Nederland de Maat Genomen ‘Measuring the Netherlands’ - experiences from the Netherlands-

Assignment Ministry of Public Health and Welfare Population-based study in order to estimate the prevalence of: (abdominal) obesity metabolic risk factors undiagnosed diabetes Target population: years of age, nationally representative sample Target number: respondents (for stratification purposes, especially SES)

Challenge was to design the study in such a way that results would be generalizable to the general population So: Representative sample Large enough to say something about subgroups (power) High response! Characterisation of non-respondents High quality standardized measures Logistically feasible …..and….within budget!!

Measurements Height, weight, waist/hip circumference Blood sample: total/HDL chol, triglyceride, fasting glucose, HbA1c ‘short’ questionnaire to fill in at home Measurements in the morning, 7-10 am, at a research center

Communication Specially designed materials with photo’s of all types of people Recommendation letter of municipal health service Local radio, newspaper (tv) We informed general practitioners in the region

General invitation scheme Letter with information and reply card -Send back reply: are you willing to participate? -If yes  invitation + questionnaire -If no  please answer non-response questions -If not returned: reminder after 3 weeks »If still no reaction  telephone calls, max. 6 times »If no contact  second (last) reminder Incentive 10 euro’s (+ simple breakfast) Examination center open 7-10 am Mo-Sat (fasting blood)

Sample Pilot: May (Tilburg) First fase: Oct-Dec Vlaardingen Oudewater Groningen Haarlemmermeer

Crude division of types of response persons invited -30 % examined -30 % actively refused 2300 were willing to answerl non-response questions -40% was never reached -for 70% of those never reached no telephone number could be found!

New approach: 2 locations maximum effort Invitation + reply card 5 euro included in invitation letter If no reaction: reminder

New approach: 2 locations maximum effort Invitation + reply card 5 euro included in invitation letter If no reaction: reminder If no reaction still  door-knocking to invite people, -Measure height and weight -if they are not willing try to get them answering the non- response questions -If not, estimate BMI (rough categories normal/overweight/severly overweight)

New approach Incentive to come to the center: 50 euro Research center open whole day+evening, our preference is fasting blood Exclude the year olds. -Design a separate strategy to reach this group Add an ‘interesting measurement’? (cost, meaning,..)

….approval from medical ethical committee….

Communication Publicity: more than before -poster in supermarkets, -local newspapers/radio/TV, -use quotes from previous respondents and general practitioner in invitation brochure -use quote of general practitioner in invitaion brochure -trigger on the envelop

Communication ‘How to sell a health survey to the public?’