Shu Xu
Shu Xu
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Clinical Associate Professor of Biostatistics
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Professional overview
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Dr. Shu Xu’s work represents a balance of both statistical and applied aspects of quantitative methodology. Her primary quantitative interests include evaluating and developing statistical methods for longitudinal data analysis. Specifically, Dr. Xu’s research focuses on various aspects of latent growth models, missing data methods, and causal inference models.
Dr. Xu has collaborated with substance use, family, and health researchers to advance and share her knowledge of quantitative methodology and pursue a better understanding of the social sciences and public health. She has conducted research with the Family Translational Research Group at NYU and the Methodology Center at the Pennsylvania State University.
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Education
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BS, Psychology, East China Normal University, Shanghai, ChinaMS, Quantitative Psychology, University of California, DavisPhD, Quantitative Psychology, University of California, Davis
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Areas of research and study
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BiostatisticsFamily researchLongitudinal Data AnalysisMissing Data MethodsMixture ModelsQuantitative Research
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Publications
Publications
Native Hawaiian and Other Pacific Islanders: Disparities in the Prevalence of Multiple Chronic Conditions
AbstractCabrera, J. D., Cuevas, A. G., Xu, S., & Chang, V. W. (n.d.).Publication year
2025Journal title
American Journal of Health PromotionAbstractPurpose: To examine multimorbidity prevalence by race/ethnicity and unique health disparities for Native Hawaiian and Other Pacific Islanders (NHPI). Design: Cross-sectional study. Setting: This study uses combined data from the 2014 National Health Interview Survey (NHIS) and the 2014 NHPI-NHIS. Sample: 38,965 adults, including a representative sample of 2,026 NHPIs. Measures: Self-reported diagnoses of ten chronic conditions and race/ethnicity, including Non-Hispanic (NH) Whites, NH Blacks, NH Asians, NH NHPIs, Hispanics and NH Mixed Race. Covariates include age, sex, marital status, education, family income, and employment status. Analysis: We used multinomial logistic regression models to evaluate the adjusted association between race/ethnicity and number of chronic conditions: none, 1, and ≥ 2 (multimorbidity). Results: Compared to Whites, Asians and Hispanics (aRRR = 0.39, P <.001 and aRRR = 0.59, P <.001) had significantly lower odds of having multimorbidity relative to no chronic condition. In contrast, Black Americans and NHPIs (aRRR = 1.27, P <.001 and aRRR = 1.22, P <.05) had significantly higher odds of multimorbidity compared to Whites. Of note, NHPIs showed significantly higher odds of multimorbidity compared to Asians (aRRR = 3.07, P <.001). Conclusion: Our findings highlight significantly higher risk of multimorbidity for NHPIs relative to Whites as well as Asians. This underscores the importance of disaggregating NHPI data from Asians as a whole. Future studies should incorporate additional social factors relevant to the NHPI community.Role of social-cognitive factors in the relationship between e-cigarette use and subsequent cigarette smoking among U.S. youth: A causal mediation analysis
Longitudinal association between e-cigarette use and respiratory symptoms among US adults: Findings from the Population Assessment of Tobacco and Health Study Waves 4–5
AbstractKarey, E., Xu, S., He, P., Niaura, R. S., Cleland, C. M., Stevens, E. R., Sherman, S. E., El-Shahawy, O., Cantrell, J., & Jiang, N. (n.d.).Publication year
2024Journal title
PloS oneVolume
19Issue
2AbstractBackground We assessed longitudinal effects of e-cigarette use on respiratory symptoms in a nationally representative sample of US adults by combustible tobacco smoking status. Methods We analyzed Waves 4–5 public-use data from the Population Assessment of Tobacco and Health Study. Study sample included adult respondents who reported no diagnosis of respiratory diseases at Wave 4, and completed Waves 4–5 surveys with no missing data on analytic variables (N = 15,291). Outcome was a validated index of functionally important respiratory symptoms based on 7 wheezing/cough questions (range 0–9). An index score of 2 was defined as having important respiratory symptoms. Weighted lagged logistic regression models were performed to examine the association between e-cigarette use status at Wave 4 (former/current vs. never use) and important respiratory symptoms at Wave 5 by combustible tobacco smoking status (i.e., never/former/current smokers), adjusting for Wave 4 respiratory symptom index, sociodemographic characteristics, secondhand smoke exposure, body mass index, and chronic disease. Results Among current combustible tobacco smokers, e-cigarette use was associated with increased odds of reporting important respiratory symptoms (former e-cigarette use: adjusted odds ratio [AOR] = 1.39, 95% confidence interval [CI]: 1.07–1.81; current e-cigarette use: AOR = 1.55, 95% CI: 1.17–2.06). Among former combustible tobacco smokers, former e-cigarette use (AOR = 1.51, 95% CI: 1.06–2.15)—but not current e-cigarette use (AOR = 1.59, 95% CI: 0.91–2.78)—was associated with increased odds of important respiratory symptoms. Among never combustible tobacco smokers, no significant association was detected between e-cigarette use and important respiratory symptoms (former e-cigarette use: AOR = 1.62, 95% CI: 0.76–3.46; current e-cigarette use: AOR = 0.82, 95% CI: 0.27–2.56). Conclusions The association between e-cigarette use and respiratory symptoms varied by combustible tobacco smoking status. Current combustible tobacco smokers who use e-cigarettes have an elevated risk of respiratory impairments.Prevalence and risk factors of PTSD symptoms: a 3-month follow-up study
The impact of the 2014 military conflict in the east of Ukraine and the Autonomous Republic of the Crimea among patients receiving opioid agonist therapies
Association of Racial Discrimination With Adiposity in Children and Adolescents
AbstractCuevas, A. G., Krobath, D. M., Rhodes-Bratton, B., Xu, S., Omolade, J. J., Perry, A. R., & Slopen, N. (n.d.).Publication year
2023Journal title
JAMA network openVolume
6Issue
7AbstractIMPORTANCE Childhood obesity is a major public health issue and is disproportionately prevalent among children from minority racial and ethnic groups. Personally mediated racism (commonly referred to as racial discrimination) is a known stressor that has been linked to higher body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) in adults, but little is known about the association of racial discrimination and childhood and adolescent adiposity. OBJECTIVE To assess the prospective association between self-reported experiences of racial discrimination and adiposity (BMI and waist circumference) in a large sample of children and adolescents in the Adolescent Brain Cognitive Development (ABCD) study. DESIGN, SETTING, AND PARTICIPANTS This cohort study used complete data from the ABCD study (2017 to 2019), involving a total of 6463 participants. The ABCD study recruited a diverse sample of youths from across the US, with rural, urban, and mountain regions. Data were analyzed from January 12 to May 17, 2023. EXPOSURE The child-reported Perceived Discrimination Scale was used to quantify racial discrimination, reflecting participants’ perceptions of being treated unfairly by others or unaccepted by society based on their race or ethnicity. MAIN OUTCOMES AND MEASURES Weight, height, and waist circumference were measured by trained research assistants. BMI z scores were computed by applying the US Centers for Disease Control and Prevention’s age and sex-specific reference standards for children and adolescents. Waist circumference (inches) was quantified as the mean of 3 consecutive measures. Measurements were taken from time 1 (ie, 2017 to 2019) and time 2 (ie, 2018 to 2020). RESULTS Of the 6463 respondents with complete data, 3090 (47.8%) were female, and the mean (SD) age was 9.95 (0.62) years. Greater racial discrimination exposure at time 1 was associated with higher BMI z score in both unadjusted (β, 0.05; 95% CI, 0.02-0.08) and adjusted regression models (β, 0.04; 95% CI, 0.01-0.08). Discrimination at time 1 was associated with higher waist circumference in unadjusted (β, 0.35; 95% CI, 0.15-0.54) and adjusted (β, 0.24; 95% CI, 0.04-0.44) models. CONCLUSIONS AND RELEVANCE In this cohort study of children and adolescents, racial discrimination was positively associated with adiposity, quantified by BMI z score and waist circumference. Interventions to reduce exposure to racial discrimination in early life may help reduce the risk of excess weight gain across throughout life.Examining the effects of cumulative environmental stressors on Gulf Coast child and adolescent health
AbstractMeltzer, G. Y., Merdjanoff, A. A., Xu, S., Gershon, R., Emrich, C. T., & Abramson, D. M. (n.d.).Publication year
2023Journal title
Population and EnvironmentVolume
45Issue
3AbstractThis study examines how community-level cumulative environmental stress affects child and adolescent emotional distress and chronic health conditions both directly and indirectly through stressors at the household, family, and individual levels. Data comes from the Women and their Children’s Health (WaTCH) Study, which sought to understand the health implications of exposure to the 2010 Deepwater Horizon oil spill (DHOS) among a cohort of 596 mothers with children ages 10 to 17 in southeastern Louisiana. Community-level environmental stress was measured using a newly developed geospatial index. Household-level stressors included previous hurricane impacts, impacts of DHOS, degree of financial difficulty, and degree of housing physical decay. Family stressors included maternal depression, self-rated physical health, and degree of parenting stress. Child stress was based on perceived stress; child mental health was based on serious emotional disturbance; and child physical health was based on diagnosis of chronic illness. Structural equation modeling used weighted least squares means and variance and theta parameterization. Results showed a significant negative direct path between community-level cumulative environmental stress and child/adolescent serious emotional disturbance and chronic illness. However, the indirect relationship through household, family, and individual-level stressors was significant and positive for both child/adolescent serious emotional disturbance and chronic illness. These findings point to the centrality of the household and family in determining child and adolescent physical and mental health outcomes in communities exposed to frequent disasters and ongoing environmental stressors.Predictors of Crosscutting Patterns of Psychological Health and Family Maltreatment
Tutorial on Causal Mediation Analysis With Binary Variables: An Application to Health Psychology Research
Use of electronic nicotine delivery system (ENDS) devices among U.S. Youth and adults: Findings from the Population Assessment of Tobacco and Health Study Waves 1–5
Cigar Use Progression Among New Cigar Initiators: A Two-Part Growth Curve Analysis Among a Youth and Young Adult Cohort
AbstractCantrell, J., Xu, S., Kreslake, J., Liu, M., & Hair, E. (n.d.).Publication year
2022Journal title
Nicotine and Tobacco ResearchVolume
24Issue
1Page(s)
28-36AbstractIntroduction: Youth and young adults (YYAs) are at high risk of cigar use. This study's objective was to examine progression and sociodemographic differences in current cigar use and frequency among new cigar initiators. Aims and Methods: We conducted a two-part latent growth model among a nationally representative cohort of cigar initiators (aged 15-25) to examine 24-month trajectories of current cigar use and frequency (n = 1483). The cohort was recruited via address-based sampling with online data collection from 2014 to 2019 and surveyed approximately every 6 months. Results: The unconditional odds of current cigar use (ie, past 30-day use) within 6 months of initiation was 0.72 (95% confidence interval: 0.63, 0.82), corresponding to a probability of 42%. The odds of current use among recent cigar initiates declined 6 months after initiation and was followed by a stabilization in use over time. Among continued users, frequency (# days used in past 30 days) increased linearly over time but remained low (3.47 days/months at 24 months). Younger individuals, non-Hispanic African Americans, those with lower subjective financial status, and current users of cigarettes, other tobacco products and/or marijuana were at highest risk within 6 months of initiation. Males, younger users, and current cigarette smokers had the highest risk for cigar progression over time. Conclusions: This study is the first to examine longitudinal cigar use patterns among YYA cigar initiators. Findings emphasize the need for research across the cigar use spectrum and the importance of interventions targeted by age, stage of use, cigarette, other tobacco, and marijuana use and key sociodemographics to interrupt use pathways. Implications: This study is the first to examine progression of cigar use among YYAs who have newly initiated cigars. Results show a high probability of current cigar use within 6 months of initiation followed by a rapid decline and stabilization over time. Frequency increases among those who continue using cigars. Males, younger users, and current cigarette smokers had the highest risk for cigar progression over time. Findings emphasize the need for targeting interventions by age, stage of use, cigarette, other tobacco, and marijuana use and key sociodemographics to interrupt use pathways.Passive exposure to e-cigarette emissions is associated with worsened mental health
Recurrent Injecting Drug Use as a Mediator between Psychiatric Disorder and Non-Fatal Overdose
AbstractBarnes, D. M., Xu, S., Cleland, C. M., McKnight, C., & Des Jarlais, D. (n.d.).Publication year
2022Journal title
Substance Use and MisuseVolume
57Issue
8Page(s)
1248-1256AbstractBackground: Unintentional drug overdose has increased markedly in the United States. Studies document an association between psychiatric disorder and unintentional overdose; we extend this research through a preliminary test of a causal model of recurrent injection drug use mediating this relationship. Methods: In a cross-sectional study of 241 adults in New York City with a possible current substance use disorder, we conducted conventional and Imai’s mediation analyses to examine if psychiatric disorder is associated with increased prevalence of ever overdosing and if recurrent injection drug use mediates this association. Our cross-sectional data permit the first step of assessing causal models: testing if statistical associations are consistent with the model. Results: Fifty-eight percent of the sample endorsed previous psychiatric disorder diagnosis and 35.7% reported ever overdosing. Imai’s mediation analysis showed that, adjusting for covariates, the total association between psychiatric diagnosis and ever overdosing (adjusted prevalence difference [aPD] = 0.16, 95% CI 0.04–0.28) was composed of a direct effect (aPD = 0.09, 95% CI −0.03 − 0.21, p = 0.136) and an indirect effect (aPD = 0.07, 95% CI 0.02–0.13). Recurrent injecting drug use contributed to 42% (ratio of indirect effect to total effect; 95% CI 12 − 100%, p = 0.02) of the association between psychiatric diagnosis and ever overdosing. Conventional mediation analysis produced similar results. Conclusions: Our results provide a warrant for taking the necessary next step for assessing a causal model using longitudinal data, potentially providing a strong rationale for intervening on psychiatric disorders to stem overdose.Relationships Between E-cigarette Use and Subsequent Cigarette Initiation Among Adolescents in the PATH Study: an Entropy Balancing Propensity Score Analysis
The Mediating Effect of E-Cigarette Harm Perception in the Relationship between E-Cigarette Advertising Exposure and E-Cigarette Use
Youth E-Cigarette Use and Functionally Important Respiratory Symptoms: The Population Assessment of Tobacco and Health (PATH) Study Waves 3 and 4
Cannabis Use and the Onset of Cigarette and E-cigarette Use: A Prospective, Longitudinal Study among Youth in the United States
E-cigarette use, systemic inflammation, and depression
Self-report measures of coercive process in couple and parent–child dyads.
High Sensitivity and Specificity Screening for Clinically Significant Intimate Partner Violence
Psychology of wearing face masks to prevent transition of COVID-19
The lump-versus-split dilemma in couple observational coding: A multisite analysis of rapid marital interaction coding system data.
Using Security Questions to Link Participants in Longitudinal Data Collection
Patterns of psychological health problems and family maltreatment among United States Air Force members
A New Look at the Psychometrics of the Parenting Scale Through the Lens of Item Response Theory