# Knowledge and Concerns About Smoking‐Related Health Risks: A Cross‐Sectional Analysis of the 2021 International Tobacco Control Japan and Korea Surveys

## TL;DR

This study compares knowledge and concerns about smoking-related health risks among smokers in Japan and Korea, finding significant differences influenced by country-specific tobacco policies.

## Contribution

The study provides a cross-national comparison of smoking-related health risk knowledge and concerns, highlighting the impact of tobacco control policies.

## Key findings

- Korean smokers showed higher knowledge of lung cancer compared to Japanese smokers.
- Japanese smokers had lower knowledge and fewer concerns about smoking-related health risks than Korean smokers.
- Greater knowledge was associated with increased concerns about health risks in both countries.

## Abstract

This cross‐sectional study examined: (i) knowledge of smoking‐related health risks among adults who currently and formerly smoke; (ii) concerns about personal health damage from smoking among adults who currently smoke; (iii) sociodemographic predictors of knowledge; and (iv) associations between knowledge and concerns in Japan and the Republic of Korea.

Data from the 2021 International Tobacco Control Surveys included adults (aged ≥ 20, ≥ 19 respectively) in Japan (n = 2956 currently smoke, n = 852 formerly smoke) and Korea (n = 3776 currently smoke, n = 194 formerly smoke). Primary outcomes included knowledge of smoking‐related health risks (six consistently measured: stroke, heart disease, lung cancer, emphysema, impotence, early death), categorised as correct or incorrect, summed into a knowledge index score and concerns about smoking damaging their own health. Survey‐weighted analyses examined country and smoking status differences and associations between knowledge, concerns and sociodemographic characteristics.

Among adults who currently smoke, knowledge of lung cancer was highest (Japan: 82.8%, Korea: 92.2%); lowest were impotence in Japan (35.7%) and heart disease in Korea (69.6%). Adults who formerly smoked had higher knowledge than those who currently smoke in Japan (4.74 [4.50–4.97] vs. 4.00 [3.82–4.18]) but not in Korea (5.05 [4.39–5.72] vs. 4.69 [4.47–4.90]). Japanese adults who currently smoke had lower knowledge and fewer concerns than their Korean counterparts (p < 0.05). Greater knowledge predicted increased concerns in both countries (OR = 1.27 [1.20, 1.35]). Only in Japan were younger age (B = 0.59 [0.06, 1.13]) and moderate income (B = 0.41 [0.16, 0.66]) associated with greater knowledge.

The observed differences in knowledge and concerns about smoking‐related health risks between Japan and Korea may reflect their contrasting tobacco control policies.