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To investigate the structure of genomic interaction network, social affiliation network analysis was performed for the yeast gene expression compendium dataset of hundreds of systematic perturbations. Network density and centrality indices of genes and groups of genes revealed the core-peripheral and the significant intermediary players that may be critical for the control of the biological system.
Social network analysis is the study of social structure. This glossary introduces basic concepts in social network analysis. It is designed to help researchers to be more discriminating in their thinking and choice of methods.
Social network analysis comprises a set of research methods that can be used to analyze the relationships among entities such as people, departments, and organizations. The purpose of the analysis is to discover patterns of relationships that affect both individual and organizational attitudes and behavior such as the adoption, diffusion, and use of new medical informatics applications. This paper presents an introduction to the concepts and methods of social network analysis. Several applications to health informatics are described.
The paper describes structural and HIV-related network characteristics and examines associations between these various social network domains and HIV risk behaviors among a sample of 356 men randomly selected from a methadone maintenance treatment program (MMTP) in New York City. Multiple logistic regression analyses suggest that (1) a higher level of perceived sexual risk among network members, referred to as "alters" in this study, was associated with an increased likelihood of the participant engaging in sexual risk behaviors; (2) participants who indicated that they exchanged encouragement with a higher number of network alters about using condoms were less likely to report engaging in unprotected sex; and (3) participants who indicated that they talked about HIV risks with a higher number of network alters were less likely to engage in unprotected sex in the past 6 months. Collectively, these findings support the notion that networks may influence the adoption of risk reduction strategies in this population. Implications of the findings for HIV prevention network interventions for men in MMTPs are discussed.
Considerable empirical research substantiates the importance of social networks on health and well-being in later life. A study of ethnic minority elders living in two low income public housing buildings in East Harlem was undertaken to gain an understanding of the relationship between their health status and social networks. Findings demonstrate that elders with supportive housing had better psychological outcomes and used significantly more informal supports when in need. However, elders with serious health problems had poorer outcomes regardless of their level of social support. This study highlights the potential of supportive living environments to foster social integration and to optimise formal and informal networks.
In a study of the link between physical disability and social relationships among the elderly, questions about social network and social support evoked a surprisingly large number of group responses. People mentioned "my grandchildren," "the people in my building," "people at the senior center," and other groups in ways that suggested that the real unit of support was extraindividual and could not be accurately understood by reference to individual people within those groups. This paper describes the frequency of such responses and the circumstances under which they emerged. Definitions of social support and of social network should not be restricted to dyadic relationships between individuals; better understanding of social support processes would derive from consideration of the kinds of social support functions best offered by groups vs. individuals and consideration of differences in the ways in which support is derived from groups and individuals.
Social network theory and analysis are applied to examine whether adolescents who fill various social positions that characterize peer group structure differ in prevalence of current smoking. One thousand and ninety-two (1,092) ninth graders in one school system named their three best friends, allowing the identification of each adolescent as clique member, clique liaison, or isolate. At four of five schools, the odds of being a current smoker were significantly higher for isolates than for clique members and liaisons. The relationship was not explained by demographic variables or by the number of friends who smoke.
While the health promoting influences of social networks have been shown in a number of studies, little attention has been paid to measurement issues within the field of epidemiology. The purpose of this paper is to propose a new set of measures of social networks for use in epidemiological research on the elderly. We use confirmatory factor analysis to test a multidimensional model of social networks using data from a large epidemiologic study of community-dwelling adults age 65 and over (U.S.A.). Confirmatory factor analysis conducted using LISREL showed that our model provides a good fit to the data after several adjustments for correlated measurement error were introduced. Based on this analysis, we developed new measures of four dimensions and a summary index of social networks. Bivariate relationships between our new measures and several sociodemographic variables of interest are also presented.
OBJECTIVES: To describe social networks, social support and mental health among non-institutionalized individuals aged 65 years or older of Barcelona (Spain), and to analyze the relationship between mental health and social network and social support in this population by gender and age subgroup. METHODS: A cross-sectional study was performed. The sample consisted of individuals aged 65 years or more (389 men and 609 women) who took part in the Household Health Survey of Barcelona in 2000. Mental health was screened through the General Health Questionnaire-12 (GHQ-12). A descriptive analysis, as well as bivariate and multivariate analyses (logistic regression), were performed to analyze the association between mental disorders and social network and social support, adjusted by perceived health status and disabilities. RESULTS: According to the GHQ-12, 21.8% of the women and 9.4% of the men had some mental disorder. Multivariate analysis showed that among men mental disorders were associated with not seeing friends regularly in the subgroup aged 75 years or more (OR = 5.76; 95% CI = 1.77-18.7) and with low social support according to Duke's profile and lack of emotional support in both age groups (65-74 years and 75 years or more). For women, mental disorders were associated with not seeing friends regularly in the subgroup aged 75 years or more and with low social support according to the Duke's profile in both age groups. CONCLUSIONS: Mental health in the elderly population in Barcelona is associated with social network and support. Policies to promote social support could improve mental health in this population.
Patients with non-insulin-dependent diabetes mellitus (NIDDM) were advised to comply with a complex behavioral regimen of diet and exercise. The relationship between social support satisfaction and social support network size was evaluated using the Social Support Questionnaire for 32 men and 44 women with a confirmed diagnosis of NIDDM. Control of diabetes, as measured by the glycosylated hemoglobin assay, was significantly correlated with social support satisfaction for women but negatively correlated with social support satisfaction for men. Social support network size differentially predicted success in a program for men and women. For women, network size was significantly correlated with failure to attend sessions and with failure to complete a diary. For these women, network size was not significantly correlated with weight loss, which was the goal of the program. For men, network size was correlated with increases in weight, cholesterol, and triglycerides over an 18-month period. We conclude that social support network size and satisfaction have different functions for men and women faced with a serious chronic illness. Network size adversely affects success in a program, whereas social support satisfaction has some benefits for women. The direction of the influence of social network may be determined by the similarity or dissimilarity of network norms to the desired behavior.
The author studied preschoolers' social networks by investigating the allocation of children's social investment within and across time in a classroom of a French nursery school during an academic year. Observations of children's social exchanges during free play revealed that social behaviors were directed toward particular group members. After an important turnover in the peer group at the beginning of the school year, the social network became more structured. Children's strong associations were mostly same sex and small sized. Even if the stability of children's connections remained low, it increased over time. High-frequency partners as well as same-sex partners were more likely to be maintained over time. These findings as well as conceptual and methodological issues are discussed from a developmental perspective.
Social networks and the support that network members provide are important resources for family caregivers in sustaining their caregiving role. Caregivers' perceptions of support from family and friends have been linked to their health status (R. Kahn & T. Antonucci, 1980; I. Sandler & M. Barrera, 1984). The purpose of this study was to explore the social networks and types of perceived support described by women who are caregivers of cognitively impaired older adults. Content analysis was used to examine interview data from a longitudinal qualitative study of 20 women caregivers of cognitively impaired older persons. An important finding of this study was the identification of a typology of social networks of the women caregivers. The caregivers' perceptions of satisfaction with support received and experience of conflict with network members varied according to the characteristics of their social network. Those caregivers who belonged to diverse social networks reported high satisfaction with the support that they received and little or no conflict. Those caregivers with kin-dominated social networks reported little satisfaction with support received and a high degree of conflict.
Increasingly, parents, teachers, and students with disabilities are advocating for interventions that go beyond skill training to provide support for participation in integrated environments and support for friendships. The present research demonstrated a social network intervention for youths with moderate and severe disabilities. Two groups of nondisabled peers were recruited to participate in weekly discussions with an adult integration facilitator to increase opportunities for social interaction for 2 students (1 with autism and 1 who was moderately mentally retarded). The groups met to discuss social interactions that had occurred with the students with disabilities and to talk about strategies to promote greater inclusion of the students into ongoing social interaction. The nondisabled students participated in the design and implementation of social skills interventions during transition times and lunch. The nondisabled students used self-monitoring data sheets to record the quantity and quality of interactions. The frequency of interaction, number of opportunities for interaction, and appropriateness of social interactions were analyzed with a multiple baseline design. Results indicated that the social network intervention was successful in increasing the quantity and quality of interactions and that the network strategy promoted the development of friendships. The results are discussed in terms of the need for additional research showing the relationships between increases in social competence, peer-mediated intervention, and the development and support of friendship.
A multirelational social network on a set of individuals may be represented as a collection of binary relations. Compound relations constructed from this collection represent various labeled paths linking individuals in the network. Since many models of interest for social networks can be formulated in terms of orderings among these labeled paths, we consider the problem of evaluating an hypothesized set of orderings, termed algebraic constraints. Each constraint takes the form of an hypothesized inclusion relation for a pair of labeled paths. In this paper, we establish conditions under which sets of such constraints may be regarded as partial algebras. We describe the structure of constraint sets and show that each corresponds to a subset of consistent relation bundles between pairs of individuals. We thereby construct measures of fit for a given constraint set. Then, we show how, in combination with the assumption of various conditional uniform multigraph distributions, these measures lead to a flexible approach to the evaluation of fit of an hypothesized constraint set. Several applications are presented and some possible extensions of the approach are briefly discussed. Copyright 2000 Academic Press.
Street children are a high priority for health policy and service planning in Kenya. Poverty, wars, famine and disease have resulted in street children having a persistent presence in African cities and towns. The Maastricht Social Network Analysis (MSNA) was implemented as the core instrument in a battery to measure the health status of the street children. Owing to the absence of census data of street children in Kenya and the difficulty in tracking this mobile population, we implemented a mixed snowball and convenience sampling design to recruit research subjects. Three hundred street and orphanage children, and 100 primary school children as a control group, were included in the study. The MSNA provided a social diagnosis that complements the clinical diagnosis of the health status of the sample. Only one main methodological question is presented: is the MSNA applicable to describe the personal social networks of (1). children and of (2). people living in a Kenyan culture? Qualitative field observations, key informant interviews and focus groups inform the adaptation of the MSNA instrument, and improve its face validity. A case series analysis is presented. The main result is that the street children population consists of distinct subgroups defined by the UNICEF classification as 'on' and 'of' the street and by gender. Street children networks have some notable deficiencies depending on the subgroup. Constant across the groups is the deficiency of service providers in their networks. The conclusion is that the MSNA is a suitable instrument for obtaining a social diagnosis and gathering other useful information that helps in understanding the social and health backgrounds, status and daily experiences of Kenyan scavenging street children. Applying the MSNA protocol was successful in the diagnosis and interpretation of the findings.
Demographic changes and social structural transformations lead to changes in family size, the family cycle and in intergenerational relationships. Contrary to an abridged and overgeneralized public, political and scientific discussion, one can, by no means, assume a decrease in family functions concerning the aged. It seems that in some areas emotional and instrumental functions of the family increase. In other areas functions are transferred and generally there is a whole new division of labor between family and other informal networks. These informal networks are obviously becoming increasingly meaningful in the sense of a family "freely chosen". Because of considerable variability in social structure generalizations in this area cannot be made. On the whole, one can expect a continuing expansion and differentiation in the range and type of support offered the elderly by the family and other networks.
In connection with an extensive examination of their health status, a representative sample of 68-year-old men (n = 621) in the city of Malmö, Sweden, were interviewed in detail regarding different aspects of the social network, social support and social influence of the individual, dental care utilisation and perceived dental health. 79% of the dentate and 7% of the edentulous subjects made regular dental visits. The most important reason for not visiting a dentist regularly was "no perceived need". Social class and different aspects of social network and social support were in univariate analyses associated with regular dental care. In the multivariate analysis, social anchorage and social participation, subconcepts of the social network, and social class showed independent associations with regular dental care. The addition of the social network and social support variables yielded a more differentiated and thereby a more valid picture of the determinants of regular dental care utilisation. These factors should therefore be considered when public health efforts to increase the number of elderly persons receiving regular dental care are made.
Using epidemiological and social network research methods, this study examines gender differences in HIV risk and protective behaviors and social network characteristics among 193 young injection drug users (IDUs) and 127 referred members of their social networks. Respondents reported on their drug use, sexual behavior, and relationships within three types of social networks: hang out (i.e., friendship); drug use; and sexual networks. Most respondents were homeless and had experienced numerous life stressors. Females' social networks consisted more predominantly of drug injectors, and members more frequently appeared multiple networks. Females reported needle sharing more frequently than males, but also reported more protective behaviors such as needle exchange use and carrying clean syringes. Young female IDUs may compound their risk by having sex and injecting with higher risk partners. However, their propensity to practice protective behaviors may provide an opening for interventions to reduce their HIV risk and that of their social network members.