Baseline recruitment and analyses of nonresponse of the Heinz Nixdorf Recall Study: identifiability of phone numbers as the major determinant of response.
The Heinz Nixdorf Recall Study is an ongoing population-based prospective cardiovascular cohort study of the Ruhr area in Germany. This paper focuses on the recruitment strategy and its response results including a comparison of participants of the baseline examination with nonparticipants. Random samples of the general population were drawn from residents' registration offices including men and women aged 45-74 years. We used a multimode contact approach including an invitational letter, a maximum of two reminder letters and phone calls for the recruitment of study subjects. Nonparticipants were asked to fill in a short questionnaire. We calculated proportions of response, contact, cooperation and recruitment efficacy to characterize the participation. Overall, 4487 eligible subjects participated in our study. Although the elderly (65-75 years) had the highest contact proportion, the cooperation proportion was the lowest among both men and women. The recruitment efficacy proportion was highest among subjects aged 55-64 years. The identifiability of the phone number of study subjects was an important determinant of response. The recruitment efficacy proportion among subjects without an identified phone number was 11.4% as compared to 65.3% among subjects with an identified phone number. The majority of subjects agreed to participate after one invitational letter only (52.6%). A second reminding letter contributed only very few participants to the study. Nonparticipants were more often current smokers than participants and less often belonged to the highest social class. Living in a regular relationship with a partner was more often reported among participants than nonparticipants.
Stang
A
A
Institute of Medical Epidemiology, Biometry and Informatics, Medical Faculty, Martin-Luther-University of Halle-Wittenberg, Magdeburger Street 27, 06097, Halle, Germany. andreas.stang@medizin.uni-halle.de
Moebus
S
S
Dragano
N
N
Beck
E M
EM
Möhlenkamp
S
S
Schmermund
A
A
Siegrist
J
J
Erbel
R
R
Jöckel
K H
KH
D000367:Age Factors; D000368:Aged; D015709:Correspondence as Topic; D003645:Death, Sudden / Q000453:epidemiology; D004812:Epidemiologic Methods; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology; D018579:Patient Selection; D011446:Prospective Studies; D045808:Refusal to Participate / Q000523:psychology / Q000706:statistics & numerical data*; D017010:Reminder Systems; D035842:Research Subjects / Q000145:classification* / Q000523:psychology; D018570:Risk Assessment; D015983:Selection Bias; D012737:Sex Factors; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D013689:Telephone / Q000145:classification*