The main cohort used for this study consisted of 199 women with high-grade serous ovarian cancer seen at the BC Cancer Agency from 1984 to 2000 (OvCaRe Ovarian Tumour Bank, Vancouver, BC, Canada).
As described previously [ 22], erythrocyte membrane n-3 FA levels were investigated in a case-cohort design, for which a representative sample of 380 children (i.e. subcohort) was selected from the main DAISY cohort using stratified sampling based on HLA-DR genotype and family history of T1D; 313 of these children had erythrocyte n-3 FA measurements.
Data on VCT uptake during the survey are linked to the main cohort dataset using anonymous unique identifiers.
To test this possibility, we estimated the association between BMI and choice between initiating glargine versus NPH independent of other covariates, fitting propensity score models equivalent to the one in the main cohort but using two electronic medical record (EMR) databases where information on BMI is available.
Using this approach, a randomly selected sub-cohort of non-cases will be selected from the main cohort and used to compare risk factors for any or all adverse outcomes.
In the main meta-analysis, we combined the individual P-values obtained for each cohort using Fisher's method (65), which allows P-values and direction of effect in each cohort to be combined taking cohort size into account, independently of β-estimates.
Although some have welcomed the introduction of the QRISK equations 30 31 and the debate about improving risk prediction, others have cautioned against their use for two main reasons; (a) the cohort used to develop both QRISK equations included patients who were not treatment naive, unlike the Framingham cohort, 32 and (b) there are large amounts of missing cholesterol data.
The primary end point was change from baseline in A1C in the main cohort, statistically tested using an ANCOVA.
With these exclusions, the cohort used in the main analysis contained 448 NF1 patients (221 male and 227 female), followed for a median of 13.6 years (range=2.4 months to 13.8 years; 87% of subjects accrued at least 13 years of follow-up), with a total of 5705 person-years of follow-up.
The main strength of the paper is the large cohort used and the fact that it is population based, which avoids the problem of selection bias.
