Neighborhood Deprivation Increases Mortality Risk in Schizophrenia, Bipolar Disorder

Neighborhood deprivation is associated with mortality risk among individuals with schizophrenia and bipolar disorder (BD), according study findings published in the journal Bipolar Disorders.

This nationwide study included data from all individuals aged 30 years and older diagnosed with schizophrenia (n=34,544) or BD (n=64,035) living in Sweden between 1997 and 2017. Risk for all-cause and cause-specific mortality were evaluated on the basis of individual characteristics and neighborhood deprivation. The Neighborhood Deprivation Index was calculated based on address and included educational status, income, employment, and welfare assistance characteristics. Low educational status was defined as less than 10 years of formal education and low income as less than 50% of individual mean income established by Statistics Sweden.

The schizophrenia and BD cohorts comprised 54.7% and 39.8% men; 21.7% and 25.2% were aged 30-39 years, 25.3% and 25.4% aged 40-49 years, and 23.0% and 21.7% were aged 50-59 years, respectively. Among patients in the schizophrenia group, 4621 had low, 17,814 moderate, and 12,109 high neighborhood deprivation. Within the BD group 13,757, 36,945, and 13,333 patients had low, moderate, and high deprivation levels, respectively.

Mortality occurred among 35.3% of individuals with schizophrenia and 20.4% of individuals with BD. The 2 most common causes of death were cancer and coronary heart disease (CHD).

Other common causes of death among the schizophrenia group were:

• psychiatric disorders;
• chronic obstructive pulmonary disease (COPD); and
• stroke.

Other common causes of death among the BD group were:

• suicide;
• psychiatric disorders; and
• stroke.

In schizophrenia, mortality was associated with:

• COPD (adjusted hazard ratio [aHR], 1.55; P <.001);
• alcoholism or related liver disorders (aHR, 1.33; P <.001);
• male gender (aHR, 1.32; P <.001);
• low educational attainment compared with ≥12 years (aHR, 1.24; P <.001);
• low (HR, 1.21; P <.001) or middle-low (aHR, 1.13; P <.001) family income compared with high income;
• CHD (aHR, 1.19; P <.001);
• high neighborhood deprivation compared with low deprivation (aHR, 1.18; P <.001); and
• increasing age (aHR, 1.08; P <.001).

Similar trends were observed in BD.

Compared with patients with low neighborhood deprivation, patients living in high neighborhood deprivation with schizophrenia were at increased risk for mortality from breast cancer (hazard ratio [HR], 2.08), lung cancer (HR, 1.48), stroke (HR, 1.39), CHD (HR, 1.37), COPD (HR, 1.30), and cancer (HR, 1.28).

In BD, cause-specific mortality risks were higher for those with high neighborhood deprivation related with COPD (HR, 1.93), CHD (HR, 1.70), diabetes (HR, 1.69), suicide (HR, 1.34), cancer (HR, 1.29), and psychiatric disorders (HR, 1.26).

The findings of this study may have been confounded by other residential disparities, such as access to medical or psychiatric services.

“The results indicate that neighborhood deprivation is an important factor to consider in order to decrease total and cause-specific mortality among patients with schizophrenia and bipolar disorder. This underscores the need for determining the possible pathways between neighborhood deprivation and mortality among patients with schizophrenia and bipolar disorder. Such research may result in more efficient preventive strategies and health policies,” concluded the researchers.