What question did this study set out to answer?

This study aims to explore the relationship between sleep quality and physical function over time in older women with breast cancer.

April 5, 2026

Abstract 2466: The association between sleep and physical function in the longitudinal TLC cohort study of women

Q: What does this research mean for the field?

Worsening sleep quality predicts subsequent physical function decline in older women, with a 10-point increase in PSQI corresponding to a 4-point lower physical function score one year later. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Key Result

Worsening sleep quality predicted physical function decline in older women, with a 10-point increase in PSQI corresponding to a 4-point lower physical function score one year later.

Key Points

This study aims to explore the relationship between sleep quality and physical function over time in older women with breast cancer.
Analyzed data from the Thinking and Living with Cancer study
Participants consisted of breast cancer survivors and non-cancer controls
Used PSQI to assess sleep quality and SF-12 PCS for physical functioning
Applied random intercept cross-lag panel models for data analysis
Breast cancer survivors had significantly worse sleep quality than controls (PSQI above 5: 43.9% vs. 29.0%; p < 0.001)
Survivors showed a clinically meaningful decline in SF-12 PCS scores over time
Each point increase in PSQI predicted a subsequent decrease in SF-12 PCS of 0.4-0.5 points for survivors
For controls, a similar trend was observed starting from year 2 to year 5, with increases in PSQI leading to declines in SF-12 PCS

Structured PICO

Does poor sleep quality predict declines in physical function in older women with and without breast cancer?

Population

767 women aged 60 and older, including newly diagnosed breast cancer survivors (n=428) and frequency-matched non-cancer controls (n=339), mean age 69.5 years.

Outcome

Physical functioning measured by the SF-12 physical component score (PCS) and the Timed Up and Go (TUG) at annual follow-ups up to 5 yearspatient reported

Poor sleep quality is associated with subsequent clinically meaningful declines in physical function among older breast cancer survivors and non-cancer controls.

Main Result

Absolute Event Rate: 0% vs 0%

Abstract

Abstract Background: Sleep disturbances, such as insomnia, are common in postmenopausal women and may negatively impact physical functioning. These disturbances are more frequent in breast cancer survivors than in the general female population. Limited data exist on how sleep affects physical function in older breast cancer patients. We analyzed whether sleep quality influences physical function at a one-year follow-up, and vice versa. Methods: Data were from the Thinking and Living with Cancer study, a multicenter, longitudinal study involving women aged 60 and older, newly diagnosed with breast cancer and frequency-matched non-cancer controls. Participants were followed annually for up to five years. Sleep quality was assessed with the PSQI (range 0-21; higher scores indicate poorer sleep quality); physical functioning was measured by the SF-12 physical component score (PCS) and the Timed Up and Go (TUG). A 3-5 point SF-12 PCS decline was considered clinically meaningful. Random intercept cross-lag panel models (RI-CLPM) analyzed associations using data from 767 women (339 controls and 428 survivors), adjusting for age, race, comorbidities, and recruitment site. Results: Mean age of participants was 69.5 years (70.0 in survivors vs. 69.3 in controls). Disrupted sleep was more common among survivors at baseline (PSQI above 5: 43.9% vs. 29.0%; p less than 0.001) and remained more prevalent during follow-up. Survivors showed a clinically meaningful decline in PCS (-2.8 points in year 1; -3.0 points over two years), whereas controls had a small, gradual, non-clinically meaningful decline (≈ -0.5 points/year). There was no clear trajectory for TUG, and the RI-CLPM revealed no significant associations between PSQI and TUG. In survivors, each 1-point higher PSQI predicted 0.4-0.5 points (P less than 0.001) lower SF-12 PCS at the subsequent annual visit during the first three years, decreasing to 0.3 points by year 4 (P = 0.03). Among controls, effects were small initially (-0.25 points, p = 0.10) but from years 2 to 5 a 1-point PSQI increase predicted 0.4-0.65 points lower SF-12 PCS (p = 0.01 to less than 0.001). For both survivors and controls, a 10-point worsening in a woman’s PSQI relative to her usual level would be expected to correspond to about a 4-point lower SF-12 PCS one year later, assuming a 0.4-point decrease in PCS per 1-point increase in PSQI. Conclusion: Sleep disruption is associated with subsequent declines in physical function among survivors and controls, which can reach clinically meaningful magnitudes as sleep quality worsens. Given the high prevalence of sleep problems among breast cancer survivors, routine monitoring for sleep disturbances and timely intervention may help preserve function in the growing population of older cancer survivors, particularly in the early years following treatment. This work was conducted with contributions from the entire TLC-Age research team. Citation Format: Cynthia Kusters, Wanting Zhai, Xingtao Zhou, Zev Nakamura, Jaeil Ahn, Ashley L. Artese, Deena Graham, Chloe Casagrande, Kathleen van Dyk, Tim A. Ahles, Traci N. Bethea, Harvey Cohen, Claudine Isaacs, Heather S. Jim, Brenna McDonald, Sunita Patel, James C. Root, Andrew Saykin, Brent Small, Jeanne S. Mandelblatt, Judith E. Carroll, TLC-Age Research Group.. The association between sleep and physical function in the longitudinal TLC cohort study of women abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2466.

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