Abstract â–¡ 89

This investigation evaluates two different methods to recruit controls during the pilot phase for a multi-center case control study. The pilot study tested the feasibility of these methods in 3 forensic medicine centers (Hamburg, Hannover and Muenster) between October 1996 and July 1997. During this period investigations of 58 SIDS victims were compared with 181 controls (Questionnaire with 168 variables).

Each case was matched with four controls for age and location. One method was to ask the pediatrician who treated the SIDS cases before death, to randomly select four age-matched patients and a second local pediatrician was also asked to select four controls. From these eight controls four were selected with the age closest to that of the SIDS victim. The other method was to select eight controls with the support of two local registration offices.

During the pilot study 92 pediatricians were asked to participate in the study of which 68 responded. (Non - response rate 26%) The mean time interval to send addresses to the study center was 29 days (range 6 - 165) and from the children only 50 met the criteria for the study design.

A total of 110 registration offices were contacted and the response rate was 100%. The mean time interval for sending the addresses was 9 days (range 1-40) and of the 440 children 434 (98,6%) met the criteria for the study design. These children were ordered by age according to the SIDS case and 128 were randomly selected. We compared the two different control groups with regard to age, socio-economic status and risk factors (prone sleeping position, smoking) and found that there was no statistically significant difference between the two groups.

Comparing the methods for recruiting controls from pediatricians versus registration offices, the pediatricians had a high non-response rate (26%) and the delay was greater (mean 29 days versus 9 days). According to these results controls for the main study beginning in November 1998 will be drawn only from the registration office.