Urinary selenium, cranial MRI, and cognitive function in American Indians: The Strong Heart Study

Area of Science:

• Environmental Health
• Neuroscience
• Epidemiology

Background:

• Selenium (Se) is an essential trace element vital for biological functions, including cerebrovascular health.
• Elevated Se concentrations can be detrimental, and American Indians experience higher rates of cerebrovascular disease.
• This study investigates the link between Se levels and brain health in older American Indians.

Purpose of the Study:

• To evaluate the association between urinary Se levels and brain health indicators in older American Indians.
• To determine if Se exposure is linked to structural brain changes and cognitive performance.
• To identify potential environmental risks related to Se intake in a vulnerable population.

Main Methods:

• Utilized data from the Strong Heart Study, a longitudinal cohort of American Indians.
• Analyzed urinary Se levels (adjusted for creatinine), brain MRI, and neuropsychological test results from 728 participants (aged 65-95).
• Employed linear regression models to assess associations, adjusting for sociodemographic factors and vascular comorbidities.

Main Results:

• Increased urinary Se was associated with adverse brain imaging findings, including abnormal sulcal atrophy, ventricular widening, and white matter hyperintensities.
• Higher Se levels were independently linked to decreased performance in verbal fluency and processing speed.
• Associations remained significant after adjusting for sociodemographics, vascular comorbidities, depression, and traumatic brain injury.

Conclusions:

• Urinary Se levels exceeding 50-60 microg Se/g creatinine are associated with adverse brain structure and cognitive function in older American Indians.
• These findings highlight potential environmental risks of high Se intake in vulnerable populations.
• Epidemiologic evidence supports public health professionals in evaluating environmental Se exposure risks.