Encyclopedia of Health and Medicine

120 The Endocrine System
frequently to maintain as tight of a balance as possible
between insulin and glucose. Type 1 diabetes
most often develops before the age of 20, giving
rise to its former designation as juvenile diabetes.
Onset is usually rapid and pronounced. Type 1
diabetes requires lifelong insulin therapy.
Before current treatments many people who
developed type 1 diabetes died from the condition
or its complications before living much longer
than early adulthood, making this a disease of the
young. However, treatment approaches are significantly
improved and many people who have type
1 diabetes now live well into old age with careful
medical and lifestyle management. Some people
refer to type 1 diabetes as insulin-dependent diabetes,
which is no more accurate than the term
juvenile diabetes because about 40 percent of people
who have type 2 diabetes also require insulin
therapy.
People who have type 1 diabetes have a higher
likelihood of developing other AUTOIMMUNE DISOR-
DERS of the endocrine system, notably thyroid conditions
such as autoimmune THYROIDITIS and
HYPOTHYROIDISM as well as autoimmune ADRENAL
INSUFFICIENCY. Type 1 diabetes is also a component
of complex endocrine disorders such as POLYGLAN-
DULAR DEFICIENCY SYNDROME and MULTIPLE ENDOCRINE
NEOPLASIA
(MEN). Women who have well-controlled
type 1 diabetes generally can conceive,
carry, and deliver a PREGNANCY with few complications,
though require close medical monitoring
and diligent prenatal care. However, type 1 diabetes
can affect FERTILITY in both women and men.
Type 2 Diabetes
Type 2 diabetes develops slowly, evolving over
years and sometimes decades as a consequence of
progressive INSULIN RESISTANCE. This form of diabetes
most commonly develops in people who are
age 50 or older, though can occur at any age
(including childhood). A strong correlation exists
between OBESITY and type 2 diabetes. Many health
experts believe type 2 diabetes is fully preventable
through lifestyle measures that incorporate nutritious
EATING HABITS, daily physical exercise, and
maintaining a healthy body weight. About 30 percent
of people diagnosed with type 2 diabetes can
control the condition through weight loss and
lifestyle measures. The rest require oral antidiabetes
medications or insulin therapy. Type 2 diabetes
may occur as a component of complex
endocrine disorders, notably insulin resistance, as
well as secondary to endocrine disorders affecting
the adrenal cortex such as CUSHING’S SYNDROME
(the adrenal steroid CORTISOL influences glucose
METABOLISM).
Gestational Diabetes
Gestational diabetes develops during pregnancy as
a consequence of the demands pregnancy places
on the mother’s body. A pregnant woman requires
up to three times as much insulin to meet the
needs of her body and the growing FETUS. However,
the hormones that support pregnancy
increase insulin resistance, reducing the woman’s
ability to use the insulin her body produces. The
consequence may be temporary type 2 diabetes.
Gestational diabetes affects about 4 percent of
pregnant women in the United States. Some
women can maintain appropriate insulin and glucose
levels through careful nutritional habits, daily
exercise, and WEIGHT LOSS AND WEIGHT MANAGEMENT.
Others may require insulin therapy (many oral
antidiabetes medications are not approved for use
during pregnancy) for the duration of pregnancy.
Untreated gestational diabetes can have serious
consequences for the baby, as the high levels of
insulin in the mother’s blood circulation increase
the amount of glucose the baby’s body can accept.
One consequence is an unusually large baby.
Rapid fetal growth is one indication that a woman
might have gestational diabetes. About 70 percent
of women who develop gestational diabetes
recover completely. The rest develop permanent
type 2 diabetes, either continuing after the end of
the pregnancy or years to decades later.
Symptoms and Diagnostic Path
The symptoms of diabetes are similar across the
types, though in type 1 may be rapid and severe.
These symptoms include
• excessive thirst and frequent urination
• unexplained weight loss
• increased APPETITE
• changes in vision
• tingling in the hands and feet