Mild cognitive impairment and dementia in a heterogeneous elderly population: prevalence and risk profile

To describe the demographic, clinical and risk profile of Mild Cognitive Impairment and dementia in a sample of elderly South Africans within a residential setting.

One hundred and forty participants residing in a group of residential homes for the elderly were assessed by psychiatrists and assigned diagnoses of dementia or Mild Cognitive Impairment (MCI). Participants diagnosed with dementia were also offered haematological investigations and a CT scan of the brain.

The sample consisted of 140 participants comprising 46.4% White, 29.3% Coloured, 20% Asian and 4.3% Black participants. There were 97 (69.3%) females and 106 (75.7%) participants had less than 12 years of education. Eleven (7.9%) dementia and 38 (27.1%) MCI cases were diagnosed. Increasing age was associated with cognitive impairment (MCI and dementia) (p=.020) but there was no association between gender and cognitive impairment (p=.165). MCI was significantly associated with a lower education level (p=.036) and no association was found between depression (current-p=.646; past-p=.719) and dementia or MCI. The presence of vascular risk factors (n=140) ranged from 66.4% (hypertension) to 14.3% (stroke). Subjective memory complaints were significantly associated with cognitive impairment (p=.001). Except for the use of the telephone (p=.225) and the television (p=.08), impairment in all domains of instrumental activities of daily living that were assessed were significantly associated with a dementia diagnosis.

The study showed that cognitive impairment was associated with increasing age and low education levels. The presence of vascular risk factors places this population at risk for future cognitive decline.