from: Great Smokies Diagnostic Laboratory
DATE: April 24, 2002, Volume 16, Number 06
THIS WEEK'S STORIES
- MILD THYROID IMBALANCES LINKED TO TREATMENT-RESISTANT DEPRESSION
- THYROID SCREENING RECOMMENDED IN PATIENTS WITH LUPUS
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MILD THYROID IMBALANCES LINKED TO TREATMENT-RESISTANT DEPRESSION
- SUBOPTIMAL LEVELS - EVEN WITHIN NORMAL RANGE - MAY AFFECT CLINICIAL
OUTCOMES IN BIPOLAR DISORDER
As the instruments of laboratory science become more precise, so too does
our understanding of how even slight biochemical imbalances in the body may
potentially affect human health.
A new study funded by the National Institute of Mental Health reports that
as many as two out of every three patients with bipolar depression may have
suboptimal thyroid hormone levels. These slight imbalances, though still
within the "normal range," appear to make these patients much more resistant
to standard drug treatments with anti-depressants.
Researchers measured thyroid hormone levels in 65 patients diagnosed in the
depressive phase of bipolar disorder. For the next 50 months, they tracked
their recovery after treatment with mood-stabilizing drug therapies,
including lithium carbonate and various antidepressant medications.
While it's already well known that both overt and subclinical thyroid
dysfunction are strongly linked with depression, the effect of more subtle
thyroid imbalances has not yet been thoroughly studied.
The study found that patients with low normal levels of free thyroxine (T4)
index or high normal levels of thyroid-stimulating hormone (TSH) levels were
much less responsive to various drug treatments for depression. On average,
these patients took nearly one year to respond to drug therapy - at least
four months longer than patients who had an optimal thyroid profile.
Thyroid hormone imbalances in these patients could develop as the central
nervous system becomes unable to self-regulate itself properly under the
stress of chronic depression. The imbalances could also be a first early
warning signal that thyroid failure is more likely to develop in these
patients in the future.
"It appears likely that patients with mood disorders are particularly
vulnerable to even minor variations in thyroid hormone levels," researchers
concluded. The imbalances that produced an effect on treatment outcomes were
even milder than those falling under the subclinical definition of
hypothyroidism. For this reason, a suboptimal thyroid profile - still within
the "normal" range - may be an important modifiable risk factor in bipolar
depression.
"These results add to the growing literature in support of the idea that
thyroid measures in the low normal range may result in a less than optimal
outcome in mood disorders," the study asserted.
NOTE: The Comprehensive Thyroid Assessment is a thorough functional
evaluation of central and peripheral thyroid metabolism and thyroid
autoimmunity, specially designed to reveal subtle, preclinical imbalances.
Because the thyroid is the main regulator of human metabolism, even slight
imbalances can affect a wide range of physiological and psychological
conditions, including mood disorders, obesity, chronic fatigue, digestive
problems, cognitive and sexual dysfunction, and cardiovascular disease.
In addition to analyzing central thyroid regulation (TSH and free T4) and
thyroid autoimmunity (anti-TG and anti-TPO), this in-depth assessment
evaluates peripheral thyroid function using free T3, rT3, free T3/rT3 ratio,
and free T4/free T3 ratio. Each test report displays markers within their
functional metabolic pathways for increased clinical relevance and insight,
with professional commentary based on individual results. Find out more
about the test at http://www.gsdl.com/assessments/thyroid/
RELATED ARTICLES AND RESOURCES:
When Thyroid Imbalance "Masquerades" As A Mood Disorder
http://www.gsdl.com/news/connections/vol14/conn20011121.html#story1
Depression and Thyroid Function
http://www.gsdl.com/assessments/finddisease/depression/thyroid.html
Source: Cole DP, Thase ME, Mallinger AG, Soares JC, Luther JF, Kupfer DJ,
Frank E. Slower treatment response in bipolar depression predicted by lower
pretreatment thyroid function. Am J Psychiatry 2002;159:116-121.
2002 Great Smokies Diagnostic Laboratory
Call 800-522-4762 for more information or send your request for test kits
and educational materials to [log in to unmask] ~~~~~~~~~~~~~
THYROID SCREENING RECOMMENDED IN PATIENTS WITH LUPUS
- RATE OF HYPOTHYROIDISM FIVE TIMES HIGHER THAN NORMAL
It can be a domino effect. When the body "turns on itself" and develops
autoimmunity, the resulting inflammation and injury can be triggered in
tissues and organs throughout the entire body. As important as treating the
condition itself, may be preserving other vital physiological functions.
A retrospective study of over 300 patients with systemic lupus erythematosus
(SLE), finds that thyroid dysfunction is so prevalent among patients with
this chronic autoimmune disorder that they may benefit significantly from
periodic clinical testing to detect and treat early signs of thyroid
disease.
Evaluating over two decades of clinical records and laboratory data, the
British researchers found that the incidence of hypothyroidism in patients
with SLE, commonly called lupus, was more than five times higher than that
in the general population. Hypothyroidism, a state of thyroid insufficiency,
can cause sluggish metabolism, weight gain, and fatigue.
About 14% of the patients with lupus also tested positive for thyroid
autoantibodies. In those with clinically diagnosed hyper or hypothyroidism,
the rate of positive detection of thyroid autoantibodies jumped to 68%.
Positive thyroid autoantibodies have been associated with increased
susceptibility to inflammation, thyroid atrophy, fetal loss, and joint pain.
It's still not clear whether thyroid autoimmune dysfunction relates directly
to disease mechanisms of SLE itself, or if its higher prevalence occurs
simply because both conditions predominantly strike the same demographic
group - young to middle-aged women.
Regardless of the reason, the relatively high rate of thyroid dysfunction in
patients with SLE - an estimated 7% will develop thyroid disease - merits
more aggressive clinical action, the authors argued. "We should thus
recommend the intermittent biochemical screening of thyroid function in
patients with SLE, particularly if they are known to have thyroid
antibodies, to identify clinical/subclinical thyroid disease."
Each year, more than 16,000 Americans develop SLE, commonly called lupus.
Currently, from 500,000 to 1.5 million Americans are estimated to have the
disease.
NOTE: Other symptoms and conditions associated with thyroid dysfunction
include chronic fatigue, headaches, cognitive dysfunction,
sexual/reproductive disorders, irritable bowel syndrome, and various skin
conditions. The Comprehensive Thyroid Assessment allows practitioners to
detect imbalances that can contribute to or worsen prognosis in these
conditions, as well as trigger symptoms that "mimic" the disorders
themselves. Visit the test page at http://www.gsdl.com/assessments/thyroid/
RELATED ARTICLES AND RESOURCES:
Sex Differences In Autoimmune Disease (full text or PDF download after free
registration)
http://www.nature.com/ni/special_focus/autoimmunity/commentaries.html
Compound In Vegetables Alters Estrogen Metabolism In Lupus
http://www.gsdl.com/news/connections/vol15/conn20020306.html#story1
Source: Pyne D, Isenberg DA. Autoimmune thyroid disease in systemic lupus
erythematosus. Concise report. Ann Rheum Dis 2002;61:70-72.
2002 Great Smokies Diagnostic Laboratory
Call 800-522-4762 for more information or send your request for test kits
and educational materials to [log in to unmask]
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