Exploring the feasibility of a cluster pilot randomised control trial to improve children's 24-hour movement behaviours and dietary intake: Happy homework.

We aimed to explore the feasibility, acceptability, and potential efficacy of Happy Homework (HH); an 8-week home-focussed intervention, with the purpose of encouraging children's positive dietary behaviours and engagement in positive physical activity (PA) and sleep behaviours. We randomised four Scottish schools (n = 71 participants; 5 classrooms) to either the HH intervention (n = 2) or usual curriculum control group (n = 2). HH consisted of movement and dietary-focused parent and child tasks. Primary outcome measures were intervention feasibility, acceptability, and potential efficacy. Secondary outcomes were objectively measured PA via ActiGraph GT3X+, sedentary behaviours (SBs) and sleep duration via activPAL4™ accelerometers and dietary behaviours, fruit and vegetable consumption and screen-time via questionnaires. After controlling for pre-test levels, post intervention stepping time and sleep duration were significantly greater for the HH group in comparison to the control group. The HH group reported eating more fruit and vegetables at post-test than the control group. Participants also reported the intervention to be enjoyable and motivating. These findings provide promising evidence that given a greater sample size, better retention and the prioritisation of health and wellbeing homework, HH could enhance children's health and wellbeing.

The impact of living in a bio-secure bubble on mental health: An examination in elite cricket.

The COVID-19 pandemic has had a profound impact on many people's lives, including the use of bio-secure environments to facilitate the continuation of professional sport. Although it is well documented that the pandemic has negatively impacted mental health, the impact of bio-bubbles on mental health is yet to be investigated. In the present study we sought to identify the impact of bio-bubbles on the mental health of those residing within, and then to explore the underlying mechanism of any such impact. Individuals (n = 68) who resided in England and Wales Cricket Board (ECB) created bio-bubbles between March 2020 and April 2021 provided data, regarding their time inside and outside of bio-bubbles, on measures of mental health and basic psychological need satisfaction and frustration. Analysis revealed that bio-bubbles increased anxiety and depression and reduced wellbeing. Additionally, MEMORE mediation analyses revealed that autonomy frustration mediated the relationship between bubble status and all mental health markers. Furthermore, compared to men, women were more likely to experience elevated levels of anxiety and depression inside the bubble. The findings suggest that bio-bubbles negatively impact mental health and further suggest that satisfaction and frustration of basic psychological needs is a contributing factor. Findings suggest organizations tasked with creating bio-bubbles would do well to tailor their environment with an awareness of the importance of basic psychological needs and sex differences in relation to mental health. To the best of our knowledge, this research represents the first investigation of the impact of bio-bubbles on mental health.

Bulls in a China Shop: Narcissism, Intragroup Conflict, and Task Cohesion.

When given opportunities for personal glory in individual settings, people high in narcissism excel. However, less is known about narcissists' influence in team contexts. Across two studies (utilizing cross-sectional and two-wave longitudinal designs) involving 706 athletes from 68 teams in total, we tested a conceptual model linking narcissism to task cohesion, via intragroup conflict, moderated by narcissistic group composition. We tested a new sports-oriented measure of intragroup conflict using Bayesian estimation and evaluated our theorizing using a multilevel conditional indirect effect hybrid model. Across both studies, we found that narcissism influenced perceptions of task cohesion via process conflict only, with a negative influence at low narcissistic group composition that was weakened (Study 1) or nullified (Study 2) at high narcissistic team composition. Collectively, these findings offer the first example of how narcissism influences task cohesion in team settings and the contextual effects of narcissistic group composition.

Vitamin D and the hepatitis B vaccine response: a prospective cohort study and a randomized, placebo-controlled oral vitamin D3 and simulated sunlight supplementation trial in healthy adults.

PURPOSE: To determine serum 25(OH)D and 1,25(OH)2D relationship with hepatitis B vaccination (study 1). Then, to investigate the effects on hepatitis B vaccination of achieving vitamin D sufficiency (serum 25(OH)D ≥ 50 nmol/L) by a unique comparison of simulated sunlight and oral vitamin D3 supplementation in wintertime (study 2). METHODS: Study 1 involved 447 adults. In study 2, 3 days after the initial hepatitis B vaccination, 119 men received either placebo, simulated sunlight (1.3 × standard-erythema dose, 3 × /week for 4 weeks and then 1 × /week for 8 weeks) or oral vitamin D3 (1000 IU/day for 4 weeks and 400 IU/day for 8 weeks). We measured hepatitis B vaccination efficacy as percentage of responders with anti-hepatitis B surface antigen immunoglobulin G ≥ 10 mIU/mL. RESULTS: In study 1, vaccine response was poorer in persons with low vitamin D status (25(OH)D ≤ 40 vs 41-71 nmol/L mean difference [95% confidence interval] - 15% [- 26, - 3%]; 1,25(OH)2D ≤ 120 vs ≥ 157 pmol/L - 12% [- 24%, - 1%]). Vaccine response was also poorer in winter than summer (- 18% [- 31%, - 3%]), when serum 25(OH)D and 1,25(OH)2D were at seasonal nadirs, and 81% of persons had serum 25(OH)D < 50 nmol/L. In study 2, vitamin D supplementation strategies were similarly effective in achieving vitamin D sufficiency from the winter vitamin D nadir in almost all (~ 95%); however, the supplementation beginning 3 days after the initial vaccination did not effect the vaccine response (vitamin D vs placebo 4% [- 21%, 14%]). CONCLUSION: Low vitamin D status at initial vaccination was associated with poorer hepatitis B vaccine response (study 1); however, vitamin D supplementation commencing 3 days after vaccination (study 2) did not influence the vaccination response. CLINICAL TRIAL REGISTRY NUMBER: Study 1 NCT02416895; https://clinicaltrials.gov/ct2/show/study/NCT02416895 ; Study 2 NCT03132103; https://clinicaltrials.gov/ct2/show/NCT03132103 .

O2 No Longer the Go2: A Systematic Review and Meta-Analysis Comparing the Effects of Giving Perioperative Oxygen Therapy of 30% FiO2 to 80% FiO2 on Surgical Site Infection and Mortality.

OBJECTIVE: To determine the effects of perioperative high (80%) versus low (30%) fraction of inspired oxygen (FiO2) on surgical site infection (SSI) and mortality in adult surgical patients. BACKGROUND: The routine use of high fraction perioperative oxygen in patients is "standard of care" and recommended by the World Health Organisation; however, whether there is truly any benefit to this therapy has been challenged by some authors. Questions have also been raised about the possibility of harm from oxygen therapy. METHOD: Randomised control trials comparing high-to-low FiO2 were located by searching MEDLINE, Embase, CENTRAL and Web of Science. The primary outcomes were SSI up to 15 days and up to any time point postoperatively and mortality up to 30 days. The data were analysed using random effects meta-analysis. RESULTS: Twelve studies involving 10,212 participants were included. At 15 days postoperatively, and at the longest point of post-operative follow-up, there was no statistically significant reduction in the risk of SSI when comparing patients who received a perioperative FiO2 of 30% to those with an FiO2 of 80% (RR 1.41, 95% CI 1.00-2.01, p 0.05 and RR 1.23, 95% CI 1.00-1.51, p 0.05). There was no statistically significant difference in mortality between the 30% FiO2 and the 80% FiO2 groups (RR 1.12, 95% CI 0.56-2.22, p 0.76). CONCLUSION: This meta-analysis showed no statistically significant difference in post-operative SSI or mortality when comparing patients receiving an FiO2 of 80% to those receiving an FiO2 of 30%.

I Am Great, but Only When I Also Want to Dominate: Maladaptive Narcissism Moderates the Relationship Between Adaptive Narcissism and Performance Under Pressure.

Narcissism-performance research has focused on grandiose narcissism but has not examined the interaction between its so-called adaptive (reflecting overconfidence) and maladaptive (reflecting a domineering orientation) components. In this research, the authors tested interactions between adaptive and maladaptive narcissism using two motor tasks (basketball and golf in Experiments 1 and 2, respectively) and a cognitive task (letter transformation in Experiment 3). Across all experiments, adaptive narcissism predicted performance under pressure only when maladaptive narcissism was high. In the presence of maladaptive narcissism, adaptive narcissism also predicted decreased pre-putt time in Experiment 2 and an adaptive psychophysiological response in Experiment 3, reflecting better processing efficiency. Findings suggest that individuals high in both aspects of narcissism perform better under pressure thanks to superior task processing. In performance contexts, the terms "adaptive" and "maladaptive"-adopted from social psychology-are oversimplistic and inaccurate. The authors believe that "self-inflated narcissism" and "dominant narcissism" are better monikers for these constructs.

Coaches Coaching Psychological Skills-Why Not? A Framework and Questionnaire Development.

This study is part of a program of research investigating coaches delivering psychological skills (PS). Here, 3 studies feature an original conceptualization of coaching PS and the development and validation of 2 questionnaires capturing the coaching of PS. The authors conducted a qualitative investigation to establish a conceptual framework that included the fundamental coaching of PS behaviors (CPS-F) and the needs-supportive coaching of PS (CPS-NS). They then tested the factor structure of 2 subsequently developed questionnaires via a Bayesian structural equation modeling approach to confirmatory factor analysis across 2 samples and ran tests of invariance, concurrent, discriminant, and predictive validity. The CPS-F questionnaire showed an excellent fit for a 3-factor model, whereas the CPS-NS demonstrated an excellent single-factor fit. Significant relationships with theoretically related constructs suggested concurrent, discriminant, and predictive validity. The findings are expected to significantly further research into our understanding of coaches coaching PS.

Anxiety and perceived psychological stress play an important role in the immune response after exercise.

There are common pathways by which psychological stress and exercise stress alter immunity. However, it remains unknown whether psychological stress plays a role in the in vivo immune response to exercise. We examined the relationship between anxiety and perceived psychological stress reported before exercise and in vivo immunity after exercise using skin sensitisation with Diphenylcyclopropenone (DPCP). In a randomised design, sixty four, thoroughly familiarised, males completed widely used psychological instruments to assess state-anxiety and perceived psychological stress before exercise, and ran either 30 minutes at 60% (30MI) or 80% (30HI) V . O2peak, 120 minutes at 60% (120MI) V . O2peak or rested (CON) before DPCP sensitisation. Cutaneous recall to DPCP was measured as the dermal thickening response to a low-dose series DPCP challenge 4-weeks after sensitisation. After accounting for exercise (R2 = 0.20; P < 0.01), multiple-regression showed that pre-exercise state-anxiety (STAI-S; ΔR2 = 0.19; P < 0.01) and perceived psychological stress (ΔR2 = 0.13; P < 0.05) were moderately associated with the DPCP response after exercise. The STAI-S scores before exercise were considered low-to-moderate in these familiarised individuals (median split; mean STAI-S of low 25 and moderate 34). Further examination showed that the DPCP response after exercise (30MI, 30HI or 120MI) was 62% lower in those reporting low vs. moderate state-anxiety before exercise (mean difference in dermal thickening: -2.6 mm; 95% CI: -0.8 to -4.4 mm; P < 0.01). As such, the results indicate a beneficial effect of moderate (vs. low) state-anxiety and perceived psychological stress on in vivo immunity after exercise. Moreover, correlations were of comparable strength for the relationship between physiological stress (heart rate training impulse) and the summed dermal response to DPCP (r = -0.37; 95% CI: -0.05 to -0.62; P = 0.01), and state-anxiety and the summed dermal response to DPCP (r = 0.39; 95% CI: 0.08 to 0.63; P < 0.01). In conclusion, state-anxiety and perceived psychological stress levels before exercise play animportant role in determining the strength of the in vivo immune response after exercise. These findings indicate a similar strength relationship for the level of state-anxiety prior to exercise and the level of physiological stress during exercise with the in vivo immune response after exercise. Future research is required to investigate exercise-immune responses in athletes, military personnel and others in physically demanding occupations experiencing higher levels of psychological stress than those reported in this study e.g. related to important competition, military operations and major life events. Nevertheless, the present findings support the recommendation that exercise scientists should account for anxiety and psychological stress when examining the immune response to exercise.

The benefit of punishment sensitivity on motor performance under pressure.

OBJECTIVE: Humans are often required to perform demanding cognitive and motor tasks under pressure. However, in such environments there is considerable interindividual variability in the ability to successfully execute actions. Here, we consider how individual differences in self-reported sensitivity to punishment influence skilled motor performance under pressure and whether this relationship is moderated by the temporal detection of threat. METHOD: Across two studies, 160 UK participants (Study 1: N = 80, Mage = 21.6, 52 males; Study 2: N = 80, Mage = 24.95, 45 males) performed a precision-grip task and received either early or late warning of an upcoming stressful manipulation involving social evaluation and performance-dependent incentives. RESULTS: In both studies, we report an interaction where punishment sensitivity was adaptive for motor performance only when threats were detected early and there was opportunity to prepare for the upcoming stressor. Further, our results suggest that the benefits of punishment sensitivity are likely underpinned by the effective use of cognitive strategies. CONCLUSION: Heightened sensitivity to punishment is adaptive for performance under pressure, provided threats are detected early and effective cognitive strategies are implemented.

Kinesthetic Imagery Provides Additive Benefits to Internal Visual Imagery on Slalom Task Performance.

Recent brain imaging research demonstrates that the use of internal visual imagery (IVI) or kinesthetic imagery (KIN) activates common and distinct brain areas. In this paper, we argue that combining the imagery modalities (IVI and KIN) will lead to a greater cognitive representation (with more brain areas activated), and this will cause a greater slalom-based motor performance compared with using IVI alone. To examine this assertion, we randomly allocated 56 participants to one of the three groups: IVI, IVI and KIN, or a math control group. Participants performed a slalom-based driving task in a driving simulator, with average lap time used as a measure of performance. Results revealed that the IVI and KIN group achieved significantly quicker lap times than the IVI and the control groups. The discussion includes a theoretical advancement on why the combination of imagery modalities might facilitate performance, with links made to the cognitive neuroscience literature and applied practice.

The Leader Ship Is Sinking: A Temporal Investigation of Narcissistic Leadership.

Individuals higher in narcissism have leader emergent tendencies. The characteristics of their personality suggest, however, that their leadership qualities will decrease over time as a function of group acquaintance. We present data from two studies that provide the first empirical support for this theoretical position within a transformational leadership framework. In Study 1 (N = 112), we tested narcissistic leadership qualities in groups of unacquainted individuals over a 12-week period. In Study 2 (N = 152), we adopted the same protocol with groups of acquainted individuals. In Study 1, narcissism was positively associated with peer-rated leadership during initial group formation but not later. In Study 2, narcissism was not significantly associated with peer-rated leadership during initial group formation and was negatively associated with peer-rated leadership later. In Study 1, transformational leadership mediated the relationship between narcissism and leadership initially but not later on. In Study 2, transformational leadership failed to mediate the relationship between narcissism and leadership throughout the study. Despite enjoying a honeymoon period of leadership, the appeal and attractiveness of the narcissistic leader rapidly wane. This decline is explained in part by their changing transformational leadership qualities.

Narcissism and antisocial behaviour in sport: The moderating role of self-compassion.

Narcissism, which features the chronic disposition to seek the opportunity to construct and maintain an inflated self, is a known risk for antisocial behaviour. However, knowledge of factors that mitigate the effects of narcissism on antisocial behaviour is lacking. In two studies we explored the hypothesis that self-compassion would protect against the link between narcissism and antisocial behaviour, such that narcissism would be less related to antisocial behaviour when self-compassion was high. Study 1 was a cross-sectional study with a sample of professional footballers (N = 208). Study 2 utilised a sample of competitive athletes from a variety of sports (N = 324) over an eight-month period. The data from both studies supported the hypothesis: Greater self-compassion was associated with a null (Study 1) or significantly attenuated (Study 2) relationship between narcissism and antisocial behaviour. We discuss the implications of the findings, including the benefits of incorporating self-compassion in sport settings.

The influence of postoperative outcomes on survival after esophageal cancer surgery: validation of a consensus-based updated textbook outcome parameter.

BACKGROUND: Esophagectomy in combination with perioperative multimodal therapy is the cornerstone of modern curative treatment for esophageal adenocarcinoma. The primary aim of this study was to assess the influence of textbook outcome (TO) as a composite quality performance indicator (QPI) and its perioperative parameters on survival in patients who underwent esophagectomy with curative intent. METHODS: Consecutive patients who underwent an esophagectomy between January 2014 and December 2022 at Christchurch Hospital were identified from a prospectively maintained hospital database. Univariable and multivariable analyses were performed to assess prognostic factors for each composite and individual postoperative outcome. Survival analysis was performed to evaluate the influence of these outcomes on overall survival. RESULTS: A total of 108 patients underwent an esophagectomy during the study period. The overall and Clavien-Dindo (CD) grade ≥ 3 postoperative complication rates were 62% and 26%, respectively. The anastomotic leak rate was 6.5% (n = 7). The TO rate, 30-day readmission rate, and 30-day mortality rate were 20%, 13%, and 1%, respectively. Resection margin and nodal disease were found to be independent prognostic factors for reduced survival. CONCLUSION: TO as originally defined and its postoperative parameters of 30-day postoperative complications and 30-day readmission are validated QPIs of esophageal cancer surgery. Updating the postoperative complication parameter to include CD grade ≥ 3 complications resulted in a positive association between achieving TO and increased survival. Our findings support the call to redefine TO based on an update to this parameter, making it a more precise QPI of esophageal cancer surgery.

Predicting patient dissatisfaction following laparoscopic Nissen fundoplication: an analysis of symptoms.

BACKGROUND: Nissen fundoplication is a well-established treatment for gastroesophageal reflux disease (GERD) with a high success rate and a long-lasting effect. However, the literature reports that a persistent, small group of patients is not fully satisfied with the outcome. Identifying this patient group preoperatively would prevent disappointment for both patients and surgeon. This has proven difficult since dissatisfaction was related to nondisease-related factors instead of typical symptoms of GERD or the objective findings of investigations. We studied our series of patients who underwent laparoscopic Nissen fundoplication to identify predictors of patient dissatisfaction and the impact of surgery on individual symptoms. METHODS: All consecutive private patients undergoing Nissen fundoplication were asked to complete a preoperative and postoperative questionnaire concerning symptoms, medication use, and satisfaction. Demographics, investigations, complications, and reinterventions were documented. A standard laparoscopic Nissen fundoplication was performed. RESULTS: Over an 11-year period 222 patients underwent surgery for GERD. The postoperative response rate to the questionnaire was 77.5 %, with dissatisfaction reported by 12.8 % of the patients. Of these dissatisfied patients, only 13.6 % had proven disease recurrence. Both satisfied and dissatisfied patients presented with an inconsistent pattern of symptoms. None of the preoperative symptoms and investigations or the patient's age and gender was predictive of postoperative dissatisfaction. Only postoperative heartburn, regurgitation, and bloating significantly correlated with patient dissatisfaction. CONCLUSION: Nissen fundoplication has a very high satisfaction rate overall. A small percentage of patients are not fully satisfied and dissatisfaction is associated with reported persistent symptoms and side effects of surgery rather than gender or preoperative symptom pattern, severity of esophagitis, or total 24 h esophageal acid exposure.

The influence of short-term postoperative outcomes on overall survival after gastric cancer surgery.

BACKGROUND: Gastrectomy with lymphadenectomy in combination with perioperative chemotherapy is the cornerstone of modern curative treatment for gastric adenocarcinoma. The primary objective of this study was to assess the influence of textbook outcome, postoperative complications, and readmission on survival in patients who underwent gastric cancer surgery. METHODS: Consecutive patients who underwent curative and prophylactic gastric resections from 2014 to 2022 at Christchurch Hospital were identified from the hospital database. Multivariable analyses were performed to assess risk factors for each postoperative outcome. A survival analysis was performed to evaluate the influence of these outcomes on overall survival. RESULTS: Seventy-seven patients underwent a gastric resection during the study period. Thirteen were prophylactic resections for E-cadherin gene mutations and 64 were for malignancy. The overall postoperative complication rate was 34%, with an anastomotic leak rate of 8% (n = 6). The 30-day readmission rate, 30-day mortality rate and 90-day mortality rate were 17%, 1%, and 5% respectively. No sociodemographic differences were identified in each outcome. An increasing day-4 CRP trajectory was observed in patients with an anastomotic leak. Postoperative complications and nodal disease were independent prognostic factors for reduced survival. CONCLUSIONS: Textbook outcome, postoperative complications, and readmission are validated quality performance indicators of gastric cancer surgery. Postoperative complications are associated with poor overall survival independent of severity or type. The underlying mechanisms of this influence remain elusive. The aggressive biology of gastric cancer, combined with the surgical morbidity and its negative influence on survival, highlights the importance of ongoing quality improvement.

Good perceived sleep quality protects against the raised risk of respiratory infection during sleep restriction in young adults.

STUDY OBJECTIVES: Prospectively examine the association between sleep restriction, perceived sleep quality (PSQ) and upper respiratory tract infection (URTI). METHODS: In 1318 military recruits (68% males) self-reported sleep was assessed at the beginning and end of a 12-week training course. Sleep restriction was defined as an individualized reduction in sleep duration of ≥2 hours/night compared with civilian life. URTIs were retrieved from medical records. RESULTS: On commencing training, approximately half of recruits were sleep restricted (52%; 2.1 ± 1.6 h); despite the sleep debt, 58% of recruits with sleep restriction reported good PSQ. Regression adjusted for covariates showed that recruits commencing training with sleep restriction were more likely to suffer URTI during the course (OR = 2.93, 95% CI 1.29-6.69, p = .011). Moderation analysis showed this finding was driven by poor PSQ (B = -1.12, SE 0.50, p = .023), as no significant association between sleep restriction and URTI was observed in recruits reporting good PSQ, despite a similar magnitude of sleep restriction during training. Associations remained in the population completing training, accounting for loss to follow-up. Recruits reporting poor PSQ when healthy at the start and end of training were more susceptible to URTI (OR = 3.16, 95% CI 1.31-7.61, p = .010, vs good PSQ). CONCLUSION: Good perceived sleep quality was associated with protection against the raised risk of respiratory infection during sleep restriction. Studies should determine whether improvements in sleep quality arising from behavioral sleep interventions translate to reduced respiratory infection during sleep restriction.

Can patient symptoms reliably predict major oesophageal motility disorders assessed by conventional water perfusion manometry?

AIM: This study aimed to determine whether symptoms can reliably predict a major disorder of oesophageal motility as assessed by conventional water perfusion manometry. METHODS: Data from patients who underwent conventional water perfusion oesophageal manometry and a pre-manometry questionnaire between October 1998 and August 2018 were extracted from a database. Clinical features (dysphagia, chest pain, regurgitation, dysphagia to a bread challenge) and combinations of these clinical features were compared to manometric diagnoses. RESULTS: Data from 546 patients were analysed. Thirty-three (6%) patients had a major disorder of motility, and 513 (94%) had normal manometry or a minor disorder of motility. 'Any dysphagia' (dysphagia as a symptom or dysphagia to a bread challenge) or 'chest pain' was experienced by all patients with a major disorder of motility and 435 of 513 patients with normal manometry or a minor disorder of motility (p=0.009). Sensitivity was 100%, and specificity was 15%, in identifying patients with a major disorder of motility using symptom combinations and a bread challenge. CONCLUSION: Symptoms and provoked dysphagia to bread were able to predict patients with a major disorder of oesophageal motility with a sensitivity of 100%. However, as specificity was 15%, confirmation with manometry is indicated if possible.

Influence of Vitamin D Supplementation by Simulated Sunlight or Oral D3 on Respiratory Infection during Military Training.

PURPOSE: This study aimed to determine the relationship between vitamin D status and upper respiratory tract infection (URTI) of physically active men and women across seasons (study 1) and then to investigate the effects on URTI and mucosal immunity of achieving vitamin D sufficiency (25(OH)D ≥50 nmol·L-1) by a unique comparison of safe, simulated sunlight or oral D3 supplementation in winter (study 2). METHODS: In study 1, 1644 military recruits were observed across basic military training. In study 2, a randomized controlled trial, 250 men undertaking military training received placebo, simulated sunlight (1.3× standard erythemal dose, three times per week for 4 wk and then once per week for 8 wk), or oral vitamin D3 (1000 IU·d-1 for 4 wk and then 400 IU·d-1 for 8 wk). URTI was diagnosed by a physician (study 1) and by using the Jackson common cold questionnaire (study 2). Serum 25(OH)D, salivary secretory immunoglobulin A (SIgA), and cathelicidin were assessed by liquid chromatography-mass spectrometry LC-MS/MS and enzyme-linked immunosorbent assay. RESULTS: In study 1, only 21% of recruits were vitamin D sufficient during winter. Vitamin D-sufficient recruits were 40% less likely to suffer URTI than recruits with 25(OH)D <50 nmol·L-1 (OR = 0.6, 95% confidence interval = 0.4-0.9), an association that remained after accounting for sex and smoking. Each URTI caused, on average, three missed training days. In study 2, vitamin D supplementation strategies were similarly effective to achieve vitamin D sufficiency in almost all (≥95%). Compared with placebo, vitamin D supplementation reduced the severity of peak URTI symptoms by 15% and days with URTI by 36% (P < 0.05). These reductions were similar with both vitamin D strategies (P > 0.05). Supplementation did not affect salivary secretory immunoglobulin A or cathelicidin. CONCLUSION: Vitamin D sufficiency reduced the URTI burden during military training.