Homelessness is a modern social and economic problem of major public health significance. In the United States of America (USA), several studies have identified different leading causes of morbidity and mortality among homeless populations.
For this systematic review, Principal Component Analysis (PCA), a multi-variate technique is applied to elucidate the strength of association of comorbidities and mortality among the U.S homeless population.
A search was conducted for published data for the 20-year period between 1/1/1998 and 12/31/2018. The keywords consisted of the terms: homeless, mortality, morbidity, United States, and health disparities. Data were drawn from cohort studies, observational studies and surveillance reports. Data were then extracted from eleven studies for meta-analysis using PCA.
The first principal component analysis (PCA1) revealed a strong correlation between the co-morbidities of heart disease, cancer, diabetes, and psychoactive substance use. By contrast, PCA2 and PCA3 were strongly correlated to respiratory disease, and transportation-related injuries, respectively. Diseases correlated to PCA1, PCA2, and PCA3 were the major causes of mortality and morbidity of US homeless people with a prevalence of 53.88% (95% Confidence Interval, Bartlett's test, Chi-square (χ) = 228.941, degree of freedom (DF = 41.924)); 26.03% (χ = 176.27, DF = 176.274) and 19.85% (χ = 131.266, DF = 131.266), respectively.
Based on the Principal Component Analysis (PCA), homeless people in the U.S. die mainly from heart disease, cancer, diabetes, and psychoactive substance use. Thus, there is a need to address health disparities and to further promote health education and intervention programs.