Participants were 7484 women born in 1921−1926 from the Australian Longitudinal Study on Women's Health who were surveyed every 3 years from 1999 to 2011. Frailty was measured at each survey using the FRAIL scale. Group-based trajectory modeling was used to assess patterns of frailty. Multinomial logistic regression was used to examine associations of trajectories with SES (level of education, occupation, and ability to manage on income) across adulthood.
Three trajectory groups were identified: low (19.5%), increasing (40.7%), and high (39.9%). Compared with women in the increasing frailty group, those who reported difficulty managing on their income in 1999 were less likely to be in the low frailty group (relative risk ratio 0.57, 95% confidence interval 0.39−0.84) and more likely to be in the high frailty group (relative risk ratio 2.65, 95% confidence interval 2.07−3.39), after adjusting for other SES variables, age, and social support. Occupation and education were not associated with trajectories of frailty.
Some women remain frailty free until age 85−90 years. The strongest impact on frailty is late-life SES.