[Factors affecting the participation rates in epidemiologic surveys].

Objective: The aim of this study was to investigate the response in health-related epidemiological investigation among Chinese population aged 15 and over. We analyzed the specific causes of non-response, and explored the effective ways to improve the response rate, so as to provide reference for future epidemiological studies of this kind. Methods: Two modes of studies regarding the prevalence of important cardiovascular diseases were used in Chongqing, during the 12(th) Five-Year Plan period in oder to find out the cause related to non-response. Intervention programs were carried out to evaluate the effects. Results: When using the concentrated mode (CM), the completion rate to the questionnaires was only 20.00% in the pre-investigation, with the response rate as 13.48%. In the deconcentrated mode (DM), the completion rate was 31.16%, with the response rate as 25.19%. After a series of incentives provided to both the respondents and the project-related core staff in the two modes, response rates of the two modes increased to the expected 60%. Conclusions: CM appeared having advantages on quality control, but was more time consuming, with higher cost, and without effective follow-up measures to improve the response rate. However, DM had the advantages on controlling the cost and could increase the response rate through making advanced appointment with the households but quality control remained difficult. Two key points should be strengthened to improve the response rates, which including: Precisely finding out the research objects and providing incentives to the respondents to attract their interests of participating in the investigation.

Occlusion and stability of synthetic femoral canal plugs used in cemented hip arthroplasty.

The occlusion and stability of five synthetic plugs used to restrict the femoral canal prior to cemented arthroplasty was assessed. A model was employed consisting of a hollow wooden dowel to simulate the canal, with adapters fixed to both ends to accommodate cement insertion and pressurization, and to produce a closed distal cavity. Three different canal diameters within the range accommodated by the plug selected were employed to assess insertion force, distal pressure during both insertion and pressurization of acrylic cement, and plug migration and leakage for each device. There was a wide variation among plugs in the magnitudes of the force and distal pressure upon plug insertion. During cement pressurization, cement leakage and/or plug migration was noted in all trials, and either of these events resulted in pressure rises in the distal cavity. Most notably, differences of only 0.5 mm in the diameter of the canal resulted in marked changes in the occlusion and stability achieved. It is concluded that for the range of canal sizes anticipated intraoperatively, these synthetic plugs appear deficient to varying extents in their ability to occlude or remain stable in the intramedullary canal.