Twins, full siblings, and half-siblings are increasingly used as comparison groups in matched cohort and matched case-control studies. The "within-pair" estimates acquired through these comparisons are free from confounding from all factors that are shared by the siblings. This has made sibling comparisons popular in studying associations thought likely to suffer confounding from socioeconomic ...

Confounding is a basic problem of comparability – and therefore has always been present in science. Originally a plain English word, it acquired more specific meanings in epidemiologic thinking about experimental and non-experimental research. The use of the word can be traced to Fisher. The concept was developed more fully in social science research, among others by Kish. Landmark developments...

the aim of the present study was to examine the periodontal condition of an adult population in three isolated regions in greece and to determine the association of periodontal disease with several demographic, behavioral and environmental factors.the study population consisted of 640 individuals, aged 20 to 69 years from three isolated regions. the following indices were assessed: pocket depth...

BACKGROUND Cancer epidemiology has been criticized for producing false-positive associations. The present analysis investigates the frequency of and factors contributing to false-positive findings in cancer epidemiology. METHODS The International Agency for Research on Cancer (IARC) Monographs Group 3 agents were examined to identify potential false-positive findings. Frequency estimates for ...

This paper reviews approximate confidence intervals for some effect parameters common in cancer epidemiology. These methods have computational feasibility and give nearly nominal coverage rates. In the analysis of crude data, the simplest type of epidemiologic analysis, parameters of interest are the odds ratio in case-control studies and the rate ratio and difference in cohort studies. These p...