“…After removing the duplicates and irrelevant results, we obtained 55 articles for full text review. The final selection obtained 27 sources ( Figure 1) (Camp et al, 1997;Newman, 1997;Travis et al, 1997;Bales et al, 2000;Middlecamp and Gross, 2002;Rosebrook, 2002;Scott et al, 2005;Epstein and Boisvert, 2006;Ayala et al, 2007;Reisig and Fees, 2007;Holmes, 2009;Doll and Bolender, 2010;Belgrave, 2011;Heyman et al, 2011;Jarrott and Smith, 2011;Kamei et al, 2011;Morita and Kobayashi, 2013;Isaki and Harmon, 2014;Skropeta et al, 2014;Low et al, 2015;Murayama et al, 2015;Thompson and Weaver, 2015;Varma et al, 2015;Sakurai et al, 2016;Teater, 2016;Yasunaga et al, 2016). Ten studies assessed the impact of IG programs upon children (Newman, 1997;Bales et al, 2000;Middlecamp and Gross, 2002;Rosebrook, 2002;Holmes, 2009;Heyman et al, 2011;Kamei et al, 2011;Isaki and Harmon, 2014;Thompson and Weaver, 2015;Yasunaga et al, 2016), 15 referred to the elder population (Ca...…”