Joseph Saenz, Emma Aguila, Laura Tanner, Brian Downer, Jorge Peniche and Rebeca Wong
Introduction and Background
Climate change is increasing the frequency and severity of droughts worldwide, presenting a major threat to human health. Although research has linked drought to poor mental health and food insecurity, its potential impact on cognitive function in older adults has remained largely unknown. This is a critical gap, especially in low- and middle-income countries (LMICs) like Mexico, where the population is aging rapidly and many may rely on rain-fed agriculture for their livelihoods. The study investigated whether exposure to a major drought between 2010 and 2012 was associated with cognitive decline in Mexican adults aged 50 and older, using multiple measures to quantify drought exposure.
Data and Methods
The researchers analyzed 6,988 participants in the Mexican Health and Aging Study (MHAS). They predicted cognitive test scores in a post-drought period (2012) using multiple measures of drought exposure, while controlling for pre-drought (2003) cognitive test scores. Individual records were linked to data from the Mexican Drought Monitor, to calculate the total months and consecutive months of drought exposure participants experienced. The study used multilevel regression models to predict memory, attention, and verbal ability while accounting for factors like age, education, wealth, and pre-drought cognitive ability.
Results
The study found that longer drought exposure was consistently linked to faster cognitive decline, particularly in memory-related tasks.
- Memory Loss: Controlling for pre-drought cognitive scores, with every six additional months of drought exposure, participants’ performance in memory tasks (Verbal Learning and Verbal Recall) was lower, indicating measurably faster cognitive decline.
- Verbal Fluency: The ability to express words such as animal names upon command showed an inverted U-shaped relationship. People with 6–11 months of drought exposure performed better than those with very few or many months of exposure, suggesting that, although mild stress or lifestyle adaptations might temporarily stimulate the brain, persistent drought (i.e., 12+ months) may lead to impairment.
- Vulnerable Groups: The negative effects of drought on cognition were most pronounced in women and the oldest participants.
- Direct Impact: The potential cognitive impacts of drought were not fully explained by changes in nutrition or mental health. This suggests one of two explanations. First, drought may act as a persistent environmentalstressor that directly impacts brain health. Second, more comprehensive measures of diet/nutrition, mental health, and stress may be needed to delineate the mechanisms through which drought may impact cognition.
Policy Implications
Historically, Mexico’s disaster policies have been reactive, providing aid only after a crisis. To protect the growing population of older adults, the study recommends further shifts toward proactive and preventative policies. Key recommendations include:
- Integrating cognitive screenings into national drought-response protocols, especially for older adults.
- Establishing community centers in drought-prone regions to provide drought-preparedness education, healthcare, and linkage to other social services and programs.
- Expanding mental health programs to help older adults cope with long-term stress and mental health problems, especially due to climate-related disasters.
Building this community-level resilience is essential to mitigate the long-term cognitive risks posed by our changing climate.
Reference
Saenz J, Aguila E, Tanner L, Downer B, Peniche J, Wong R. Drought and cognitive function in older adults: results from the Mexican health and aging study. Environment International. 2026 Feb;208:110053. doi:10.1016/j.envint.2026.110053
Suggested Citation
Saenz J, Aguila E, Tanner L, Downer B, Peniche J, Wong R. Drought and cognitive function in older adults: results from the Mexican health and aging study. CAPAS Research Synopsis 1(1). doi:10.1016/j.envint.2026.110053
Acknowledgments
This study was conducted with support from the National Institutes of Health/National Institute on Aging [grant numbers R01AG018016; P30AG066589-03S1]. The MHAS is partly sponsored by the Instituto Nacional de Estadística y Geografía (INEGI) in Mexico. The National Institutes of Health/National Institute on Aging and Instituto Nacional de Estadística y Geografía were not involved in the study design, analysis, data interpretation, writing of the manuscript, or the decision to submit this manuscript.