Smoking cessation is the most powerful intervention to modify progress of chronic obstructive pulmonary disease (COPD), and nicotine dependence is one of the most important determinants of success or failure in smoking cessation. We evaluated nicotine dependence status and investigated factors associated with moderate to high nicotine dependence in patients with COPD.
We included 53 current smokers with COPD in the Korean Obstructive Lung Disease II cohort enrolled between January 2014 and March 2016. Nicotine dependence was measured by using Fagerstrom test for nicotine dependence (FTND). Cognitive function was assessed by Korean version of Montreal Cognitive Assessment.
The median FTND score was 3, and 32 patients (60%) had moderate to high nicotine dependence. The median smoking amount was 44 pack-years, which was not related to nicotine dependence. Multiple logistic regression analysis revealed that high education status (odds ratio, 1.286; 95% confidence interval, 1.036–1.596; p=0.023), age <70 (odds ratio, 6.407; 95% confidence interval, 1.376–29.830; p=0.018), and mild to moderate airflow obstruction (odds ratio, 6.969; 95% confidence interval, 1.388–34.998; p=0.018) were related to moderate to high nicotine dependence.
Nicotine dependence does not correlate with smoking amount, but with education level, age, and severity of airflow obstruction. Physicians should provide different strategies of smoking cessation intervention for current smokers with COPD according to their education levels, age, and severity of airflow obstruction.
Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide
We evaluated nicotine dependence status and investigated factors associated with moderate to high nicotine dependence in current smokers with COPD in the Korean Obstructive Lung Disease (KOLD) II cohort.
All subjects were selected from the KOLD cohort II, which prospectively recruited subjects with obstructive lung disease from the pulmonary clinics of 11 referral hospitals in Korea from January 2014 through March 2016. The inclusion criteria were followings: (1) age ≥40 years; (2) post-bronchodilator forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) <0.7; and (3) current smoker, who has smoked greater than 100 cigarettes in his or her lifetime and has smoked in the last 28 days. Patients with severe tuberculosis destroyed lung disease, bronchiectasis or acute lung inflammation were excluded. The study protocol was approved by the institutional review boards of the 11 hospitals.
At the time of inclusion, a standard questionnaire was used to obtain information on smoking history, level of education, and comorbidities. COPD assessment test (CAT) was used for evaluation of COPD impact on health status. The level of dyspnea was assessed by modified Medical Research Council (MMRC) grade.
Spirometry was performed according to the American Thoracic Society/European Respiratory Society guidelines
Severe airflow obstruction is defined as FEV1 <50% predicted.
Patients responded to the Fagerstrom test for nicotine dependence (FTND)
Cognitive function was also assessed by Korean version of Montreal Cognitive Assessment (MoCA-K)
Descriptive data are expressed as medians with interquartile range, and frequencies are expressed as number (%). A chi-square test was used to compare categorical variables, while continuous variables were compared using the Mann-Whitney U test. A p-value of <0.05 was regarded as statistically significant. Multiple logistic regression analysis was used to investigate factors associated with moderate to high nicotine dependence including variables, which had p-value of <0.05 in univariate analysis.
Fifty-three current smokers with COPD were included. Total 268 subjects were selected from the KOLD cohort II and excluded seven non-smokers, 204 ex-smokers, and four non-responders for questionnaire (
Factors related to moderate to high nicotine dependence were relatively young age (66 years vs. 76 years, p=0.013), high education status (12 years vs. 6 years, p=0.003), and high cognitive function (24 vs. 22, p=0.021). However, there are no differences of MMRC grade, CAT score, FEV1, and pack-years of cigarette smoking between two groups according to nicotine dependence (
Multiple logistic regression analysis revealed that high education status (odds ratio, 1.286; 95% confidence interval, 1.036–1.596; p=0.023), age <70 (odds ratio, 6.407; 95% confidence interval, 1.376–29.830; p=0.018), and mild to moderate airflow obstruction (odds ratio, 6.969; 95% confidence interval, 1.388–34.998; p=0.018) were related to moderate to high nicotine dependence (
We investigated factors associated with nicotine dependence in current smokers of Korean COPD cohort. High education status was the most significant factor related to nicotine dependence in current smokers with COPD, which is consistent with a previous study
In the current study, patients with moderate to high nicotine dependence showed younger age <70. It is consistent with results in previous studies: two studies included COPD patients and the other included diabetic patients
The COPD patients with better lung function showed moderate to higher nicotine dependence in this study. The study of Kim et al.
The participants had median smoking amount of 44 packyears and median FTND of 3.0. In a study of Lindberg et al.
Even though nicotine can enhance cognitive functions and emotional processing in some conditions
Although some studies of COPD smokers showed a positive correlation between smoking amount and nicotine dependence
The current work has some limitations. The number of participants was small. A large number of current smokers with COPD are needed to identify factors associated with nicotine dependence in COPD. It is difficult to say that our research subjects are representative of the whole COPD because they were recruited from tertiary medical institutions rather than primary medical institutions. Nevertheless, our cohort was well-designed, and surveys were conducted by well-trained nurses. Another limitation is that we did not investigate other factors known to be related to nicotine dependence such as household income, marital status, genetic factors, age at onset of smoking, depression, and drinking status.
This study assessed nicotine dependence in current smokers with COPD. We found that higher education level, mild to moderate airflow obstruction, and age <70 were associated with moderate to high nicotine dependence. In order to provide effective smoking cessation intervention for current smokers with COPD, physicians need to consider the level of individual education, age, and severity of airflow obstruction.
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (2010-0027945).
Variable | Value (n=53) |
---|---|
Male sex | 52 (98) |
Age, yr | 67 (63–75) |
BMI, kg/m2 | 23.1 (20.1–24.9) |
Comorbid disease | |
Diabetes mellitus | 8 (15) |
Hypertension | 4 (8) |
MMRC | 1 (1–2) |
CAT | 14.0 (8.0–19.5) |
Spirometry | |
FVC, L | 3.41 (2.89–4.03) |
FVC, % predicted | 89 (80–99) |
FEV1, L | 1.69 (1.32–2.01) |
FEV1, % predicted | 61 (47–70) |
FEV1/FVC, % | 48 (42–55) |
FEV1 <50% predicted | 16 (30) |
Smoking, pack-yr | 44 (36–59) |
FTND score | 3 (1–5) |
FTND ≥4 | 32 (60) |
Education, yr | 9 (6–12) |
MoCA-K score | 24 (21–26) |
MoCA-K <23 | 24 (45) |
Inhaled treatment | 41 (77) |
LAMA | 37 (69) |
LABA | 35 (66) |
ICS or ICS/LABA | 19 (36) |
Combined* | 36 (67) |
Values are presented as number (%) or median (interquartile rage).
*LAMA+LABA, LAMA+ICS, or LAMA+ICS/LABA.
BMI: body mass index; MMRC: modified Medical Research Council; CAT: chronic obstructive pulmonary disease assessment test; FVC: forced vital capacity; FEV1: forced expiratory volume in 1 second; FTND: Fagerstrom test for nicotine dependence; MoCA-K: by Korean version of Montreal Cognitive Assessment; LAMA: longacting muscarinic antagonists; LABA: long-acting b2 agonists; ICS: inhaled corticosteroids.
Variable | Low nicotine dependence (n=21) | Moderate to high nicotine dependence* (n=32) | p-value |
---|---|---|---|
Male sex | 21 (100) | 31 (97) | 0.413 |
Age, yr | 72 (66–76) | 66 (61–70) | 0.013 |
BMI, kg/m2 | 23.4 (20.4–25.5) | 22.3 (19.6–24.4) | 0.244 |
Comorbid disease | |||
Heart disease | 2 (10) | 2 (6) | 0.388 |
Diabetes mellitus | 2 (9) | 6 (19) | 0.359 |
MMRC | 1 (1–2) | 1 (1–2) | 0.461 |
CAT | 11 (8–18) | 15 (7–21) | 0.472 |
Spirometry | |||
FVC, L | 3.34 (2.84–3.88) | 3.47 (2.95–4.06) | 0.296 |
FVC, % predicted | 86 (75–98) | 90 (80–101) | 0.439 |
FEV1, L | 1.48 (1.15–2.01) | 1.76 (1.49–2.16) | 0.127 |
FEV1, % predicted | 52 (44–74) | 62 (53–69) | 0.288 |
FEV1/FVC | 46 (40–53) | 49 (44–56) | 0.244 |
FEV1 <50% predicted | 10 (48) | 6 (19) | 0.025 |
Smoking, pack-yr | 50 (33–58) | 43 (36–60) | 0.749 |
Education, yr | 6 (3–12) | 12 (9–12) | 0.003 |
MoCA | 22 (18–26) | 24 (22–27) | 0.021 |
MoCA <23 | 13 (62) | 11 (34) | 0.049 |
Treatment | |||
Inhaled treatment | 18 (86) | 24 (75) | 0.347 |
Compliance | 2 (11) | 4 (17) | 0.611 |
Values are presented as number (%) or median (interquartile rage).
*Moderate to high nicotine dependence is FTND ≥4.
BMI: body mass index; MMRC: modified Medical Research Council; CAT: chronic obstructive pulmonary disease assessment test; FVC: forced vital capacity; FEV1: forced expiratory volume in 1 second; MoCA-K: by Korean version of Montreal Cognitive Assessment; FTND: Fagerstrom test for nicotine dependence.
Odds ratio | 95% CI | p-value | |
---|---|---|---|
Age <70 yr | 6.407 | 1.376–29.830 | 0.018 |
FEV1≥50% predicted | 6.969 | 1.388–34.998 | 0.018 |
MoCA-K | 1.182 | 0.951–1.470 | 0.132 |
Education, yr | 1.286 | 1.036–1.596 | 0.023 |
CI: confidence interval; FEV1: forced expiratory volume in 1 second; MoCA-K: by Korean version of Montreal Cognitive Assessment.