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Background: A growing body of evidence suggests that depression is related to dementia in older adults. Previous research has been done in high-income countries and there is a lack of studies in low- and middle income countries (LMICs)., Objective: To examine the relationship between depressive symptoms and incidence of dementia in a population-based study of older adults in Latin America., Methods: The study is a part of the 10/66 Dementia Research Group's population survey and includes 11,472 older adults (baseline mean age 74 years) from Cuba, Dominican Republic, Mexico, Peru, Puerto Rico, and Venezuela. The baseline examinations were done in 2003-2007 and the follow-up examinations 4 years later. Semi-structured psychiatric interviews gave information about ICD-10 depression and sub-syndromal depression (i.e., ≥4 depressive symptoms) at baseline. Information on dementia were collected at the follow-up examination. Competing risk models analyzed the associations between depression and incidence of dementia and the final model were adjusted for age, sex, education, stroke, and diabetes. Separate analyses were conducted for each site and then meta-analyzed by means of fixed effect models., Results: At baseline, the prevalence of depression was 26.0% (n = 2,980): 5.4% had ICD-10 depression and 20.6% sub-syndromal depression. During the follow-up period, 9.3% (n = 862) developed dementia and 14.3% (n = 1,329) deceased. In the pooled analyses, both ICD-10 depression (adjusted sub-hazard ratio (sHR) 1.63, 95% confidence interval (CI) 1.26-2.11) and sub-syndromal depression (adjusted sHR 1.28, 95% CI: 1.09-1.51) were associated with increased incidence of dementia. The Higging I2 tests showed a moderate heterogeneity across the study sites., Conclusion: Our findings suggest that late-life depression is associated with the incidence of dementia in LMICs in Latin America, which support results from earlier studies conducted in high-income countries.

Background: Chronic obstructive pulmonary disease (COPD) is a major disease burden which accounts for 5% of all deaths globally, with most of those (>90%) occurring in lower to middle income countries (LMIC). It is also emerging as an important modifiable dementia risk factor., Objective: To address the knowledge gap surrounding the nature of the associations between COPD, dementia, and mortality, and the geographical variation of those associations in LMIC., Methods: Data from the 10/66 study surveying 15,394 participants (mean age 74 years, 62% female) across 8 countries was used to estimate the prevalence of self-reported COPD and its association with incident dementia and premature death. Proportional sub-hazards models using a cumulative incidence function were applied to identify the probability of incident dementia onset given the risk of premature death, with estimates pooled across countries via random effect meta-analysis., Results: Over the 3-year follow-up, almost 10% of participants developed dementia and 14% were deceased. COPD was not significantly associated with dementia incidence except in Cuba. However, fully adjusted models indicated that individuals with COPD were at a 28% increased risk of premature death, a trend present across most countries when analyzed individually., Conclusion: The link between COPD and dementia is currently somewhat different and weaker in LMIC than in developed countries. This may be because premature death in the populations studied mask the development of clinical dementia. Given the global trend toward increased life expectancy, it is critical that the disease burden associated with COPD be addressed without delay if a further rise in dementia prevalence associated with COPD is to be avoided in LMIC.

Background: Western diets are associated with obesity, vascular diseases, and metabolic syndrome and might increase dementia risk in later life. If these associations are causal, those low- and middle-income countries experiencing major changes in diet might also see an increasing prevalence of dementia., Objective: To investigate the relationship of dietary supply and the prevalence of dementia in mainland China, Hong Kong, and Taiwan over time using existing data and taking diagnostic criteria into account., Methods: Estimated total energy supply and animal fat from the United Nations was linked to the 70 prevalence studies in mainland China, Hong Kong, and Taiwan from 1980 to 2012 according to the current, 10 years, and 20 years before starting year of investigation. Studies using newer and older diagnostic criteria were separated into two groups. Spearman's rank correlation was calculated to investigate whether trends in total energy, animal fat supply, and prevalence of dementia were monotonically related., Results: The supply of total energy and animal fat per capita per day in China increased considerably over the last 50 years. The original positive relationship of dietary supply and dementia prevalence disappeared after stratifying by newer and older diagnostic criteria and there was no clear time lag effect., Conclusion: Taking diagnostic criteria into account, there is no cross-sectional or time lag relationship between the dietary trends and changes in dementia prevalence. It may be too early to detect any such changes because current cohorts of older people did not experience these dietary changes in their early to mid-life.