Potential for dementia prevention in Latin America and Africa based on population-attributable fraction estimates – Authors' reply
Authors: Naaheed Mukadam, Andrew Sommerlad, Jonathan Huntley, Gill Livingston
Journal: The Lancet Global Health (2019)

We thank Deborah Oliveira and Cleusa Ferri for their interest in our Article on potentially modifiable risk factors in low-income and middle-income countries (LMICs).1Mukadam N Sommerlad A Huntley J Livingston G Population attributable fractions for risk factors for dementia in low-income and middle-income countries: an analysis using cross-sectional survey data.Lancet Glob Health. 2019; 7: e596-e603Summary Full Text Full Text PDF PubMed Scopus (84) Google Scholar We agree that data from Africa is scarce in many such studies and welcome their study on population attributable fractions (PAF) in Portugal, Brazil, and Mozambique. In their Correspondence, Oliveira and Ferri comment on the discrepancy between our estimates of PAF in other Latin American countries and their lower estimate in Brazil. As we acknowledge in our Article, each country has a unique risk profile so we would expect differences in estimates. Additionally, Oliveira and Ferri estimated PAF for seven as opposed to nine risk factors, so one would expect their estimates to be lower, especially as one of the omitted risk factors was hearing loss, which has a high prevalence and high relative risk for dementia so would be expected to contribute significantly to an overall PAF estimate. In their Correspondence they further suggest that our higher estimate might be due to the possibility that the 10/66 dementia diagnosis protocols overestimate dementia prevalence. If this were the case, this would not affect the PAF, which is purely based on prevalence of the risk factor for dementia (not the prevalence of dementia) and the relative risk associated with it. We used previously published estimates of relative risks2Livingston G Sommerlad A Orgeta V et al.Dementia prevention, intervention, and care.Lancet. 2017; 390: 2673-2734Summary Full Text Full Text PDF PubMed Scopus (2366) Google Scholar and did not calculate them using 10/66 data. We agree with them that further efforts to explore differences and clarify the potential for dementia prevention in LMICs are needed. We also welcome further investigation into other potentially modifiable risk factors for dementia and, particularly, where LMICs are included in considerations. We declare no competing interests. Population attributable fractions for risk factors for dementia in low-income and middle-income countries: an analysis using cross-sectional survey dataThe dementia prevention potential in India, China, and this sample of Latin American countries is large, and greater than in high-income countries. Less education in early life, hypertension, hearing loss, obesity, and physical inactivity have particularly high PAFs and could be initial targets for dementia prevention strategies. Full-Text PDF Open AccessPotential for dementia prevention in Latin America and Africa based on population-attributable fraction estimatesWe read with interest the study by Mukadam and colleagues1 in The Lancet Global Health, which reported population-attributable fractions (PAFs) for nine risk factors for dementia, based on data from the 10/66 Dementia Research Group studies carried out in eight low-income and middle-income countries (LMICs). We also welcome the commentary by Walker and Paddick,2 highlighting the scarcity of data from Africa and suggesting a cautious approach to using PAF, especially given that the PAFs are based on self-reported cross-sectional data in 10/66, and that the number of cases of dementia may be overestimated in this cohort. Full-Text PDF Open AccessPotential for dementia prevention in Latin America and Africa based on population-attributable fraction estimatesIn The Lancet Global Health, Mukadam and colleagues1 presented an important and useful analysis of data from India, China, and six Latin American countries in which they considered the population attributable fraction (PAF) for nine dementia risk factors.1 The risk factors they considered were low educational attainment, hearing loss, hypertension, obesity, smoking, depression, physical inactivity, social isolation, and diabetes. This study provides important evidence for putative intervention targets that could decrease the burden of dementia in low-income and middle-income countries (LMICs). Full-Text PDF Open Access