Higher Serum Triglyceride Levels in Early-Onset Schizophrenia

To the Editor: Patients with schizophrenia often have disturbances in lipid regulation (1). However, we know of no reports concerning the duration of schizophrenia and serum triglyceride levels. We report findings from a general population study of the Northern Finland 1966 Birth Cohort on the correlation between serum triglyceride levels and the age at onset of schizophrenia. The cohort is an unselected, general population birth cohort ascertained during mid-pregnancy and comprises 12,058 children in the provinces of Lapland and Oulu born alive during 1966 (2). Permission to gather data was obtained from the Ministry of Social and Health and the Ethics Committee of the University of Oulu.

In 1997, the members of the cohort currently living in Northern Finland or in the capital area were invited for a clinical examination. After complete description of the study to the subjects, written informed consent was obtained. Our study group consisted of 31 cohort members (18 men and 13 women) who were older than 16 years, appeared in the Finnish Hospital Discharge Register through the end of 1997, and had a diagnostic code of 295 (ICD-8 or ICD-9) or F20 (ICD-10). All diagnoses were scrutinized and validated for DSM-III-R criteria (3). Serum triglyceride levels were determined after an overnight fast by enzymatic methods.

We found higher triglyceride levels in the 17 patients who were ≤20 years old at the beginning of schizophrenia (mean=1.7, SD=0.7) compared with the 14 patients with later onset (mean=1.4, SD=0.9) or the 5,453 nonhospitalized comparison subjects (mean=1.2, SD=0.7). The Mann-Whitney U test showed a significant difference between the first and third groups (p<0.01), and Pearson’s correlation coefficient showed a negative correlation between the age at onset and the level of serum triglycerides (r=–0.35, p=0.05). One explanation may be a genetic linkage since hypertriglyceridemia may be related to the more severe forms of schizophrenia. On the other hand, cognitive disorders in these patients may lead to a poor diet, and a more prolonged exposure to antipsychotics may further raise triglyceride levels. A recent study demonstrated that both novel and conventional antipsychotics may be associated with dyslipidemia but also that patients are infrequently monitored for these parameters (4). Our finding may imply that patients with early-onset schizophrenia are at special risk for the cardiovascular complications of hypertriglyceridemia, and their serum lipid levels should be monitored regularly as part of their treatment.