Relationship between saliva level of 3-methoxy-4-hydroxyphenylglycol and mental health in the elderly general population.

Aims: A large number of studies on the monoamine systems in Alzheimer's disease (AD) have found abnormalities of the noradrenergic system in the brain, but there has been no report concerning the relationship between noradrenergic activity and cognitive function in elderly living in a community. The aim of the present study was to explore the relationship between saliva level of 3-methoxy-4-hydroxyphenylglycol (sMHPG) and mental health in this population.

Methods: The study was to examine the relationship between sMHPG and performance on the Mini-Mental State Examination (MMSE), Frontal Assessment Battery (FAB), and Beck Depression Inventory (BDI) in 213 elderly people living in the local community.

Results: sMHPG in female subjects was positively correlated with age (r = 0.24, P = 0.003) and negatively correlated with scores on the MMSE (r = -0.26, P = 0.0016) and FAB (r = -0.19, P = 0.024), even after controlling for the effect of age (MMSE r = -0.20, P = 0.013). Notably, sMHPG was correlated with the pentagon drawing score (P = 0.0008) of MMSE. sMHPG was significantly correlated with BDI score in male subjects, but negatively correlated in female subjects. A gender difference was found in the relationship between the sMHPG and BDI score.

Conclusion: The measurement of sMHPG may be a useful marker of mental health in elderly community-dwelling subjects.