Malaria, mental disorders, immunity and their inter-relationships - A cross sectional study in a household population in a health and demographic surveillance site in Kenya

BACKGROUND: Both malaria and mental disorders are associated with immune changes. We have previously reported the associations between malaria and mental disorders. We now report associations between malaria, mental disorders and immunity. METHODS: A household survey of malaria, mental disorders and immunity was conducted in a health and demographic surveillance system's site of 70,000 population in an area endemic for malaria in western Kenya. A random sample of 1190 adults was selected and approached for consent, blood samples and structured interview. FINDINGS: We found marginally raised CD4/CD3 ratios of participants with malaria parasites, but no difference in CD4/CD3 ratios for participants with common mental disorder (CMD) or psychotic symptoms. People with psychotic symptoms had increased levels of IL-6, IL-8, and IL-10, and lower levels of IL-1beta. People with CMD had higher levels of IL-8 and IL-10. People with malaria had higher levels of IL-10 and lower levels of TNF-alpha. At the bivariate level, CMD was associated with log TNF-α levels using unadjusted odds ratios, but not after adjusting for malaria. Psychotic symptoms were associated with log IL-10 and log TNF-α levels at the bivariate level while in the adjusted analysis, log TNF-α levels remained highly significant.. INTERPRETATION: This is the first population based study of immune markers in CMD and psychotic symptoms, and the first to examine the 3 way relationship with malaria. Our findings suggest that TNF-α may mediate the relationship between malaria and CMD. FUND: The study was funded by UK Aid, Department for International Development, Kenya office.