most older adults either cannot walk 8 feet safely or cannot walk fast enough to use a pedestrian crossing in the UK. The health impacts on older adults include limited independence and reduced opportunities for physical activity and social interaction. An assumed normal walking speed for pedestrian crossings of 1.2 m/s is inappropriate for older adults and revision of these timings should be considered.

ObjectivesDietary intake is a key aspect of occupational health. To capture the characteristics of dietary behaviour that is affected by occupational environment that may affect disease risk, a collection of prospective multiday dietary records is required. The aims of this paper are to: (1) collect multiday dietary data in the Airwave Health Monitoring Study, (2) describe the dietary coding procedures applied and (3) investigate the plausibility of dietary reporting in this occupational cohort.DesignA dietary coding protocol for this large-scale study was developed to minimise coding error rate. Participants (n 4412) who completed 7-day food records were included for cross-sectional analyses. Energy intake (EI) misreporting was estimated using the Goldberg method. Multivariate logistic regression models were applied to determine participant characteristics associated with EI misreporting.SettingBritish police force employees enrolled (2007–2012) into the Airwave Health Monitoring Study.ResultsThe mean code error rate per food diary was 3.7% (SD 3.2%). The strongest predictors of EI under-reporting were body mass index (BMI) and physical activity. Compared with participants with BMI<25 kg/m2, those with BMI>30 kg/m2 had increased odds of being classified as under-reporting EI (men OR 5.20 95% CI 3.92 to 6.89; women OR 2.66 95% CI 1.85 to 3.83). Men and women in the highest physical activity category compared with the lowest were also more likely to be classified as under-reporting (men OR 3.33 95% CI 2.46 to 4.50; women OR 4.34 95% CI 2.91 to 6.55).ConclusionsA reproducible dietary record coding procedure has been developed to minimise coding error in complex 7-day diet diaries. The prevalence of EI under-reporting is comparable with existing national UK cohorts and, in agreement with previous studies, classification of under-reporting was biased towards specific subgroups of participants.

Background:Patients with stage I testicular seminoma are typically diagnosed at a young age and treatment is associated with low relapse and mortality rates. The long-term risks of adjuvant radiotherapy in this patient group are therefore particularly relevant.Methods:We identified patients and obtained treatment details from 12 cancer centres (11 United Kingdom, 1 Norway) and ascertained second cancers and mortality through national registries. Data from 2629 seminoma patients treated with radiotherapy between 1960 and 1992 were available, contributing 51 151 person-years of follow-up.Results:Four hundred and sixty-eight second cancers (excluding non-melanoma skin cancers) were identified. The standardised incidence ratio (SIR) was 1.61 (95% confidence interval (CI): 1.47–1.76, P<0.0001). The SIR was 1.53 (95% CI: 1.39–1.68, P<0.0001) when the 32 second testicular cancers were also excluded. This increase was largely due to an excess risk to organs in the radiation field; for pelvic–abdominal sites the SIR was 1.62 (95% CI: 1.43–1.83), with no significant elevated risk of cancers in organs elsewhere. There was no overall increase in mortality with a standardised mortality ratio (SMR) of 1.06 (95% CI: 0.98–1.14), despite an increase in the cancer-specific mortality (excluding testicular cancer deaths) SMR of 1.46 (95% CI: 1.30–1.65, P<0.0001).Conclusion:The prognosis of stage I seminoma is excellent and it is important to avoid conferring long-term increased risk of iatrogenic disease such as radiation-associated second cancers.

BackgroundClustering of multiple health-compromising behaviours is associated with an increased risk of various chronic diseases. There are few studies on patterns of clustering of multiple health-compromising behaviours in adolescents. Therefore, the aim of this study is to assess how six health-compromising behaviours, namely, low fruit consumption, high sweet consumption, less frequent tooth brushing, low physical activity, physical fighting and smoking, cluster among Saudi male adolescents.MethodsA representative stratified cluster random sample of 1,335 Saudi Arabian male adolescents living in Riyadh city answered a questionnaire on health-related behaviours. Hierarchical Agglomerative Cluster Analysis (HACA) was used to identify cluster solutions of the six health-compromising behaviours.ResultsHACA suggested two broad and stable clusters for the six health-compromising behaviours. The first cluster included low fruit consumption, less frequent tooth brushing and low physical activity. The second cluster included high sweets consumption, smoking and physical fighting.ConclusionsThe six health-compromising behaviours clustered into two conceptually distinct clusters among Saudi Arabian male adolescents, one reflecting non-adherence to preventive behaviours and the second undertaking of risk behaviours. Clustering of health behaviours has important implications for health promotion.

102 Background: Numerous studies have shown the clinical utility of ctDNA, a non-invasive biomarker to detect MRD and stratify CRC patients who are more likely to relapse. We present an analysis of MRD detection in CRC patients from a prospective multicentre UK study, who were monitored pre- and post-surgery before adjuvant chemotherapy (ACT). Methods: The study recruited patients diagnosed with stage II-III CRC (n=122), including a subset of rectal patients who underwent tri-modality treatment (TMT). All patients had their primary tumor resected and 56% (68/122) received ACT. Paired plasma samples (n=244) were collected before surgery/neaodjuvant chemoradiotherapy and after surgery; median follow-up for survival was 15.48 months (0.16 - 42.1 months). Individual tumors and matched germline DNA were whole-exome sequenced and somatic single nucleotide variants (SNVs) identified. Multiplex PCR assays were designed to track tumor-specific SNVs (Signatera, bespoke mPCR NGS assay) in plasma samples. The study evaluated ctDNA status and clinical outcomes including radiologic imaging. Cox regression was used to calculate recurrence-free survival (RFS) in patients stratified by post-op ctDNA status. Patients were also stratified into low and high-risk groups based on the clinicopathological features. Multivariate analysis was performed with covariates: ctDNA, age, gender, laterality, stage, number of lymph node resected, MSI & TMB. Results: Pre-treatment ctDNA was detected in 93.4% (100/107) of patients. Post-operative ctDNA status prior to ACT was assessed in 107 patients, of whom, 13% (14/107) were MRD-positive (MRDpos). Of the MRDpos patients 42.9% (6/14) eventually relapsed. In contrast, only 8.6% (8/93) of MRD-negative (MRDneg) cases relapsed (HR: 10; 95% CI: 3.3-30; p<0.001). MRD rates stratified by risk features in each of the stages with respective recurrence rates are shown in Table. In stage III patients (n=64), 45.4% (5/11) of the MRDpos patients relapsed, whilst only 17% (9/53) of the MRDneg cases relapsed (HR: 9; 95% CI:2.6-32; p<0.0001). In the multivariate analysis, ctDNA status was the most significant prognostic factor associated with RFS (HR: 28.8, 95% CI: 3.5-234.1; p<0.001). Conclusions: Postoperative ctDNA analysis with tumor informed assay enables detection of CRC patients at high-risk of recurrence. Early detection of MRD could guide ACT decisions in intervention trials and is currently underway in TRACC. Clinical trial information: NCT04050345. [Table: see text]