Clinical trial NCT04326686: Measuring Individual Responses to a Wholegrains and Nuts Intervention to Reduce Blood Pressure in Prehypertension
Official title: Examining Factors Influencing Adherence to and Efficacy of a Wholegrains and Nuts Intervention to Reduce Blood Pressure in Prehypertension: a Series of N-of-1 Interventional Studies
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Prehypertension
Keywords: N-of-1
Ecological Momentary Assessment
Blood pressure
Whole grains
Nuts
Lead sponsor: University of Aberdeen
Sponsor class: OTHER
Collaborators: name: Biotechnology and Biological Sciences Research Council
name: Unilever R&D
First posted: 2020-03-30
Enrollment: 12
Sex: ALL
Minimum age (years): 18
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: This is a series of N-of-1 studies where data from each participant will be analysed separately. Each study follows an A1-B-A2 design consisting of an initial observation phase, an intervention phase and a follow-up phase, each of 8 weeks duration.
Primary purpose: PREVENTION

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.

Eligibility criteria: Inclusion Criteria:

* 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

Exclusion Criteria:

* 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.

Primary outcomes:
measure: Adherence to wholegrains and nuts consumption
timeFrame: 8-week intervention period
measure: Change in plasma alkylresorcinol levels reflecting wholegrains intake
timeFrame: Every 4 weeks from start of study up to 24 weeks
measure: Change in blood pressure
timeFrame: From start of study up to 24 weeks
Secondary outcomes:
measure: Correlation between adherence and blood pressure change
timeFrame: 8-week intervention period
measure: Total, LDL and HDL cholesterol levels
timeFrame: 4-week blood samples
measure: Amount of wholegrains and nuts consumed during follow-up reported using PRO-Diary questionnaires
timeFrame: 8-week follow-up phase
measure: Determination of personal factors which correlate with study outcomes using Ecological Momentary Assessment (EMA) through the PRO-Diary device
timeFrame: 24 weeks
Other outcomes:
Locations:
city: Aberdeen
country: United Kingdom
facility: The Rowett Institute, University of Aberdeen
state: Aberdeen City
Study officials:
affiliation: The Rowett Institute, University of Aberdeen
name: Baukje de Roos
role: PRINCIPAL_INVESTIGATOR
References: