A CDC scientist
analyzed international trends in the rates of two birth defects that can
affect males: hypospadias and cryptorchidism.
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Hypospadias is a
birth defect characterized by the urethral opening not being correctly
located at the tip of the penis. The urethral opening is usually
located closer to the body on the ventral side of the penis in a boy
with hypospadias. Surgery is often required.
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Cryptorchidism is
when one or both of the testes have not descended into the scrotum by
the time a full term infant is born. If it persists it can require
surgery.
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Researchers from
seven European nations and the United States have published reports of
increasing rates of hypospadias during the 1960s, 1970s, and 1980s.
Reports of increasing rates of cryptorchidism have come primarily from
England. In the 1990s, these reports have become one focus of the
debate over endocrine disruption.
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This study examines
more recent data from a larger number of countries to determine
whether such increases are worldwide and continuing and whether the
increases show any geographic patterns.
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The International
Clearinghouse of Birth Defects Monitoring Systems and individual
systems provided the data. Countries were categorized into rough
quintiles by gross domestic product in 1984.
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Hypospadias
increases were most marked in two U.S. systems and in Scandinavia and
in Japan. The increases leveled off in many systems after 1985.
Increases were not seen in less affluent nations.
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Cryptorchidism rates
were available for 10 systems. This anomaly clearly increased in two
U.S. systems and in the South American system but not elsewhere. Since
1985, rates have declined in most systems.
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Better diagnosis,
more complete reporting, and better surveillance systems may have
contributed to or caused the upward trends in hypospadias. Possible
real causes include demographic changes and endocrine disruption.
