Netherlands Epidemiology of Obesity study

The prevalence of overweight and obesity has risen dramatically over the past
decades.
Obesity has been associated with a range of diseases, most notably diabetes
mellitus and cardiovascular disease, the number one cause of death in
industrialised countries. These include myocardial infarction, ischemic stroke,
peripheral artery disease, deep vein thrombosis and pulmonary embolism. In
addition, obesity may lead to disabling disorders such as osteoarthritis and
chronic obstructive pulmonary disease and asthma. Moreover, obesity is related
to stress, anxiety and depression.
Insights into how obesity leads to disease are only just emerging. It has
become clear that the adipocyte is not an inert storage unit of fat, but that
this cell is highly active in controlling and signalling, both humoral and via
the autonomic nervous system, thus affecting whole body metabolism. This led to
the concept of toxic effects of adipose tissue.
The diseases that affect overweight and obese individuals are all common
diseases that exact a heavy toll on society. Therefore, the study of the
occurrence of these diseases, the interplay between, and with, additional
genetic and acquired risk factors, and the relation between the various disease
outcomes, is relevant to obese and non-obese individuals alike. Performing a
study among obese individuals may therefore be seen as the use of a model in
which the incidence of disease is increased, and relations relevant to the
aetiology and pathophysiology of the common diseases can be more readily
studied.

Primary general objectives of the NEO study

1. To study the pathways that lead to common diseases in overweight and obese
individuals.
2. To identify novel determinants of various diseases and conditions in
overweight and obese individuals.
3. To study interrelationships between diseases, newly identified determinants
with each other and with classical,
established risk factors.

Secondary general objectives of the NEO Study

1. To identify novel determinants of various subclinical conditions in
overweight and obese individuals.
2. To develop novel methods for determining the risk of various diseases and
conditions in asymptomatic
overweight and obese individuals, in addition to established
prognostic markers.
3. To assess the burden of disease in a population-based cohort of overweight
and obese individuals.
4. To investigate the optimal diagnostic method to define overweight and
obesity in terms of predicting various
diseases.

The NEO study is a population-based, prospective cohort study.

The participants will complete multiple validated questionnaires, collect
24-hours or 12-hours urine, and undergo a series of measurements at the NEO
study site. These include anthropometric assessments and blood pressure, body
composition, blood sampling both fasting, and 30 minutes and 2.5 hours after a
mixed meal, resting EKG, carotid artery IMT and distensibility, and pulmonary
function tests. In a random subset of participants visceral fat, liver
triglyceride content, and pulse wave velocity of the aorta will be measured by
MRI, or assessment of basal metabolic rate, extensive echocardiography, or a
5-day continuous recording of physical activity and heart rate (variability)
with a
combined accelerometer and 2 ECG pads (ActiHeart).

Participants will receive the results of tests for which, according to national
guidelines, testing is recommended (e.g. blood pressure, and levels of glucose,
total and HDL-cholesterol, triglycerides, and renal function). Abnormal levels
will be marked and will be accompanied by an advice to consult their general
practitioner. Furthermore, any abnormal pulmonary function tests will be
followed by an invitation for a more extensive pulmonary function test to
identify chronic pulmonary obstructive disease or asthma. Abnormal results of
the MRI scan that may have consequences for their health will be disclosed to
the participants and their general practitioners. Results of other measurements
will not be disclosed.

Participation in the NEO study in total takes at least 2 days (including
completing the questionnaires and collection of 24-hours urine) to a maximum of
5 days ( when the participant is assigned to Actiheart). The NEO study will
produce a wealth of information allowing the study of possible causes of
disease in overweight or obese individuals. Urine, blood and DNA will be stored
in a biobank allowing future analyses of many new questions without new blood
sampling necessary. Eventually the result may lead to future identification and
treatment of high risk individuals.

For the second measurements the participants will complete multiple validated
questionnaires, collect a morning spot urine, a feacal sample, and undergo a
series of measurements at the NEO study site. These include anthropometric
assessments and blood pressure, body composition, fasting blood sampling,
carotid artery IMT, pulmonary function tests, a fibroscan and a pinpricktest.
In random subsets of participants abdominal and liver fat, heart function or
knee osteoarthritis will be measured by MRI, or bone density by DXA, or a hair
sample will be taken, or physical activity will be measured during a week with
a wrist-worn triaxial accelerometer (Actigraph).The second measurement will
take in total 1 day with or without an extra appointment to undergo MRI
scanning. Those participants with Actigraph will wear the watch for a week and
return it to us in a supplied envelop.