Tobacco and Public Health - TCSC Indonesia

606
SMOKING AND OTHER DISORDERS
Relative risk of hip fracture
(smokers relative to
nonsmokers)
8
5
4
3
2
1
0.4
50
Age (years)
Fig. 34.1 The relative risk of having a hip fracture in smokers compared to non-smokers in
19 studies of post-menopausal women according to age (cohort studies are indicated by solid
circles and case–control studies by open circles). Taken from Law and Hackshaw (1997).
Infertility
55 60 65 70 75 80 85 90
About 25% of women of reproductive age experience some degree of infertility. It is
defined in several ways, but it is generally accepted to be when conception has not
occurred after 12 consecutive months of unprotected intercourse. Women who smoke
are less likely to conceive or take longer to conceive. A meta-analysis of eight cohort
studies (based on 20 059 women) showed that women who smoked were 42% (95% CI
27–58%) more likely to be infertile than non-smokers (Augood et al. 1998). It is likely
that such a relationship exists because the risk also increases with increasing cigarette
consumption and in several studies the risks were still raised after allowing for several
potential confounding factors (such as alcohol and coffee intake and oral contraception
use). The subject is reviewed by Augood et al. (1998) and Baird (1992), both of
which describe the evidence and the limitations to determining causality.
Miscarriage
It is well established that women who smoke are more likely to have a miscarriage,
and that the association is causal. A meta-analysis of seven cohort studies (based on
86 633 pregnancies) yields a 24% increase in risk (95% CI 19–30%) in smokers compared
to non-smokers; all of the individual studies yielded statistically significant
results. It is estimated that 3–7.5% of miscarriages can be attributable to smoking