# Longitudinal associations of body composition with sleep problems in the first two years after colorectal cancer treatment

## TL;DR

This study explores how body composition changes over two years after colorectal cancer treatment relate to sleep problems in survivors.

## Contribution

The study identifies a potential link between BMI increases and reduced sleep problems in colorectal cancer survivors.

## Key findings

- Sleep problems were highest at 6 weeks post-treatment and decreased over time.
- Intra-individual increases in BMI were associated with fewer sleep problems over time.
- No significant overall longitudinal associations were found between body composition parameters and sleep problems.

## Abstract

Sleep problems are a frequent concern of colorectal cancer (CRC) survivors. Research on modifiable lifestyle factors that may mitigate sleep problems is sparse. Therefore, we investigated how various body composition parameters are longitudinally associated with sleep problems from 6 weeks up to 24 months post-treatment.

In a prospective cohort of 396 stage I-III CRC survivors, home-based repeated measurements were conducted at diagnosis and at four post-treatment time points. The insomnia scale of the EORTC QLQ-C30 (range: 0–100) was used to measure sleep problems. Anthropometric measurements of adiposity (BMI, fat percentage, waist-hip ratio) and of muscle mass and muscle function (mid-upper arm muscle circumference, handgrip strength) were employed. Linear mixed models were applied to analyze overall longitudinal associations, and hybrid models were used to disentangle inter- and intra-individual components.

At 6 weeks post-treatment, 47.0% of participants reported sleep problems and symptom severity was at its highest; a decline was observed thereafter. In confounder-adjusted models, no statistically significant overall longitudinal associations of different body composition parameters with sleep problems were found. Intra-individual analyses revealed that increases in BMI were related to less sleep problems over time (β per 1 kg/m2: -2.8, 95% CI -4.4; -1.2).

BMI increases in the first 24 months post-treatment were associated with decreased sleep problems.

These findings must be interpreted with caution due to the observational design, yet might suggest a potential link between weight regain and sleep problems among CRC survivors recovering from the physical and mental impact of cancer treatment.

The online version contains supplementary material available at 10.1007/s00520-025-10018-6.