early breast development in Puerto Rican girls has been a long-standing
mystery in public health. First noted two decades ago (Pérez
1983), no explanation has ever been confirmed. Girls in Puerto
suffer from the highest rate of " premature
thelarche" ever recorded.
et al. provide data linking this public health anomaly to
exposure. The link does not prove causation, but is sufficiently
strong to warrant urgent study. Can causation be established, and
where does the phthalate exposure originate?
did they do?
Colon et al. measured the presence of certain phthalates
in the blood of 41 girls experiencing early breast development and
a matched set of controls. The average age of girls with premature
thelarche was 31 months.
did they find?
They found high phthalate levels in the girls suffering from premature
thelarche compared to the controls. The most dramatic difference
they found was for DEHP, a known anti-androgen. Average for cases
was 450 parts per billion vs. an average of controls of 70 ppb.
In other words, girls with premature thelarche had DEHP concentrations
almost 7 times that of the control group. This result was statistically
all cases of premature thelarche in the study sample contained elevated
levels of DEHP.
does this mean?
"The present study provides the first analytical evidence of
the presence of plastic additives with known estrogenic activity
in girls with premature thelarche. In a study conducted in 1997
that included 17,077 girls, Herman-Giddens
et al. reported that girls in the United States are developing
pubertal characteristics at younger ages than previously reported.
These authors concluded that the possibility that the increasing
use of certain plastics and insecticides that degrade into substances
that have estrogen-related physiological effects on living things
should be investigated in relation to the earliest onset of puberty."
after the publication of this study, the CDC
reported widespread phthalate contamination among adult Americans,
but with no companion data on health impacts. The current study
(Colon et al.) documents phthalate contamination in a pattern
that suggests health impacts. It is restricted geographically to
Puerto Rico, and deals with an age cohort different from the CDC's
focus. Taken together, these two studies raise very large red flags
for the debate about phthalate safety.
al. are very careful to point out that their study does not