We restricted the NESARC sample to respondents aged 18–65 for comparability with the age range of KECA respondents. In addition, to ensure the comparability between the two surveys categorical variables were created using identical cut points, i.e., age: 18–24, 25–34, 35–44, 45–65; marital status: married/cohabiting, widowed/divorced/separated, never married; educational attainment: < 12 years, 12 years, 13–15 years, 16+ years; income: low, moderate, high. Cutoffs for low, moderate and high incomes quarters were based on the observed income distributions for both countries. Low income level was set at the 1st quartile; moderate income level was at the 2nd and 3rd quartiles; and high income level was set at the 4th quartile.
