Table 3.
Weighted estimation of prevalence and trend in adolescent daily smokers in South Korea, 2005–2021
| Trends in daily smokers | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 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 | 5.4 (5.2 to 5.6) | 5.9 (5.7–6.2) | 4.0 (3.9–4.2) | 3.0 (2.8–3.2) | 2.3 (2.1–2.5) | 2.3 (2.1–2.5) | –0.208 (–0.230 to –0.187) | –0.094 (–0.124 to –0.065) | 0.114 (0.077 to 0.151) | 0.759 (0.696 to 0.828) |
| Sex | ||||||||||
| Male | 7.5 (7.2–7.8) | 8.8 (8.5–9.1) | 6.4 (6.2–6.7) | 4.6 (4.4–4.9) | 3.3 (3.0–3.7) | 3.2 (3.0–3.5) | –0.166 (–0.186 to –0.146) | –0.123 (–0.152 to –0.093) | 0.043 (0.007 to 0.079) | 0.700 (0.640 to 0.765) |
| Female | 3.0 (2.8–3.2) | 2.8 (2.6–2.9) | 1.5 (1.3–1.6) | 1.2 (1.1–1.4) | 1.2 (1.0–1.4) | 1.3 (1.1–1.5) | –0.343 (–0.376 to –0.309) | –0.005(–0.046 to –0.056) | 0.338 (0.304 to 0.372) | 0.994 (0.869 to 1.137) |
| Grade | ||||||||||
| 7th–9th grade (middle school) | 2.4 (2.3–2.5) | 2.9 (2.7–3.0) | 1.6 (1.5–1.7) | 1.1 (1.0–1.2) | 0.8 (0.7–0.9) | 0.7 (0.6–0.8) | –0.254 (–0.279 to –0.228) | –0.141 (–0.186 to –0.096) | 0.113 (0.061 to 0.165) | 0.661 (0.577 to 0.757) |
| 10th–12th grade (high school) | 10.2 (9.7–10.7) | 10.1 (9.7–10.5) | 7.3 (7.0–7.7) | 5.3 (5.0–5.6) | 4.2 (3.7–4.6) | 4.2 (3.8–4.6) | –0.241 (–0.266 to –0.216) | –0.086 (–0.119 to –0.052) | 0.155 (0.113 to 0.197) | 0.778 (0.705 to 0.858) |
| Region of residence | ||||||||||
| Rural | 5.6 (5.2–5.9) | 6.2 (5.8–6.5) | 4.1 (3.9–4.4) | 3.2 (2.9–3.4) | 2.4 (2.1–2.8) | 2.5 (2.2–2.8) | –0.215 (–0.245 to –0.185) | –0.085 (–0.123 to –0.047) | 0.130 (0.082 to 0.178) | 0.777 (0.695 to 0.868) |
| Urban | 5.2 (4.9–5.5) | 5.7 (5.4–6.0) | 3.9 (3.7–4.2) | 2.8 (2.6–3.1) | 2.1 (1.8–2.5) | 2.0 (1.7–2.3) | –0.203 (–0.233 to –0.174) | –0.110 (–0.157 to –0.064) | 0.093 (0.038 to 0.148) | 0.731 (0.635 to 0.840) |
| Sadness or despair | ||||||||||
| Without symptoms | 4.1 (3.9–4.3) | 4.6 (4.4–4.8) | 3.3 (3.1–3.4) | 2.4 (2.3–2.6) | 1.7 (1.5–1.9) | 1.7 (1.5–1.9) | –0.193 (–0.217 to –0.168) | –0.117 (–0.152 to –0.082) | 0.076 (0.033 to 0.119) | 0.706 (0.636 to 0.784) |
| With symptoms | 7.5 (7.1–7.8) | 8.5 (8.2–8.9) | 6.2 (5.9–6.5) | 4.6 (4.3–4.9) | 4.1 (3.6–4.5) | 3.8 (3.5–4.3) | –0.150 (–0.173 to –0.126) | –0.062 (–0.099 to –0.026) | 0.088 (0.045 to 0.131) | 0.847 (0.763 to 0.940) |
| Substance use | ||||||||||
| No use | 5.2 (4.9–5.4) | 5.8 (5.5–6.0) | 3.9 (3.8–4.1) | 2.9 (2.7–3.1) | 2.3 (2.0–2.5) | 2.3 (2.1–2.5) | –0.203 (–0.225 to –0.182) | –0.087 (–0.117 to –0.057) | 0.116 (0.079 to 0.153) | 0.776 (0.711 to 0.847) |
| With substance use | 19.0 (17.5–20.7) | 19.5 (18.0–21.1) | 21.1 (19.0–23.4) | 15.4 (13.6–17.3) | 8.0 (5.6–11.4) | 7.7 (5.2–11.2) | –0.042 (–0.097 to –0.012) | –0.216 (–0.298 to –0.135) | –0.174 (–0.266 to –0.082) | 0.471 (0.343 to 0.646) |
| The highest educational level of parents | ||||||||||
| High school or lower | 6.7 (6.4–7.0) | 7.6 (7.3–7.9) | 5.7 (5.4–7.0) | 4.3 (4.0–4.6) | 3.1 (2.6–3.6) | 3.0 (2.6–3.5) | –0.110 (–0.133 to –0.087) | –0.106 (–0.143 to –0.069) | 0.004 (– 0.040 to 0.048) | 0.698 (0.611 to 0.797) |
| College or higher | 4.0 (3.8–4.3) | 4.7 (4.4–4.9) | 3.2 (3.1–3.4) | 2.4 (2.3–2.6) | 1.6 (1.4–1.9) | 1.6 (1.4–1.8) | –0.188 (–0.215 to –0.162) | –0.142 (–0.179 to –0.105) | 0.046 (0.000 to 0.092) | 0.647 (0.574 to 0.729) |
| Economic level | ||||||||||
| High to middle high | 4.2 (4.0–4.4) | 5.1 (4.8–5.4) | 3.4 (3.2–3.6) | 3.0 (2.8–3.2) | 2.3 (2.0–2.6) | 2.1 (1.9–2.4) | –0.152 (–0.182 to –0.123) | –0.112 (–0.150 to –0.074) | 0.040 (–0.008 to 0.088) | 0.727 (0.648 to 0.816) |
| Middle to low | 6.3 (6.0–6.5) | 6.5 (6.2–6.7) | 4.5 (4.3–4.8) | 3.2 (3.0–3.4) | 2.4 (2.2–2.7) | 2.5 (2.3–2.7) | –0.218 (–0.240 to –0.197) | –0.093 (–0.125 to –0.061) | 0.125 (0.086 to 0.164) | 0.756 (0.687 to 0.831) |
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