Midlife mobility limitation and later-life functional deterioration: A 15-year study from Taiwan

Background

Midlife mobility limitation may signal elevated later-life disability risk, but longitudinal evidence linking mobility trajectories before older age to subsequent instrumental activities of daily living (IADL) deterioration remains limited.

Methods

This 15-year longitudinal study used five waves of data from the Taiwan Longitudinal Study on Ageing. We included 1,094 participants aged 50–57 years at baseline. Mobility limitation was measured as difficulties across eight physical function items. The first three waves were used to construct midlife mobility trajectories using k-means clustering for longitudinal data. The final two waves assessed later-life IADL deterioration, defined as increased difficulties across six IADL items from the third wave. Multivariable logistic regression with repeated observations examined associations between mobility trajectories and IADL deterioration, adjusting for sociodemographic characteristics, living arrangement, and third-wave IADL score.

Results

Five mobility trajectories were identified: stable-low (n = 783, 71.6%), late increase (n = 106, 9.7%), transient increase (n = 96, 8.8%), early-high recovery (n = 56, 5.1%), and persistently high (n = 53, 4.8%). Compared with the stable-low group, all other trajectories had higher odds of IADL deterioration: late increase (OR = 2.45, 95% CI: 1.56–3.84), transient increase (OR = 2.32, 95% CI: 1.54–3.48), early-high recovery (OR = 3.67, 95% CI: 2.25–6.00), and persistently high (OR = 3.92, 95% CI: 2.08–7.42). IADL deterioration was more likely at the later follow-up wave (OR = 1.72, 95% CI: 1.32–2.22).

Conclusions

Mobility limitation before older age, including transient patterns, were associated with later-life IADL deterioration. Midlife mobility assessment may support early risk identification and life-course strategies to prevent functional decline in ageing populations.

Key messages

• Mobility limitation before older age, even when transient, was associated with higher odds of later-life IADL deterioration.

• Midlife mobility assessment may support earlier risk identification and life-course strategies for preventing functional decline in ageing populations.