Cardiometabolic diseases, including type 2 diabetes (T2DM) and cardiovascular disease (CVD), are common. Approximately one in three deaths annually are caused by CVD in Aotearoa New Zealand (AoNZ)(1). The Mediterranean dietary pattern is associated with a reduced risk of cardiometabolic disease in epidemiological and interventional studies(2,3). However, implementing the Mediterranean diet into non-Mediterranean populations can be challenging(4). Some of these challeanges include facilitating consumption of unfamiliar foods and the cultural and social context of food consumption. AoNZ produces a rich source of high-quality foods consistent with a Mediterranean dietary pattern. He Rourou Whai Painga is collaborative project combining contributions from food industry partners into a Mediterranean Diet pattern and providing foods, recipes and other support to whole household/whānau. The aim was to test if a New Zealand food-based Mediterranean diet (NZMedDiet) with behavioural intervention improves cardiometabolic health and wellbeing in individuals at risk. This presentation will review the background to the research, the process of forming a collaboration between researchers and the food industry, the design and implementation of a complex study design (see protocol paper)(5), with results from the initial randomised controlled trial. We conducted several pilot studies(6,7,8) to inform the final design of the research, which was a combination of two randomised controlled trials (RCT 1 and 2) and a longitudinal cohort study. RCT-1 compared 12-weeks of the NZMedDiet to usual diet in participants with increased cardiometabolic risk (metabolic syndrome severity score (MetSSS) >0.35). The intervention group were provided with food and recipes to meet 75% of their energy requirements, supported by a behavioural intervention to improve adherence. The primary outcome measure was MetSSS after 12 weeks. Two hundred individuals with mean (SD) age 49.9 (10.9)yrs with 62% women were enrolled with their household/whānau. After 12 weeks, the mean (SD) MetSSS was 1.0 (0.7) in the control (n = 98) and 0.8 (0.5) in the intervention (n = 102) group; estimated difference (95% CI) of -0.05 (-0.16 to 0.06), p=0.35. A Mediterranean diet score (PyrMDS) was greater in the intervention group 1.6 (1.1 to 2.1), p<0.001, consistent with a change to a more Mediterranean dietary pattern. Weight reduced in the NZMedDiet group compared with control (-1.9 kg (-2.0 to -0.34)), p=0.006 and wellbeing, assessed by the SF-36 quality of life questionnaire, improved across all domains p<0.001. In participants with increased cardiometabolic risk, food provision with a Mediterranean dietary pattern and a behavioural intervention did not improve a metabolic risk score but was associated with reduced weight and improved quality of life.

Unanchored population-adjusted indirect comparisons (PAICs) such as matching-adjusted indirect comparison (MAIC) and simulated treatment comparison (STC) attracted a significant attention in the health technology assessment field in recent years. These methods allow for indirect comparisons by balancing different patient characteristics in single-arm studies in the case where individual patient-level data are only available for one study. However, the validity of findings from unanchored MAIC/STC analyses is frequently questioned by decision makers, due to the assumption that all potential prognostic factors and effect modifiers are accounted for. Addressing this critical concern, we introduce a sensitivity analysis algorithm for unanchored PAICs by extending quantitative bias analysis techniques traditionally used in epidemiology. Our proposed sensitivity analysis involves simulating important covariates that were not reported by the comparator study when conducting unanchored STC and enables the formal evaluating of the impact of unmeasured confounding in a quantitative manner without additional assumptions. We demonstrate the practical application of this method through a real-world case study of metastatic colorectal cancer, highlighting its utility in enhancing the robustness and credibility of unanchored PAIC results. Our findings emphasise the necessity of formal quantitative sensitivity analysis in interpreting unanchored PAIC results, as it quantifies the robustness of conclusions regarding potential unmeasured confounders and supports more robust, reliable, and informative decision-making in healthcare.

Cardiometabolic diseases are highly prevalent in Aotearoa New Zealand(1). Dietary intake is a modifiable risk factor for such diseases and certain dietary patterns, specifically the Mediterranean diet (MedDiet), are associated with improved metabolic health(2). This study aims to test whether an intervention of a Mediterranean dietary pattern incorporating high quality New Zealand foods (NZMedDiet pattern) using behaviour change science can improve the metabolic health of participants and their household/whānau. This is a multi-centre, three-stage trial, with two randomised controlled trials (RCTs), both parallel groups, superiority trials, and a longitudinal cohort study. The first RCT (RCT1) is a comparison of the NZMedDiet pattern implemented using behaviour science compared to usual diet for 12 weeks, and the second (RCT2) is a behaviour-change intervention compared to no intervention for 12 weeks, administered after participants have been exposed to the intervention in RCT1. The third stage is a longitudinal cohort study where all participants are followed for up to a year. The primary outcome measure for each stage is the metabolic syndrome severity score (MetSSS). Two hundred index participants and their household/whānau have been recruited and randomised into the trial. Participants are from four centres, two of which are University research units (University of Auckland (n = 57) and University of Otago, Christchurch (n = 60)), one a community-based traditional meeting place (Tu¯ Kotahi Māori Asthma and Research Trust at Ko¯kiri Marae in Lower Hutt, Wellington (n = 19)), and the other based at a hospital-based research unit (the Centre for Endocrine Diabetes and Obesity Research (CEDOR) in Wellington (n = 64). The trial will test whether the NZMedDiet pattern and behaviour change support improves the cardiometabolic health of people in New Zealand.

Mica domains have received less attention in the literature than smectite quasi-crystals. This study was conducted to determine whether mica crystals form domains in suspension, the conditions in which those domains exist, and the distribution of adsorbed Na and Ca ions in the domains. Particle size distributions and electrophoretic mobilities (EM) of Silver Hill illite in suspension densities of 0.5 g liter−1 were determined by photon correlation spectroscopy (PCS). Solutions at salt concentration from 2 to 10 mmolc liter−1, sodium adsorption ratio (SAR) from 0 to ∞ (mmol liter−1)0.5, and pH values 5, 7, and 9 were used to prepare the clay suspensions. The particle size of Silver Hill illite suspensions showed a bimodal distribution. Through PCS measurements at low angles, the second peak of the bimodal distribution of the illite was found to be associated with the rotational movement of the b-dimension of the particles. Illite domains broke down in the range of SAR 10 to 15 (mmol liter−1)0.5 equivalent to exchangeable sodium percentages (ESP) of 13 to 18. Illite thus demonstrates a similar stability to smectites that require ESP ≈ 15 to disaggregate quasi-crystals. The EM of the illite particles increased drastically when the SAR increased from 2 to 10 (mmol liter−1)0.5. This increase in EM could not be explained exclusively by the change in the particle size. Cation demixing is required to explain the increase of the zeta potential at the shear plane. The EM of the Silver Hill illite was doubled when the pH increased from 5 to 9 at SAR > 15, but no pH effect was found when SAR < 15. The effect of pH on the EM at SAR values > 15 can be understood if we consider that at SAR > 15 most of the particles are single platelets. The relative importance of variable charge on single platelets or crystals is apparently greater than on domains because the pH affected the mobility of the individual crystals but not the mobility of the domains. The combination of particle size distribution and EM data gives additional information about the zero point of charge of the variable charge, also called point of zero net proton charge (PZNPC) of the clay. For Silver Hill illite, we estimate a PZNPC value between 5 and 7.