Association of chronic stress, depression symptoms and cortisol with low saliva flow in a sample of south-Brazilians aged 50 years and older

Background: Few studies have evaluated the relationship between depression symptoms, chronic stress or physiological measures of stress such as cortisol levels and saliva secretion. Objective: To evaluate the association of low saliva flow with chronic stress, depression symptoms and cortisol in a population aged 50 years and older. Methods: Participants (n = 227) were recruited from community clubhouses and among dementia caregivers. Stress was assessed using the Lipp's Stress Symptoms Inventory and salivary cortisol measurements. In addition, taking care of a relative with dementia was included as a proxy variable for chronic stress. Depression was assessed using the Beck Depression Inventory. Saliva flow rate was assessed by measuring unstimulated and chewing-stimulated saliva flow. Further saliva samples were collected (morning, noon, night) for cortisol analysis by means of radioimmunoassay. Results: Gender, being a dementia caregiver, self-reported diabetes and prescriptive medication intake were independently associated with a low stimulated saliva flow. Prescriptive medication intake was also associated with a low unstimulated saliva flow. Conclusion: Caregiving, a proxy of chronic stress, was associated with low stimulated saliva flow, indicating that stress may have a potential role in salivary gland hypofunction.