Smoking is one of the top natural causes of death in patients with schizophrenia, according to a new study.
Researchers found that schizophrenia patients were 4.7 times more likely to die within the 6.2 years of follow-up if they were smokers.
But in half the patients with immune conditions, diabetes was also a leading cause of death. Nearly one third of patients with schizophrenia also had urinary tract infections.
“These findings underscore the life-shortening effects of smoking in this population and the urgent need to more vigorously promote smoking cessation,” said study author Faith Dickerson of the Sheppard Pratt Health System, Baltimore.
Of 517 participants in the study, six died of unnatural causes and 25 died of natural causes, primarily heart-related conditions. Other natural causes were respiratory, neoplastic, infectious, blood disease, and mental (delirium, in one patient).
Evidence of exposure to viruses was also associated with death, including the presence of antibodies to Epstein–Barr virus (EBV) and to Herpes Simplex virus type 1 (HSV-1). These were linked to a 1.13- and 1.22-fold risk increase, respectively.
The researchers note that the association with HSV-1 infection is a new finding, and hypothesize that it could be related to cognitive function. The researchers had previously found a strong association between HSV-1 and cognitive functioning in schizophrenia patients — a factor that they did not adjust for in the current study.
An underlying EBV infection, on the other hand, could be reactivated and have a harmful effect on patients with compromised immune function, they suggest.
Problems concerning the immune system were found in 20 percent of patients who died compared to 4.7 percent of those who did not — raising the risk of death to a significant 4.5-fold increase.
The most common immunologic condition was insulin-dependent diabetes, found in 16 of 33 patients with such conditions.
Cardiovascular problems were most common in survivors as well as in patients who died, and were tied to a 2.5-fold increased mortality risk.
Finally, genitourinary conditions, particularly urinary tract infections, were found in 32 percent of patients who died, compared with 8.6 percent of those who survived — a 4.35-fold increased mortality risk.
“It is of note that urinary tract infections have been found to be highly prevalent in persons with acute psychotic symptoms,” said the researchers.
The study was published in the journal Schizophrenia Research.
Source: Schizophrenia Research