Tobacco and Public Health - TCSC Indonesia

608
SMOKING AND OTHER DISORDERS
large well-conducted studies, with adequate allowance for possible confounding factors
such as alcohol before a causal link can be firmly established.
Hormonal system
Diabetes
Studies have shown that smokers are more likely to develop type II (non-insulin
dependent) diabetes mellitus than never-smokers. Table 34.12 shows the results from
some cohort studies; they indicate that men who smoke more than 20 or 25 cigarettes
per day have about a two-fold increase in risk while women in this smoking category
have about a 50% increase. The risks remain high after adjustment for other factors
that are associated with both smoking and diabetes, such as body mass index (an indicator
of obesity) and alcohol intake. The risk also increases with increasing cigarette
consumption. These studies show that the risk is reduced in ex-smokers, indicating the
importance of quitting, especially considering that diabetes is itself a risk factor for
cardiovascular disease, renal disease, and retinopathy. It has been shown that smoking
can promote insulin resistance and that smokers tend to have higher glucose concentrations,
both of which can contribute to development of the disorder. Reviews of this
subject can be found in Dierkx et al. (1996) and Haire-Joshu et al. (1999).
Oral cavity
There is now much evidence showing that smoking is associated with various oral disorders.
As well as the common side effects of halitosis and teeth discolouration, there
are more serious consequences such as periodontal disease, caries, and acute ulcerative
gingivitis (for a review, see Allard et al. 1999; Winn 2001).
Periodontitis
Periodontitis is a common chronic disorder amongst adults and there have been many
studies that have reported on the association with smoking. Although the biological
mechanism for the effect of smoking on periodontal disease is uncertain the epidemiological
data is clear. The studies, cross-sectional and cohort, have looked at the risk of
having a diagnosis of periodontitis or measuring markers of it (such markers are used
in diagnosis). Table 34.13 shows some of the studies in which relative risks were
reported. Smokers have about a four-fold increase in risk (Tomar and Asma 2000). It
has been postulated that smokers only have a poorer oral hygiene (which itself is a
cause of periodontitis) and so the observed associations are due to confounding factors.
However, several studies have adjusted for this factor, as well as other confounding
factors (such as income), and there is still an effect of smoking. Smoking is also associated
with more severe disease and it can delay the healing process. Reviews can
be found in Qandil et al. (1997) and Salvi et al. (1997).