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Determining Soil-transmitted Helminth Infection Status and Physical Fitness of School-aged Children
Published on: August 22, 2012
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Public Health
Dvir Dori1, Bruna Seixas Lima2, Carlos Tyler Roncero2
1Rotman Research Institute-Baycrest, TORONTO, ON, Canada.
Alzheimer'S & Dementia : the Journal of the Alzheimer'S Association
|December 23, 2025
Summary
Suboptimal thyroid function, including higher-normal TSH or low-normal FT4, does not increase cognitive decline risk. This study found no association, cautioning against unproven thyroid interventions for cognitive health.
Area of Science:
- Endocrinology
- Neurology
- Gerontology
Background:
- Emerging hypotheses link "suboptimal" thyroid function, characterized by higher-normal TSH or low-normal FT4, to increased cognitive decline and dementia risk.
- This study investigates the association between thyroid function and cognitive status in older adults.
Purpose of the Study:
- To test the hypothesis that "suboptimal" thyroid function (higher-normal TSH or low-normal FT4) is associated with cognitive decline and dementia.
- To evaluate the clinical significance of thyroid function within the higher-normal and low-normal ranges for cognitive health.
Main Methods:
- Utilized data from 991 participants (aged 50-91) in the COMPASS-ND cohort, covering a spectrum of cognitive statuses.
- Classified thyroid function as "optimal" (TSH<2.0 µIU/ml or FT4≥16.74 pmol/L) or "suboptimal" for analysis.
- Employed Chi-square analysis to assess the association between thyroid function categories and cognitive impairment.
Main Results:
- Chi-square analysis of 883 participants revealed no significant association between "suboptimal" thyroid function and cognitive impairment for TSH (p=0.69) or FT4 (p=0.96).
- True hypothyroidism was infrequent in the cohort.
- A high percentage (98.6%) of participants with elevated TSH levels also exhibited normal FT4 levels, suggesting euthyroidism.
Conclusions:
- The findings refute claims that higher-normal TSH or low-normal FT4 levels elevate the risk of cognitive decline or dementia.
- Highlights the need for caution regarding redefining TSH cutoffs or implementing unproven thyroid supplementation strategies for cognitive enhancement.
- Suggests current thyroid function reference ranges are appropriate for assessing cognitive health risk.
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