The pituitary gland secretes a hormone, thyrotropin, which influences function of the thyroid gland.  Researchers at Harvard Medical School and the Beth Israel Deaconess Medical Center have released the findings of their study, which reveals a link between Alzheimer’s disease and both low levels and high levels of thyrotropin.

Zaldy S. Tan, MD, MPH, of Hebrew SeniorLife, led the research team through the study of 1,864 men and women whose average age was 71.  The study’s participants enrolled between 1977 and 1979 and all were found to be free of dementia at the time of enrollment.  Each participant was re-evaluated for dementia at two-year increments, for an average of 12.7 years.

During the course of the study, 209 individuals were diagnosed with Alzheimer’s disease.  Their thyrotropin levels were measured as part of the study.

In cases where a woman’s thyrotropin levels were lowest, defined as less than 1 milli-international unit per liter, and highest, more than 2.1 milli-international units, her risk of developing Alzheimer’s disease was more than double that of women with normal levels of the hormone.  Thyrotropin levels played no significant role in the male study participants who developed the disease.

No one knows at this point if a woman’s level of thyrotropin triggers the Alzheimer’s disease or if the disease affects her thyrotropin levels but the research team suggests further studies to confirm their findings before basing Alzheimer’s diagnoses on thyrotropin levels.  Full details of the study can be found in the July 28 issue of JAMA’s Archives of Internal Medicine.

Source: JAMA