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	Kapslad fall-kontrollstudie	Kohortstudie
Ämnesområde	Epidemiologi	Epidemiologi
Familj	Process / pipeline	Process / pipeline
Ursprungsår	1973–1977	Mid-20th century (formal epidemiological design codified ~1950s)
Upphovsperson	Nathan Mantel (1973); D. C. Thomas (1977 formalization)	Doll & Hill (British Doctors Study, 1951); Snow (cholera, 1854)
Typ	Hybrid observational study design	Observational longitudinal study design
Ursprungskälla	Thomas, D. C. (1977). Addendum to: Methods of cohort analysis: Appraisal by application to asbestos mining. Journal of the Royal Statistical Society, Series A, 140(4), 469–491.	Rothman, K. J., Greenland, S., & Lash, T. L. (2008). Modern Epidemiology (3rd ed.). Lippincott Williams & Wilkins. ISBN: 978-0781755641
Alias	NCC study, nested CC design, case-control within cohort, density sampling case-control	longitudinal study, follow-up study, panel study, incidence study
Närliggande	6	6
Sammanfattning	A nested case-control study is an efficient observational design embedded within a defined cohort. For each participant who develops the outcome of interest (a case), a small number of matched controls are sampled from those still at risk at the same point in time. This density-sampling strategy yields odds ratios that approximate incidence-rate ratios from the full cohort at a fraction of the data-collection cost — making it the preferred alternative when measuring exposures for all cohort members would be prohibitively expensive or technically demanding.	A cohort study assembles a group of individuals who share a common starting point — typically freedom from the outcome of interest — and follows them over time to observe who develops the outcome. By comparing incidence rates between exposed and unexposed subgroups, researchers can estimate relative risk and absolute risk differences. Cohort studies are the gold-standard observational design for measuring disease incidence and establishing temporal relationships between exposure and outcome.