Table 4 presents the results of discrete-time survival analyses examining the association between cohort and first onset of use of each drug type. The model adjusts for age differences in the cohorts by examining differential risk at each year of life assuming linear associations between cohort and risk. The associations are remarkably consistent across countries and drug types, in that every one of the ORs is <1.0, indicating that risk at any given age is consistently higher in more recent cohorts than in older cohorts. The ORs have been normed to reflect relative-odds per 10 y of life. An OR of 0.8, for example, indicates that the odds of first use in any given year of life is, on average, only 80% as high among respondents who were age A at the time of interview compared to respondents who were age A − 10 y at interview.
