Impact of loneliness on illness and death in people

From
http://www.ncbi.nlm.nih.gov/pubmed/19968414
Alone in the Crowd: The Structure and Spread of Loneliness in a Large
Social Network
Nicholas A. Christakis

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Humans are an irrepressibly meaning-making species, and a large
literature has developed showing that perceived social iso- lation
(i.e., loneliness) in normal samples is a more important predictor of a
variety of adverse health outcomes than is objective social isolation
(e.g., (Cole et al., 2007; Hawkley, Masi, Berry, & Cacioppo, 2006;
Penninx et al., 1997; Seeman, 2000; Sugisawa, Liang, & Liu, 1994). In an
illustrative study, Caspi, Harrington, Moffitt, Milne, & Poulton (2006)
found that loneliness in adoles- cence and young adulthood predicted how
many cardiovascular risk factors (e.g., body mass index, waist
circumference, blood pressure, cholesterol) were elevated in young
adulthood and that the number of developmental occasions (i.e.,
childhood, adoles- cence, young adulthood) at which participants were
lonely pre- dicted the number of elevated risk factors in young
adulthood. Loneliness has also been associated with the progression of
Alzheimer's disease (Wilson et al., 2007), obesity (Lauder, Mum- mery,
Jones, & Caperchione, 2006), increased vascular resistance (Cacioppo,
Hawkley, Crawford, et al., 2002), elevated blood pres- sure (Cacioppo,
Hawkley, Crawford, et al., 2002; Hawkley et al., 2006), increased
hypothalamic pituitary adrenocortical activity (Adam, Hawkley, Kudielka,
& Cacioppo, 2006; Steptoe, Owen, Kunz-Ebrecht, & Brydon, 2004), less
salubrious sleep (Cacioppo, Hawkley, Berntson, et al., 2002; Pressman et
al., 2005), dimin- ished immunity (Kiecolt-Glaser et al., 1984; Pressman
et al., 2005), reduction in independent living (Russell, Cutrona, de la
Mora, & Wallace, 1997; Tilvis, Pitkala, Jolkkonen, & Strandberg, 2000),
alcoholism (Akerlind & Hornquist, 1992), depressive symptomatology
(Cacioppo et al., 2006; Heikkinen & Kauppinen, 2004), suicidal ideation
and behavior (Rudatsikira, Muula, Siziya, & Twa-Twa, 2007), and
mortality in older adults (Penninx et al., 1997; Seeman, 2000).
Loneliness has even been associated with gene expression: specifically,
the under-expression of genes bear- ing anti-inflammatory glucocorticoid
response elements and over- expression of genes bearing response
elements for proinflamma- tory NF-B/Rel transcription factors (Cole et
al., 2007).
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