Tobacco and Public Health - TCSC Indonesia

Introduction
Chapter 34
Smoking and other disorders
Allan Hackshaw
Given that smoking consists of several thousand chemicals and toxins it is no wonder
that it is associated with a wide range of diseases. Since the first epidemiological studies
linking smoking with lung cancer, there has been an abundance of studies (epidemiological
and biological) that have shown smokers to be at a higher (or in a few cases,
lower) risk of developing certain disorders. Smoking is an established cause of several
cancers, respiratory disease, and cardiovascular disease; these are described elsewhere
in this book. Here, I describe disorders other than those just mentioned and provide an
overview of published reviews and the results of published meta-analyses where available.
I also present the results from cohort studies that are based on incident cases
(where possible), thus aiming to ensure that smoking has preceded the disorder and
avoiding some of the possible biases associated with case–control studies. The studies
referenced here may not be all that are available. The disorders reviewed here are by no
means all those that are or may be associated with smoking. They represent ones that
are relatively common in the population and in which smoking has, in the past, been
regarded as a risk factor.
Gastrointestinal system
Smoking is associated with several disorders of the gastrointestinal tract. Table 34.1
shows pooled relative risks of some of the main disorders obtained from meta-analyses.
Peptic ulcer
Peptic ulcers (gastric or duodenal) are relatively common amongst adults. Many
epidemiological studies have shown that smokers are about twice as likely to develop
peptic ulcers than non-smokers, including several large cohort studies that looked at
incidence of the disease (Table 34.2). Risk increases with increasing cigarette consumption
(Paffenberger et al. 1974; Anda et al. 1990) and it is lower in ex-smokers (Anda
et al. 1990; Vessey et al. 1992; Doll et al. 1994). Studies have also showed that smoking
can delay the healing process once ulcers have developed and it can increase the risk of
recurrence. The evidence is consistent with that from biological studies from which