Daily social interactions, close relationships, and systemic inflammation in two samples: Healthy middle-aged and older adults.
OBJECTIVE
Systemic inflammation is thought to be a biological mediator between social relationship quality and premature mortality. Empirical work has yielded mixed support for an association of social relationship variables with systemic inflammation, perhaps due to methodological limitations. To date, research in this literature has focused on global perceptions of social relationships, with limited attention to the covariance of characteristics of daily social interactions with inflammation. Here, we examine whether daily interactions, as assessed by ecological momentary assessment (EMA), associate with peripheral markers of inflammation among midlife and older adults.


METHODS
Global social support and integration were measured using the Interpersonal Support Evaluation List (ISEL) and the Social Network Index (SNI), respectively, in older adults from the Pittsburgh Healthy Heart Project (PHHP), and in middle-aged adults from the Adult Health and Behavior Project-II (AHAB-II). Using time-sampled EMA, we assessed the proportion of the day spent in positive and negative social interactions. Systemic markers of inflammation were interleukin (IL)-6 and C-reactive protein (CRP).


RESULTS
Global measures of support and integration did not associate with inflammation in either sample. In older adults, relative frequency of total positive interactions, those with close others (i.e. spouse, friends, family), and those with coworkers predicted lower concentrations of IL-6 in fully adjusted models, accounting for age, sex, race, education, BMI, smoking and alcohol. In middle-aged adults, relative frequency of positive interactions with close others was also inversely associated with IL-6 level and relative frequency of negative marital interactions was unexpectedly inversely associated with CRP level.


CONCLUSIONS
Characteristics of daily social interactions among midlife and older adults associate with markers of systemic inflammation that are known to predict risk for cardiovascular disease. Ambulatory measures may better capture health-relevant social processes in daily life than retrospective, global self-report measures.
Department of Psychology, University of Pittsburgh, PA, USA. Electronic address: amb311@pitt.edu.
Amoha
A
Bajaj
Department of Psychology, University of Pittsburgh, PA, USA.
Neha A
NA
John-Henderson
Department of Psychology, University of Pittsburgh, PA, USA.
Jenny M
JM
Cundiff
Department of Psychology, University of Pittsburgh, PA, USA.
Anna L
AL
Marsland
Department of Psychology, University of Pittsburgh, PA, USA.
Stephen B
SB
Manuck
Department of Psychology, University of Pittsburgh, PA, USA; Department of Psychiatry, University of Pittsburgh, PA, USA.
Thomas W
TW
Kamarck
D000367:Age Factors; D000368:Aged; D002097:C-Reactive Protein / Q000378:metabolism; D006801:Humans; D007249:Inflammation; D015850:Interleukin-6 / Q000097:blood; D007398:Interpersonal Relations; D008297:Male; D008875:Middle Aged; D012944:Social Support
C508600:IL6 protein, human; D015850:Interleukin-6; D002097:C-Reactive Protein
Cardiovascular disease; Close others; Ecological momentary assessment; Inflammation; Marital interactions; Social integration; Social interactions; Social support