Drought and cognitive function in older adults: results from the Mexican health and aging study

Drought represents a climate-related exposure impacting communities across the globe. Drought exposure has been linked with adverse human health, including poorer mental health and nutritional outcomes. It is unknown whether drought exposure relates to cognitive function. We evaluated cognitive function in adults aged 50+ by length of exposure to a major drought occurring between 2010 and 2012 in Mexico. We used individual-level data from the Mexican Health and Aging Study (n = 6988), drawing from pre-drought (2003) and post-drought (2012) waves, linked with monthly municipality-level information from the Mexican Drought Monitor on drought exposure produced by the Mexican National Water Commission. We employ multilevel regression models, with inverse probability of attrition weighting, to examine how length of drought exposure is related with post-drought cognition, controlling for pre-drought cognition and nutritional/mental health covariates. Whether quantified as the total number of months of drought exposure or the longest streak of consecutive months of drought exposure, longer drought exposure was negatively related with Verbal Learning and Verbal Recall performance over time but exhibited an inverse U-shaped association with Verbal Fluency. Findings were similar when using various thresholds of drought severity (i.e., severe to exceptional drought). Associations between drought and cognition were not explained by nutrition or mental health covariates. Public health and policy efforts should seek to build community-level resilience and infrastructure to enable effective coping with persistent environmental stressors, especially among older adults, to mitigate effects on health and well-being.