Our study shows that the curvilinear relationship
between U-Cd and K-Cd described
in industrial workers and assumed in recent
models does not hold for the entire general
population with a low environmental exposure
to Cd. Over a lifetime, U-Cd shows
age-related variations that appear to be largely
determined by recent Cd intake and by the
renal handling of proteins, particularly LMW
proteins. These findings are particularly relevant
for epidemiological studies of health risks
associated with low environmental exposures
to Cd. Observations in these studies based on
U-Cd would be substantiated by the use of
cumulative intake indicators that are unlikely
to be confounded by recent Cd exposure and
physiological variations in renal elimination of
the metal. Various indicators might be used
for that purpose based on, for instance, residence
time in the studied area, consumption
of locally produced foods, or Cd dietary intake
estimated from food contamination data.