Table 2.
Weighted estimation of prevalence and trend in adolescent ever smokers in South Korea, 2005–2021
| Characteristics | 2005–2008 | 2009–2012 | 2013–2016 | 2017–2019 | 2020 (Early pandemic) | 2021 (Mid pandemic) | The trend before the pandemic, β (95% CI)a | The trend during the pandemic, β (95% CI)a | Trend difference, βdiff (95% CI) | OR (95% CI)b |
|---|---|---|---|---|---|---|---|---|---|---|
| Smoking, weighted % (95% CI) | ||||||||||
| Overall | 27.7 (27.3–28.1) | 25.9 (25.5–26.3) | 18.3 (17.9–18.8) | 13.6 (13.2–14.0) | 10.2 (9.7–10.7) | 9.8 (9.3–10.3) | −0.312 (−0.323 to −0.300) | − 0.123 (− 0.141 to − 0.105) | 0.189 (0.168 to 0.210) | 0.704 (0.669 to 0.741) |
| Sex | ||||||||||
| Male | 32.8 (32.3–33.3) | 33.3 (32.8–33.8) | 26.3 (25.9–26.8) | 19.5 (19.0–19.9) | 13.8 (13.1–14.5) | 13.1 (12.4–13.7) | −0.237 (−0.249 to −0.225) | −0.155 (−0.172 to −0.137) | 0.082 (0.061 to 0.103) | 0.642 (0.610 to 0.676) |
| Female | 21.9 (21.5–22.4) | 17.6 (17.2–18.1) | 9.6 (9.3–9.9) | 7.3 (7.0–7.6) | 6.3 (5.8–6.7) | 6.4 (6.0–6.8) | −0.461 (−0.476 to −0.446) | −0.054 (−0.078 to −0.029) | 0.407 (0.378 to 0.436) | 0.853 (0.798 to 0.912) |
| Grade | ||||||||||
| 7th–9th grade (middle school) | 22.4 (22.0–22.8) | 21.2 (20.9–21.6) | 13.0 (12.7–13.3) | 8.7 (8.4–9.0) | 5.7 (5.4–6.1) | 5.1 (4.8–5.5) | −0.369 (−0.382 to −0.357) | −0.174 (−0.194 to −0.155) | 0.195 (0.172 to 0.218) | 0.605 (0.570 to 0.642) |
| 10th–12th grade (high school) | 36.2 (35.5–36.9) | 32.1 (31.4–32.9) | 25.5 (24.8–26.2) | 19.6 (19.0–20.3) | 15.5 (14.6–16.5) | 15.5 (14.6–16.4) | −0.297 (−0.315 to −0.280) | −0.100 (−0.124 to −0.076) | 0.197 (0.167 to 0.227) | 0.750 (0.701 to 0.802) |
| Region of residence | ||||||||||
| Rural | 28.6 (28.0–29.3) | 26.6 (26.0–27.3) | 18.9 (18.4–19.5) | 14.2 (13.7–14.7) | 10.9 (10.2–11.7) | 10.2 (9.5–10.9) | −0.319 (−0.336 to −0.302) | −0.122 (−0.146 to −0.098) | 0.197 (0.168 to 0.226) | 0.714 (0.667 to 0.764) |
| Urban | 26.7 (26.2–27.2) | 25.1 (24.5–25.6) | 17.6 (17.0–18.2) | 12.9 (12.3–13.5) | 9.1 (8.4–9.9) | 9.3 (8.7–10.1) | −0.306 (−0.322 to −0.290) | −0.124 (−0.152 to −0.097) | 0.182 (0.150 to 0.214) | 0.687 (0.635 to 0.744) |
| Sadness or despair | ||||||||||
| Without symptoms | 23.7 (23.3–24.1) | 22.1 (21.7–22.5) | 16.0 (15.6–16.4) | 11.8 (11.4–12.2) | 8.3 (7.8–8.9) | 8.0 (7.5–8.4) | −0.298 (−0.312 to −0.285) | −0.141 (−0.162 to −0.121) | 0.157 (0.132 to 0.182) | 0.665 (0.626 to 0.706) |
| With symptoms | 34.2 (33.7–34.8) | 33.1 (32.5–33.6) | 24.8 (24.2–25.4) | 18.7 (18.2–19.3) | 15.6 (14.8–16.5) | 14.9 (14.1–15.8) | −0.265 (−0.278 to −0.251) | −0.090 (−0.112 to −0.068) | 0.175 (0.149 to 0.201) | 0.782 (0.736 to 0.830) |
| Substance use | ||||||||||
| No use | 27.1 (26.7–27.5) | 25.4 (25.0–25.8) | 18.1 (17.7–18.5) | 13.3 (13.0–13.7) | 10.1 (9.5–10.6) | 9.7 (9.2–10.2) | −0.308 (−0.320 to −0.296) | −0.118 (−0.136 to −0.100) | 0.190 (0.168 to 0.212) | 0.713 (0.677 to 0.751) |
| With substance use | 62.0 (60.2–63.8) | 60.2 (58.4–62.1) | 58.2 (55.6–60.8) | 45.1 (42.5–47.6) | 25.5 (21.0–30.7) | 24.9 (20.1–30.4) | −0.200 (−0.242 to −0.157) | −0.271 (−0.336 to −0.207) | − 0.071 (− 0.148 to 0.006) | 0.411 (0.332 to 0.509) |
| The highest educational level of parents | ||||||||||
| High school or lower | 31.7 (31.2–32.2) | 30.0 (29.4–30.5) | 23.1 (22.5–23.7) | 18.0 (17.4–18.7) | 13.4 (12.4–14.4) | 13.0 (12.1–14.0) | −0.214 (−0.227 to −0.202) | −0.111 (−0.133 to −0.089) | 0.103 (0.078 to 0.128) | 0.694 (0.643 to 0.748) |
| College or higher | 23.5 (23.0–24.0) | 22.4 (22.0–22.9) | 15.9 (15.5–16.4) | 12.3 (11.8–12.7) | 8.4 (7.9–8.9) | 8.0 (7.5–8.5) | −0.285 (−0.300 to −0.271) | −0.151 (−0.171 to −0.130) | 0.134 (0.109 to 0.159) | 0.638 (0.599 to 0.679) |
| Economic level | ||||||||||
| High to middle high | 23.6 (23.2–24.1) | 22.5 (22.0–23.0) | 15.7 (15.3–16.1) | 12.6 (12.2–13.1) | 9.4 (8.8–10.1) | 9.0 (8.4–9.6) | −0.304 (−0.320 to −0.288) | −0.124 (−0.147 to −0.101) | 0.180 (0.139 to 0.221) | 0.702 (0.657 to 0.750) |
| Middle to low | 30.2 (29.7–30.7) | 27.6 (27.1–28.1) | 20.0 (19.6–20.5) | 14.6 (14.2–15.0) | 10.7 (10.1–11.4) | 10.5 (10.0–11.0) | −0.306 (−0.318 to −0.294) | −0.126 (−0.145 to −0.107) | 0.180 (0.158 to 0.202) | 0.694 (0.657 to 0.734) |
The numbers in bold indicate a significant difference (P < 0.05)
CI confidence interval, KYRBS, Korea Youth Risk Behavior Web-based Survey, OR, odds ratio
aWeighted β was considered using the linear regression technique, and this method included the KYRBS cycle (2005–2008, 2009–2012, 2013–2016, 2017–2019, 2020, and 2021) as a continuous variable
bWeighted OR was considered using the logistic regression technique, and this method included the KYRBS cycle (2017–2019 versus 2020–2021 [COVID-19 pandemic]) as a categorical variable