PRevention of knee Osteoarthritis in Overweight Females (PROOF); long-term follow-up

The current project is a follow-up of an in 2012 completed randomized
controlled trial on the effects of a lifestyle intervention aimed at weight
loss and a placebo-controlled glucosamine sulphate intervention in middle-aged
overweight women. A total of 407 women between 50 and 60 years participated in
this study. After an average follow-up of 2.5 years, there was a small but
significant decrease in body weight in the intervention group of the life style
intervention. It this relatively short follow-up period, only a positive trend
of the lifestyle intervention on the development of knee osteoarthritis was
found. There was no preventive effect of the glucosamine sulphate demonstrated.
However, there appeared to be a negative effect of the glucosmaine sulphate on
the number of people with elevated blood sugar after 30 months.
International literature dictates that in order to evaluate the effects of
weight reduction on health factors a minimum follow-up period of four years is
necessary. That is why we want to approach all participants of the original
trial now, after an average of 6.5 years, again. Moreover, this enables us to
evaluate the intervention effects on the development of clinical and
radiographic knee OA seperately, whereas these were combined for feasibility
reasons in the original trial. 95% of all participants who have been to the
final measurement of the original trial has given permission to be approached
for a possible continuation of the trial.

The aim of the current project is to evaluate the long-term effects of a) a
pragmatic lifestyle intervention aimed at weight loss and b) a 30-month
placebo-controlled intervention with glucosamine sulphate on the development of
knee osteoarthritis after 6.5 years in overweight women.

All women who have given their consent to be contacted again, will be written
to ask for their participation. By phone, inclusion and exclusion criteria will
be checked, any questions will be answered and after consent of the subject an
appointment for a single measurement will be made.
During this measurement, a questionnaire and a physical examination will be
administered, an X-ray and MRI of both knees will be made and a blood sample
will be drawn by vena punction. After these measurements (± 90 minutes), the
participation of the subject is directly ended; there is no intervention tested
and there will be no follow-up.

The measurements are the same as performed at the final measurement of the
original trial, so all participants will be familiar with the burden of
participation. The burden of participation and the risks of the measurements to
be carried out are very low. It is only a single measurement of ± 90 minutes,
with only a slightly increased risk in making the X-rays (radiation) and
obtaining a sample of blood through the vena puncture.