Colorectal cancer remains a leading cause of cancer death worldwide, and early detection with faecal tests demonstrably reduces mortality. But the benefit of screening hinges on uptake. European guidelines consider a participation rate of at least 45 percent acceptable and 65 percent desirable, yet reported figures across programmes range from roughly 23 to 63 percent, with persistent socioeconomic gaps. In Italy, national participation averaged 34.9 percent in 2023, ranging from 18.9 percent in Lazio to 64.2 percent in Veneto. Tuscany, despite its long-standing programmes, sat at 45.8 percent, comfortably above the minimum but short of the desirable benchmark, leaving a large pool of chronic non-responders whom standard letters had repeatedly failed to reach.

The new trial, part of the BESTcc project evaluating behavioural interventions in Tuscany’s screening programmes, is grounded in dual-process theory. Traditional efforts to boost screening participation have appealed to reflective, deliberative reasoning, the slow System 2 of psychological models. Behavioural economics instead targets the fast, automatic System 1, using small contextual modifications, or nudges, such as feedback on past behaviour or social norm messages, to shape decisions without restricting choice. Two earlier randomized trials in Florence, Rome and Turin had tested such messages among previous non-responders with encouraging but sometimes inconsistent results, and the Tuscan team set out to replicate the approach in a larger, geographically diverse population spanning both urban and rural screening organizations.

The study employed a 2×2 factorial randomized design. Between January 2022 and April 2024, eligible individuals who had not responded to at least two consecutive screening invitations and had never been screened were allocated in a 3:1:1:1 ratio to one of four arms: a control group receiving the standard invitation letter, a feedback group, a minority-norm group, and a combined group receiving both messages. The messages themselves were identical to those used in the previous trials, co-developed and pretested with public and patient representatives through qualitative focus groups. The feedback message gently informed recipients that they had unfortunately not responded to previous invitations while stressing that it is never too late to take care of their health. The minority-norm message noted that in many areas six out of ten people invited accept the invitation and that the recipient belonged to the minority who did not. Exclusions covered personal history of colorectal cancer, adenomas or inflammatory bowel disease, recent colonoscopy, or a recent faecal occult blood test.

The trial was registered with the ISRCTN registry in 2022 and approved by the Ethics Committees of the Local Health Units in Tuscany, with individual informed consent waived because the trial was integrated into routine screening, an Essential Level of Care within the Italian National Health System. Randomization was performed individually with a pseudo-random number generator, and although blinding of researchers and participants was impossible, participants did not know they were part of a study and enrolment staff were blinded to the allocation sequence. Importantly, the team also verified that the added sentences did not compromise clarity, using automated natural language processing readability tools validated by crowd-sourced comprehension testing; the modified letters proved as easy to understand as the standard version.

The primary outcome was the return of a faecal immunochemical test within 90 days of the first invitation, analyzed by intention to treat, which even included people whose letters were returned undelivered. In the control group, 6.5 percent of 42,732 participants returned a test. Uptake was significantly higher in all three intervention arms: 8.4 percent in the feedback condition, 7.4 percent with the minority-norm message, and 7.7 percent in the combined condition. The 2×2 factorial analysis revealed a significant interaction between the two message types, with an odds ratio of 0.80 for the interaction term, prompting the researchers to report each modality separately against the control rather than pooling them.

Because participation rates varied substantially across the ten screening programmes, the statisticians built a mixed-effects logistic regression with random intercepts and random slopes for each programme, a model whose superiority over a single-level alternative was confirmed by likelihood ratio testing. The intraclass correlation attributable to programme-level clustering was 0.0884. In this adjusted model, feedback carried an adjusted odds ratio of 1.31 for participation, the minority-norm message 1.17, and the combination 1.22, all statistically significant relative to control, with no significant differences among the three intervention conditions. Women participated more than men, and people aged 60 to 70 were less likely to respond than those aged 54 to 59.

The age-stratified results carried the most practical weight. Among 60-to-70-year-olds, all three messages worked, and the combined message was the strongest performer there, with an adjusted odds ratio of 1.49. Among the younger 54-to-59 group, only feedback showed a significant effect, with an adjusted odds ratio of 1.21. Translated into absolute terms, feedback produced the best figures: an absolute risk reduction of 1.84 percentage points overall, meaning roughly 54 invitations bearing the feedback sentence were needed to generate one additional screened person, improving to 48 invitations in the older subgroup. The combined message achieved an absolute risk reduction of 2.40 percent and a number needed to invite of 57 among those aged 60 to 70.

Why did stacking the two nudges not outperform either alone? The authors offer several speculative explanations, carefully flagged as such because no process data on message perception or recall were collected. The minority-norm message already contains an implicit feedback element, since telling recipients they are part of the minority who did not participate inherently reminds them of their past behaviour, so the explicit feedback sentence may have added little new information. Longer or more complex combined messages may also have diluted attention, or ceiling effects may have limited further gains. The researchers recommend that future studies incorporate brief process measures, such as recall, perceived relevance and comprehension, and explore factorial designs, message sequencing or qualitative interviews to disentangle these mechanisms, as well as testing more clearly distinct interventions such as deadlines.

The findings arrive with clear caveats and clear strengths. Household spill-over could not be controlled since members of the same family could be randomized to different arms, message placement within the letter may have limited salience, and the analysis was restricted to age and sex without socioeconomic variables such as deprivation, education or health literacy. Nevertheless, the trial’s scale, its objective participation data, its single-region consistency and its focus on the hardest-to-reach group, people who had ignored two consecutive invitations, make the result compelling for screening organizers. The interventions are essentially free, requiring only small edits to existing letters, and the effects were demonstrated in a mix of long-established and newer programmes. The authors caution that organized, population-based faecal-test programmes differ from opportunistic or colonoscopy-based systems, and that cultural norms and trust in health authorities shape how such messages land, so extrapolation elsewhere should be cautious. Within that frame, the message is simple: a reminder of what someone has not done, and an honest account of what their neighbours have, may be enough to bring the reluctant back into the prevention fold.

Subject of Research: Behavioural economics messages to increase participation in population-based colorectal cancer screening among previous non-responders in Tuscany

Article Title: Testing feedback and social norms messages to increase participation: the BestCC randomized controlled trial among non-respondents in population-based colorectal cancer screening programmes in Tuscany

Article References: Gorini, G., Betti, E., Falini, P., Carreras, G., Mallardi, B., Migliori, M., Giorgi, D., Tramalloni, D., Cosimi, A., Venturi, G., Ravelli, A. A., Iossa, A., Battisti, F., Stoffel, S. T., & Mantellini, P. (2026). Testing feedback and social norms messages to increase participation: the BestCC randomized controlled trial among non-respondents in population-based colorectal cancer screening programmes in Tuscany. SSM – Population Health, Article 101974. https://doi.org/10.1016/j.ssmph.2026.101974

Image Credits: AI Generated

DOI: Not provided

Keywords: colorectal cancer screening, behavioural economics, nudge, social norms, feedback messages, FIT test, randomized controlled trial, Tuscany, screening participation, non-responders, public health, health communication

The study was conducted within the Center of Active Ageing Project in St. Pölten, Austria, and recruited community-dwelling volunteers aged 60 to 80 who could walk with or without aids. After exclusions for missing assessments and withdrawals, the final analytic sample comprised 126 participants with a mean age of 67.7 years, roughly 63 percent of them women, and a mean body mass index of 28.1 kilograms per square metre. Importantly, this was a generally healthy and well-functioning cohort: nutritional screening placed 98.4 percent of participants in the normal range, and only 4.8 percent were classified as at risk for sarcopenia based on sex-specific phase angle cut-offs derived from bioelectrical impedance analysis. The participants completed two supervised 60-minute sessions each week, one full-body resistance-training session and one neuromotor session focused on coordination, mobility, and balance.

The resistance training followed a carefully periodised progression referenced to each participant’s estimated one repetition maximum. During the first three weeks, participants performed two sets of 20 repetitions at 75 percent of their one repetition maximum; from weeks four to six, the load increased to 80 percent for two sets of 12 to 15 repetitions; and from weeks seven to twelve, they progressed to three sets of 8 to 12 repetitions at 85 percent. The programme targeted all major upper-limb, lower-limb, and trunk muscle groups with individualised load progression, and the neuromotor sessions became progressively more demanding. Sessions were delivered by a multidisciplinary team of physiotherapists and sport scientists, who, together with dietitians, also provided brief education on healthy lifestyle, safe exercise, nutrition, and ageing-related risks.

What sets this study apart methodologically is how the researchers handled the sheer volume of measurement data. At baseline and after 12 weeks, participants underwent a comprehensive battery covering anthropometry, body composition, resting hemodynamics, upper and lower extremity function, walking capacity, static and dynamic balance, joint mobility, muscle strength, health-related quality of life, nutritional risk, physical activity level, and medical history. Starting from 43 outcome measures, the team applied a multistep dimensionality reduction procedure based on principal component analysis to distil the data into 14 key indicators, which were then aggregated into four latent domains: body composition, muscle capacity, functional performance, and pain and health-related quality of life. The four-domain solution explained 72.7 percent of the variance in the retained indicators, with functional performance and body composition each contributing roughly a quarter of that explained variance.

To capture overall responsiveness, the researchers combined the four domain scores into a composite Multidomain Quality Outcome Index, calculated as the unweighted mean of the standardised factor scores at each time point. Individual change was quantified as the difference between post-intervention and baseline z-scores, with higher values indicating improvement. Participants were classified as multidomain responders if their composite index change reached at least 0.33 standardised mean difference units, a threshold described in the multidimensional rehabilitation literature as both perceptible and clinically meaningful. The authors emphasise that this cut-off was selected a priori as a conservative, descriptive candidate threshold and should not be interpreted as a validated clinical standard, particularly since it was derived and applied within the same sample.

The headline finding was the dramatic and consistent improvement in functional performance, which registered a standardised mean difference of 0.67, by far the largest effect in the study. Eighty percent of participants improved in this domain, encompassing gains in the 30-second Chair Stand test, the Timed Up and Go test, and both usual and fast-paced 10-metre walking speed. The composite index improved by a more moderate 0.30 standardised mean difference, with 59.5 percent of participants showing overall improvement. By contrast, muscle capacity remained essentially stable, body composition showed a slight negative shift, and changes in pain and health-related quality of life were strikingly heterogeneous, with nearly equal proportions of participants improving and worsening in that domain. The authors note that baseline performance was already high, with a mean Timed Up and Go time of 6.10 seconds, faster than pooled age-specific reference values, making recovery from impairment an implausible explanation for the gains.

When the researchers applied the responder threshold, 46 percent of participants qualified as responders, while the remaining 54 percent did not. Crucially, the non-responders were not simply people who failed to benefit. They still exhibited measurable improvements in functional performance, but their profiles were characterised by worsening in the pain and quality-of-life domain and small deteriorations in muscle capacity and body composition. The only baseline difference between the groups emerged in the pain and quality-of-life domain, where responders reported poorer subjective health at the outset. This suggests that responder status was driven largely by baseline symptom burden and the potential for subjective improvement rather than by any objective functional or physiological impairment, a finding with significant implications for how clinicians interpret short-term exercise outcomes in healthy ageing populations.

The pattern of early functional gains without parallel structural change fits well with established exercise physiology. Neural adaptations are known to dominate the early phases of resistance training, while hypertrophic responses typically require longer intervention periods or higher training intensities. In this framework, resistance-based exercise primarily enhances neuromuscular efficiency and coordination, producing functional improvements even in the absence of measurable changes in muscle mass. The study’s regression analyses reinforced the complexity of the picture: baseline characteristics such as sex, age, body mass index, physical activity, and nutritional status explained a strong proportion of variance in baseline muscle capacity but had limited explanatory value for short-term changes. Poorer baseline pain and quality-of-life scores and lower composite index values were associated with greater overall improvement, consistent with baseline dependency and regression-to-the-mean phenomena well documented in rehabilitation science.

The authors are careful to acknowledge the limitations of their design. As a single-arm study without a non-exercising control group, the observed changes cannot be categorically attributed to the intervention alone; learning effects, test familiarisation, spontaneous change, and regression to the mean may all have contributed. The self-selected, healthy cohort with preserved baseline function may also have introduced ceiling effects, particularly for subjective outcomes, and body composition was assessed with bioelectrical impedance rather than reference imaging. No formal adjustment for multiple comparisons was applied, and the four-domain structure, composite index, and responder threshold were all developed within the same sample, meaning external validation in independent cohorts is required before clinical application.

Nevertheless, the study’s central message carries real weight for geriatric medicine and preventive health. With the global population aged 60 and older projected to reach approximately 2.1 billion by 2050, and with healthy life expectancy failing to keep pace with lifespan gains, identifying who truly benefits from exercise interventions, and who does not, is becoming a pressing clinical question. By showing that nearly half of healthy older adults can display meaningful functional gains while their subjective wellbeing or structural metrics quietly deteriorate, the study makes a compelling case that multidomain outcome monitoring, rather than reliance on performance tests alone, may be essential for catching unfavourable trajectories early and adjusting exercise prescriptions before small setbacks become lasting ones.

Subject of Research: Multidomain clinical outcome changes and non-responder identification in healthy older adults after 12 weeks of resistance-based exercise training.

Article Title: Multidomain changes in clinical outcomes after 12 weeks of resistance-based exercise training in healthy older adults: a four‑domain framework for identifying non‑responders

Article References: Matko, Š., Strasser, B., Steinecker-Frohnwieser, B., Stamm, T., Kern, H., Löfler, S., Hochenwarter, S., Prüfer, F., Unger, A., Tirpáková, V., Cvecka, J., Šarabon, N., & Grote, V. (2026). Multidomain changes in clinical outcomes after 12 weeks of resistance-based exercise training in healthy older adults: a four‑domain framework for identifying non‑responders. European Geriatric Medicine. https://doi.org/10.1007/s41999-026-01614-8

Image Credits: AI Generated

DOI: 10.1007/s41999-026-01614-8

Keywords: healthy ageing, resistance training, sarcopenia, functional performance, multidomain assessment, rehabilitation outcomes, non-responders, health-related quality of life, body composition, muscle capacity, older adults, exercise intervention