Læknablaðið - 01.10.1967, Page 39

LÆKNABLAÐIÐ
185
In this article a Cardiovascular Population study to be performed by
the Icelandic Heart Association is described. The aims of the study are:
1. To perform a study of males in the capital of Iceland, Reykja-
vik, and its suburbs (a community with ca. 110.000 inhabitants),
where 30% of 16 age groups from 33—60 years old will be
studied with respect to I.H.D., claudication intermittens, high blood
pressure, diabetes mellitus and various high risk factors in I.H.D.
This study will be performed according to WHO recommendations
in a standardized manner. Later women of same age groups will be
studied.
2. To perform a follow-up study in 3 years on the groups investigated
and control groups (from same age groups not investigated at the
initial examination). Thus being able to “estimate” the meaning of
so called risk factors.
3. Study the natural history of cardiovascular disease.
4. To evaluate the possible gains of a population study as a Health
Control.
5. To involve those or at least a part of those who seem to have high
risk of developing I.H.D. in a controlled therapeutic trial.
It is proposed that Iceland is a suitable country for a population study,
ljecause of a
1. National roster system, facilitating the loeation of every partici-
pant.
2. The population is rather stable.
3. The autopsy-rate is one of the highest in Europe (32% of overall
mortality).
4. Good communications.
5. There is a National Health Service in Iceland which covers more
than 90% of the population which enables us to get rather reliabie
information on past history of the participants and non-participants.
It is stressed that the approach used in epidemiological study differs
from that used in clinical medicine. The definition of a disease must be
simple enough to be applied on a mass scale, to subjects who undergo a
limited examination. The diagnostic method must be sufficiently objective
and reproducible. It is preferable to record manifestation of a disease
rather than to “diagnose” a disease, and, to record as many items as pos-
sible in a reproducible way. The selection of criteria for diagnosis may
wait until the stage of analysis.
Our intention is to use WHO criteria and WHO recommended tests,
therefore, our level of specifity and sensitivity should not vary from other
population studies already performed according to WHO standards.
It is stressed that the technic has to be valid, precise, practical and as
free from systematic variations as possible. Investigators must agree on
the measurement definition and on how their measurements are to be
made. The reliability and validity of every method to be used in the study
must be objectively measured.
Examples on which age-groups should be chosen in a cardiovascular
study and some examples between observer variation both within and be-