Chronic stress, salivary cortisol, and alpha-amylase in children with asthma and healthy children.

The present study examined whether chronic stress is related to daily life levels of salivary alpha-amylase (sAA), a marker for sympathetic activity, and cortisol in healthy children versus children with asthma. Children's sAA and cortisol levels were measured repeatedly over 2 days. Chronic stress measures included interviews with children about chronic home life stress and interviews with parents about one marker of socioeconomic status, parental education. Among children with asthma, higher chronic stress was associated with lower daily sAA output, while among healthy children, higher chronic stress was associated with flatter cortisol slopes. In conclusion, chronically stressed children with asthma showed lower salivary alpha-amylase output, indicating lower sympathetic activity, and implying a possible mechanism for increased susceptibility to symptom exacerbations. In contrast, higher cortisol levels in healthy children with chronic stress may indicate, for example, an increased risk for infectious diseases. This dichotomy emphasizes the different biological effects of chronic stress depending on illness status.