Does self-efficacy mediate the cross-sectional relationship between perceived quality of health care and self-management of diabetes? Results from Diabetes MILES - Australia

OBJECTIVE: Quality of health care (QoC) and self-efficacy may affect self-management of diabetes, but such effects are not well understood. We examined the indirect role of diabetes-specific self-efficacy (DSE) and generalised self-efficacy (GSE) in mediating the cross-sectional relationship between self-reported QoC and diabetes self-management.

DESIGN: Diabetes MILES-Australia was a national survey of 3,338 adults with diabetes. We analysed data from 1,624 respondents (Age: M=52.1, SD=13.9) with type 1 (T1D; n=680) or type 2 diabetes (T2D; n=944), who responded to a version of the survey containing key measures.

MAIN OUTCOME MEASURES: Self-reported healthy eating, physical activity, self-monitoring of blood glucose frequency, HbA1c, medication/insulin adherence. RESULTS: We used Preacher and Hayes' bootstrapping method, controlling for age, gender and diabetes duration, to test mediation of DSE and GSE on the relationship of QoC with each self-management variable. We found statistically significant but trivial mediation effects of DSE and of GSE on most, but not all, variables (all effect sizes <0.06).

CONCLUSION: Support for mediation was weak, suggesting that relationships amongst these variables are small and that future research might explore other aspects of self-management in diabetes.

Explaining engagement in self-monitoring among participants of the DESMOND self-monitoring trial: a qualitative interview study

BACKGROUND: The Diabetes Education and Self-Management for Ongoing and Newly Diagnosed (DESMOND) Self-monitoring Trial reported that people with newly diagnosed type 2 diabetes attending community-based structured education and randomized to self-monitoring of blood glucose (SMBG) or urine monitoring had comparable improvements in biomedical outcomes, but differences in satisfaction with, and continued use of monitoring method, well-being and perceived threat from diabetes. OBJECTIVES: To explore experiences of SMBG and urine monitoring following structured education. We specifically addressed the perceived usefulness of each monitoring method and the associated well-being. METHODS: Qualitative semi-structured interviews with 18 adults with newly diagnosed type 2 diabetes participating in the DESMOND Self-monitoring Trial (SMBG, N=10; urine monitoring, N=8)~12 months into the trial. Analysis was informed by the constant comparative approach. RESULTS: Interviewees reported SMBG as accurate, convenient and useful. Declining use was explained by having established a pattern of managing blood glucose with less frequent monitoring or lack of feedback or encouragement from health care professionals. Many initially positive views of urine monitoring progressively changed due to perceived inaccuracy, leading some to switch to SMBG. Perceiving diabetes as less serious was attributable to lack of symptoms, treatment with diet alone and-in the urine-monitoring group-consistently negative readings. Urine monitoring also provided less visible evidence of diabetes and of the effect of behaviour on glucose. CONCLUSIONS: The findings highlight the importance for professionals of considering patients' preferences when using self-monitoring technologies, including how these change over time, when supporting the self-care behaviours of people with type 2 diabetes.

The relationships between illness and treatment perceptions with adherence to diabetes self-care: A comparison between Arabic-speaking migrants and Caucasian English-speaking patients

Aims
To compare illness and treatment perceptions between Arabic-speaking immigrants and Caucasian English-speaking people with type 2 diabetes, and explore the relationships between these beliefs and adherence to self-care activities.
Methods

A cross-sectional study was conducted in healthcare settings with large Arabic populations in metropolitan and rural Victoria, Australia. Adherence to self-care activities, illness and treatment perceptions, and clinical data were recorded. Bivariate associations for continuous normally distributed variables were tested with Pearson's correlation. Non-parametric data were tested using Spearman's rank correlation coefficient.
Results

701 participants were recruited; 392 Arabic-speaking participants (ASPs) and 309 English-speaking participants (ESPs). There were significant relationships between participants’ illness and treatment perceptions and adherence to diabetes self-care activities. ASPs’ negative beliefs about diabetes were strongly and significantly correlated with poorer adherence to diet recommendations, exercise, blood glucose testing and foot care. ASPs were significantly less adherent to all aspects of diabetes self-care compared with ESPs: dietary behaviours (P = <0.01; 95% confidence interval (CI) = −1.17, −0.84), exercise and physical activity (P = <0.001, 95% CI −1.14, −0.61), blood glucose testing (P = <0.001) and foot-care (P = <0.001). 52.8% of ASPs were sceptical about prescribed diabetes treatment compared with only 11.2% of the ESPs. 88.3% of ASPs were non-adherent to prescribed medication, compared with 45.1% of ESPs.

Conclusions
Arabic-speaking migrants’ illness and treatment perceptions were significantly different from the English-speaking group. There is a pressing need to develop new innovative interventions that deliver much-needed improvements in adherence to self-care activities and key health outcomes.

Diabetes text-message self-management support program (SMS4BG): A pilot study

BACKGROUND: The increasing prevalence of diabetes and costly long-term complications associated with poor glycemic control are issues facing health services worldwide. Diabetes self-management, with the support of health care providers, is critical for successful outcomes, however, frequent clinical contact is costly. Text messages via short message service (SMS) have the advantage of instant transmission at low cost and, given the ubiquity of mobile phones, may be the ideal platform for the delivery of diabetes self-management support. A tailored text message-based diabetes support intervention called Self-Management Support for Blood Glucose (SMS4BG) was developed. The intervention incorporates prompts around diabetes education, management, and lifestyle factors (healthy eating, exercise, and stress management), as well as blood glucose monitoring reminders, and is tailored to patient preferences and clinical characteristics. OBJECTIVE: To determine the usability and acceptability of SMS4BG among adults with poorly controlled diabetes. METHODS: Adults (aged 17 to 69 years) with type 1 (n=12) or type 2 diabetes (n=30), a hemoglobin A1c (HbA1c) over 70 mmol/mol (8.6%), and who owned a mobile phone (n=42) were recruited to take part in a 3-month pilot study of SMS4BG. At registration, participants selected the modules they would like to receive and, where appropriate, the frequency and timing of blood glucose monitoring reminders. Patient satisfaction and perceptions of the usability of the program were obtained via semistructured phone interviews conducted at completion of the pilot study. HbA1c was obtained from patient records at baseline and completion of the pilot study. RESULTS: Participants received on average 109 messages during the 3-month program with 2 participants withdrawing early from the study. Follow-up interviews were completed with 93% of participants with all reporting SMS4BG to be useful and appropriate to their age and culture. Participants reported a range of perceived positive impacts of SMS4BG on their diabetes and health behaviors. HbA1c results indicated a positive impact of the program on glycemic control with a significant decrease in HbA1c from baseline to follow-up. CONCLUSIONS: A tailored text message-based intervention is both acceptable and useful in supporting self-management in people with poorly controlled diabetes. A randomized controlled trial of longer duration is needed to assess the efficacy and sustainability of SMS4BG.

Undiagnosed hypertension in a rural district in Bangladesh: The Bangladesh Population-based Diabetes and Eye Study (BPDES)

Hypertension is mainly asymptomatic and remains undiagnosed until the disease progresses. The objective of the study was to determine the prevalence of and risk factors for hypertension in rural Bangladesh. Using a population-based cluster random sampling strategy, 3096 adults aged ⩾30 years were recruited from a rural district in Bangladesh. Data collected included two blood pressure (BP) measurements, fasting blood glucose, socio-demographic and anthropometric measurements. Hypertension was defined as systolic BP (SBP) ⩾140 mm Hg or diastolic BP (DBP) ⩾90 mm Hg or self-reported diagnosed hypertension. Logistic regression techniques were used for data analyses. The crude prevalence of hypertension was 40% (95% confidence interval (CI) 38-42%) of which 82% were previously undiagnosed. People from lower socio-economic status (SES) had a significantly higher percentage of undiagnosed hypertension compared with people with higher SES (P<0.001). There was no significant gender difference in severity of hypertension. Males with higher education level compared with no education had a higher prevalence of hypertension (odds ratio 2.34, 95% CI 1.49-3.69). Older age and waist circumference in both genders, and diabetes, lack of physical activity in females were found to be associated with higher prevalence of hypertension. Our research suggests the prevalence of undiagnosed hypertension was higher in the rural area in Bangladesh than that reported from the rural area in neighbouring India and China. Lower SES was associated with a higher risk of undiagnosed hypertension. Public health programs at the grass-roots level must emphasise the provision of primary care and preventive services in managing this non-communicable disease.

Mothers after gestational diabetes in Australia (MAGDA) : a randomised controlled trial of a postnatal diabetes prevention program

BACKGROUND: Gestational diabetes mellitus (GDM) is an increasingly prevalent risk factor for type 2 diabetes. We evaluated the effectiveness of a group-based lifestyle modification program in mothers with prior GDM within their first postnatal year. METHODS AND FINDINGS: In this study, 573 women were randomised to either the intervention (n = 284) or usual care (n = 289). At baseline, 10% had impaired glucose tolerance and 2% impaired fasting glucose. The diabetes prevention intervention comprised one individual session, five group sessions, and two telephone sessions. Primary outcomes were changes in diabetes risk factors (weight, waist circumference, and fasting blood glucose), and secondary outcomes included achievement of lifestyle modification goals and changes in depression score and cardiovascular disease risk factors. The mean changes (intention-to-treat [ITT] analysis) over 12 mo were as follows: -0.23 kg body weight in intervention group (95% CI -0.89, 0.43) compared with +0.72 kg in usual care group (95% CI 0.09, 1.35) (change difference -0.95 kg, 95% CI -1.87, -0.04; group by treatment interaction p = 0.04); -2.24 cm waist measurement in intervention group (95% CI -3.01, -1.42) compared with -1.74 cm in usual care group (95% CI -2.52, -0.96) (change difference -0.50 cm, 95% CI -1.63, 0.63; group by treatment interaction p = 0.389); and +0.18 mmol/l fasting blood glucose in intervention group (95% CI 0.11, 0.24) compared with +0.22 mmol/l in usual care group (95% CI 0.16, 0.29) (change difference -0.05 mmol/l, 95% CI -0.14, 0.05; group by treatment interaction p = 0.331). Only 10% of women attended all sessions, 53% attended one individual and at least one group session, and 34% attended no sessions. Loss to follow-up was 27% and 21% for the intervention and control groups, respectively, primarily due to subsequent pregnancies. Study limitations include low exposure to the full intervention and glucose metabolism profiles being near normal at baseline. CONCLUSIONS: Although a 1-kg weight difference has the potential to be significant for reducing diabetes risk, the level of engagement during the first postnatal year was low. Further research is needed to improve engagement, including participant involvement in study design; it is potentially more effective to implement annual diabetes screening until women develop prediabetes before offering an intervention. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12610000338066.

La résistance à l’insuline en insuffisance rénale chronique et le risque de développer un diabète de type 2 : un cercle vicieux

L’insuffisance rénale chronique (IRC) est caractérisée par de multiples déséquilibres homéostatiques tels que la résistance à l’insuline. Peu d’études se sont intéressées aux mécanismes sous-jacents à cette résistance à l’insuline en IRC. De plus, il est méconnu si cette résistance à l’insuline peut mener au développement d’un diabète de type II chez des patients prédisposés. Dans un modèle d’IRC, le rat Sprague-Dawley (CD) néphrectomisé 5/6e, on observe une corrélation entre la gravité de l’atteinte rénale, évaluée par la créatinine sérique, et l’hyperglycémie, évaluée par la fructosamine sérique (R2 = 0.6982, p < 0.0001). Cependant, cet état hyperglycémique n’est pas observable lors d’une glycémie à jeun. Lors d’un test de tolérance au glucose, on observe une plus grande élévation de la glycémie (AUC 1.25 fois, p < 0.0001) chez le rat atteint d’IRC. Par contre, la sécrétion d’insuline au cours de ce même test n’augmente pas significativement (AUC ≈ 1.30 fois, N.S.) en comparaison aux rats témoins. Malgré une élévation des taux d’insuline en IRC suivant un bolus de glucose, les tissus périphériques ne montrent pas d’augmentation de la captation du glucose sanguin suggérant un défaut d’expression et/ou de fonction des transporteurs de glucose chez ces rats. En effet, on observe une diminution de ces transporteurs dans divers tissus impliqués dans le métabolisme du glucose tel que le foie (≈ 0.60 fois, p < 0.01) et le muscle (GLUT1 0.73 fois, p < 0.05; GLUT4 0.69 fois, p < 0.01). En conséquence, une diminution significative du transport insulinodépendant du glucose est observable dans le muscle des rats atteint d’IRC (≈ 0.63 fois, p < 0.0001). Puisque les muscles sont responsables de la majorité de la captation insulinodépendante du glucose, la diminution de l’expression du GLUT4 pourrait être associée à la résistance à l’insuline observée en IRC. La modulation de l’expression des transporteurs de glucose pourrait être à l’origine de la résistance à l’insuline en IRC. Cela dit, d’autres mécanismes peuvent aussi être impliqués. En dépit de cette importante perturbation du transport du glucose, nous n’avons pas observé de cas de diabète de type II chez le rat CD atteint d’IRC. Dans un modèle de rat atteint d’un syndrome métabolique, le rat Zucker Leprfa/fa, l’IRC provoque une forte hyperglycémie à jeun (1.5 fois, p < 0.0001). De plus, l’IRC chez le rat Zucker provoque une réponse glycémique (AUC 1.80 fois, p < 0.0001) exagérée lors d’un test de tolérance au glucose. Une forte résistance à l’insuline est mesurée au niveau des muscles puisque la dose usuelle d’insuline (2mU/mL) n’est pas suffisante pour stimuler la captation du glucose chez le rat Zucker atteint d’IRC. De plus, une modulation similaire des transporteurs de glucose peut être observée chez ces deux espèces. Par contre, environ 30% (p < 0.001) des rats Zucker atteints d’IRC avaient une glycosurie. L’IRC en soi ne mènerait donc pas au développement d’un diabète de type II. Par contre, lorsqu’une résistance à l’insuline est présente antérieurement au développement d’une IRC, cela pourrait précipiter l’apparition d’un diabète de type II chez ces patients prédisposés.

La résistance à l’insuline en insuffisance rénale chronique et le risque de développer un diabète de type 2 : un cercle vicieux

L’insuffisance rénale chronique (IRC) est caractérisée par de multiples déséquilibres homéostatiques tels que la résistance à l’insuline. Peu d’études se sont intéressées aux mécanismes sous-jacents à cette résistance à l’insuline en IRC. De plus, il est méconnu si cette résistance à l’insuline peut mener au développement d’un diabète de type II chez des patients prédisposés. Dans un modèle d’IRC, le rat Sprague-Dawley (CD) néphrectomisé 5/6e, on observe une corrélation entre la gravité de l’atteinte rénale, évaluée par la créatinine sérique, et l’hyperglycémie, évaluée par la fructosamine sérique (R2 = 0.6982, p < 0.0001). Cependant, cet état hyperglycémique n’est pas observable lors d’une glycémie à jeun. Lors d’un test de tolérance au glucose, on observe une plus grande élévation de la glycémie (AUC 1.25 fois, p < 0.0001) chez le rat atteint d’IRC. Par contre, la sécrétion d’insuline au cours de ce même test n’augmente pas significativement (AUC ≈ 1.30 fois, N.S.) en comparaison aux rats témoins. Malgré une élévation des taux d’insuline en IRC suivant un bolus de glucose, les tissus périphériques ne montrent pas d’augmentation de la captation du glucose sanguin suggérant un défaut d’expression et/ou de fonction des transporteurs de glucose chez ces rats. En effet, on observe une diminution de ces transporteurs dans divers tissus impliqués dans le métabolisme du glucose tel que le foie (≈ 0.60 fois, p < 0.01) et le muscle (GLUT1 0.73 fois, p < 0.05; GLUT4 0.69 fois, p < 0.01). En conséquence, une diminution significative du transport insulinodépendant du glucose est observable dans le muscle des rats atteint d’IRC (≈ 0.63 fois, p < 0.0001). Puisque les muscles sont responsables de la majorité de la captation insulinodépendante du glucose, la diminution de l’expression du GLUT4 pourrait être associée à la résistance à l’insuline observée en IRC. La modulation de l’expression des transporteurs de glucose pourrait être à l’origine de la résistance à l’insuline en IRC. Cela dit, d’autres mécanismes peuvent aussi être impliqués. En dépit de cette importante perturbation du transport du glucose, nous n’avons pas observé de cas de diabète de type II chez le rat CD atteint d’IRC. Dans un modèle de rat atteint d’un syndrome métabolique, le rat Zucker Leprfa/fa, l’IRC provoque une forte hyperglycémie à jeun (1.5 fois, p < 0.0001). De plus, l’IRC chez le rat Zucker provoque une réponse glycémique (AUC 1.80 fois, p < 0.0001) exagérée lors d’un test de tolérance au glucose. Une forte résistance à l’insuline est mesurée au niveau des muscles puisque la dose usuelle d’insuline (2mU/mL) n’est pas suffisante pour stimuler la captation du glucose chez le rat Zucker atteint d’IRC. De plus, une modulation similaire des transporteurs de glucose peut être observée chez ces deux espèces. Par contre, environ 30% (p < 0.001) des rats Zucker atteints d’IRC avaient une glycosurie. L’IRC en soi ne mènerait donc pas au développement d’un diabète de type II. Par contre, lorsqu’une résistance à l’insuline est présente antérieurement au développement d’une IRC, cela pourrait précipiter l’apparition d’un diabète de type II chez ces patients prédisposés.

Therapeutic education, the premise of adherence to the type 2 diabetes therapeutic regimen

Background: type 2 diabetes mellitus includes changes in lifestyle in its etiology of prevention, but the evidence is clear —even when people know what to do and what they want to do, they simply do not adopt adherence behaviors. Structured education will allow improving not only metabolic control, but also the adjustment process to a new situation of disease, as well as to develop the patient’s skills in order to make him the key manager of his illness. Objectives: To determine patients’ adherence to prescribed therapeutic regimens. Material and methods: Quantitative, cross-sectional, non-experimental, descriptive, correlational study, with a sample of 102 people with type 2 diabetes, aged between 40 and 85 years old, mostly male (51.96%). The evaluation protocol included social-demographic and clinical questionnaire, Diabetes Self-care Scale and a questionnaire on Diabetes’ knowledge. We also used HbA1c in order to directly assess adherence. Results: It appears that there is no statistically signiicant correlation between socio-demographic variables such as gender and age and adherence. Variables, such as blood glucose monitoring, speciic diet compliance and knowledge, reveal a statistically signiicant effect on adherence (P < .05). Conclusion: The evidence is clear on the urgent need to recognize the importance of measuring patient adherence to a diabetes treatment plan for the maintenance of glycaemic control. We suggest the reinforcement of educational programs in people with type 2 diabetes so as to improve adherence to self-care.

Public health implications of dietary fiber intake to reduce the cost of chronic diseases

Objective: To assess the epidemiological evidence on dietary fiber intake and chronic diseases and make public health recommendations for the population in Romania based on their consumption. Populations that consume more dietary fiber from cereals, fruits and vegetables have less chronic disease. Dietary Reference Intakes recommend consumption of 14 g dietary fiber per 1,000 kcal, or 25 g for adult women and 38 g for adult men, based on epidemiologic studies showing protection against cardiovascular disease, stroke, hypertension, diabetes, obesity, metabolic syndrome, gastrointestinal disorders, colorectal -, breast -, gastric -, endometrial -, ovarian - and prostate cancer. Furthermore, increased consumption of dietary fiber improves serum lipid concentrations, lowers blood pressure, blood glucose leads to low glycemic index, aids in weight loss, improve immune function, reduce inflammatory marker levels, reduce indicators of inflammation. Dietary fibers contain an unique blend of bioactive components including resistant starches, vitamins, minerals, phytochemicals and antioxidants. Dietary fiber components have important physiological effects on glucose, lipid, protein metabolism and mineral bioavailability needed to prevent chronic diseases. Materials and methods: Data regarding diet was collected based on questionnaires. We used mathematical formulas to calculate the mean dietary fiber intake of Romanian adult population and compared the results with international public health recommendations. Results: Based on the intakes of vegetables, fruits and whole cereals we calculated the Mean Dietary Fiber Intake/day/person (MDFI). Our research shows that the national average MDFI was 9.8 g fiber/day/person, meaning 38% of Dietary Requirements, and the rest of 62% representing a “fiber gap” that we have to take into account. This deficiency predisposes to chronic diseases. Conclusions and recommendations:The poor control of relationship between dietary fiber intake and chronic diseases is a major issue that can result in adverse clinical and economic outcomes. The population in Romania is at risk to develop such diseases due to the deficient fiber consumption. A model of chronic diseases costs is needed to aid attempts to reduce them while permitting optimal management of the chronic diseases. This paper presents a discussion of the burden of chronical disease and its socio-economic implications and proposes a model to predict the costs reduction by adequate intake of dietary fiber.

Experience modulates the psychophysiological response of airborne warfighters during a tactical combat parachute jump

We aimed to analyse the effect of experience level in the psychophysiological response and specific fine motor skills of novel and expert parachute warfighters during a tactical combat parachute jump. We analysed blood oxygen saturation, heart rate, salivary cortisol, blood glucose, lactate and creatinkinase, leg strength, isometric hand-grip strength, cortical arousal, specific fine motor skills and cognitive anxiety, somatic anxiety and self-confident before and after a tactical combat parachute jump in 40 warfighters divided in two group, novel (n = 17) and expert group (n = 23). Novels presented a higher heart rate, lactate, cognitive anxiety, somatic anxiety and a lower self-confident than experts during the jump. We concluded that experience level has a direct effect on the psychophysiological response since novel paratroopers presented a higher psychophysiological response than compared to the expert ones, however this result neither affected the specific fine motor skills nor the muscle structure after a tactical combat parachute jump.

Predictors of in-hospital mortality among cardiogenic shock patients. Prognostic and therapeutic implications

Cardiogenic shock (CS) has a poor prognosis. The heterogeneity in the mortality through different subgroups suggests that some factors can be useful to perform risk stratification and guide management. We aimed to find predictors of in-hospital mortality in these patients. We analyzed all cases of cardiogenic shock due to medical conditions admitted in our intensive acute cardiovascular care unity from November 2010 till November 2015. Clinical, biochemical and hemodynamic variables were registered, as was the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile at 24 h of CS diagnosis. From a total of 281 patients, 28 died within the first 24 h and were not included in the analysis. A total of 253 patients survived the first 24 h, mean age was 68.8 ± 14.4 years, and 174 (68.8%) were men. Etiologies: acute coronary syndrome 146 (57.7%), acute heart failure 60 (23.7%), arrhythmias 35 (13.8%), and others 12 (4.8%). A total of 91 patients (36.0%) died during hospitalization. We found the following independent predictors of in-hospital mortality: age (odds ratio [OR] 1.032, 95% confidence interval [CI] 1.003–1.062), blood glucose (OR 1.004, 95% CI 1.001–1.008), heart rate (OR 1.014, 95% CI 1.001–1.028), and INTERMACS profile (OR 0.168, 95% CI 0.107–0.266). In patients with CS the INTERMACS profile at 24 h of diagnosis was associated with higher in-hospital mortality. This and other prognostic variables (age, blood glucose, and heart rate) may be useful for risk stratification and to select appropriate medical or invasive interventions.

Text message-based diabetes self-management support (SMS4BG): study protocol for a randomised controlled trial.

BACKGROUND: Addressing the increasing prevalence, and associated disease burden, of diabetes is a priority of health services internationally. Interventions to support patients to effectively self-manage their condition have the potential to reduce the risk of costly and debilitating complications. The utilisation of mobile phones to deliver self-management support allows for patient-centred care at the frequency and intensity that patients desire from outside the clinic environment. Self-Management Support for Blood Glucose (SMS4BG) is a novel text message-based intervention for supporting people with diabetes to improve self-management behaviours and achieve better glycaemic control and is tailored to individual patient preferences, demographics, clinical characteristics, and culture. This study aims to assess whether SMS4BG can improve glycaemic control in adults with poorly controlled diabetes. This paper outlines the rationale and methods of the trial. METHODS/DESIGN: A two-arm, parallel, randomised controlled trial will be conducted across New Zealand health districts. One thousand participants will be randomised at a 1:1 ratio to receive SMS4BG, a theoretically based and individually tailored automated text message-based diabetes self-management support programme (intervention) in addition to usual care, or usual care alone (control). The primary outcome is change in glycaemic control (HbA1c) at 9 months. Secondary outcomes include glycaemic control at 3 and 6 months, self-efficacy, self-care behaviours, diabetes distress, health-related quality of life, perceived social support, and illness perceptions. Cost information and healthcare utilisation will also be collected as well as intervention satisfaction and interaction. DISCUSSION: This study will provide information on the effectiveness of a text message-based self-management support tool for people with diabetes. If found to be effective it has the potential to provide individualised support to people with diabetes across New Zealand (and internationally), thus extending care outside the clinic environment. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12614001232628 .

An investigation of the possible health-promoting modes of action of regular- and super- doses of phytase in the broiler chicken

The overall objective of this thesis was to study the effects of regular and high (super-) doses of phytase in the gut of broilers, with the aim of documenting the mechanism of their action leading to improvements in animal health. Phytase is often supplemented to commercial broiler diets to facilitate the hydrolysis of plant phytate and release of phosphorus for utilisation. Although not the original intention of its addition, phytase supplementation leads to improvements in growth performance parameters and enhanced nutrient utilisation. Further benefits have also been observed following the addition of super-doses of phytase which are not explained by an increase in phosphorus release, and thus have been termed ‘extra-phosphoric effects’. Using diets formulated to be adequate or marginally deficient in available phosphorus (aP; forming the negative control, NC), phytase was supplemented at 1,500 and 3,000 FTU/kg phytase in the first study (both super-doses) and the partitioning of nutrients within the body was investigated. It appeared that there were some metabolic changes between 1,500 and 3,000 FTU/kg, switching between protein and fat accretion, potentially as a consequence of nutrient availability, although these changes were not reflected by changes in growth performance parameters. However, the loss of the NC treatment without phytase on day 12 limits the comparison of the phytase within the NC treatment, but does allow for comparison of each dose at adequate or low dietary aP levels. As expected, a greater degree of phytate hydrolysis was achieved with 3,000 than with 1,500 FTU/kg phytase, but changes in carcass accretion characteristics were greater with 1,500 than 3,000 FTU/kg. Using these findings and the observation that there were no further changes in the parameters measured by increasing phytase from 1,500 to 3,000 FTU/kg (aside from phytate hydrolysis), 1,500 FTU/kg phytase was selected as the super-dose to be used in subsequent studies. The next study considered the influence of regular (500 FTU/kg) and super doses (1,500 FTU/kg) of phytase from within the gut. Overall, it was observed that changes were occurring to the gut environment, which ultimately would influence the absorptive capacity and conditions for further phytate hydrolysis. Dietary treatment influenced gut conditions such as pH, intestinal morphology and bacterial populations which can subsequently influence nutrient utilisation and potential for growth. The subsequent study was designed to investigate the effects within the gut in more detail. The release of nutrients from phytate hydrolysis and their bioavailability within the digesta can influence conditions within intestine, facilitating enhanced absorption. One of the parameters investigated was the expression of genes involved in the transport of nutrients in the intestine. Overall, there were few significant dietary treatment influences on gene expression in the intestine, however there was a dose-dependent response of phytase on the expression of the jejunual divalent mineral transporter. This indicates a change in divalent mineral bioavailability in the intestine, with correlations with inositol phosphate esters (IPs) being identified. This is likely explained by the IPs produced by phytase hydrolysis and accumulating in the digesta, differing between regular and high doses of phytase. It became apparent that interactions between the products of phytate hydrolysis (IP3, IP4) and minerals in the digesta had the potential to influence the gut environment and subsequent nutrient bioavailability and overall phytase action. The final study was designed to increase the content of the IPs, and investigate the influence of phytase under these conditions. As the complete hydrolysis of phytate to myo-inositol has been reported to be beneficial due to its proposed insulin mimetic effects, myo-inositol was also supplemented to one of the diets to see if any further benefits would be observed when supplemented alongside super-doses of phytase. Neither increased concentrations of the higher IP esters (IP6, IP5 and IP4) nor myo-inositol (myo-) had any effect on broiler growth performance, however there were still apparent beneficial influences of phytase supplementation. The results suggest considerable and important interactions between minerals and IP esters within the digesta, which ultimately have the potential to influence gut conditions and thus nutrient utilisation and growth performance. Reduced concentrations of blood glucose in the high IP ester diet with additional phytase supplementation suggest some insulin-like effects of myo- production. Additionally, the lack of effect of myo- supplementation on blood glucose and insulin concentrations suggests a difference between the structure of phytase-produced myo- and supplemented myo-. Although there were no improvements in growth performance by increasing phytase from 500 to 1,500 FTU/kg, there were changes occurring at the level of the gut and expression of genes in the intestine, influencing nutrient utilisation and the partitioning of nutrients within the body. There are many factors to be considered when supplementing phytase, with dietary nutrient content and nutrient release and IP production during phytate hydrolysis having an influence on phytase action, nutrient absorption and conditions within the gut. Super-doses of phytase may be beneficial for maintaining optimal gut conditions, clearing IP esters from the digesta, reducing their potential to form complexes with minerals and other nutrients, ultimately influencing the efficiency of production.

Función endotelial y lipemia postprandial en adultos normolipídicos: Efecto del estado nutricional

El objetivo del presente estudio fue cuantificar la contribución del sobrepeso en la magnitud de la lipemia posprandial en sujetos normolipídicos. Se incluyeron 33 adultos normolipídicos en dos grupos (n=20, sobrepeso y (n=13 eutróficos, 66% hombres, edad media 31,2±7,6 años). Se midió la vasodilatación mediada por flujo (VMF), la velocidad de onda de pulso (VOP), el perfil lipídico, el cociente Log TG/c-HDL, la glucosa y presión arterial tras una ingesta estándar con alto contenido de grasa (79% Kcal/grasa). Se calculó, el Z-score de riesgo cardiovascular a partir de la suma de los residuos tipificados (Z) de las variables de riesgo cardiovascular. El estado de lipemia posprandial se midió en ayuno (0 min) y a los (60, 120, 180, y 240 min) posprandiales. El valor basal de la VMF y la VOP fue de 6,9±5,9% y 7.0±0.8 m/s, respectivamente. Se identificó que la lipemia posprandial reducía la WMF en 19,2% a los 60 min (5,9±1,5%) y a los 240 min (3,7±1,2%) (p<0,04), respectivamente. Este hallazgo se acompañó con un aumento en la VOP (p<0,05). Al dividir los sujetos en dos grupos según el IMC, los participantes en sobrepeso muestran cifras más elevadas en el Z-score de riesgo cardiovascular, la VOP, el Log TG/c-HDL y el Δ-VOP, (p<0,001). En conclusión los sujetos clasificados en sobrepeso muestran un perfil cardiometabolico asociado con un mayor riesgo cardiovascular.