Egocentric social network correlates of physical activity

BACKGROUND

The social environment might play an important role in explaining people's physical activity (PA) behavior. However, little is known regarding whether personal networks differ between physically active and physically inactive people. This study aimed to examine the relationship between personal network characteristics and adults' physical (in)activity.

METHODS

An egocentric social network study was conducted in a random sample in Switzerland (n = 529, mean age of 53 years, 54% females). Individual and personal network measures were compared between regular exercisers and non-exercisers. The extent of these factors' association with PA levels was also examined.

RESULTS

Non-exercisers (n = 183) had 70% non-exercising individuals in their personal networks, indicating homogeneity, whereas regular exercisers (n = 346) had 57% regularly exercising individuals in their networks, meaning more heterogeneous personal networks. Additionally, having more regular exercisers in personal networks was associated with higher PA levels, over and above individual factors. Respondents with an entirely active personal network reported, on average, 1 day of PA more per week than respondents who had a completely inactive personal network. Other personal network characteristics, such as network size or gender composition, were not associated with PA.

CONCLUSION

Non-exercisers seem to be clustered in inactive networks that provide fewer opportunities and resources, as well as less social support, for PA. To effectively promote PA, both individuals and personal networks need to be addressed, particularly the networks of inactive people (e.g., by promoting group activities).

[The association between the characteristics of egocentric network and HIV prevalence among men who have sex with men]

Objective: This study aimed to analyze the association between the characteristics of egocentric network and HIV prevalence among men who have sex with men (MSM) through social network analysis. Methods: The study was conducted in Guangzhou city from November 2016 to June 2017 using convenient sampling method. Participants were recruited from 13 voluntary counseling and testing (VCT) locations. Data were collected by using nomination generation and nomination interpretation methods. Questionnaire includes two parts, the first part about the social tie, and the second one about social demography and behavioral characteristics of respondents and their nominees. The multivariate logistic regression was applied to quantify the association. Results: 8.67%(93/1 073) HIV antibody positive MSM had been detected in 1 073 respondents who nominated 4 301 partners in total. Compared to egocentric sexual network with a size of 1-2, the size of sexual network larger than 3 (OR=1.68, 95%CI: 1.07-2.65) were associated with HIV infection. Compared to egocentric risk sexual network with a size of 1-2, the size of risk sexual networks larger than 3 (OR=1.87, 95%CI: 1.06-3.31) were associated with HIV infection. There were no significant association between marital similarity of respondents and their nominees, the type of the relationship of sexual partners and HIV prevalence (P>0.05). Conclusion: The composition of social network in MSM is related to their susceptibility of HIV infection. MSM population with a large sexual network is more susceptible to HIV infection.

[Characteristics and influencing factors regarding social relations among men who have sex with men]

Objective: To study the characteristics of social relations and relative factors among MSM in Guangzhou. Methods: Data was collected through a cross-sectional study in Guangzhou from November 2016 to May 2017. Sample size was estimated and participants were recruited from the voluntary counseling and testing services (VCT) which were set for MSM population, by nongovernmental organizations (NGOs) and the Centers for Disease Control and Prevention (CDC). Social ties and demographic characteristics of the respondents and their sexual partners were analyzed through both Chi square test and generalized estimating equations (GEE). Results: A total of 1 073 MSM, together with their nominated 4 301 partners were successfully recruited and involved in this study. Age (OR=1.2, P=0.01) and non-internet based intercourse (OR=1.65, P<0.01) were easy to form close relation with strong ties. Compared with MSM traditional venues (chess and cards room, tea room bathhouse, club), general public venue (bars, KTV, parks, shopping malls, schools, restaurants) (OR=1.46-3.12, P<0.01) showed close relation with strong ties. Our finding showed that MSM at the age of 18-25 preferred to build weak ties with the older MSM, while the 26-30-year-olds and 31-40-year-olds prefer to establish weak ties with younger partners but the 41-50-year-olds preferred to develop weak ties with one that were ten years younger. Conclusions: Clusters were noticed in the MSM populations when grouping and making friends with ones at different age. Characteristics regarding the relationship between sexual partners in choosing venues and ways of dating were different. Targeted intervention programs need to be explored innovatively.

Can Burt's Theory of Structural Holes be Applied to Study Social Support Among Mid-Age Female Sex Workers? A Multi-Site Egocentric Network Study in China

The epidemic of HIV/AIDS continues to spread among older adults and mid-age female sex workers (FSWs) over 35 years old. We used egocentric network data collected from three study sites in China to examine the applicability of Burt's Theory of Social Holes to study social support among mid-age FSWs. Using respondent-driven sampling, 1245 eligible mid-age FSWs were interviewed. Network structural holes were measured by network constraint and effective size. Three types of social networks were identified: family networks, workplace networks, and non-FSW networks. A larger effective size was significantly associated with a higher level of social support [regression coefficient (β) 5.43-10.59] across the three study samples. In contrast, a greater constraint was significantly associated with a lower level of social support (β -9.33 to -66.76). This study documents the applicability of the Theory of Structural Holes in studying network support among marginalized populations, such as FSWs.

Random errors in egocentric networks

The systematic errors that are induced by a combination of human memory limitations and common survey design and implementation have long been studied in the context of egocentric networks. Despite this, little if any work exists in the area of random error analysis on these same networks; this paper offers a perspective on the effects of random errors on egonet analysis, as well as the effects of using egonet measures as independent predictors in linear models. We explore the effects of false-positive and false-negative error in egocentric networks on both standard network measures and on linear models through simulation analysis on a ground truth egocentric network sample based on facebook-friendships. Results show that 5-20% error rates, which are consistent with error rates known to occur in ego network data, can cause serious misestimation of network properties and regression parameters.