Although all models converged properly, the models with unconstrained hazard (models M1C1 and M1C2) required fixing numerous parameter estimates during estimation. This was mainly due to small proportions of reported first use during one or more of the time intervals, and to lack of variability in the number of minor alleles of one or more of the SNPs at a given time interval. Recall that in unconstrained models, SNP effects are estimated specific for each time-interval. Results of the unconstrained models are therefore not presented in Table 2.
