According to the World Health Organization
(WHO 2007), 80 million people worldwide
are afflicted with chronic obstructive pulmonary
disease (COPD), and 3 million died
from COPD in 2005. The WHO also predicts
that COPD will be the fourth leading
cause of death globally by 2030. Recent attention
has focused on evaluating the relationship
between pulmonary function and cadmium
body burden and the possible role of cadmium
in the development of pulmonary
diseases such as COPD and emphysema.
Cadmium is a trace element that has no
nutritive function in humans (NewmanTaylor
1998), and it is a probable lung carcinogen
in humans according to the Agency
for Toxic Substances and Disease Registry
(ATSDR 1999) Toxicological Profile for
Cadmium. The toxicity of cadmium in the
lungs has been well documented in animal
studies. For example, cadmium inhalation produces
a pulmonary inflammatory response in
mammals (Kirschvink et al. 2006), and daily
doses of 1.6 mg/m3 cadmium aerosol over a
6-week period were associated with acute pulmonary
damage and emphysema in rats (Hart
1986). Thus, pulmonary toxicity studies in
animals support the hypothesis that reduced
lung function among smokers may be partially
attributable to cadmium in cigarette smoke.
Primary nonoccupational sources of cadmium
exposure within the general population include
ingestion of contaminated food (Järup et al.
1998; Kido et al. 1992) and inhalation of cigarette
smoke (Järup et al. 1998; Satarug and
Moore 2004), and smokers have higher body
burdens of cadmium than nonsmokers (Erzen
and Kragelj 2006; Grasseschi et al. 2003; Järup
et al. 1998; Mutti et al. 2006).