The association of intra-individual determinants and the physical environment with lifestyle behaviour and glucose metabolism - Follow-up Hoorn Study 2021

Although prevention programmes show that lifestyle modification is effective to
prevent type 2 diabetes (T2D), the general population is largely unable to
adopt a healthy lifestyle. Moreover, such prevention programs are ineffective
to maintain over a longer period of time. More insight is needed in the
determinants of adoption of a healthy lifestyle and their role in disturbance
of glucose metabolism and T2D risk. Theoretical models such as the
socio-ecological model provide insights in such upstream determinants of
lifestyle behaviours, for example motivation. Despite this, very few studies
have actually investigated the association of more upstream factors with
disease outcomes and whether this potential association can be explained by
health behaviours. More insight in these associations can provide insights for
prevention programs to address these underlying factors or identify those at
high risk to develop T2D. The Hoorn study is a longstanding population-based
cohort study with the primary aim to investigate the prevalence and risk
factors of T2D. The Hoorn study was initiated in 1989 and since then several
additional follow-up rounds have been conducted, also with sampling of new
participants in 2007. Therefore, the Hoorn study provides an excellent
opportunity to address these research questions.

Primary objective:
- to determine the association of the intra-individual determinants and
the physical environment in regulating lifestyle behaviour and in turn the
occurrence of pre-T2D and T2D in the general population.

Secondary Objective(s):
- To determine the association between the intra-individual determinants and
physical environment with secondary outcomes of the individual continuous
measures of glucose metabolism (glucose, insulin, insulin sensitivity) in the
general population;
- To determine the association between the intra-individual determinants and
physical environment with secondary outcomes of obesity in the general
population;
- To determine the association between the intra-individual determinants and
physical environment determinants and complications of T2D, such as
cardiovascular disease and psychological problems in the general population;
- To determine the mediation effect of the lifestyle behaviours in the
association between intra-individual determinants and physical environment and
glucose metabolism in the general population.

Prospective cohort study.

Participants are asked to visit the research institute 1 time. This takes in
total 5 hours. Several non-invasive questionnaires are taken. Anthropometry and
blood pressure are determined. During the first visit (4 hours), an oral
glucose tolerance test (OGTT) is administered in those without diabetes. All
participants are requested to fast before they come to the research center
(starting 10pm the evening before the study; and to refrain from alcohol from 5
pm the evening before the study), participants are allowed to drink water.
Blood is taken. Participants are also asked to bring a urine and faeces sample.
All participants are asked to wear an accelerometer for a week.

Participants with diabetes are asked to take a Walking Speed Test.