Poverty matters: contextualizing the syndemic condition of psychological factors and newly diagnosed HIV infection in the United States.

BACKGROUND: 'Syndemic factors', defined as co-occurring psychological conditions including major depressive disorder, substance and alcohol use, and intimate partner violence, have been shown to increase HIV incidence among MSM in the United States. However, this relationship has not been well characterized in the general population, particularly in the context of poverty.
DESIGN: Prospective cohort study including a nationally-representative sample of 34 427 men and women in the National Epidemiologic Survey on Alcohol and Related Conditions wave 1 (2001-2002) and wave 2 (2004-2005).
METHODS: Weighted multivariable logistic regression models were used to assess the association between syndemic factors and newly diagnosed HIV infection, and to assess how living below the poverty line (based on 2001 US Poverty Guidelines) modified this relationship.
RESULTS: The proportion of participants reporting new HIV diagnosis in the past year was 0.22%, increasing from 0.19% among individuals with no syndemic factor to 5.1% among those with four syndemic factors. Adjusting for potentially confounding factors, each additional syndemic factor was associated with a 47% increase in odds of HIV infection [adjusted odds ratio (aOR) 1.47, 95% confidence interval (CI) 1.30-1.65]. The effect of syndemic factors was stronger among individuals living below federal poverty guidelines (aOR 1.96, 95% CI 1.57-2.44) compared to those living above poverty guidelines (aOR 1.21, 95% CI 1.07-1.36).
CONCLUSIONS: Among the US general population, the association between co-occurring syndemic factors and incident HIV infection was stronger in the setting of poverty. Mental health interventions, particularly in socioeconomically disadvantaged areas, should be considered to reduce transmission of HIV.