Gary Yu


Gary Yu headshot

Gary Yu

Associate Research Scientist
Adjunct Associate Professor

1 212 998 5486

433 First Ave
Room 745G
New York, NY 10010
United States

Gary Yu's additional information

Gary Yu, PhD, is an associate research scientist and adjunct associate professor at NYU Rory Meyers College of Nursing. He has conducted statistical analyses of data on multiple NIH-funded research projects. 

His dissertation focused on creating a new statistical technique for clustering individuals based on their patterns of responses (e.g., on a questionnaire of drug items). He extended the finite mixture model to allow for the number of repeated measures to be incorporated and contribute to the clustering of individuals. The dimension of the repeated measures can be summarized into a count of responses and can be assumed to follow a truncated Poisson distribution. This information can be included in what is called a dimension informative finite mixture model (DIMM) [NIH/NHLBI R01HL111195]. This model was originally developed and applied to continuous physical activity data, and it has been applied to binary drug items among men who have sex with men (MSM) in the United States and among male sex workers (MSW) in Vietnam.

Yu earned his PhD in biostatistics from Columbia University, MPH in epidemiology from Boston University, and BS in Bioengineering from the University of California, Berkeley.

PhD, Biostatistics - Columbia University (2014)
MPH, Epidemiology - Boston University (2006)
BS, Bioengineering - University of California, Berkeley (2004)

Substance use

Faculty Honors Awards

Bernard Challenor Spirit Prize, Mailman School of Public Health, Columbia University (2014)


Multiple Chronic Conditions among Seriously Ill Adults Receiving Palliative Care

Murali, K. P., Yu, G., Merriman, J. D., Vorderstrasse, A., Kelley, A. S., & Brody, A. A. (2023). Western Journal of Nursing Research, 45(1), 14-24. 10.1177/01939459211041174
The objective of this study was to characterize multiple chronic conditions (MCCs) among seriously ill adults receiving palliative care at the end of life. A latent class analysis was conducted to identify latent subgroups of seriously ill older adults based on a baseline Charlson comorbidity index (CCI) measurement, a measure of comorbidity burden, and mortality risk. The three latent subgroups were: (1) low to moderate CCI with MCC, (2) high CCI with MCC, and (3) high CCI and metastatic cancer. The “low to moderate CCI and MCC” subgroup included older adults with chronic obstructive pulmonary disease (COPD), cardiovascular disease, congestive heart failure, myocardial infarction, dementia, diabetes, and lymphoma. A “high CCI and MCC” subgroup included individuals with severe illness including liver or renal disease among other MCCs. A “high CCI and metastatic cancer” included all participants with metastatic cancer. This study sheds light on the MCC profile of seriously ill adults receiving palliative care.

Combined Race and Gender Trend Disparities in Depressive Symptoms among U.S. High School Students: 1999–2019

Grunin, L., Yu, G., & Cohen, S. (2022). Issues in Mental Health Nursing, 43(9), 824-834. 10.1080/01612840.2022.2067274
In 2019, over 3.2 million adolescents in the U.S. reported depressive symptoms—a number that continues to increase annually. Not only can depression negatively impact an adolescent’s academic performance, social development, and cognitive function, but it is also the most common condition associated with suicide. Previous studies have reported prevalence rates and statistical trends by either gender or race. We conducted an in-depth analysis of the current racial and gender trend disparities in adolescent depressive symptoms by examining linear and quadratic trends from the Youth Behavior Risk Survey (N = 158,601) over two decades (1999–2019), stratified by gender and race subgroups, both separately and combined. This novel quantitative method allows for a more nuanced approach when exploring social and cultural influences on adolescent depressive symptoms. We found a significant difference in the prevalence of depressive symptoms between males and females among Black, Hispanic, and multiracial adolescents in each separate year of pooled data. However, an increased prevalence trend over the 20-year period was only seen among the females of these three racial categories. White and Asian female adolescents also exhibited a statistical increase in prevalence of depressive symptoms over time. The only group of males with a significant trend increase over time were White adolescents. Understanding the intersection of gender and race in adolescent depressive symptoms trends enhances evidence for nurses and other healthcare professionals when developing and implementing targeted, effective prevention and intervention measures.

Comparison of social cognition using an adapted Chinese version of the Reading the Mind in the Eyes Test in drug-naive and regularly medicated individuals with chronic schizophrenia and healthy controls in rural China

Deng, F., Phillips, M. R., Cai, B., Yu, G., Qian, M., Grivel, M. M., Chen, H., Ouyang, X., Xue, F., Zhao, M., Kegeles, L. S., Susser, E. S., Keshavan, M. S., Stone, W. S., & Yang, L. H. (2022). Psychological Medicine, 52(15), 3655-3667. 10.1017/S003329172100043X
Background Social cognition has not previously been assessed in treatment-naive patients with chronic schizophrenia, in patients over 60 years of age, or in patients with less than 5 years of schooling. Methods We revised a commonly used measure of social cognition, the Reading the Mind in the Eyes Test (RMET), by expanding the instructions, using both self-completion and interviewer-completion versions (for illiterate respondents), and classifying each test administration as 'successfully completed' or 'incomplete'. The revised instrument (RMET-CV-R) was administered to 233 treatment-naive patients with chronic schizophrenia (UT), 154 treated controls with chronic schizophrenia (TC), and 259 healthy controls (HC) from rural communities in China. Results In bivariate and multivariate analyses, successful completion rates and RMET-CV-R scores (percent correct judgments about emotion exhibited in 70 presented slides) were highest in HC, intermediate in TC, and lowest in UT (adjusted completion rates, 97.0, 72.4, and 49.9%, respectively; adjusted RMET-CV-R scores, 45.4, 38.5, and 34.6%, respectively; all p < 0.02). Stratified analyses by the method of administration (self-completed v. interviewer-completed) and by education and age ('educated-younger' v. 'undereducated-older') show the same relationship between groups (i.e. NC>TC>UT), though not all differences remain statistically significant. Conclusions We find poorer social cognition in treatment-naive than in treated patients with chronic schizophrenia. The discriminant validity of RMET-CV-R in undereducated, older patients demonstrates the feasibility of administering revised versions of RMET to patients who may otherwise be considered ineligible due to education or age by changing the method of test administration and carefully assessing respondents' ability to complete the task successfully.

Correlates of Suicide Ideation and Resilience Among Native- and Foreign-Born Adolescents in the United States

Stark, L., Seff, I., Yu, G., Salama, M., Wessells, M., Allaf, C., & Bennouna, C. (2022). Journal of Adolescent Health, 70(1), 91-98. 10.1016/j.jadohealth.2021.07.012
Purpose: Nearly 20% of U.S. adolescents have considered suicide. Yet, gaps remain in understanding correlates of resilience and suicide risk, especially among populations born outside the United States who may face unique migration- and acculturation-related stressors. This study adds to the literature by exploring correlates of suicide ideation among a diverse population. Methods: This study analyzes quantitative data (N = 357) from the Study of Adolescent Lives after Migration to America, in Detroit and Harrisonburg. More than 40% of the sample was born outside the United States, with the majority born in the Middle East and North Africa. Path analysis was used to model dual outcomes of resilience and suicide ideation using measures of hope, school belonging, stressful life events, and being born outside the United States. Results: Suicide ideation and resilience were negatively correlated (ß = -.236[.069]; p < .001). Adolescents with greater hope (ß = .367; p < .001) and school belonging (ß = .407; p < .001) reported higher resilience, while lower levels of school belonging correlated with higher levels of suicide ideation (ß = -.248; p = .009). More stressful life events were associated with suicide ideation (ß = .243; p < .001), while fewer were correlated with resilience (ß = -.106; p = .003). Being born outside the United States was associated with suicide ideation (ß = .186; P-.015), with this finding driven by those from the Middle East and North Africa region, who faced significantly increased risk of suicide ideation (ß = .169; p = .036). Conclusions: Findings suggest that adolescents born in the Middle East and North Africa region may represent a vulnerable group needing targeted and culturally responsive interventions to destigmatize mental health and psychosocial well-being, boost existing sources of resilience, and encourage help-seeking behaviors.

Multimorbidity patterns in adult day health center clients with dementia: a latent class analysis

Sadarangani, T., Perissinotto, C., Boafo, J., Zhong, J., & Yu, G. (2022). BMC Geriatrics, 22(1). 10.1186/s12877-022-03206-0
Background: Persons living with dementia (PLWD) in adult day centers (ADCs) represent a complex and vulnerable population whose well-being is at risk based on numerous factors. Greater knowledge of the interaction between dementia, chronic conditions, and social determinants of health would enable ADCs to identify and target the use of their resources to better support clients in need of in-depth intervention. The purpose of this paper is to (a) classify PLWD in ADCs according to their level of medical complexity and (b) identify the demographic, functional, and clinical characteristics of those with the highest degree of medical complexity. Methods: This was a secondary data analysis of 3052 clients with a dementia diagnosis from 53 ADCs across the state of California between 2012 and 2019. The most common diagnosis codes were organized into 28 disease categories to enable a latent class analysis (LCA). Chi-square test, analysis of variance (ANOVA), and Kruskal-Wallis tests were conducted to examine differences among latent classes with respect to clinical and functional characteristics. Results: An optimal 4-class solution was chosen to reflect chronic conditions among PLWD: high medical complexity, moderate medical complexity, low medical complexity, and no medical complexity. Those in the high medical complexity were taking an average of 12.72 (+/− 6.52) medications and attending the ADC an average of 3.98 days (+/− 1.31) per week—values that exceeded any other class. They also experienced hospitalizations more than any other group (19.0%) and met requirements for the nursing facility level of care (77.4%). In addition, the group experienced the greatest frequency of bladder (57.5%) and bowel (15.7%) incontinence. Conclusions: Our results illustrate a high degree of medical complexity among PLWD in ADCs. A majority of PLWD not only have multimorbidity but are socially disadvantaged. Our results demonstrate that a comprehensive multidisciplinary approach that involves community partners such as ADCs is critically needed that addresses functional decline, loneliness, social isolation, and multimorbidity which can negatively impact PLWD.

A Web- and Mobile-Based Intervention for Women Treated for Breast Cancer to Manage Chronic Pain and Symptoms Related to Lymphedema: Results of a Randomized Clinical Trial

Fu, M. R., Axelrod, D., Guth, A. A., Scagliola, J., Rampertaap, K., El-Shammaa, N., Qiu, J. M., McTernan, M. L., Frye, L., Park, C. S., Yu, G., Tilley, C., & Wang, Y. (2022). JMIR Cancer, 8(1). 10.2196/29485
Background: The-Optimal-Lymph-Flow (TOLF) is a patient-centered, web- and mobile-based mHealth system that delivers safe, easy, and feasible digital therapy of lymphatic exercises and limb mobility exercises. Objective: The purpose of this randomized clinical trial (RCT) was to evaluate the effectiveness of the web- and mobile-based TOLF system for managing chronic pain and symptoms related to lymphedema. The primary outcome includes pain reduction, and the secondary outcomes focus on symptom relief, limb volume difference measured by infrared perometer, BMI, and quality of life (QOL) related to pain. We hypothesized that participants in the intervention group would have improved pain and symptom experiences, limb volume difference, BMI, and QOL. Methods: A parallel RCT with a control–experimental, pre- and posttest, and repeated-measures design were used. A total of 120 patients were recruited face-to-face at the point of care during clinical visits. Patients were randomized according to pain in a 1:1 ratio into either the arm precaution (AP) control group to improve limb mobility and arm protection or The-Optimal-Lymph flow (TOLF) intervention group to promote lymph flow and limb mobility. Trial outcomes were evaluated at baseline and at week 12 after the intervention. Descriptive statistics, Fisher exact tests, Wilcoxon rank-sum tests, t test, and generalized linear mixed effects models were performed for data analysis. Results: At the study endpoint of 12 weeks, significantly fewer patients in the TOLF intervention group compared with the AP control group reported chronic pain (45% [27/60] vs 70% [42/60]; odds ratio [OR] 0.39, 95% CI 0.17-0.90; P=.02). Patients who received the TOLF intervention were significantly more likely to achieve a complete reduction in pain (50% [23/46] vs 22% [11/51]; OR 3.56, 95% CI 1.39-9.76; P=.005) and soreness (43% [21/49] vs 22% [11/51]; OR 2.60, 95% CI 1.03-6.81; P=.03). Significantly lower median severity scores were found in the TOLF group for chronic pain (MedTOLF=0, IQR 0-1 vs MedAP=1, IQR 0-2; P=.02) and general bodily pain (MedTOLF=1, IQR=0-1.5 vs MedAP=1, IQR 1-3; P=.04). Compared with the AP control group, significantly fewer patients in the TOLF group reported arm/hand swelling (P=.04), heaviness (P=.03), redness (P=.03), and limited movement in shoulder (P=.02) and arm (P=.03). No significant differences between the TOLF and AP groups were found in complete reduction of aching (P=.12) and tenderness (P=.65), mean numbers of lymphedema symptom reported (P=.11), ≥5% limb volume differences (P=.48), and BMI (P=.12). Conclusions: The TOLF intervention had significant benefits for breast cancer survivors to manage chronic pain, soreness, general bodily pain, arm/hand swelling, heaviness, and impaired limb mobility. The intervention resulted in a 13% reduction (from 40% [24/60] to 27% [16/60]) in proportions of patients who took pain medications compared with the AP control group, which had a 5% increase (from 40% [24/60] to 45% [27/60]). A 12% reduction (from 27% [16/60] to 15% [9/60]) in proportions of patients with ≥5% limb volume differences was found in the TOLF intervention, while a 5% increase in the AP control group (from 40% [24/60] to 45% [27/60]) was found. In conclusion, the TOLF intervention can be a better choice for breast cancer survivors to reduce chronic pain and limb volume.

Associations of Insomnia Symptoms With Cognition in Persons With Heart Failure

Gharzeddine, R., Yu, G., McCarthy, M. M., & Dickson, V. V. (2021). Western Journal of Nursing Research, 43(12), 1105-1117. 10.1177/0193945920988840
Although cognitive impairment is common among persons with heart failure and negatively impacts self-care, hospitalization, and mortality, the associations between cognitive impairment and insomnia symptoms are not clearly understood. The purpose of this study was to explore these associations and examine if they are maintained after adjusting for relevant sociodemographic, clinical, and lifestyle factors. Guided by the Neurocognitive model of insomnia and sleep and the self-care conceptual model, a cross-sectional data analysis using parametric testing was conducted on the Health and Retirement Study wave 2016. Difficulty initiating sleep and early morning awakening, but not difficulty maintaining sleep were significantly associated with poorer cognitive performance in the bivariate and multivariate analysis. Our results are suggestive of different phenotypes of insomnia symptoms that may have different associations with cognition in persons with heart failure. Further research using objective measurements of insomnia symptoms and detailed neuropsychiatric testing of cognition is needed to confirm this conclusion.

Brush swab as a noninvasive surrogate for tissue biopsies in epigenomic profiling of oral cancer

Viet, C. T., Zhang, X., Xu, K., Yu, G., Asam, K., Thomas, C. M., Callahan, N. F., Doan, C., Walker, P. C., Nguyen, K., Kidd, S. C., Lee, S. C., Grandhi, A., Allen, C. T., Young, S., Melville, J. C., Shum, J. W., Viet, D. T., Herford, A. S., Roden, D. F., Gonzalez, M. L., Zhong, J. F., & Aouizerat, B. E. (2021). Biomarker Research, 9(1). 10.1186/s40364-021-00349-x
Background: Oral squamous cell carcinoma (OSCC) has poor survival rates. There is a pressing need to develop more precise risk assessment methods to tailor clinical treatment. Epigenome-wide association studies in OSCC have not produced a viable biomarker. These studies have relied on methylation array platforms, which are limited in their ability to profile the methylome. In this study, we use MethylCap-Seq (MC-Seq), a comprehensive methylation quantification technique, and brush swab samples, to develop a noninvasive, readily translatable approach to profile the methylome in OSCC patients. Methods: Three OSCC patients underwent collection of cancer and contralateral normal tissue and brush swab biopsies, totaling 4 samples for each patient. Epigenome-wide DNA methylation quantification was performed using the SureSelectXT Methyl-Seq platform. DNA quality and methylation site resolution were compared between brush swab and tissue samples. Correlation and methylation value difference were determined for brush swabs vs. tissues for each respective patient and site (i.e., cancer or normal). Correlations were calculated between cancer and normal tissues and brush swab samples for each patient to determine the robustness of DNA methylation marks using brush swabs in clinical biomarker studies. Results: There were no significant differences in DNA yield between tissue and brush swab samples. Mapping efficiency exceeded 90% across all samples, with no differences between tissue and brush swabs. The average number of CpG sites with at least 10x depth of coverage was 2,716,674 for brush swabs and 2,903,261 for tissues. Matched tissue and brush swabs had excellent correlation (r = 0.913 for cancer samples and r = 0.951 for normal samples). The methylation profile of the top 1000 CpGs was significantly different between cancer and normal samples (mean p-value = 0.00021) but not different between tissues and brush swabs (mean p-value = 0.11). Conclusions: Our results demonstrate that MC-Seq is an efficient platform for epigenome profiling in cancer biomarker studies, with broader methylome coverage than array-based platforms. Brush swab biopsy provides adequate DNA yield for MC-Seq, and taken together, our findings set the stage for development of a non-invasive methylome quantification technique for oral cancer with high translational potential.

Characterizing Glycemic Control and Sleep in Adults with Long-Standing Type 1 Diabetes and Hypoglycemia Unawareness Initiating Hybrid Closed Loop Insulin Delivery

Malone, S. K., Peleckis, A. J., Grunin, L., Yu, G., Jang, S., Weimer, J., Lee, I., Rickels, M. R., & Goel, N. (2021). Journal of Diabetes Research, 2021. 10.1155/2021/6611064
Nocturnal hypoglycemia is life threatening for individuals with type 1 diabetes (T1D) due to loss of hypoglycemia symptom recognition (hypoglycemia unawareness) and impaired glucose counter regulation. These individuals also show disturbed sleep, which may result from glycemic dysregulation. Whether use of a hybrid closed loop (HCL) insulin delivery system with integrated continuous glucose monitoring (CGM) designed for improving glycemic control, relates to better sleep across time in this population remains unknown. The purpose of this study was to describe long-term changes in glycemic control and objective sleep after initiating hybrid closed loop (HCL) insulin delivery in adults with type 1 diabetes and hypoglycemia unawareness. To accomplish this, six adults (median age=58 y) participated in an 18-month ongoing trial assessing HCL effectiveness. Glycemic control and sleep were measured using continuous glucose monitoring and wrist accelerometers every 3 months. Paired sample t-tests and Cohen's d effect sizes modeled glycemic and sleep changes and the magnitude of these changes from baseline to 9 months. Reduced hypoglycemia (d=0.47-0.79), reduced basal insulin requirements (d=0.48), and a smaller glucose coefficient of variation (d=0.47) occurred with medium-large effect sizes from baseline to 9 months. Hypoglycemia awareness improved from baseline to 6 months with medium-large effect sizes (Clarke score (d=0.60), lability index (d=0.50), HYPO score (d=1.06)). Shorter sleep onset latency (d=1.53; p<0.01), shorter sleep duration (d=0.79), fewer total activity counts (d=1.32), shorter average awakening length (d=0.46), and delays in sleep onset (d=1.06) and sleep midpoint (d=0.72) occurred with medium-large effect sizes from baseline to 9 months. HCL led to clinically significant reductions in hypoglycemia and improved hypoglycemia awareness. Sleep showed a delayed onset, reduced awakening length and onset latency, and maintenance of high sleep efficiency after initiating HCL. Our findings add to the limited evidence on the relationships between diabetes therapeutic technologies and sleep health. This trial is registered with (NCT03215914).

Co-Occurrence of Symptoms and Gut Microbiota Composition Before Neoadjuvant Chemotherapy and Radiation Therapy for Rectal Cancer: A Proof of Concept

González-Mercado, V. J., Lim, J., Yu, G., Penedo, F., Pedro, E., Bernabe, R., Tirado-Gómez, M., & Aouizerat, B. (2021). Biological Research for Nursing, 23(3), 513-523. 10.1177/1099800421991656
Purpose: To examine a) whether there are significant differences in gut microbial diversity and in the abundance of gut microbial taxa; and b) differences in predicted functional pathways of the gut microbiome between those participants with high co-occurring symptoms and those with low co-occurring symptoms, prior to neoadjuvant chemotherapy and radiation therapy (CRT) for rectal cancer. Methods: Rectal cancer patients (n = 41) provided stool samples for 16 S rRNA gene sequencing and symptom ratings for fatigue, sleep disturbance, and depressive symptoms prior to CRT. Descriptive statistics were computed for symptoms. Gut microbiome data were analyzed using QIIME2, LEfSe, and the R statistical package. Results: Participants with high co-occurring symptoms (n = 19) had significantly higher bacterial abundances of Ezakiella, Clostridium sensu stricto, Porphyromonas, Barnesiella, Coriobacteriales Incertae Sedis, Synergistiaceae, Echerichia-Shigella, and Turicibacter compared to those with low co-occurring symptoms before CRT (n = 22). Biosynthesis pathways for lipopolysaccharide, L-tryptophan, and colanic acid building blocks were enriched in participants with high co-occurring symptoms. Participants with low co-occurring symptoms showed enriched abundances of Enterococcus and Lachnospiraceae, as well as pathways for β-D-glucoronosides, hexuronide/hexuronate, and nicotinate degradation, methanogenesis, and L-lysine biosynthesis. Conclusion: A number of bacterial taxa and predicted functional pathways were differentially abundant in patients with high co-occurring symptoms compared to those with low co-occurring symptoms before CRT for rectal cancer. Detailed examination of bacterial taxa and pathways mediating co-occurring symptoms is warranted.