The impact of homocysteine, B12, and D vitamins levels on functional neurocognitive performance in HIV-positive subjects

BACKGROUND: The correlation among high levels of total homocysteine, low levels of B12vitamin, and neurocognitive impairment in HIV negative patients has been the main research topic in some of the latest reviews. The aim of this study was to examine if the alteration of homocysteine, B12 vitamin, and D vitamins plasma levels was present in HIV-positive, and their relationship with cognitive function. METHODS: 57 HIV infected were enrolled and underwent the serum measurement of homocysteine, B12, and D vitamins. The neurocognitive evaluation investigated 5 cognitive domains, through a neuropsychological battery test RESULTS: Homocysteine was found to be elevated in 70.2% of cases, B12 vitamin mean levels were low in 8 participants (14.0%), and 8 patients had D hypovitaminosis (14.0%). Abnormal homocysteine levels were associated with worse performance of verbal fluency (p = 0.003) and worse executive function (Stroop E test p = 0.040). The 25-OH D hypovitaminosis was associated with worse performances in executive functions in three different tests: Stroop E (p = 0.049), Trail B (p = 0.035), and Wais Digit Span (p = 0.042). Pathological levels of B12 Vitamin were also associated to worse performances in executive functions (Trail B Test and Wais Digit Span respectively p = 0.002 and 0.029) and with a lower speed in psychomotor processing (Peg Board Test on dominant hand, p = 0.014). CONCLUSIONS: In this study serum homocysteine, B12, and D vitamin levels are associated with neurocognitive performances; in fact low performance neurocognitive was correlated with hyperhomocysteine and low B12vitamin, and D vitamin levels. Evidence of the alteration of these parameters could facilitate the early identification of a neurocognitive impairment.