Case-cohort design in practice – experiences from the MORGAM Project

Sangita Kulathinal¹ , Juha Karvanen² , Olli Saarela² and Kari Kuulasmaa² for the MORGAM Project³

¹Indic Society for Education and Development, 1, Swami Enterprises Complex. Tigrania road, Tapovan Bridge, Nashik 422 009, India

²Department of Health Promotion and Chronic Disease Prevention, National Public Health Institute, Mannerheimintie 166, 00300 Helsinki, Finland

³For the participants of the MORGAM Project, see Acknowledgements

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Epidemiologic Perspectives & Innovations 2007, 4:15doi:10.1186/1742-5573-4-15


Published:	4 December 2007

Abstract

When carefully planned and analysed, the case-cohort design is a powerful choice for follow-up studies with multiple event types of interest. While the literature is rich with analysis methods for case-cohort data, little is written about the designing of a case-cohort study. Our experiences in designing, coordinating and analysing the MORGAM case-cohort study are potentially useful for other studies with similar characteristics. The motivation for using the case-cohort design in the MORGAM genetic study is discussed and issues relevant to its planning and analysis are studied. We propose solutions for appending the earlier case-cohort selection after an extension of the follow-up period and for achieving maximum overlap between earlier designs and the case-cohort design. Approaches for statistical analysis are studied in a simulation example based on the MORGAM data.