Introduction
The health problems caused by smoking have become an important
consideration for public health. According to a World Health
Organization (WHO) report, smoking is a significant factor leading to
cardiovascular and respiratory diseases and more than 20 different types
or subtypes of cancer[1, 2]. More than eight million people die from
tobacco use each year, and most of these deaths occur in low- and
middle-income countries[3]. However, tobacco use is not only harmful
to smokers themselves, as second-hand smoke also affects non-smokers.
According to WHO statistics, 1.2 million deaths each year are related to
second-hand smoke exposure. More noteworthy is the impact of smoking, or
second-hand smoke, on pregnant women and children. Each year, 65,000
children die from diseases related to second-hand smoke[4]. Smoking
during pregnancy can also cause lifelong health problems for
babies.[5] Therefore, various countries and organizations strive to
find effective ways to help tobacco-dependent people quit smoking.
Alcohol use disorder (AUD) is one of the most common mental disorders in
the world[6]. From 2012 to 2013, the prevalence rates of 12-month
and lifetime AUD among adults aged 18 years and older in the United
States were 13.9% and 29.1%, respectively, which accounted for
approximately 33 million and 685 million people[7]. The
corresponding
Diagnostic
and Statistical Manual of Mental Disorders (DSM-IV) rates increased by
12.7% and 43.6% for 12-month and lifetime AUD, respectively, over the
year 2001[8]. For many people, AUD is a chronic recurrent remissive
disorder[9]. Regardless of the intervention, at least 60% of people
with AUD will relapse within six months of treatment and return to
dangerous levels of alcohol consumption[10, 11]. The chronic
addiction cycle of AUD is related to a variety of biological,
psychological, and social characteristics[12]. Among them, smoking
is closely related to drinking. Studies have shown that smoking is
associated with excessive drinking, increased alcohol withdrawal
symptoms, a higher relapse probability, or early relapse after treatment
in individuals recovering from dangerous drinking habits[13, 14].
Therefore, the development of smoking cessation treatment programs for
this population is important for their long-term health and recovery
from addiction.
For people with alcohol dependence or heavy alcohol use, smoking
cessation drugs have also been shown to reduce alcohol consumption and
cravings[15]. The drugs currently approved by the United States Food
and Drug Administration for the treatment of alcohol dependence (such as
acetamide, naltrexone, or disulfiram) have a small to moderate effect on
drinking[16, 17] but may not be as beneficial for smoking
cessation[18]. Nicotine replacement therapy (NRT), bupropion, and
varenicline are widely available prescriptions for smoking cessation. In
the United States and the European Union, these drugs are licensed as
first-line treatments for adjuvant smoking cessation treatment and are
widely recommended in many national guidelines[19]. There are also
studies[20] testing the effectiveness and safety of these drugs for
treating people with alcohol dependence who are trying to quit smoking.
The purpose of this systematic review and meta-analysis was to assess
the effectiveness and safety risks of drug therapies for smoking
cessation in patients with alcohol dependence. The outcomes will help to
provide relevant information for alcohol addicts, clinicians, and
policymakers.