INTRODUCTION
The human cognitive function can be affected by many factors. Among these factors, testosterone has been thought to play a neuroprotective role in the brain. There have been several studies attempting to correlate cognitive function with testosterone. However, the results of them were inconsistent. The limitation of previous study is that majority of them were conducted in small groups and there have been no study based on Asian data. Furthermore, the effects of physical function on cognition were neglected and unadjusted and there are less studies on female testosterone compared to male.
OBJECTIVE
This study aimed to investigate the association between serum free testosterone (FT) level and cognitive function in elderly women.
METHODS
This is a cross-sectional study using the Korean Frailty and Aging Cohort Study (KFACS) database for the elderly living in a community (1582 females) in the 70-84 age group. Cognitive dysfunction is defined as the below 24 points in Mini-Mental Status Examination in the Korean version of the CERAD Assessment Packet (MMSE-KC) and lower 25% of the value measured by Trail Making Test (TMT), Frontal Assessment Battery (FAB), Digit span, Word list memory, recall and recognition. Lowest quartile groups in skeletal muscle index (appendicular skeletal muscle mass(ASM)/height²) are defined as sarcopenia and below 9 points of Short Physical Performance Battery (SPPB) are considered poor function group. The duration of education is divided in two groups based on graduation from junior high school or not. Univariate and multivariate logistic regression analyses were performed to investigate the association between FT level and cognitive function.
RESULTS
Low FT level was associated with decreased cognitive function in most of cognitive function test results except Word list recognition task (Table 2, univariate analysis). These associations were maintained in MMSE-KC, TMT, FAB, Word list memory task after adjusting for all potential confounding factors including skeletal muscle index and SPPB (Table 2, model 2 and 3). Analyses based on four categories in FT level revealed a higher odds ratio (OR) in the lower quartile groups in univariate analysis and multivariate analyses (Table 3).
CONCLUSION
Decreased cognitive function is associated with low FT level in elderly women. And it seems the lower the FT value, the greater the risk of cognitive decline. Additional long term follow up studies are needed to determine the predictability of cognitive disorders with testosterone level. |
