Optimizing sports performance in China: Investigating the influence of training, recovery, motivation, and environmental support within a moderation-mediation framework.

The expansion of sports in China is astounding. Given the country's focus on athletic achievement, it is crucial to comprehend the different facets of sports. This research examines China's athletic success in training, recuperation, motivation, and environment. The moderation-mediation strategy is used to understand how these variables affect athletic performance. This study fills a gap in understanding Chinese players' on-field performance. The study examined 355 Chinese athletes from various regions and sports. The sample has a balanced gender distribution, diverse age distribution, and representation from various regions. Furthermore, training programs, recovery strategies, motivation, psychological well-being, support systems, and experience levels influence athletes' sports performance. The study reveals that the coefficients indicate that training, recuperation tactics, motivation, and support systems affect athletic performance. Psychological health emerges as a critical mediator in explaining the effects of these factors on performance outcomes. Additionally, athlete experience moderates the influence of these variables, highlighting nuanced differences. These findings offer crucial insights for enhancing the performance of Chinese athletes. By adopting a moderation-mediation approach, this research illuminates the interconnected dynamics among key components, enriching our understanding of avenues for athlete improvement. Specifically, the results underscore the interconnectedness of athletes' psychological well-being, on-field experience, and competitive performance, emphasizing the importance of tailored interventions. This study could help Chinese politicians, sports psychologists, and coaches enhance athletes' performance.

Experimental demonstration of constant amplitude modulation heterodyne interferometry.

In the space gravitational wave detection, numerous laser interferometer strategies have been proposed to reduce the complexity of traditional heterodyne interferometers. Previously, we proposed a novel interferometric strategy and simulated its effectiveness, called CAM (constant amplitude modulation) heterodyne interferometry. Compared with other methods, the CAM can introduce the OPT (optical pilot tone) for the common-mode noise rejection. In this paper, we present the first, to our knowledge, experimental verification of this technique. The experimental results indicate that OPT can successfully eliminate sampling jitter, enabling the corrected noise to meet the requirements of space gravitational wave detection. This provides a new approach for further optical optimization and noise elimination in the future.

Multi-frequency signal acquisition and phase measurement in space gravitational wave detection.

To enhance the accuracy of phase measurement and to prevent tracking errors, it is crucial to effectively read the multi-frequency signal in space gravitational wave detection. In this paper, a novel signal acquisition method called the multi-frequency acquisition algorithm is proposed and implemented. Different from the traditional single-frequency acquisition, the signal characteristics of amplitude and frequency are both considered to better distinguish different frequency components. A phasemeter integrated with the acquisition method and narrow-bandwidth digital phase-locked loop is constructed for the method test and verification. The results show that the multi-frequency acquisition unit can capture all the frequencies of an input signal in several milliseconds. The precision is better than ±200 Hz under a low SNR (signal-to-noise ratio) of 0 dB. The phase noise can reach 2 µrad/Hz1/2 in the frequency range of 0.1-1 Hz and satisfy the requirement of the space gravitational wave detection in all frequency ranges.

Verification of Laser Heterodyne Interferometric Bench for Chinese Spaceborne Gravitational Wave Detection Missions.

Construction of laser heterodyne interferometric bench to measure tiny translation and tilt with picometer- and nanoradian-level sensitivity in the millihertz band is critical for the success of spaceborne gravitational wave detection, including the LISA, Taiji, and Tianqin missions. In this paper, we report on the construction and testing of a laser heterodyne interferometric bench that contains two optical path designs, the dual-beam heterodyne interferometry and the polarization-multiplexing heterodyne interferometry. The measurement sensitivity of translation and tilt reaches below 3 pm/Hz1/2 and 12 nrad/Hz1/2 for frequencies above 10 mHz, respectively. As a technical verification platform, stabilization loops of amplitude and phase and coherence analysis are also conducted through the bench. Furthermore, we demonstrate initial implements of phase-locking technology and multiple degree of freedom measurements as the extended applications of the constructed bench. The achieved results show that the laser interferometric bench would serve as an excellent experimental platform for the technology demonstration and verification of future Chinese spaceborne gravitational wave detection.

Effect of Virtual Reality Upper Limb Rehabilitation Training on Older Adults.

Virtual reality has gained more attention in the physical training field, but few studies focus on the effects of VR on older adults. Based on existing study we suggest that VR-based upper limb training might be more effective for older adults and used functional near inferred spectrum and movement analysis to evaluate the effects of VR-based training on older adults. 20 older and 20 youth adults were recruited to perform VR training by extending their upper limb to reaching the objects, and non-VR training as a contrast. Both age-related and task-related differences were found in cortical activation, showing that the VR training has aroused more cortical activation. The older groups have more intensive movement but perform worse in terms of task completion. Both groups performed better in VR, and the difference in the older group was higher.

Design and Construction of the Optical Bench Interferometer for the Taiji Program.

A kind of full-function two-sided optical bench interferometer (OBI) is designed to meet the practical requirements of the Taiji Program for space gravitational wave detection. The main optical paths are arranged on the A-side for transmission and interference, and other optical paths and electronic devices are placed on the B-side. According to the design scheme, we successfully constructed two OBIs by using hydrogen-oxygen catalytic stress-free bonding technology. When the OBI is installed and adjusted, the position and Angle error of the interference beam are controlled within 30 µm and 50 µrad through the self-designed precision mechanical clamping mechanism and beam position measuring device. The built OBI was placed on the vibration isolation platform in the vacuum tank for the stability test. The test results show that the noise of the OBI is less than 10 pm/√Hz in the frequency band of 0.1 Hz to 1 Hz, which meets the noise budget requirements of the Taiji Pathfinder in the middle- and high-frequency band.

Using DWS Optical Readout to Improve the Sensitivity of Torsion Pendulum.

In space gravitational wave detection missions, a drag-free system is used to keep the test mass (TM) free-falling in an ultralow-noise environment. Ground verification experiments should be carried out to clarify the shielding and compensating capabilities of the system for multiple stray force noises. A hybrid apparatus was designed and analyzed based on the traditional torsion pendulum, and a technique for enhancing the sensitivity of the torsion pendulum system by employing the differential wavefront sensing (DWS) optical readout was proposed. The readout resolution experiment was then carried out on an optical bench that was designed and established. The results indicate that the angular resolution of the DWS signal in optical readout mode can reach the level of 10 nrad/Hz1/2 over the full measurement band. Compared with the autocollimator, the sensitivity of the torsional pendulum is noticeably improved, and the background noise is expected to reach 4.5 × 10-15 Nm/Hz1/2@10 mHz. This method could also be applied to future upgrades of similar systems.

Measurement of pressure discomfort threshold in auricular concha for in-ear wearables design.

In an effort to mitigate the homogenization of in-ear wearables, designers have been focusing on finding new solutions to enhance user comfort. While the concept of pressure discomfort thresholds (PDT) in humans has been applied to product design, research on the auricular concha remains scarce. In this study, we conducted an experiment to measure the PDT at six points in the auricular concha of 80 participants. Our results showed that the tragus was the most sensitive area and that gender, symmetry, and Body Mass Index (BMI)had no significant effect on PDT. Based on these findings, we generated pressure sensitivity maps of the auricular concha to aid in the optimization of in-ear wearable design.

Olanzapine With or Without Fosaprepitant for Preventing Chemotherapy Induced Nausea and Vomiting in Patients Receiving Highly Emetogenic Chemotherapy: A Phase III Randomized, Double-Blind, Placebo-Controlled Trial (ALLIANCE A221602).

PURPOSE: A protocol was developed to evaluate the value of an NK-1 receptor antagonist for preventing nausea and vomiting resulting from highly emetogenic chemotherapy when an olanzapine-based antiemetogenic regimen was used. MATERIALS AND METHODS: A221602, a prospective double-blind, placebo-controlled clinical trial, was developed to compare 2 -olanzapine-containing antiemetic regimens, one with an NK-1 receptor antagonist (aprepitant or fosaprepitant) and one without. Trial patients had a malignant disease for which they received intravenous highly emetogenic chemotherapy (single day cisplatin ≥ 70 mg/m2 or doxorubicin plus cyclophosphamide on 1 day). Patients on both arms received commonly administered doses of a 5-HT3 receptor antagonist, dexamethasone, and olanzapine. Additionally, patients were randomized to receive an NK-1 receptor antagonist (fosaprepitant 150 mg IV or aprepitant 130 mg IV) or a corresponding placebo. The primary objective was to compare the proportion of patients with no nausea for 5 days following chemotherapy between the 2 study arms. This trial was designed to test for the noninferiority of deleting the NK-1 receptor antagonist, with noninferiority defined as a decrease in freedom from nausea by less than 10%. RESULTS: A total of 690 patients were entered on this trial, 50% on each arm. The proportion of patients without nausea for the complete 5-day study period was 7.4% lower (upper limit of the one-sided 95% confidence interval was 13.5%) in the arm without an NK-1 receptor antagonist compared with the arm with an NK-1 receptor antagonist. CONCLUSION: This trial did not provide sufficient evidence to support that deletion of the NK-1 receptor antagonist was as good as keeping it, as a part of a 4-drug antiemetic regimen for highly emetogenic chemotherapy (ClinicalTrials.gov Identifier: NCT03578081).

Study on the Effect of Micro-Force Perturbations and Temperature Fluctuation on Interferometer for the Taiji Program.

To increase the interferometric measurement resolution in the Taiji program, we present a noise suppression method in this paper. Taking the specific micro-force perturbation and temperature fluctuation in the Taiji-1 interferometer as an example, we set up and experimentally verified the corresponding transfer function to quantify the effect of both noise sources on the interferometric results. Consistent results were obtained between the numerical and experimental results for the transfer function. It is instructive to eliminate the micro-force perturbations and temperature fluctuations during on-orbit interferometric measurement for as long as the acquisition of the force or temperature distribution of related surfaces and the corresponding transfer functions. This indicates that the method can be used for noise sensing and more in the field of noise elimination and measurement resolution improvement for future Taiji program interferometers.

Constant amplitude modulation heterodyne interferometry.

Laser interferometer with picometer precision is a key technology in the space gravitational wave detection. Many interferometry strategies have been put forward for the multiple purposes in the past 10 yr. We propose a new interferometry method, called constant amplitude modulation (CAM) heterodyne interferometry. Differently, the CAM provides an optical pilot tone (OPT) for the noise correction theme. Compared with the analog pilot tone, the OPT can record and correct more noises, such as the analog to digital converter sampling jitter, the photodetector noise and the analog front-end noise. From the discussion, the modulated depth ϕmodulate=1.375 rad and the power ratio of the beam split n=0.432 are the best choice for the CAM-modulated parameter. Moreover, a simulated case has been implemented for the verification of the CAM strategy. Therefore, the CAM gives us another excellent choice in the optical design of the interferometer.

A functional near-infrared spectroscopy study of the effects of video game-based bilateral upper limb training on brain cortical activation and functional connectivity.

Video game-based therapies are widely used in rehabilitation. Compared with conventional bilateral upper limb training (CBULT), the effects of video game-based bilateral upper limb training (VGBULT) on brain cortical activation and functional connectivity, still not fully clear. We have developed a VGBULT system, and measured the brain activity of 20 elderly subjects (10 male, mean age = 62.4 ± 5.8) while performing CBULT and VGBULT tasks by using functional near infrared spectroscopy (fNIRS). The results showed that the cerebral cortex of the two groups both showed significant activation (p < 0.05), compared with the baseline; In the VGBLUT group, the activation of motor cortex (MC) and prefrontal cortex (PFC) was stronger, and the functional connectivity between PFC and MC was also enhanced. This study showed that VGBULT is potentially more beneficial for the elderly neural activities and cognitive control, and provides a theoretical basis for future research and development of such rehabilitation products. Moreover, fNIRS is a reliable tool for tracking brain activation in the evaluation of retraining regimens.

Age-related changes in brain functional networks under multisensory-guided hand movements assessed by the functional near - Infrared spectroscopy.

OBJECTIVES: This study aims to explore the age-related effects of hand rehabilitation training under multisensory stimulation interaction on brain functional networks. METHODS: A multisensory stimulation training glove (MSTG) was designed to realize 3 sensory guidance modes, namely audio-visual guidance (AVG), visual guidance (VG) and no guidance (NG). This study recruited 20 older subjects as the experimental group and 22 young people as the control group. Functional near-infrared spectroscopy (fNIRS) was used to monitor haemoglobin concentration in the motor cortex (MC), prefrontal cortex (PFC), temporary lo be (TL) and occipital lobe (OL) under three different guidance stages, and further analysed the cortical activation and functional connectivity (FC). RESULTS: Multisensory guidance stage showed more activation and higher FC in all subjects. The activated brain regions of the older subjects showed bilateral activation, which is consistent with the Hemispheric Asymmetry Reduction in Older Adults (HAROLD) model. In terms of brain region coordination, older people have a more balanced and denser functional network in the left and right hemispheres compared to younger people. Meanwhile, multisensory stimulation produced a positive training effect on the number of training and reaction time. CONCLUSION: Audio-visual combined stimulation had a significant gain effect on hand training at different ages. However, older adults induce a wider range of cortical activations. At the same time, young and older people have different intercortical coordination networks. All these results provide theoretically and applied references for multisensory stimulation in the prevention and rehabilitation of ageing and brain neurological disorders.

Diet and Health-related Quality of Life Among Men on Active Surveillance for Early-stage Prostate Cancer: The Men's Eating and Living Study (Cancer and Leukemia Group 70807 [Alliance]).

BACKGROUND: Health-related quality of life (HRQoL) among patients with localized prostate cancer (PC) on active surveillance (AS) and whether it may be improved through lifestyle-focused interventions remain underdefined. OBJECTIVE: To assess longitudinal changes in HRQoL in patients who received and those who did not receive a behavioral intervention that increased vegetable intake. DESIGN, SETTING, AND PARTICIPANTS: A secondary analysis of participants in the Men's Eating and Living (MEAL) study (Cancer and Leukemia Group 70807 [Alliance]), a randomized trial of vegetable consumption in patients on AS, was conducted. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Patient-reported outcomes (PROs) included the Memorial Anxiety Scale for Prostate Cancer (MAX-PC), the Expanded Prostate Cancer Index Composite 26 (EPIC-26), and the Functional Assessment of Cancer Therapy Scale-Prostate (FACT-P). Areas under the curves (AUCs) were used to summarize serial HRQoL. RESULTS AND LIMITATIONS: PROs were completed in 87% (n = 387) of the intention-to-collect population. Baseline characteristics of patients completing HRQoL measures did not differ significantly from the entire study population or between groups. Baseline scores were high for all PROs and remained stable over 24 mo, with no significant differences from baseline at any time point. In adjusted analyses, there were no significant differences in summary AUC measures comparing control with intervention for the total MAX-PC score (p = 0.173); EPIC-26 domains of urinary incontinence (p = 0.210), urinary obstruction (p = 0.062), bowel health (p = 0.607), sexual health (p = 0.398), and vitality (p = 0.363); and total FACT-P scores (p = 0.471). CONCLUSIONS: Among men with localized PC on AS enrolled in a randomized trial, HRQoL was high across multiple domains at baseline, remained high during follow-up, and did not change in response to a behavioral intervention that increased vegetable intake. PATIENT SUMMARY: Patients with localized prostate cancer enrolled on active surveillance experience minimal cancer-associated anxiety, suffer low levels of cancer-associated symptoms, and perceive high physical and emotional well-being.

Randomized Phase II Study of Two Doses of Pixantrone in Patients with Metastatic Breast Cancer (NCCTG N1031, Alliance).

BACKGROUND: Anthracycline use in metastatic breast cancer (MBC) is hindered by cumulative exposure limits and risk of cardiotoxicity. Pixantrone, a novel aza-anthracenedione with structural similarities to mitoxantrone and anthracyclines, is theorized to exhibit less cardiotoxicity, mainly due to lack of iron binding. We conducted a randomized phase II study to evaluate the efficacy and safety of 2 dosing schedules of pixantrone in patients with refractory HER2-negative MBC. METHODS: Intravenous pixantrone was administered at 180 mg/m2 every 3 weeks (group A) versus 85 mg/m2 on days 1, 8, and 15 of a 28-day cycle (group B). Primary endpoint was objective response rate (ORR) and secondary endpoints included progression-free survival (PFS), median 6-month PFS, overall survival (OS), safety, quality of life, and serial assessment of circulating tumor cells. A 20% ORR was targeted as sufficient for further testing of pixantrone in this patient population. RESULTS: Forty-five patients were evaluable, with 2 confirmed partial responses in group A and 1 in group B. The trial was terminated due to insufficient activity. Overall median PFS and OS were 2.8 (95% confidence interval [CI]: 2.0-4.1) and 16.8 (95% CI: 8.9-21.6) months, respectively. Notable overall grade 3-4 adverse events were the following: neutrophil count decrease (62%), fatigue (16%), and decrease in ejection fraction (EF) (4%). CONCLUSION: Pixantrone has insufficient activity in the second- and third-line MBC setting. It appears, however, to have limited cardiotoxicity. (ClinicalTrials.gov ID: NCT01086605).

Inter-spacecraft offset frequency setting strategy in the Taiji program.

For controlling the beat frequency of heterodyne interferometry so that the Taiji program can detect gravitational waves in space, an offset frequency setting strategy based on a linear programming algorithm is proposed. Considering factors such as Doppler frequency shift, phase-locking scheme, laser relative intensity noise, and phase detector bandwidth, inter-spacecraft offset frequency setting results suitable for the Taiji program are obtained. During the six years of running the detection process, the use of frequency bounds in the range of [5 MHz, 25 MHz] showed that offset frequencies will remain unchanged for a maximum of 1931 days. If the upper and lower bounds are adjusted, and the relative motion between spacecraft is further constrained, the offset frequencies do not need to change during the time of the mission. These results may provide insights into selecting the phase detector and designing operation parameters such as orbit and laser modulation frequency in the Taiji program.

Efficacy of Treatment With Armodafinil for Cancer-Related Fatigue in Patients With High-grade Glioma: A Phase 3 Randomized Clinical Trial.

IMPORTANCE: Nearly 96% of patients with high-grade glioma (HGG) report moderate-to-severe fatigue. Armodafinil is a psychostimulant that might help cancer-related fatigue in patients with HGG. OBJECTIVE: To determine whether armodafinil reduces fatigue in patients with HGG and moderate-to-severe fatigue. DESIGN, SETTING, AND PARTICIPANTS: In this randomized multicenter, phase 3, double-blinded, placebo-controlled clinical trial, adults with HGG and moderate-to-severe fatigue who were clinically stable at least 4 weeks after completing radiation therapy were randomized to receive armodafinil daily (150 mg or 250 mg) or placebo over 8 weeks. A score of at least 6 out of 10 on severity scale for the brief fatigue inventory scale, with 10 being the worst, was required to suggest moderate-to-severe fatigue. Patients were allowed stable doses of corticosteroids but were excluded if they required increasing amounts of corticosteroids, were receiving some other treatment for fatigue, or had an uncontrolled seizure disorder. The study was conducted from June 2013 to December 15, 2019. INTERVENTIONS: Patients were randomized to 150 mg of armodafinil, 250 mg of armodafinil, or placebo for a total of 8 weeks with assessments at weeks 4 and 8. MAIN OUTCOMES AND MEASURES: The primary outcome was efficacy in treating cancer-related fatigue. Secondary outcomes included safety, neurocognitive function, and quality of life. Patients were evaluated at baseline and at weeks 4 and 8. Efficacy between the placebo and the 2 doses of study drug was determined by an improvement by 2 points on the 0 to 10 brief fatigue inventory scale. Kruskal-Wallis and χ2 tests were used and followed by confirmatory analyses. RESULTS: A total of 328 patients were enrolled, of whom 297 had evaluable end point data. Of these, 103 received 150 mg of armodafinil (mean [SD] age, 58.5 [11.9] years; 42 women [40.8%]), 97 250 mg of armodafinil (mean [SD] age, 56.6 [12.5] years; 37 women [38.1%]), and 97 placebo (mean [SD] age, 57.1 [12.5] years; 39 women [40.2%]). There was no difference in the proportion of patients who achieved clinically meaningful fatigue reduction between arms (28% [95% CI 20%-30%] for 150 mg of armodafinil, 28% [95% CI 19%-38%] for 250 mg of armodafinil, and 30% [95% CI 21%-40%] for placebo). There was a statistically significant reduction in global fatigue for corticosteroid users compared with nonusers (-0.7 [95% CI, -1.5 to -0.3] vs -1.7 [95% CI, -2.1 to -1.3]; P < .001). More patients (2 vs 7) reported insomnia with treatment with 250 mg of armodafinil. CONCLUSIONS AND RELEVANCE: The results of this randomized clinical trial found no meaningful benefit of using treatment with armodafinil to reduce cancer-related fatigue in patients with HGG. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01781468.

A low-noise analog frontend design for the Taiji phasemeter prototype.

The Taiji program plans to utilize the laser interferometer to measure the movement at the picometer level between free-floating test masses. As the phase readout equipment, the phasemeter needs to obtain the beat note with an accuracy of µrad/Hz. The main source of noise in the phasemeter is the analog frontend of the analog to digital converter. A self-designed phasemeter prototype with a low-noise analog frontend, which includes the theme of the pilot tone correction, has been developed and tested for the Taiji program in this Note. The experimental results show that the performance of the developed phasemeter can satisfy the Taiji sensitivity requirement in the whole frequency range. The sensitivity of the board can reach 0.5 µrad/Hz in the frequency range of 0.1-1 Hz. Therefore, the prototype gives us a good model for the fully functional Taiji phasemeter.

Prognostic and Predictive Impact of Primary Tumor Sidedness for Previously Untreated Advanced Colorectal Cancer.

BACKGROUND: Unplanned subgroup analyses from several studies have suggested primary tumor sidedness (PTS) as a potential prognostic and predictive parameter in metastatic colorectal cancer (mCRC). We aimed to investigate the impact of PTS on outcomes of mCRC patients. METHODS: PTS data of 9277 mCRC patients from 12 first-line randomized trials in the ARCAD database were pooled. Overall survival (OS) and progression-free survival (PFS) were assessed using Kaplan-Meier and Cox models adjusting for age, sex, performance status, prior radiation/chemotherapy, and stratified by treatment arm. Predictive value was tested by interaction term between PTS and treatment (cetuximab plus chemotherapy vs chemotherapy alone). All statistical tests were 2-sided. RESULTS: Compared with right-sided metastatic colorectal cancer patients (n = 2421, 26.1%), left-sided metastatic colorectal cancer patients (n = 6856, 73.9%) had better OS (median = 21.6 vs 15.9 months; adjusted hazard ratio [HRadj] = 0.71, 95% confidence interval [CI] = 0.67 to 0.76; P < .001) and PFS (median = 8.6 vs 7.5 months; HRadj = 0.80, 95% CI = 0.75 to 0.84; P < .001). Interaction between PTS and KRAS mutation was statistically significant (Pinteraction < .001); left-sidedness was associated with better prognosis among KRAS wild-type (WT) (OS HRadj = 0.59, 95% CI = 0.53 to 0.66; PFS HRadj =0.68, 95% CI = 0.61 to 0.75) but not among KRAS mutated tumors. Among KRAS-WT tumors, survival benefit from anti-EGFR was confirmed for left-sidedness (OS HRadj = 0.85, 95% CI = 0.75 to 0.97; P = .01; PFS HRadj = 0.77, 95% CI = 0.67 to 0.88; P < .001) but not for right-sidedness. CONCLUSIONS: The prognostic value of PTS is restricted to the KRAS-WT population. PTS is predictive of anti-EGFR efficacy, with a statistically significant improvement of survival for left-sidedness mCRC patients. These results suggest treatment choice in mCRC should be based on both PTS and KRAS status.

The Influence of Vitamin D on Mammographic Density: Results from CALGB 70806 (Alliance) a Randomized Clinical Trial.

Current therapies for breast cancer prevention only prevent estrogen receptor positive (ER+) disease and toxicity limits use of these agents. Vitamin D is a potential prevention therapy for both ER+ and ER- disease and is safe with few side effects. This study evaluates the effect of 1-year of vitamin D supplementation on mammographic density (MD), a biomarker of breast cancer risk in a multicenter randomized controlled trial. Premenopausal women with ≥25% MD and no history of cancer were randomly assigned to 2,000 international units (IU) of vitamin D or placebo orally daily for 1 year. Change in percent MD was evaluated using Cumulus software after all participants completed treatment. Three hundred women enrolled between January 2011 and December 2013 with a mean age of 43 and diverse ethnicity [14% Hispanic, 12% African American (AA)]. Supplementation significantly increased vitamin D levels compared with placebo (14.5 ng/mL vs. -1.6 ng/mL; P < 0.0001) with all participants on the vitamin D arm achieving vitamin D sufficiency at 12 months. Vitamin D was safe and well tolerated. After adjustment for baseline MD, the mean between-arm difference (vitamin D vs. placebo) at 1 year was -0.75 (-0.26, 1.76; P = 0.56). A greater effect was seen for women with ≥50% MD and AA women, although neither reached significance. This randomized controlled trial demonstrated significant improvement in vitamin D levels with 2,000 IU for 1 year, with 100% of supplemented women achieving sufficiency. However, a null effect was seen regarding change in MD for premenopausal women (the primary outcome of the study). PREVENTION RELEVANCE: Current therapies for breast cancer prevention only prevent estrogen receptor positive (ER+) disease and are underutilized due to toxicity and side effects. Vitamin D is a potential prevention therapy for both ER+ and ER- disease and is safe with few side effects.