Table 1.
Characteristics of included articles.
| Authors | Country | Age mean (SD) | Age range | Sample size | Sampling timepoint (Before COVID-19) | Sampling timepoint (During COVID-19) |
|---|---|---|---|---|---|---|
| Abid et al. (2021) | Tunisia | 8.66 (3.30) | 5–12 | 100 | Not reported | (Apr to May 2020) |
| Aguilar-Farias et al. (2020) | Chile | 3.10 (1.38) | 1–5 | 3,157 | Not reported | (Mar to Apr 2020) |
| Alonso-Martínez et al. (2021) | Spain | 4.29 (0.76) | 4–6 | 425 | (Sep to Dec 2019) | (Mar to Apr 2020) |
| Breidokienè et al. (2021) | Lithuania | 9.65 (1.94) | 6–14 | 306 | Not reported | 2020 |
| Bringolf-Isler et al. (2021) | Switzerland | Not reported | 5–11 | 1,712 | (2014 and 2015) | 2022 |
| Brzęk et al. (2021) | Poland | Not reported | 3–5 | 1,316 | Not reported | (Apr to Nov 2020) |
| Burdzovic Andreas and Brunborg (2021) | Norway | Grade 11 (est. 16) | Not reported | 2,536 | 2017 | (Oct to Dec 2020) |
| Chen et al. (2021) | China | Not reported | 11–20 | 13,440 | (Feb 2020) | (Apr 2020) |
| Chen et al. (2022) | Sweden | 13.60 (0.4) | Not reported | 1,901 | (Sep 2017 and Jan 2020) | (Feb and Nov 2020) |
| Dragun et al. (2020) | Croatia | 17.00 (1.00) | Not reported | 1,093 | (2018 and 2019) | (May 2020) |
| Francisco et al. (2020) | Italy, Spain, Portugal | 9.15 (4.27) | 3–18 | 1,480 | Not reported | (Mar to Apr 2020) |
| Ghanamah and Eghbaria-Ghanamah (2020) | Israeli | Not reported | 5–11 | 382 | Not reported | (Dec 2020) |
| Ghorbani et al. (2021) | Iran | 16.28 (0.97) | 15–17 | 136 | Not reported | (Oct 2020 to Feb 2021) |
| Gibert et al. (2021) | USA | 8.01 (1.75) | Not reported | 144 | Not reported | (May to Jul 2020) |
| Hossain et al. (2021) | Bangladesh | 4.50 (0.15) | Not reported | 65 | (Mar to Jun 2019) | (May 2020) |
| Hyunshik et al. (2021) | Japan | 3.60 (0.3) | 3–5 | 591 | (Oct 2019) | (Oct 2020) |
| Ishimoto et al. (2022) | Japan | Not reported | 8–12 | 293 | (Dec 2019) | (March 2020) |
| Jackson et al. (2021) | USA | 13.84 (2.74) | 10–18 | 624 | Not reported | (Apr to Jun 2020) |
| Jauregui et al. (2021) | Mexico | 3.30 (0.20) | 1–5 | 631 | Not reported | (Apr to Jul 2020) |
| Jester and Kang. (2021) | UK | 16.64 (1.29) | 15–18 | 55 | Not reported | (Apr to Jun 2020) |
| Jovanović et al. (2021) | Croatia | 12.72 (1.17) | 10–15 | 1,370 | Not reported | (May 2021) |
| Kang et al. (2021) | China | 16.30 (1.30) | Not reported | 4,898 | Not reported | (Mar 2020) |
| Kuhn et al. (2022) | USA | Not reported | 3–15 | 75 | (Oct 2017 to Mar 2020) | (May to Jul 2020) |
| Laurier et al. (2021) | Canada | 15.26 (1.46) | 11–17 | 133 | Not reported | (Jun to Aug 2020) |
| Lim et al. (2021) | Singapore | *Median (IQR) 8 (6–11) | 3–16 | 593 | Not reported | (Apr to Jun 2020) |
| Lu et al. (2021) | China | 15.26 (0.46) | Not reported | 965 | Not reported | (May 2020) |
| Łuszczki et al. (2021) | Poland | 10.51 (2.13) | 6–15 | 1,016 | (Feb to Mar 2020) | (Feb to Mar 2021) |
| McArthur et al. (2021) | Canada | Not reported | 9–11 | 846 | (2017–2019) | (May to Aug 2020) |
| Medrano et al. (2021) | Spain | 12.10 (2.40) | 8–16 | 404 | (Sep to Dec 2019) | (Mar to Apr 2020) |
| Mzadi et. al. (2022) | Morocco | 16.55 (0.96) | 15–18 | 807 | (2014–2015) | (Sep 2020 to Feb 2021) |
| Ren et al. (2021) | China | 13.14 | 10–17 | 1,487 | Not reported | (Apr 2020) |
| Wang et al. (2021) | China | 9.10 (1.33), 13.90 (1,40) | 6–11, 12–16 | 12,186 | Not reported | (May to Jul 2020) |
| Wunsch et al. (2021) | Germany | 10.36 (4.04) | 4–17 | 1,711 | Not reported | (Apr 2020) |
| Zhang et al. (2020) | China | 11.63 (1.23) | 9–14 | 9,979 | Not reported | (Mar 2020) |
*
Only age median.