• OBJECTIVE: To compare the thermal environment of infants who died of the sudden infant death syndrome with that of age matched control infants. (ox.ac.uk)
  • Infants who died were matched with two controls, one for age and one for age and birth weight. (ox.ac.uk)
  • Thermal measurements were conducted at the death scene for cases and at the scene of last sleep for control infants, who were visited unexpectedly within four weeks of the index infant's death on a day of similar climatic conditions. (ox.ac.uk)
  • RESULTS: Cases had more excess thermal insulation for their given room temperature (2.3 togs) than matched controls (0.6 togs) (p = 0.009). (ox.ac.uk)
  • Although information of such extraneous factors is collected and quantitatively adjusted for when they are known to be present, findings from observational epidemiological studies are generally less conclusive than those from experimental studies because of the less strict control of extraneous factors. (gfmer.ch)
  • Several studies have used standard cohort analyses to study precursors to breast cancer, e.g. use of hormonal contraceptives, which is a covariate easily measured on all of the women in the cohort. (wikipedia.org)
  • For a more detailed account of design, conduct and analyses of epidemiological studies, the reader is referred to textbooks and methodological articles given in the list of references. (gfmer.ch)
  • By utilizing data previously collected from a large cohort study, the time and cost of beginning a new case-control study is avoided. (wikipedia.org)
  • Depending on the time when the cohort study is initiated relative to occurrence of the disease(s) to be studied, one distinguishes between current and historical cohort studies. (gfmer.ch)
  • Given the inherent time frame required of this approach, it can be very challenging to employ such a study in conflict and post-conflict settings where conditions can change rapidly. (endvawnow.org)
  • And looking back in time (a retrospective study) costs less because following people forward in time understandably, in and of itself, would have to require money and time. (studentdoctor.net)
  • But any time you pick and choose who is in your study, there exists the chance you're inadvertently picking and choosing people who share a second variable. (studentdoctor.net)
  • Since you're looking back in time with a case-control study, not only are we non-random, but we also know people are poor historians. (studentdoctor.net)
  • The inherent structure of the study acknowledges that we couldn't possibly be fully aware of other confounding/risk factors that may have popped up over time. (studentdoctor.net)
  • Within what period of time after operation will the development of endophthalmitis qualify as a case - one day, one week, or one month? (cehjournal.org)
  • In our example, controls could be defined as patients who underwent elective intraocular surgery during the same period of time. (cehjournal.org)
  • all exposed cases were currently on IMD treatment at the time of the stool sample, the na├»ve cases had never been exposed to an IMD. (nih.gov)
  • Ways to account for the random sampling include conditional logistic regression, and using inverse probability weighting to adjust for missing covariates among those who are not selected into the study. (wikipedia.org)
  • We consider inverse probability-weighted Cox regression models weighted by 1.0 divided by the probability of ever being sampled as control. (lww.com)
  • Sign up for Insight Alerts highlighting editor-chosen studies with the greatest impact on clinical care. (aappublications.org)
  • A notified case is classified as "confirmed" if there is definitive laboratory evidence (detection by nucleic acid testing or isolation by culture), or suggestive laboratory evidence (single point serology) together with a compatible clinical illness (coughing illness lasting 2 weeks associated with paroxysms, inspiratory whoop, or posttussive vomiting). (aappublications.org)
  • We report the clinical features of these children and of those of age and sex matched controls who have remained allergic to peanut. (pubmedcentralcanada.ca)
  • The conclusions that can be drawn from findings of these types of studies are, however, much weaker compared to those of cohort and case-control studies. (gfmer.ch)
  • This is not to say that findings from cohort and case-control studies always reflect true associations which can be universally generalized. (gfmer.ch)
  • The study findings indicated that workers exposed to vinyl-chloride gas experienced a significant excess of liver cancer, particularly the rare angiosarcoma of the liver. (cdc.gov)
  • The objective of this study was to identify and quantify the determinants of nonsynostotic plagiocephaly in infants. (aappublications.org)
  • r can be estimated from previous studies - note that r is the phi (correlation) coefficient that is given for a two by two table if you enter it into the StatsDirect r by c chi-square function. (statsdirect.com)