Incidence of dementia and association with APOE genotype in older Cubans

Juan J. Llibre Rodríguez,Juan C. Llibre-Guerra,Cleusa P. Ferri,Beatriz Marcheco Teruel,Adolfo Valhuerdi Cepero,Isis Y. Sanchez Gil,Jorge J. Llibre-Guerra,Martin Prince,Ana M. López Medina

doi:10.1590/s1980-57642014dn84000009

Abstract

ObjectiveIn an admixed population of older Cubans, the incidence and association of APOE and sociodemographic risk factors with dementia incidence was estimated.MethodsA single-phase survey (baseline) of all over 65-year-olds residing in seven catchment areas in Cuba (n=2944) was conducted between 2003 and 2007. Dementia diagnosis was established according to DSM-IV and 10/66 criteria. APOE genotype was determined in 2520 participants. An incidence wave was conducted 4.5 years after cohort inception in order to estimate incidence and associations with sociodemographic risk factors of the APOE ε4 genotype.ResultsThe incidence rate of DSM IV dementia was 9.0 per 1000 person-years (95% CI 7.2-11.3) and of 10/66 dementia was 20.5 per 1000 person-years (95% CI, 17.6-23.5). Older age, a family history of dementia and APOE ε4 genotype were independent risk factors for incident 10/66 dementia. APOE genotype was associated cross-sectionally with dementia prevalence, but the effect on the incidence of dementia was attenuated, and only apparent among those in the youngest age group.ConclusionThe incidence of dementia in the older Cuban population is relatively high and similar to levels reported in Europe and North-America. The study showed that the relationship between APOE ε4 and incident dementia is stronger in the younger-old than the older-old and that this change must be taken into account in models of dementia.

Highlights

By 2020, the Americas will have a population of 200 million older adults, with over half living in Latin American and the Caribbean
Cell DNA was extracted and ApoE4 genotype determined by PCR, following the standard protocol for determination of the apolipoprotein E genotype and identification of the three alleles APOE ε2, APOE ε3 and APOE ε4.17 The same protocols for interviews and assessments were employed in both the longitudinal phase of the study and at baseline
There was a high prevalence of cardiovascular risk factors and of chronic non-communicable disease; more than 40% of participants were current smokers, 73.9% of participants had been told that they were hypertensive, 18.5% had received a diagnosis of diabetes, and 7.8% reported a stroke diagnosed by a clinician

Summary

INTRODUCTION

By 2020, the Americas will have a population of 200 million older adults, with over half living in Latin American and the Caribbean. A few incidence studies have been conducted in LMIC, which, generally, report lower incidence rates compared to high-income countries (HIC).[3,4,5]. Cuba is a middle-income country with a highly admixed and rapidly ageing population of 11.3 million. By the year 2020 Cuba will be the country in Latin America with the highest proportion of older adults (25% aged 60 years and over).[9]. The main aims of this study were to describe dementia incidence and the association between APOE ε4 carriers and sociodemographic risk factors with dementia incidence among older Cubans

METHODS

RESULTS

DISCUSSION