10/66 Dementia Research Group: recently published survey data for seven Latin America sites

We read with great interest the review by Nitrini et al. on the prevalence of dementia in Latin America recently published in International Psychogeriatrics (Nitrini et al., 2009). Accurate up-to-date figures are essential for policy-making and planning, therefore the review is very welcome. With unfortunate timing, the 10/66 Dementia Research Group's population-based surveys on the prevalence of dementia were published in the Lancet (Llibre Rodriguez et al., 2008a; 2008b) shortly after this review was submitted to International Psychogeriatrics. The 10/66 surveys included seven sites in five Latin American countries: Peru, Cuba, Dominican Republic, Mexico and Venezuela. The studies were all one-phase catchment area surveys, with samples of 2944 in Cuba and between 1904 and 2011 in other countries, giving a total sample size of 10,794. We present in Table 1 the prevalence of dementia according to our cross-culturally validated 10/66 diagnosis and according to DSM-IV criteria, in each of the Latin American sites, using the same age group stratification as per Nitrini's review. We also present the pooled estimates for each age group. The 10/66 estimates are in general more homogenous than those presented in the review, but similar to the overall pooled estimate. DSM-IV prevalence is lower. We have attributed this discrepancy to an under-reporting of cognitive decline and social/occupational impairment by relatives, particularly in rural and least developed regions (Llibre Rodriguez et al., 2008b). We have shown that, at least for Cuba, the 10/66 Dementia Diagnosis agreed better than the DSM-IV with a clinician gold standard diagnosis, as a high proportion of Clinical Dementia Rating mild and moderate cases were missed by DSM-IV (Prince et al., 2008).

Table 1. Prevalence of dementia (10/66 and DSM-IV) (%) and 95% CI according to the 10/66 diagnosis and DSM-IV in the 10/66 Dementia Research Group's seven Latin American countries

In summary, our findings broadly support the review's conclusion that the prevalence of dementia may be relatively high in the Latin American region. In the interests of comprehensiveness, we thought it might be helpful to draw the attention of your readers to this further substantial data from the region that has recently become available.