“…Nine studies focused on SHS [14–16,18,20,21,23,24,26]. Another study focused on social variables including SHS [13,22], low birth weight [17], breastfeeding [19], and associated factors [25,27]. Studies were conducted in the United States (US) [15–17,19,27], Japan [18,21,22,24,26], eight European countries [13], the United Kingdom (UK) [14], South Africa [20], Belgium [23], and Sweden [25].…”