Participation rates in Epidemiologic studies: Pedro Ramos

Introduction

It is widely perceived that participation rates in epidemiologic studies have declined in recent years. High nonparticipation levels have a harmful effect in all studies, especially in those in which the underlying causes of such a phenomenon are associated with the epidemiologic area of interest. Thus, it is important to look into this matter more deeply.

Purpose

The aim of this study was to investigate the profile of the individual that agrees to participate in epidemiologic studies and the profile of who doesn’t. The main goal is to set out a statistical model which allows us to predict the chances of a subject with a given set of characteristics to become a part of a study with epidemiologic nature. We considered several factors such as age, gender, education level, marital status, the distance between the Hospital and the area where the patient lives and how often he goes to the Hospital.

Results

We have now evidence that men more often decline Epidemiologic study participation. About 64.4% of the individuals that do not agree to take part in epidemiologic studies are men and 35.6% are women. The average age of participants is 64.7 years; the age average of nonparticipants is 70.5 years. Surprisingly, the distance between the Hospital and individual’s home has not stood out so far as a relevant factor to justify participation rates. On the contrary, the number of years of education appears to matter in the sense that subjects with higher education levels tend to be more open to participate than individuals with less years of schooling.

Discussion

With this approach we hope to diagnose the reasons why study participation has been declining and hope to contribute to strategies to increase participation rates in public health studies.

Acknowledgements: This study has been supported by FCT (COMPETE/QREN) grant ref: PTDC/DPT-EPI/0412/2012.

Key messages

• High nonparticipation levels have a harmful effect in all studies, especially in those in which the underlying causes of such a phenomenon are associated with the epidemiologic area of interest

• We hope to find out the reasons why study participation has been shrinking so that low participation rates can be avoided