Abstract

Relationship between Schizophrenia and Low-Income Based on Age and Sex: Results from a Nation-wide Population-Based Longitudinal Study

Author(s): Chun-Te Lee, Chiu-Yueh Hsiao, Jia-Fu Lee, Yi-Chyan Chen, Oswald Ndi Nfor, Jing-Yang Huang, Lee Wang, Chien-Chang Ho, Yung-Po Liaw

Background:

The aim of this study was to examine the relationship between low-income and schizophrenia among the Taiwanese population.

Methods and Findings:

We recruited 1,773,693 participants (15,098 low-income and 1,758,595 non-low-income individuals) from the National Health Insurance Research Database (NHIRD). Low-income individuals were identified in 2001–2003 and followed up from 2004 to 2010 to ascertain a positive diagnosis of Schizophrenia. Cox proportional hazard regression analysis was used to determine the hazard ratios (HRs) with their 95% confidence interval (CI). The attributable risk percent (AR%) was also determined. The prevalence of schizophrenia was 0.26% in non-low-income and 1.23% in low-income individuals. In the low-income group, the incidence rates were 0.71 (0.45-1.11), 3.46 (2.61-4.57), 3.22 (2.22-4.66), and 1.67 (0.97-2.87) per 10,000 person-months in men, and 0.31 (0.16-0.59), 1.85 (1.40-2.46), 1.48 (0.80-2.75), and 1.86 (0.97-3.57) per 10,000 person-months in women aged 0-17, 18-44, 45-64 and ≥65 years, respectively. Higher incidence rates were evident in the 18-64 age category of low-income individuals. The adjusted HRs were 4.06 (2.52-6.53), 6.42 (4.82-8.58), 13.03 (8.80-19.30), and 7.48 (4.22-13.28) in low-income men, and 1.87 (0.96-3.66), 4.66 (3.48-6.23), 4.02 (2.15-7.53), and 5.47 (2.79-10.72) in low-income women aged 0-17, 18-44, 45-64, and ≥65 years, respectively. The adjusted AR% of schizophrenia were 75.4%, 84.4%, 92.3%, and 86.6% in low-income males, and 46.6%, 78.5%, 75.1%, and 81.7% in low-income females of above age categories.

Conclusions: Schizophrenia was more common in low-income individuals compared to their non-low-income counterparts. In the low income group, schizophrenia was more common in men than in women under 65.