Browsing by Subject "Geriatric Medicine"

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    Open Access
    The associations between plasma homocysteine, vitamin B12, folate, the Apolipoprotein E genotype and Alzheimer's Disease
    (2014) Mohamed, Ilhaam; Combrinck, M I
    Background: Alzheimer's disease (AD), the commonest form of dementia, affects people in both industrialised and developing countries. Risk factors for the development of AD include age, the presence of the Apolipoprotein ε4 allele, low vitamin B₁₂ and folate levels, and elevated plasma homocysteine concentrations. Most research involving the associations between these risk factors and AD have been conducted in Europe and North America. We know little about AD and its risk factors in a low to middle income country like South Africa, where nutrition is poor and the background population ApoE ε4 allelic frequency is high. Objective: In this prospective observational study, I wished to determine the relationships between plasma homocysteine, vitamin B₁₂, folate, ApoE ε4 status and cognition in a sample of older persons from the greater Cape Town metropolitan area of the Western Cape region of South Africa. Methods: Cognitively healthy controls and AD participants, diagnosed using NINCDS-ADRDA criteria, were recruited from the community. The study had both cross-sectional and longitudinal components. Cross-sectionally, I related non-fasting plasma homocysteine concentrations, vitamin B₁₂ levels, folate concentrations and the ApoE ε4 genotype to scores from a battery of cognitive tests including the Mini Mental State Examination (MMSE), the Cambridge Cognitive Examination (CAMCOG) and the Learning Subscale score of the CAMCOG. In the longitudinal analysis, I tested whether baseline plasma homocysteine concentrations related to cognitive decline one year after the initial assessment. Results: One hundred and thirteen participants were recruited: 60 controls and 53 AD participants. Plasma homocysteine levels increased with age (rs= 0.418, p<0.001) and were inversely related to cognitive scores in all participants. Homocysteine concentrations were inversely related to vitamin B₁₂ and folate in all study participants (vitamin B₁₂rₛ= -0.47, p<0.001, folaterₛ=-0.33, p=0.001). Homocysteine was inversely related to cognition but, in a regression model, this relation was confounded by the effects of age and years of education. Another regression model showed that vitamin B₁₂ and age independently predicted cognitive scores. There were more ApoE ε4 carriers in the AD group compared with controls and ε4 carrier status was significantly associated with AD. The ApoE ε4 allele modified the relationship between homocysteine and cognition. The association between homocysteine and cognition was strong in ApoE ε4 carriers (e.g. MMSE,rₛ=0.33, p=0.003), but absent in ε4 non-carriers. High baseline homocysteine concentrations did not predict cognitive decline 1 year later. Conclusions: These findings, the first from an African low to middle income country, are consistent with those from studies in industrialised countries. Plasma homocysteine levels increased with age and were inversely related to vitamin B₁₂ and folate. The ApoE ε4 allele strengthened the association between homocysteine and cognition, probably through mechanisms that increase neuronal susceptibility to homocysteine toxicity. My study supports the idea that homocysteine-lowering therapy can reduce the risk of developing AD or slow the progression of the disease.
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    Dementia Subtypes, Cognitive Decline and Survival Among Older Adults Attending a Memory Clinic in Cape Town, South Africa: A Retrospective Study
    (2023) Ssonko, Michael; Combrinck, Marc; Kalula, Sebastiana; Naganathan, Vasi
    Background: There are no published longitudinal studies from Africa of people with dementia seen in memory clinics. The aim of this study was to determine the proportions of the different dementia subtypes, rates of cognitive decline, and predictors of survival in patients diagnosed with dementia and seen in a memory clinic. Methods: Data were collected retrospectively from clinic records of patients aged ≥60 seen in the memory clinic at Groote Schuur Hospital, Cape Town, South Africa over a 10-year period. Diagnostic and Statistical Manual of Mental Disorders (DSM–5) criteria were used to identify patients with Major Neurocognitive Disorders (dementia). Additional diagnostic criteria were used to determine the specific subtypes of dementia. Linear regression analysis was used to determine crude rates of cognitive decline, expressed as mini-mental state examination (MMSE) points lost per year. Changes in MMSE scores were derived using mixed effects modelling to curvilinear models of cognitive change, with time as the dependent variable. Multivariable cox survival analysis was used to determine factors at baseline that predicted mortality. Results: Of the 165 patients who met inclusion criteria, 117(70.9%) had Major Neurocognitive Disorder due to Alzheimer's disease (AD), 24(14.6%) Vascular Neurocognitive Disorder (VND), 6(3.6%) Dementia with Lewy Bodies (DLB), 5(3%) Parkinson disease-associated dementia (PDD), 3(1.8%) fronto-temporal dementia, 4(2.4%) mixed dementia and 6(3.6%) other types of dementia. The average annual decline in MMSE points was 2.2(DLB/PDD), 2.1(AD) and 1.3(VND). Cognitive scores at baseline were significantly lower in patients with 8 compared to 13 years of education and in those with VND compared with AD. Factors associated with shorter survival included age at onset greater than 65 (HR=1.82, 95% C.I. 1.11, 2.99, p=0.017), lower baseline MMSE (HR=1.05, 95% C.I. 1.01, 1.10, p=0.029) , Charlson's comorbidity scores of 3 to 4 (HR=1.88, 95% C.I. 1.14, 3.10, p=0.014), scores of 5 or more (HR=1.97, 95% C.I. 1.16, 3.34, p=0.012) and DLB/PDD (HR=3.07, 95% C.I. 1.50, 6.29, p=0.002). Being female (HR=0.59, 95% C.I.0.36, 0.95, p=0.029) was associated with longer survival. Conclusions: Knowledge of dementia subtypes and survival outcomes will help inform decisions about patient selection for potential future therapies and for planning dementia services in resource-poor settings.
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    Medication in the elderly : an outpatient survey
    (1987) Davis, Christopher Karl; Meiring, Peter
    The aging process is associated with disease states that may be painful, disabling and life-threatening. Elderly patients frequently have more than one disorder and appropriate pharmacotherapy may result in polypharmacy (treatment with multiple drugs). This situation, combined with age-related alterations in the handling of and sensitivity to drugs, predisposes older patients to adverse drug reactions (ADR's). This study was undertaken to assess the actual risks and potential benefits of long-term polypharmacy in the management of elderly hospital out-patients. A particular aim was to get some indication of whether or not polypharmacy was justifiable in the study population. Accordingly, the medical records of 132 ambulatory patients, 70 years of age and over, who had been attending the general out-patient department of a large teaching hospital for a period of twelve months or longer, were retrospectively examined. The patient's age, diagnoses, prescribed medication, ADR's and clinical therapeutic benefit were assessed, recorded and analyzed. The average patient age in the sample studied was 77,6 years. 71% of the sample were females. 419 disorders were identified, giving an average of 3,17 per patient. 603 drugs were prescribed in total, giving an average of 4, 57 per patient. There was no statistically significant association between increasing age and the number of diagnoses per patient or the number of drugs prescribed. Medication was felt to be therapeutically effective in 63% of the patients, whilst an ADR was noted in 14% of the sample. There was no statistically significant difference in the age, number of diseases or number of drugs prescribed between the total group, the ADR group and the non-ADR group. These parameters were therefore not useful in identifying those patients more likely to experience an ADR. The apparent effectiveness of the medication prescribed and the relatively low incidence of ADR' s in the group studied suggests that appropriate and judicious multiple drug therapy can benefit many elderly ambulatory patients and therefore polypharmacy could be regarded as permissible in this context. Apart from these observations, this dissertation also includes recommendations on ways to minimize the incidence of ADRs in the elderly, and areas for ongoing research in this field are identified.
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    The prevalence of Legionella and mycoplasma seropositivity in the elderly in Cape Town
    (1997) Muller, Greta; Louw, Stephen; Roditi, Denise
    Background: Community acquired pneumonia causes 5,9% of deaths in elderly South Africans. Mortality rates are increased in those in whom initiation of therapy with an appropriate agent has been delayed. Whereas Mycoplasma pneumoniae and Legionella pneumophila are sensitive to the macrolides or tetracycline, they do not respond to the currently recommended first-line agents for community acquired pneumonia, penicillin or a cephalosporin. It was therefore necessary to assess the prevalence of exposure to these 2 organisms in the elderly in order to determine whether a modification in the recommendations may be justified. Methods: Study population and survey: Subjects were residents of 4 old age homes in Cape Town who were older than 60 years and willing to participate. Written consent was obtained, a demographic and medical history questionnaire was completed, and a sample of blood was drawn. Laboratory methods: The indirect fluorescent antibody tests (Zeus Scientific Inc, New Jersey, USA) were used to detect the presence of antibodies to Mycoplasma pneumoniae and Legionella pneumophila. Results: The participation rate in this study was high, with 88,4% (677/766) taking part. Seropositivity for both of these organisms was low. There were 17 participants (2, 51 %) with antibodies to mycoplasma (IgG only in 8, IgM only in 1, and both IgG and IgM in the remaining 8). Titres were low with only 1 IgM titre of 16, and only 3 IgG titres of 64. Antibodies to Legionella were demonstrated in only 9 participants (1,33%). All these titres were 128 or above. Conclusions: It is concluded that first-line therapy for community acquired pneumonia should adhere to the current guidelines published by the South African Pulmonology Society. There is no indication for the routine use of agents active against Legionella or mycoplasma. Clearly, these antibiotics should be introduced if specific pointers to infection with one of these organisms are found. Because of the low seropositivity rate, the indirect fluorescent antibody test for these 2 agents has a high specificity in this population. This may be of use in making a diagnosis in an acute infection Further studies are required to elucidate the immunological response to these organisms in elderly persons. A further survey should be done to determine the seropositivity rate to these agents in community dwelling elderly.