Syndemic factors associated with HIV risk for gay and bisexual men: comparing latent class and latent factor modeling

Syndemics theory has been proposed as a framework for understanding the role of multiple risk factors driving the HIV epidemic among gay and bisexual men. Previous studies have examined five syndemic indicators (polydrug use, depression, childhood sexual abuse, sexual compulsivity, and intimate partner violence). Many of these studies have utilized sum scores, the total number of syndemic factors endorsed, to quantify syndemic stress. This approach assumes a unidimensional latent factor and equivalence of factor loadings. It also overlooks the possibility that patterns, or classes, of syndemic factor endorsement may be present. The current study utilized survey data from 669 gay and bisexual men to test assumptions of unidimensionality and factor loading equivalence and to examine the utility of identifying latent classes of syndemic stress. Analysis supported operationalizing syndemics as a unidimensional latent factor. Assumptions of loading equality were not supported. Meaningful profiles of syndemic stress were not evident in latent class analysis results.