Objective: Psychobiological research on aging in humans is confounded by individual differences that remain to be characterized more precisely. The present study was designed to address this issue by examining the impact of Network Cultivation, a behavioral tendency to strengthen one’s social ties on diurnal cortisol profiles in healthy Chinese elders in Hong Kong.
Methods:Authors performed secondary analysis of data reported by Lai  using multilevel modelling. Seventy-eight healthy seniors provided saliva samples over two consecutive days at immediately, 3, 6, 9, and 12 hours after waking. Cortisol levels were assayed by using an enzyme-linked immunosorbent assay kit (ELISA) developed for use in saliva. Social network cultivation was measured with the Cultivation subscale of the Support Network Scale (SNS) that had been validated in prior studies with Chinese participants. The relationship between network cultivation and diurnal cortisol rhythms was examined using a mixed effect model.
Results:Cortisol levels declined significantly from waking to 12 hours thereafter and the rate of decline decreased significantly over time. In comparison to socially proactive participants, those having lower scores in Network Cultivation exhibited a higher diurnal cortisol level and a less efficient or flatter decline. The effect of Network Cultivation remained significant after controlling the influences of gender, age, waking time, and socioeconomic status.
Conclusions: An attenuated behavioural tendency in cultivating social ties in the elders is associated with a higher cortisol level and a flatter diurnal decline, which may increase susceptibility to agerelated diseases. Further research is warranted to uncover the psychophysiological mechanisms translating social network cultivation into altered functioning of the hypothalamic-pituitaryadrenocortical axis.