Thomas Sawczuk

Introduction: Promoting healthier and more sustainable diets is needed to improve population and planetary health. However, limited evidence has described how these intersecting issues vary together by socioeconomic position. Our study uses novel large-scale retailer consumer purchase data, adjusted for known biases, to explore socioeconomic inequalities in health and environmental impacts of food and beverage purchases.Methods: Data were household-level loyalty card records from a major UK supermarket retailer between 24th July and 31st December 2022 (n = 117 710). The health-related outcome was proportion of purchases that were ‘High in Fat, Salt or Sugar’ (HFSS), determined using the UK nutrient profile model. We estimated three environmental outcomes: total greenhouse gas emissions, total land use footprint, and total water use from food purchases. Multilevel regression with post-stratification was used to estimate each outcome measure by level of neighbourhood socioeconomic deprivation, adjusted for age, household size, distance to nearest supermarket, and urbanicity. We also described environmental outcomes by food category across level of deprivation. Results: Households residing in the most deprived 10% of areas purchased a larger proportion of HFSS items than households in the least deprived 10% of areas. Households in the least deprived 10% of areas had a greater absolute environmental impact. However, when considered per weight of items, households in the most deprived 10% of areas purchased items that contributed to higher greenhouse emissions per kg but had lower impacts for land use. Soft drinks, ready meals, pasta, and pastry products were identified as key food categories for targeted ‘food swaps’ to reduce environmental inequalities. Conclusions: Our novel application of retailer loyalty card data shows how these data can offer valuable insights for informing strategies to promote healthy, sustainable, and equitable diets. Tackling environmental inequalities in food purchases requires tailoring approaches to different population groups.

This study investigated head acceleration event (HAE) probabilities between common contact‐drills in rugby league. Fifteen professional male academy players participated in three training sessions, completing standardised contact‐drills while wearing custom‐fitted iMGs, all sessions were filmed. HAE data (peak linear acceleration and peak angular acceleration) were captured, synchronised, and processed alongside video data. Binomial logistic regression and ordinal mixed‐effect regression models were used to calculate overall and exceedance probabilities. Data included 1402 (93 ± 50 per player) contact‐drill observations, of which 133 had HAEs ≥ 5 g (9 ± 8 per player). Substantial variability in probability for HAEs ≥ 5 g (1.3%–41.3%) was observed across drills. Standing wrestle had the highest HAE ≥ 5 g probability (41.3%; CI: 31.0%–52.3%), while tackle shield hits at 1 m had the lowest (1.3%; CI: 0.5%–3.4%). HAE probability was greater for tacklers than ball‐carriers. Overall, probability of a HAE ≥ 25 g was < 1.1%. Standardised contact‐drills varied in HAE probabilities, but chances of higher magnitude HAEs was low for all drills. Overall, the probability of a HAE during standardised contact‐drills was low, although practitioners should consider the differences (i.e., the variability) in HAE probabilities when managing HAE training exposure.

Background: Supermarket transaction data has the potential to provide a wide-scale understanding of population dietary behaviours, but its relationship with consumption is unclear as purchases are typically made at the household level while consumption occurs at the individual level. These behaviours may differ by weight status. This study assessed whether calorific screening thresholds improved the agreement between objective consumer purchase data and self-reported dietary intake for people living with (PLWOw/Ob _with ) and without (PLWOw/Ob _without ) overweight/obesity. Methods: Participants ( N = 642) from a retailer’s loyalty card database completed a 170-item food frequency questionnaire, shared transaction records, height, weight, and household composition data for this study. Nutrients (energy, sugar, total fat, saturated fat, protein, and sodium) from supermarket transaction purchases were allocated to the study individual proportionally based on their household composition. Bland-Altman analyses were used to assess the agreement and bias between objective consumer purchase data and self-reported dietary intake globally, and between PLWOw/Ob _with and PLWOw/Ob _without , across a range of calorific screening thresholds. Results: No agreement was identified between objective consumer purchase data and self-reported dietary intake for any of the nutrients when the data were analysed without screening thresholds. However, agreement was identified when screening thresholds were employed at ≥1000 Kcal/day (energy, sugar, total fat and saturated fat) or ≥1500 Kcal/day (protein and sodium). PLWOw/Ob _with consumed greater energy (19%), sugar (36%), total fat (22%) and saturated fat (25%) than they were estimated to have purchased at the retailer. PLWOw/Ob _without only consumed more sugar (19%). Conclusions: The application of screening thresholds based on estimated individual calories purchased may provide a valuable preprocessing step within the analysis of consumer purchase data, allowing agreement to be achieved for absolute nutrient values. Differences in bias between PLWOw/Ob _with and PLWOw/Ob _without show that insights into purchase and consumption patterns can be identified using consumer purchase data.

Background: This study simulated the effect of reducing contact training duration on overall in-season head acceleration event (HAE) exposure within men’s and women’s rugby union. Methods: Players ( n = 982) from two professional men’s and two semi-professional women’s competitions wore instrumented mouthguards in training and match-play for one season. Generalised linear mixed models were used to estimate the in-season weekly HAE exposures per position, sex and contact type. Simulation of modelled estimates evaluated the impact of reducing contact load guidelines by 25%, 50% and 75% (scenario 1), and replacing full contact training with controlled contact (scenario 2) or non-contact (scenario 3) training for different seasonal match exposures. Previously established contact load guidelines were used as a reference point. Results: HAEs were decreased by a maximum of 3.2 per week (0–95 HAEs per season; 0–23%). In scenario 1, the decrease in HAEs was disproportionately smaller than the reduction in contact training duration (e.g. 23.7% reduction in overall rugby minutes for 7% decrease in HAEs). Scenario 2 decreased HAEs similarly to scenario 1 but with no reduction in contact time. Scenario 3 decreased HAEs proportionally with contact time reductions (e.g. 8.9% decrease in HAEs >10 g for 9.6% reduction in overall rugby minutes). Conclusions: HAEs were reduced in all scenarios, but the reduction was relatively small due to the low overall rate of HAEs in training. Policymakers should be aware of the tradeoffs involved in any change. Managing individuals with higher HAE exposures may be more appropriate than reducing contact training guidelines.

Objectives: The aim of this study was to describe the incidence and magnitude of head acceleration events (HAEs) during elite men’s and women’s rugby union training for different contact training levels and drill types. Method: Data were collected during the 2022–23 and 2023–24 seasons from 203 men and 125 women from 13 clubs using instrumented mouthguards (iMGs) during in-season training. One author reviewed the training videos to identify the contact level and drill type. HAE incidence was calculated per player minute. Results: For men’s forwards and backs, only 4.7% and 5.8% of HAEs were ≥ 25 g and ≥ 1.5 Krad/s ² , and 3.4% and 4.4% for women’s forwards and backs, respectively. The incidence of ≥ 5 g and ≥ 0.4 Krad/s ² was highest during full-contact training for men’s forwards (0.20/min) and backs (0.16/min) and women’s forwards (0.10/min). HAE incidence was 2–3 times higher during repetition-based compared with game-based training drills for men’s forwards (0.25/min vs 0.09/min) and backs (0.22/min vs 0.09/min) and women’s forwards (0.09/min vs 0.04/min) and backs (0.08/min vs 0.03/min). HAE incidences were halved when repetition-based training drills used pads compared with no pads for men’s forwards (0.21/min vs 0.44/min) and backs (0.17/min vs 0.30/min), and women’s forwards (0.06/min vs 0.14/min) and backs (0.06/min vs 0.10/min). Conclusion: The average HAE incidence (~ 13–20% of weekly HAEs) and magnitude during an in-season training week is very low compared with matches. Opportunities to materially reduce HAE exposure in training are likely more limited than previously assumed. Future research on HAE load and injury, and understanding players’ specific weekly training exposure, may inform effective individual player management.

ObjectiveTo assess whether calorific screening thresholds improved the agreement between objective consumer purchase data, from supermarket transaction records, and self-reported dietary intake, from a Food Frequency questionnaire (FFQ), for people living with (PLWOw/Obwith) and without (PLWOw/Obwithout) overweight/obesity.DesignParticipants were recruited across a one-year period (1st June 2020 – 31st May 2021). Six screening thresholds were employed, using the estimated number of calories purchased for the individual, to filter participant data. Bland-Altman analyses were compared between PLWOw/Obwith and PLWOw/Obwithout for energy, sugar, total fat, saturated fat, protein and sodium.SettingPartnered with a large UK retailer.ParticipantsParticipants (N=1788) were recruited via the retailer’s loyalty card customer database. Participants with completed FFQs, shared transaction records, height, weight and household composition data were included for analysis (N=642).ResultsAgreement was found between objective purchase data and self-reported dietary intake at ≥1000 Kcal/day (energy, sugar, total fat and saturated fat) and ≥1500 Kcal/day (protein and sodium). PLWOw/Obwith consumed greater energy (19%), sugar (36%), total fat (22%) and saturated fat (25%) than they were estimated to have purchased at the retailer. PLWOw/Obwithout only consumed greater sugar (19%). ConclusionsThe application of screening thresholds based on estimated individual calories purchased may provide a valuable preprocessing step within the analysis of consumer purchase data, allowing agreement to be found for absolute nutrient values. Differences in bias between PLWOw/Obwith and PLWOw/Obwithout show that insights into purchase and consumption patterns can be identified using consumer purchase data.

This study aimed to introduce a novel Bayesian Mixture Model approach to the development of an EPV model in rugby league, which could produce a smooth pitch surface and estimate individual possession outcome probabilities. 99,966 observations from the 2021 Super League season were used. A set of 33 centres (30 in the field of play, 3 in the opposition try area) were located across the pitch. Each centre held the probability of five possession outcomes occurring (converted/unconverted try, penalty, drop goal and no points). Probabilities at each centre were interpolated to all locations on the pitch and estimated using a Bayesian approach. An EPV measure was derived from the possession outcome probabilities and their points value. The model produced a smooth pitch surface, which was able to provide different possession outcome probabilities and EPVs for every location on the pitch. Differences between team attacking and defensive plots were visualised and an actual vs expected player rating system was developed. The model provides significantly more flexibility than previous zonal approaches, allowing much more insightful results to be obtained. It could easily be adapted to other sports with similar data structures.

Sex, chronological age, and maturity potentially impact multidimensional health-related characteristics (i.e. motor competence, physical fitness, psychosocial, physical activity), which adds to the challenges of reversing current youth health-related concerns. Previous research fails to optimally assess such characteristics and consider sex, age, and maturity among youth. Therefore, the aims were to 1) present the multidimensional health-related characteristics of 9-14-year-olds from the UK, 2) examine sex differences, and 3) account for the effect of age and maturity on such characteristics. Eighty-one girls (mean age = 12.8 ± 1.2 years) and 136 boys (mean age = 13.1 ± 1.2 years) were purposively sampled and assessed across each of the four health-related domains. Multiple ANCOVA analyses examined sex differences among characteristics while accounting for chronological age. Pearson's correlations were used to evaluate the associations between maturity and multidimensional health-related characteristics. Multidimensional health-related characteristics were lower than similar populations and highly variable. Boys outperformed girls on most physical measures (ES = -0.76 to 0.76), elicited greater self-determined motivation (ES = 0.36), greater perceived competence (ES = 0.54), and engaged in more vigorous physical activity (ES = 0.78). Small age effects were present across some characteristics (e.g. isometric mid-thigh pull). Associations between maturity and multidimensional health-related characteristics were different for boys and girls (e.g. maturity offset positively associated with motor competence scores in girls only). Results suggest that multidimensional health-related characteristics of 9- to 14-year-olds are a concern, and are impacted by sex, age, and maturity. Identifying methods to improve multidimensional health-related characteristics which considers sex, age, and maturity are required. Assessing multidimensional health-related characteristics across youth is recommended to inform and measure interventions.