Understanding of glycemic response using contextual data and modeling * a pilot study

Many people in the Western world have an unhealthy lifestyle, including an
unhealthy dietary pattern. Elevated postprandial blood glucose levels, as well
as high variability in glucose levels are associated with major risk for
prediabetes, type II diabetes and cardiovascular diseases. The use of glycemic
index of food products for controlling glycemic responses has limited efficacy.
Zeevi et al., have shown that the glycemic response on food is highly personal
and not directly linked to the glycemic index of food products. Based on a
cohort of 800 people using multiple measurements, a prediction model based on
mainly the microbiome was made. Surprisingly, known factors influencing
glycemic response like stress levels, quality of sleep and physical activity
were not found. A problem with these big cohorts is the quality of data that is
collected, the lack of contextual data and the laboratory setting in which the
data is collected (which doesn*t necessarily reflect real-life). The proposed
research is part of a research program on Personalized Nutrition and Health
(PNH). The ultimate goal of the program is to enhance the health and wellbeing
of people by empowering consumers to choose and maintain an optimal
personalized diet and lifestyle.

The primary goal is to obtain and investigate the added value of real-life high
quality contextual data (e.g. food intake, physical activity, sleep, wellbeing)
to understand and predict the fluctuations in individual glucose levels. The
secondary objective is to define what metrics of glucose profiles can best be
used to personalize lifestyle recommendations with respect to food intake and
physical activity.

During this observational pilot study 24 volunteers will use a continuous
glucose monitor (CGM) to self-monitor their glucose levels. Additionally, their
activity patterns, heart rate and sleep quality and quantity are monitored
using a Philips ELAN wristband. Furthermore, the participant is asked to
register their food intake and score their wellbeing using a smartphone app.
The duration of the pilot study is approximately two weeks. Since the
continuous glucose sensor requires a 12 hour initialization period, one day
before the start of the pilot, the glucose sensor will be applied on the
participants upper arm. During the first week of the pilot a baseline
measurement is performed using an Oral Glucose Tolerance Test (OGTT). The
participant is asked to fast 10 hours before performing the OGTT. Afterwards
the participant is asked to fill in a satiety questionnaire regarding the OGTT
in the HowAmI app. Additionally, the participant is asked to start wearing the
ELAN wristband and using the apps to register their food intake and answer
questions regarding their wellbeing. During the remaining days of the pilot the
participant can consume their normal diet, but are asked to ensure some
repetition (e.g. consume the same breakfast, lunch and snacks for three days
during the measuring period). To aid subjects in this we will provide them with
some snacks. After 13 days of self-monitoring a debriefing will take place in
which all the participants can ask questions about the study and their personal
data observations. Furthermore, the participants will return the glucose sensor
and the smartwatch and answer questions about their experiencees with
participating in the study (via an online questionnaire).

Disadvantes of participating in this study can be 1) There are some tasks to
required, e.g. keeping track of food intake and answering the wellbeing
questionnaires. 2) there is a small risk of skin irritation, rash or erythema
due to the glucose sensor or ELAN sensor, if this happens the participant is
asked to contact the study leader and replacement of the sensor will be
considered or participation in the study will be ended if the sensor is
removed. 3) A potential risk is concern amongst participants to learn about
health issues they are not familiar with.