Early and late life events and salivary cortisol in older persons

BACKGROUND: It has been hypothesized that stressful life events are associated with changes in hypothalamic-pituitary-adrenal (HPA) axis regulation, which increases susceptibility to psychiatric disorders. We investigated the association of early and late life events with HPA axis regulation in older persons.

METHOD: Within the Longitudinal Aging Study Amsterdam (LASA) 1055 participants (47% male), aged 63-93 years, collected saliva within 30 min after waking and late in the evening. Early and late life events were assessed during a home interview. The associations between life events and cortisol levels were examined using linear regression and analysis of covariance with adjustments for demographics, cardiovascular risk factors and depressive symptoms.

RESULTS: Within our sample, the median morning and evening cortisol levels were 15.0 nmol/l [interdecile range (10-90%): 7.4-27.0 nmol/l] and 2.8 nmol/l (10-90%: 1.5-6.3 nmol/l), respectively. Persons who reported early life events showed lower levels of natural log-transformed morning cortisol [B=-0.10, 95% confidence interval (CI) -0.17 to -0.04] and flattened diurnal variability of cortisol (B=-1.06, 95% CI -2.05 to -0.08). Those reporting two or more late life events showed higher levels of natural log-transformed morning cortisol (B=0.10, 95% CI 0.02-0.18) and higher diurnal variability (B=1.19, 95% CI 0.05-2.33). No associations were found with evening cortisol.

CONCLUSIONS: The results of this large population-based study of older persons suggest a differential association of early and late life events with HPA axis regulation; early life events were associated with a relative hypo-secretion of morning cortisol and flattened diurnal variability, while late life events were associated with elevated secretion of morning cortisol and high diurnal variability of cortisol.