Establishing associated risk factors, including fungal and parasitic infections among Malaysians living with schizophrenia

Abstract

The aetiology of schizophrenia is multifactorial, and the identification of its risk factors are scarce and highly variable. A cross-sectional study was conducted to investigate the risk factors associated with schizophrenia among Malaysian sub-population. A total of 120 individuals diagnosed with schizophrenia (SZ) and 180 non-schizophrenic (NS) individuals participated in a questionnaire-based survey. Data of complete questionnaire responses obtained from 91 SZ and 120 NS participants were used in statistical analyses. Stool samples were obtained from the participants and screened for gut parasites and fungi using conventional polymerase chain reaction (PCR). The median age were 46 years (interquartile range (IQR) 37 to 60 years) and 35 years (IQR 24 to 47.75 years) for SZ and NS respectively. Multivariable binary logistic regression showed that the factors associated with increased risk of SZ were age, sex, unemployment, presence of other chronic ailment, smoking, and high dairy consumption per week. These factors, except sex, were positively associated with the severity of SZ. Breastfed at infancy as well as vitamin and supplement consumption showed a protective effect against SZ. After data clean-up, fungal or parasitic infections were found in 98% (39/42). of SZ participants and 6.1% (3/49) of NS participants. Our findings identified non-modifiable risk factors (age and sex) and modifiable lifestyle-related risk factors (unemployment, presence of other chronic ailment, smoking, and high dairy consumption per week) associated with SZ and implicate the need for medical attention in preventing fungal and parasitic infections in SZ.

Figure 1

Flow chart for recruitment of patients for the administration of questionnaire and stool collection for fungal and parasitic screening in individuals with Schizophrenia (SZ).

Figure 2

Flow chart for recruitment of patients for the administration of questionnaire and stool collection for fungal and parasitic screening in individuals without Schizophrenia (NS).

Figure 3

UpSet diagram illustrates the number of mixed infections in SZ patients (n = 42). The bar graph to the right indicate the number of infections screened in patient stool samples by pathogen group. The connected nodes indicate the concurrent infection by different pathogen group.

Figure 4

UpSet diagram illustrates the number of infections in NS patient stool samples (n = 49). The bar graph to the right indicate the number of infections screened in patient stool samples by pathogen group.

Figure 5

Percentage of fungal or parasitic infection by severity of schizophrenia. The figure shows the prevalence of fungal or parasitic infection among SZ and NS cohort group after the filtration of questionnaires. All NS individuals are categorized as the healthy group whereas SZ individuals are categorized into mild, moderate, and severe groups.