Social support and glycemic control in type 2 diabetes: a systematic review of observational studies.

We aim to systematically review observational studies examining the association between social support and glycemic control in adults with type 2 diabetes.We searched MEDLINE, PsycINFO, EMBASE, Scopus, Web of Science and Sociological Abstracts to July 2012 for observational studies investigating the association between structural or functional aspects of social support (social networks, community ties, marital status, family support, perceived, actual, emotional or instrumental social support) and glycemic control (HbA1c).From electronic and reference searches, 29 studies were eligible. Twenty different assessments of social support were used. Family support and composite measures of support were most frequently associated with reduced HbA1c. There was no evidence for a beneficial effect of other support measures on HbA1c.We found marked variation in population, setting, measurement of social support and definition of outcome, limiting the methodological validity of research. Social support may be important in the management of type 2 diabetes, the need for consensus and standardization of measures is highlighted.The presence of informal support should be explored in routine diabetes care.