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Incidence of and Risk Factors for Dementia in the Ibadan Study of Aging
Author(s) -
Gureje Oye,
Ogunniyi Adesola,
Kola Lola,
Abiona Taiwo
Publication year - 2011
Publication title -
journal of the american geriatrics society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.992
H-Index - 232
eISSN - 1532-5415
pISSN - 0002-8614
DOI - 10.1111/j.1532-5415.2011.03374.x
Subject(s) - medicine , dementia , nigerians , incidence (geometry) , hazard ratio , gerontology , demography , cohort , cohort study , confidence interval , physics , disease , optics , sociology , political science , law
OBJECTIVES: To describe the incidence of dementia in a representative sample of elderly Yoruba Nigerians and provide information about the risk factors. DESIGN: In‐home face‐to‐face assessments conducted on a community cohort selected using multistage clustered sampling of households, with baseline between November 2003 and August 2004 (n=2,149) and follow‐up approximately 39 months later (n=1,408). SETTING: Eight contiguous, predominantly Yoruba‐speaking states in Nigeria. PARTICIPANTS: Persons aged 65 and older free of dementia at baseline (n=1,225). MEASUREMENTS: Dementia was ascertained using two instruments: the 10‐Word Delayed Recall Test and the Clinician Home‐based Interview to assess Function, both with demonstrated validity and cultural applicability. RESULTS: At 3‐year follow‐up, 85 participants had developed dementia. With a total 3,888 risk years for the sample, the estimated incidence of dementia was 21.85 per 1,000 person‐years (95% confidence interval=17.67–27.03). Compared with men, the age‐adjusted hazard ratio (HR) for women was 2.12 ( P =.002). Incidence increased linearly with age such that, compared with participant aged 65 to 74, the HR, adjusted for sex, for participants aged 75 to 84 was 2.84 ( P <.001) and for those aged 85 and older was 4.13 ( P <.001). Greater incidence of dementia was found with more‐rural residence and poorer economic status. Participants with poor social engagement at baseline were at significantly greater risk of incident dementia. CONCLUSION: Incident dementia in Yoruba Nigerians is higher than previously reported. Indices of social isolation are risk factors for incident dementia in this population.