“…Most were conducted in North America [7][8][9]11,[17][18][19][20][21]23,24,[28][29][30]32,33,37,39,40,42,44]; six in Scandinavia [25][26][27]36,38,41] and Europe [16,22,31,35,43,45]; and two in Australia/New Zealand [12,34]. Around half of the studies were interested in NHL incidence as the outcome [12,16,18,[25][26][27][33][34][35][36][37][38][39][40][41][42]…”