Table 1. Demographic variables related to the study region, year, sample size, age, and gender as observed in the selected studies.

Study ID	Region of study	Investigation year	Total sample size (number)	Age range (years)	Gender ratio
Al-Groosh et al. [15]	Baghdad	2022	332	29-58	165 males
Khayat et al. [16]	Israel	2021	310	11-49	153 males
Macri et al. [17]	Italy and Spain	2022	411	7-15	Unspecified
Paco et al. [18]	Portugal	2021	42	28.14 (mean)	6 males
Radej et al. [19]	Poland	2022	48	11.5-50.3	15 males
Yan et al. [20]	China	2022	262	21.2 (mean)	91 males
Yap et al. [21]	Singapore	2021	164	15-40	60 males
Ye et al. [22]	China	2022	570	24.44 (mean)	1:2.3 (male-to-female ratio)
Zhai et al. [23]	South Korea	2020	182	17-40	100 males