“…In most of the studies, the level of the data (and analysis) was national. The exceptions were six papers that dealt with Nomenclature of Territorial Units of Statistics (NUTS2) regions [31,62,63,66], otherwise defined areas [51] or cities [56], and seven others that were multilevel designs and utilized both country-and region-level data [57], individual-and city-or countrylevel [35], individual-and country-level [44,45,48], individual-and neighborhood-level [64], and city-region-(NUTS3) and country-level data [65]. Parallel to that, the data type was predominantly longitudinal, with only a few studies using purely cross-sectional data [25, 33, 43, 45-48, 50, 62, 67, 68, 71, 72], albeit in four of those [43,48,68,72] two separate points in time were taken (thus resulting in a kind of "double cross-section"), while in another the averages across survey waves were used [56].…”