nested study

nested study

a study, usually case control, which recruits study subjects from a population whose characteristics are known because its members are already the subjects of an existing larger study (for example, a cohort study or a large randomized controlled trial).
References in periodicals archive ?
Nested study within a cluster randomized controlled trial of three types of financial incentives and no incentives (control).
We carried out a nested study to evaluate the effect of pay for performance on black patients.
This was repeated for both the baseline (August-November 2007) and final (April-July 2009) performance periods in the nested study of black patients.
The nested study was conducted from a cohort of 926 healthy subjects enrolled from the low-income, unplanned settlement in Sultanabad area in eastern Karachi to find out the prevalence of deficiencies of folate, vitamin B6 and vitamin B12.
For the nested study (September 2009 to October 2010), 858 healthy adults were included who had no acute or chronic illness, were non-pregnant, and were not taking vitamin D supplements for the preceding 6 months The study was approved by the Ethics Review Committee of the Aga Khan University, Karachi, and informed consent was obtained from all the participants.
Additionally, a nested study on 34 patients to evaluate the accuracy and feasibility of transmission of echo pictures and heart sounds to Amrita Institute of Medical Sciences, Kochi via satellite using Indian Satellite Research Organization's network was also carried out.
The nested study population included 248 women who met criteria for preeclampsia and 679 women without preeclampsia who were control subjects.
The GISSI-HF was a nested study designed to test two hypotheses.
9) Recently, a nested study within the Women's Intervention Nutrition Study did show that women with breast cancer who decreased their fat intake to a median of 33 g/day had a hazard ratio of 0.
In a nested study comprising 825 wives of men in the circumcision arm and 783 wives of men in the control arm who were followed for 1 year, the respective rates of symptomatic genitourinary disease in the intervention and control arms were 12.