Plasma homocysteine—a marker of vascular disease in elderly patients with mental illness
Introduction
Many studies have reported significantly higher plasma tHcy in elderly patients with mental illness than in control subjects [1], [2], [3], [4], [5]. Plasma tHcy concentration is a function of a complex interaction between age and multiple genetic and environmental factors [6]. Thus, there are many different determinants of plasma tHcy concentration. The most important are cobalamin/folate status, renal function, and age [6].
Since many clinical and epidemiological studies published during the last 3 decades show that even mild hyperhomocysteinemia is associated with vascular disease [6], [7], [8], [9], [10], [11], we have investigated elderly patients with organic and non-organic mental disease with regard to the presence of vascular disease [1], [12], [13]. Briefly, our findings in these studies [1], [12], [13] showed that patients with mental illness and any forms of vascular disease had significantly higher plasma tHcy concentration than patients without vascular disease and that elevated plasma tHcy in mental illness was mainly associated with the presence of vascular disease and not related to the specific psychogeriatric diagnosis. The high frequency of comorbidity of vascular disease and mental illness might indicate a possibility to prevent and treat organic and non-organic mental disease by actively counteracting vascular disease in these patients.
Plasma tHcy concentration might be a marker for vascular disease in elderly patients with mental illness. In the present study we have investigated the influence of renal function and cobalamin/folate status on the association between plasma tHcy level and vascular disease in a population of consecutively enrolled elderly patients with mental illness. The relation of plasma tHcy concentration and its determinants to vascular disease was investigated by logistic regression analyses in all enrolled patients (Group I, n = 448) and in a subgroup of these patients (Group II, n = 359) where all those with signs of cobalamin/folate deficiency and/or impaired renal function (as judged by serum cystatin C and/or serum creatinine) were excluded. Furthermore, the relation of plasma tHcy concentration and its determinants to vascular disease was also investigated in demented and non-demented patients.
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Study populations
The present study population consisted of 448 patients consecutively enrolled (185 males and 263 females, 75 (55–87) years, median and 10–90th percentiles) who were referred to the Psychogeriatric Department at Lund University Hospital for diagnostic assessments and treatment. Patients on any kind of ongoing vitamin substitution were excluded from the study. The diagnosis was based on psychiatric, neurological, somatic, and laboratory investigations, psychometric testing, measurements of
Results
Table 1 presents the distribution of age, biochemical variables, and the number of patients with and without vascular disease in all enrolled patients (Group I) and in the subgroup of patients where patients with cobalamin/folate deficiency (8 patients) and impaired renal function (81 patients) have been excluded (Group II). Concentrations of plasma tHcy, serum cystatin C, serum cobalamin, serum folate, and serum creatinine were determined in all patients. Plasma tHcy was lower in patients in
Discussion
Many studies have shown that a significant association exists between plasma tHcy levels and vascular disease [6], [7], [8], [9], [10], [11]. Furthermore cobalamin/folate status, renal function and age have been shown to be the major determinants of plasma tHcy concentration [6]. Several mechanisms have been suggested to explain the homocysteine-induced vascular damage [6], [11], among others cobalamin/folate deficiencies. Plasma tHcy is considered to reflect the functional status of cobalamins
Acknowledgments
This work was supported by grants from the Swedish Medical Research Council (grant no. 3950), the Alzheimer Foundation Sweden, the Sjöbring Foundation, the Swedish Heart Lung Foundation, the Albert Påhlsson Foundation and the County Council of Malmöhus.
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