Loneliness, social isolation and behavioral and biological health indicators in older adults.

A number of mechanisms have been proposed through which social isolation and loneliness may affect health, including health-related behavioral and biological factors. However, it is unclear to what extent isolation and loneliness are independently associated with these pathways. The objective of the present analysis was to determine the impact of social isolation and loneliness, individually as well as simultaneously, on health-related behavioral and biological factors using data from the English Longitudinal Study of Ageing (ELSA). Data on health behaviors (smoking and physical activity), hypertension and hypercholesterolemia were analyzed from 8688 participants and data on biological indicators - C-reactive protein and fibrinogen - were analyzed from over 5000 of these participants who had also provided blood samples. Loneliness was measured using the short form of the Revised UCLA scale and an index of social isolation was computed incorporating living arrangements, frequency of contact with friends, family and children and participation in social activities. Logistic models were run to predict health behaviors, hypertension and hypercholesterolemia. Linear regression models were used for analyses on continuous outcomes (CRP and fibrinogen). All analyses were adjusted for age, gender, depression, limiting long-standing illness and marital status-adjusted wealth. Fewer than 2% of participants reported being lonely all the time, while nearly 7% had the highest possible scores on social isolation. Both social isolation and loneliness were independently associated with a greater risk of being inactive as well as reporting multiple health risk behaviors, while social isolation was also associated with smoking behavior. Neither social isolation nor loneliness was associated with an increased risk of hypertension. However, social isolation was positively associated with CRP and fibrinogen levels. Thus, loneliness and social isolation may affect health independently through their effects on health behaviors. In addition, social isolation may also affect health through inflammatory processes associated with the development of cardiovascular disease.