In a case-control study of second primary cancers in Moscow, there were 165 cases and 294 controls, matched for site of first primary, duration of follow-up since first primary and relapse history.
Even with developmentally matched samples, for primary cell cultures, culture conditions and days in vitro (DIV) also affect the dynamics of gene expression as shown in [ 34].
These breast cancer brain metastatic specimens and breast tumors were matched for patient age upon primary tumor detection and the ER status of the primary tumor.
One control will be randomly selected for each case from the population, matched for age, gender and primary care center.
We carried out an observational retrospective cohort study, matched for propensity score, linking primary care medical records to data from national mandatory Swedish registries.
Patients were matched for various parameters (gender, primary tumor site, tumor staging, lymph node involvement, presence of metastasis, HPV status and treatment modalities; Table 1).
For each eligible patient with type 2 diabetes, two non-diabetic comparators were selected at random from computerised lists of patients registered with primary care, matched for age (within 1 year), sex and GP practice.
24 A recent systematic review and meta-analysis comparing healthy controls versus children with OSA and primary snoring, matched for gender, 34 provides limited statistical support for an association between OSA and cephalometric measurements in children aged 0 18 years.
For inclusion within the trial, teeth had to be: pairs of unrestored carious primary molars; matched for tooth type, dental arch, and extent of caries (radiographically ≤ or >1/2 way through dentine); and symptomless, with no clinical or radiographic signs of pulpal pathology on bitewing radiography as assessed by the GDP.
