909Testing ‘hardening hypotheses’ in 30 Global Adult Tobacco Survey countries: an ecological study

Background Evidence from high-income countries suggests “softening” but not “hardening” occurs when smoking prevalence decreases; however, evidence is lacking from developing countries. Methods We constructed heaviness of smoking index (HIS) based on cigarettes smoked per day (CPD) and time-to-first-cigarette (TTFC) and a score of 4-6 was high nicotine dependence; Hardcore smokers (HCS) are daily smokers who smoked within 30 minutes after waking up, smoke ≥10 cigarettes per day, have not made any quit attempts in 12 months, and have no intention to quit at all or during next 12 months; light smokers (<10 CPD or occasional smokers). We plotted two-way linear prediction graphs using country-level data and estimated Spearmańs rank-correlation coefficient. On pooled data multi-level binary logistic regression analyses for HCS, high dependence and light smoker. Results Among men and women range (lowest vs. highest) of rates varied between countries and were lower among women. Daily smoking prevalence was moderately and positively correlated with hard-core smoking (Rsp=0.473), and high dependence (Rsp=0.384) but negatively correlated with light smoking (Rsp=-0.677). HCS and high dependence were associated with socio-economic factors but effect sizes were higher for women. Among GDP and tobacco control score showed protective effect for HCS and high dependence but increased risk for light smoking. Conclusions Positive relationship of daily smoking with HCS and high dependence and its negative relationship with light smoking is contrary to “hardening hypothesis”. Key messages Hardening may not happen in developing countries as well.

Genetic and depressive traits moderate the reward-enhancing effects of acute nicotine in young light smokers

Rates of light smoking have increased in recent years and are associated with adverse health outcomes. Reducing light smoking is a challenge because it is unclear why some but not others, progress to heavier smoking. Nicotine has profound effects on brain reward systems and individual differences in nicotine’s reward-enhancing effects may drive variability in smoking trajectories. Therefore, we examined whether a genetic risk factor and personality traits known to moderate reward processing, also moderate the reward-enhancing effects of nicotine. Light smokers (n=116) performed a Probabilistic Reward Task to assess reward responsiveness after receiving either nicotine or placebo (order counterbalanced). Individuals were classified as nicotine dependence ‘risk’ allele carriers (rs16969968 A-allele carriers) or non-carriers (non-A-allele carriers), and self-reported negative affective traits were also measured. Across the whole sample, reward responsiveness was greater following nicotine compared to placebo (p=0.045). For Caucasian A-allele carriers but not non-A-allele carriers, nicotine enhanced reward responsiveness compared to placebo for those who received the placebo first (p=0.010). Furthermore, for A-allele carriers but not non-A-allele carriers who received nicotine first, the enhanced reward responsiveness in the nicotine condition carried over to the placebo condition (p<0.001). Depressive traits also moderated the reward-enhancing effects of nicotine (p=0.010) and were associated with more blunted reward responsiveness following placebo but enhanced reward responsiveness following nicotine. These findings suggest that individual differences in a genetic risk factor and depressive traits alter nicotine’s effect on reward responsiveness in light smokers and may be important factors underpinning variability in smoking trajectories in this growing population.

Psychosocial Factors Associated with Smoking Cessation Attempts in Korean High School Students Who Engage in Intermittent and Light Smoking

Purpose: This study aimed to identify psychosocial factors associated with smoking cessation attempts among Korean high school students who engage in intermittent and light smoking.Methods: Cross-sectional secondary data derived from the 2018 Korea Youth Risk Behavior Web-Based Survey were analyzed within the framework of the biopsychosocial model. The sample comprised 829 high school students who reported current intermittent and light smoking, which was defined as cigarette smoking on 1~29 days in a 30-day period and no more than 10 cigarettes per day. Purposeful selection logistic regression analysis was performed.Results: In total, 71.7% (n=586) of the respondents had tried to stop smoking during the past 12 months. The main result was that respondents who had viewed an anti-smoking advertisement in the past year significantly more smoking cessation attempts than those who had not (adjusted odds ratio=2.59; 95% confidence interval=1.45~4.62, <i>p</i>=.001).Conclusion: To encourage smoking cessation attempts among high school students who engage in intermittent and light smoking, healthcare providers, including school and community nurses, should develop effective interventions using anti-smoking advertisements tailored to adolescents’ interests and developmental stage.