Total serum homocysteine in senile dementia of Alzheimer type

✍ Scribed by Andrew McCaddon; Gareth Davies; Peter Hudson; Stephen Tandy; Howard Cattell

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 129 KB
• Volume: 13
• Category: Article
• ISSN: 0885-6230
• DOI: 10.1002/(sici)1099-1166(199804)13:4<235::aid-gps761>3.0.co;2-8

✦ Synopsis

Objective. The main hypothesis was that subtle vitamin B12 de®ciencies occur more commonly in senile dementia of Alzheimer type (SDAT) than in healthy elderly individuals, and may be revealed by elevated total serum homocysteine (tHcy). A subsidiary hypothesis was that such de®ciencies would be nutritionally independent as determined by retinol binding protein (RBP).

Design. A prospective case-controlled survey.

Setting. A Welsh urban psychogeriatric assessment centre and local general practice.

Patients. Thirty patients, aged 65 or over, seen consecutively in 1994 with features compatible with DSM-III-R criteria for primary degenerative dementia of Alzheimer type and 30 cognitively intact age-matched control subjects.

Measures. Diagnosis was assessed using the CAMDEX. Cognitive scores were evaluated with the CAMCOG scale for patients and MMSE scores for control subjects. tHcy was measured using high performance liquid chromatography (HPLC), and RBP assayed by a radial immunodiusion method.

Results. Patients had a highly signi®cant elevation of tHcy compared with controls (p 5 0.0001). Multiple regression highlighted the interrelated eects of tHcy and total serum cobalamin on cognitive scores. RBP did not dier between groups. Macrocytosis was absent, and neutrophil hypersegmentation uncommon, in hyperhomocysteinaemic patients.

Conclusions. SDAT patients have signi®cantly elevated tHcy. This is independent of RBP determined nutritional status. `Classical' haematological changes of cobalamin or folate de®ciency are poor predictors of tHcy in these patients. Aberrant cobalamin tissue delivery appears to contribute to SDAT cognitive decline. Relative contributions of other tHcy determinants require further investigation.