Number of living siblings, social engagement, and cognitive decline among older Mexican adults

Research on the association between adult siblings and later life cognition is limited. Sibship size may impact cognitive development in early childhood and shape opportunities for social support and social interaction throughout life, potentially influencing cognitive health later in life. Siblings can also be a source of engagement to the community and expand social environments that enhance cognition. Using lifecourse and cognitive enrichment frameworks, we examine the association between the number of living siblings in later life and cognitive health among older Mexican adults and whether social engagement in community activities moderates the association. Data come from the 2012, 2015, 2018, and 2021 waves of the Mexican Health and Aging Study (n = 14,872 adults age 50+). Latent growth curve models evaluate how one's number of living siblings relates with levels of latent general cognitive ability and nine-year cognitive decline, and whether these associations differ by social engagement. Results showed that each additional sibling was associated with higher cognitive ability but was unrelated to cognitive decline. Social engagement in community activities was associated with higher levels of cognitive ability but a faster pace of cognitive decline. Social engagement did not moderate the association between the number of living siblings and cognitive functioning or decline. The findings broaden our understanding of the salience of siblings and social engagement in community activities for older Mexicans' health. Future research is needed on alternative social support for older adults amidst Mexico's changing demographics that challenge the reliance on traditional sources of family support in later life.