Change in physical function among women as they age: findings from the Australian Longitudinal Study on Women's Health

Decline in physical function is common in older age, with important consequences for health-related quality of life, health care utilisation, and mortality. This study aimed to identify patterns of change in physical functioning (PF) for women in later life. PF was measured longitudinally using the ten-item subscale of the Medical Outcomes Study 36-item Short Form Health Survey, for 10 515 participants of the Australian Longitudinal Study on Women's Health, who completed at least two surveys between 1999 (aged 73-78 years) and 2011 (aged 85-90 years). Conditional and unconditional latent profile analysis was conducted separately for deceased and surviving subgroups of women to uncover latent patterns of change in PF scores over time. Four patterns of change were identified for women who were still alive in 2011 (N = 5928), and four similar classes for deceased women (N = 4587): (1) 'poor PF' representing women with low PF scores, (2) 'moderate PF', (3) 'high PF', and (4) 'very high PF', where scores remained very high. All patterns exhibited a decrease in PF over time. Factors which predict low PF included sedentary levels of exercise, obese and overweight BMI, difficulty managing on income, and lower education. The results provided evidence for a gradual decrease in PF for all women with age; however, there was no evidence for an increased rate of decline prior to death.