Additional file 1: Fig. S1. Study process flow. Fig. S2. Overlapping disease conditions. Fig. S3. Prevalence of multimorbidity by age group and survey (weighted). Table S1. Summary overview of included surveys. Table S2. A. Disease conditions by survey and method of measurement. B. Self-reported questions in each survey. Table S3. Prevalence of each disease condition by survey (weighted). Table S4. Prevalence of multimorbidity by age group and sex (weighted). Table S5. SABSSM 2017 Regression. Table S6. Factors associated with multimorbidity in adjusted models