHI(2h-0h), P = .010), but the change before and after snack 2, RHI(6h-4h), was negative (P = .026), indicating reduced endothelial function after repeated snacking. The oxidative stress marker changed over time (P = .043), increasing after snack 1 and decreasing before snack 2, with no change after snack 2. The antioxidant marker increased 2 hours after each snack (P = .003). Responses to fixed snacks over time were not different from variable snacks, although power was low; the effect size was large for antioxidant capacity, medium for oxidative stress, and small for RHI. Snacking after fasting resulted in a transiently improved peripheral vascular response that disappeared with a second snack. Antioxidant capacity appeared to help limit oxidative stress from repeated snacking in these healthy male subjects.