Sex and educational inequalities across functional ability trajectories in Chile: A sequence analysis of a 17-year national panel

Context Research on disability and functional ability has increasingly moved from cross-sectional descriptions toward longitudinal analyses of intra-individual change. This shift has shown that functional ability follows heterogeneous pathways, encompassing stability, progressive deterioration, fluctuating limitations, partial recovery, and death. However, evidence remains concentrated in high-income countries, and fewer studies have examined long-term functional ability trajectories in Latin American contexts marked by rapid population aging and high socioeconomic inequality. In addition, comparisons across sex and educational groups require trajectory typologies that are constructed in a way that makes group comparisons methodologically comparable. Methods We used six observation points from the Chilean Social Protection Survey, a nationally representative longitudinal survey, covering the period 2004–2020. The analytic sample included 2,681 individuals aged 46–65 at baseline, contributing 16,086 person-wave observations. Functional ability was measured through self-reported limitations in activities of daily living and classified into five states: no limitation, low limitation, middle limitation, high limitation, and deceased. We reconstructed individual functional ability sequences over 17 years and applied optimal matching followed by hierarchical clustering. To ensure comparability across sex and educational groups, trajectory typologies were estimated within each baseline age group using the full age-group-specific sample. We then examined how membership in these pooled trajectory types varied by sex and educational attainment, referencing the composition of each trajectory type to the overall composition of its baseline age group. Findings Across the four baseline age groups, detailed trajectories were grouped into three broader types: mostly non-declining, progressive-declining, and equivocal-declining. Mostly non-declining trajectories were prevalent in all age groups, although their internal composition changed with baseline age, moving from stable good functional ability in younger age groups toward preserved functional ability before death in older age groups. Progressive-declining trajectories were especially visible among respondents aged 56–60 at baseline and remained substantial among those aged 61–65. Equivocal-declining trajectories were more frequently composed of women, most markedly among respondents aged 61–65 at baseline, and of respondents with primary education or less in the three younger age groups. Sex differences in trajectory membership were statistically significant in all age groups, while educational differences were statistically significant in the first three age groups. Conclusions Long-term functional ability trajectories in Chile are heterogeneous and socially patterned. By deriving pooled trajectory typologies within each baseline age group before comparing sex and educational groups, and by referencing group composition to the marginal composition of each age group, this study provides comparable evidence on how functional aging unfolds across socially stratified groups in an understudied Latin American context.