Measuring Individual Responses to a Wholegrains and Nuts Intervention to Reduce Blood Pressure in Prehypertension
- Conditions
- Prehypertension
- Registration Number
- NCT04326686
- Lead Sponsor
- University of Aberdeen
- Brief Summary
The aim of the study is to investigate whether physiological, psychological and environmental factors, at an individual level, modify a) adherence, and b) blood pressure response, to a nuts and wholegrains intervention in participants at risk for developing high blood pressure. For 24 weeks, participants will, on a daily basis, monitor their own blood pressure using a wireless blood pressure monitor and respond to short semi-personalised questionnaires using a wrist-worn device, which also measures activity levels. Participants will receive an intervention of wholegrain foods and nuts to substitute into their diets for 8 weeks, between two 8-week observation periods. The length of the study periods will enable repeated measurements to be taken, in order to assess what factors, on an individual level, are associated with fluctuations in the outcomes. This will provide an insight into the types of factors that can help to explain individual fluctuations in adherence and physiological outcomes, such as blood pressure, that are common in nutrition studies. In the future, this should help in tailoring the way the investigators deliver effective individualised interventions, and enable researchers to be better able to consider and control for factors that can affect adherence and response to dietary interventions.
- Detailed Description
The study will be conducted as an interventional N-of-1 study with an A1-B-A2 design of 8 weeks per study period. Prior to the study, participants will be screened and if eligible, will complete a number of baseline questionnaires to provide an overview of their typical eating and lifestyle-related behaviours, and general health. A second visit prior to the start of the study will then be arranged, where participants will undergo a semi-structured interview. Responses from the interview, in combination with their baseline questionnaire responses, will be used to identify factors specific to the participant that show some degree of variability. These will form the basis of the semi-personalised questionnaires delivered via the wrist-worn PRO-Diary device for the duration of the study. During the study, participants will visit the institute in a fasted state every 4 weeks (7 visits total), in order to provide a blood sample for assessment of cholesterol levels and for assessment of biomarkers of wholegrains intake. At the first visit, participants will receive the wireless blood pressure monitor and PRO-Diary wrist device programmed with twice-daily questionnaires at times convenient to the participant. After 2 weeks and every 4 weeks thereafter, participants will be sent a link by email to complete a 24-hour dietary recall. After 8 weeks, participants will begin the intervention phase and receive wholegrains equivalent to 3 portions a day and 1 portion of unsalted nuts per day for the following 8 weeks. Participants will be able to choose from a variety of wholegrain products commonly available at supermarkets. They will also receive dietary advice to follow a Dietary Approaches to Stop Hypertension (DASH) diet aimed at lowering blood pressure. All other measures will continue as previously. At week 16, the wholegrains and nuts will be withdrawn and participants will be followed up for a further 8 weeks. At their final visit to the institute, they will complete the same validated questionnaires as at baseline. Results from the study will be analysed using N-of-1 dynamic modelling to analyse trends over time and determine whether any personalised factors significantly affected adherence to intervention or blood pressure response.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 12
- Mildly elevated blood pressure levels: systolic blood pressure (SBP) >120 <=140mmHg and/or diastolic blood pressure (DBP) >80 <=90mmHg.
- Low habitual intake of wholegrains: <=7 portions/week
- Body Mass Index (BMI) between 18-35
- Possessing a smartphone capable of running the Qardio app in conjunction with the QardioArm wireless blood pressure monitor
- SBP <120 or >140mmHg or DBP <80 or >90mmHg. Participants with SBP > 140 or DBP > 90 will be advised to visit their GP to have their blood pressure reassessed in a clinical setting.
- Diagnosed with diabetes
- Clinically diagnosed with hypertension or hypercholesterolemia
- Unstable or untreated thyroid disorder
- Taking blood pressure- or cholesterol-lowering medications (e.g. beta blockers or statins)
- Following a low carbohydrate/gluten free diet
- Coeliac disease/gluten insensitivity
- Any food allergies
- Being on a weight loss diet or having lost >5kg in the last 6 months
- Any history of an eating disorder
- >7 portions/week habitual wholegrains consumption
- Having taken part in a study where wholegrains were provided in the last 3 months
- Not possessing a smartphone to run the Qardio app.
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- SINGLE_GROUP
- Primary Outcome Measures
Name Time Method Adherence to wholegrains and nuts consumption 8-week intervention period Number of portions of wholegrains consumed and whether a portion of nuts were consumed, reported daily via the PRO-Diary wrist device.
Change in blood pressure From start of study up to 24 weeks Blood pressure (both systolic and diastolic) will be taken daily by participants via the QardioArm wireless blood pressure monitor. 3 measurements are taken automatically and averaged.
Change in plasma alkylresorcinol levels reflecting wholegrains intake Every 4 weeks from start of study up to 24 weeks Concentration of alkylresorcinols as a measure of wholegrains intake in nmol/L
- Secondary Outcome Measures
Name Time Method Total, LDL and HDL cholesterol levels 4-week blood samples Fasted blood samples will be taken to determine whether wholegrains and nuts consumption has an effect on blood cholesterol levels.
Correlation between adherence and blood pressure change 8-week intervention period Correlation between adherence and blood pressure change will be examined using N-of-1 dynamic modelling. Daily blood pressure measurements and PRO-Diary questionnaire responses will be provided during the whole study. Questionnaire responses will be given on a Visual Analogue Scale from 0-100.
Determination of personal factors which correlate with study outcomes using Ecological Momentary Assessment (EMA) through the PRO-Diary device 24 weeks Participants will respond to semi-personalised questionnaires daily using a Visual Analogue Scale from 0-100 using the PRO-Diary device. The PRO-Diary will also track movement collected during 60-second epochs via accelerometry. The influence of these factors on the primary and secondary outcomes above will be aggregated using N-of-1 dynamic modelling. Due to the semi-personalised nature of the questionnaires, the exact predictors examined in each N-of-1 study will differ. Analysis of each N-of-1 study will be conducted separately.
Amount of wholegrains and nuts consumed during follow-up reported using PRO-Diary questionnaires 8-week follow-up phase For the final 8 weeks of the study, provision of wholegrains and nuts will cease but participants will continue to be asked about their consumption of these products through daily PRO-Diary questionnaires. This is to determine if habit formation has occurred and led to continuation of consumption of these products
Trial Locations
- Locations (1)
The Rowett Institute, University of Aberdeen
🇬🇧Aberdeen, Aberdeen City, United Kingdom