Dr. Andrea S. Mendoza-Vasconez' research has primarily focused on the promotion and maintenance of physical activity among Latino populations, using both quantitative and qualitative research methods. Dr. Mendoza-Vasconez is interested in citizen science as a means of empowering and mobilizing underserved communities, and in the use of technology to tailor interventions in a behavioral precision medicine approach.

Outside of research, Dr. Mendoza-Vasconez loves spending time with her family (especially her baby daughter Olivia), biking, learning new and challenging things (like surfing!), and traveling to new places (which will unfortunately be done sparingly in the future in an effort to reduce her ecological footprint).

Professional Education

  • Doctor of Philosophy, San Diego State University (2019)
  • Bachelor of Arts, Connecticut College (2008)
  • Master of Public Health, Claremont Graduate School (2014)
  • BA, Connecticut College, Film Studies/Computer Science (2008)
  • MPH, Claremont Graduate University, Public Health (2014)
  • PhD, University of California San Diego, Public Health (2019)

Stanford Advisors

All Publications

  • Lapse, Relapse, and Recovery in Physical Activity Interventions for Latinas: a Survival Analysis. International journal of behavioral medicine Mendoza-Vasconez, A. S., Arredondo, E. M., Larsen, B. n., Crespo, N. n., Hurst, S. n., Marcus, B. H. 2021


    Physical activity (PA) research extensively focuses on initiation of PA, yet lapse and relapse among PA intervention participants are less well understood, particularly among minority populations such as Latinas in the USA. This study aimed to (1) determine the probability of lapse during two PA interventions for Latinas; (2) assess demographic, psychosocial, and environmental predictors of the amount of time until first lapse; and (3) identify factors predictive of lapse recovery.Data from 176 Latina intervention participants were pooled. Survival functions and Kaplan-Meier curves were used to illustrate probability of lapse. Cox proportional hazard models assessed predictors of time to lapse. Logistic regressions identified predictors of lapse recovery.The probability of lapse after 1 month of starting to exercise was 18%, escalating to 34% after 4 months. Predictors of earlier lapse included various psychosocial constructs (i.e., self-efficacy and various processes of change), but none of the measured environmental factors, and only one demographic factor (≥ 2 children under 18). Increased use of consciousness raising at 2 months was associated with lower likelihood of lapse recovery, yet use of behavioral processes of change at 6 months was associated with higher likelihood of recovery.Lapsing may not be pre-determined by demographic and environmental characteristics. On the other hand, skills that can be learned through interventions, such as skills to improve self-efficacy, seem important in the delay or prevention of lapses. Results pertaining to lapse recovery are less clear.

    View details for DOI 10.1007/s12529-020-09943-z

    View details for PubMedID 33415695

  • What Is App With Maintenance? Regular And Enhanced Physical Activity Maintenance Among Latinas Mendoza-Vasconez, A. S., Crespo, N., Hurst, S., Larsen, B., Marcus, B., Arredondo, E. LIPPINCOTT WILLIAMS & WILKINS. 2020: 286
  • Design and rationale for a randomized trial of a theory- and technology- enhanced physical activity intervention for Latinas: The Seamos Activas II study. Contemporary clinical trials Benitez, T. J., Dunsiger, S. I., Pekmezi, D. J., Larsen, B. A., Mendoza-Vasconez, A. S., Linke, S. E., Bock, B. C., Gans, K. M., Hartman, S. J., Marcus, B. H. 2020: 106081


    Latina women report disproportionately high rates of physical inactivity and related chronic health conditions. Physical activity (PA) efforts to date have shown modest success in this at-risk population; thus, more effective interventions are necessary to help Latinas reach national PA guidelines and reduce related health disparities. This paper describes the design, rationale, and baseline findings from the Seamos Activas II intervention.The ongoing RCT will test the efficacy of the Seamos Saludables PA print intervention vs. a theory-and technology-enhanced version (Seamos Activas II). The purpose of the study is to increase the percentage of Latinas meeting the national PA guidelines compared to the prior trial, improve biomarkers related to disease, and extend generalizability to a broader and more representative population of Latinas (i.e. Mexican/Mexican-Americans). Intervention refinements included further targeting key constructs of Social Cognitive Theory, and incorporating interactive text message-based self-monitoring strategies. The primary outcome is change in minutes per week of MVPA measured by ActiGraph GT3X+ accelerometers at 6- and 12-months. Secondary PA outcomes assessed by the 7-Day PA Recall will be used to corroborate findings.Participants (N = 199) are Latinas 18-65 years (mean = 43.8) of predominantly Mexican origin (89%). At baseline, objectively measured MVPA was 39.51 min/week (SD = 71.20, median = 10) and self-reported MVPA was 12.47 min/week (SD = 22.54, median = 0).Participants reported generally low self-efficacy and higher cognitive vs. behavioral processes of change.Addressing interactivity and accountability through text messaging, and more rigorously targeting theoretical constructs may be key to helping Latinas achieve nationally recommended PA levels and thereby reducing health disparities.

    View details for DOI 10.1016/j.cct.2020.106081

    View details for PubMedID 32687974

  • Association Between Physical Activity Intervention Website Use and Physical Activity Levels Among Spanish-Speaking Latinas: Randomized Controlled Trial JOURNAL OF MEDICAL INTERNET RESEARCH Linke, S. E., Dunsiger, S. I., Gans, K. M., Hartman, S. J., Pekmezi, D., Larsen, B. A., Mendoza-Vasconez, A. S., Marcus, B. H. 2019; 21 (7): e13063


    The internet's low cost and potential for high reach makes Web-based channels prime for delivering evidence-based physical activity (PA) interventions. Despite the well-studied success of internet-based PA interventions in primarily non-Hispanic white populations, evidence on Spanish-speaking Latinas' use of such interventions is lacking. The recent rise in technology use among Latinas in the United States, a population at heightened risk for low PA levels and related conditions, suggests that they may benefit from Web-based PA interventions tailored to their cultural and language preferences.The goal of the research was to examine participant engagement with various features of an internet-based PA intervention for Latinas and explore how use of these features was differentially associated with adoption and maintenance of PA behavior change.Pasos Hacia la Salud tested a Spanish-language, culturally adapted, individually tailored, internet-based PA intervention versus a Spanish language, internet-based, Wellness Contact Control condition for underactive Latinas (N=205, mean age 39.2 [SD 10.5] years, 84% Mexican American). These analyses examined engagement with the website and explored how use was associated with adoption and maintenance of moderate to vigorous physical activity (MVPA) behavior.Overall, participants logged on to the website an average of 22 times (SD 28) over 12 months, with intervention participants logging on significantly more than controls (29 vs 14.7, P<.001). On average, participants spent more time on the website at months 1, 4, and 6 compared to all other months, with maximum use at month 4. Both log-ins and time spent on the website were significantly related to intervention success (achieving higher mean minutes of MVPA per week at follow-up: b=.48, SE 0.20, P=.02 for objectively measured MVPA and b=.74, SE 0.34, P=.03 for self-reported MVPA at 12 months, controlling for baseline). Furthermore, those meeting guidelines by the Centers for Disease Control and Prevention for PA at 12 months (≥150 minutes per week of MVPA) logged on significantly more than those not meeting guidelines (35 vs 20 over 12 months, P=.002). Among participants in the intervention arm, goal-setting features, personal PA reports, and PA tips were the most used portions of the website. Higher use of these features was associated with greater success in the program (significantly more minutes of self-reported MVPA at 12 months controlling for baseline). Specifically, one additional use of these features per month over 12 months translated into an additional 34 minutes per week of MVPA (goals feature), 12 minutes per week (PA tips), and 42 minutes per week (PA reports).These results demonstrate that greater use of a tailored, Web-based PA intervention, particularly certain features on the site, was significantly related to increased PA levels in NCT01834287;

    View details for DOI 10.2196/13063

    View details for Web of Science ID 000478074300001

    View details for PubMedID 31342902

    View details for PubMedCentralID PMC6685130

  • Effect of physical activity on depression symptoms and perceived stress in Latinas: A mediation analysis MENTAL HEALTH AND PHYSICAL ACTIVITY Mendoza-Vasconez, A. S., Marquez, B., Linke, S., Arredondo, E. M., Marcus, B. H. 2019; 16: 31–37
  • Psychometrics of the self-efficacy for physical activity scale among a Latina women sample BMC PUBLIC HEALTH Mendoza-Vasconez, A. S., Marquez, B., Benitez, T. J., Marcus, B. H. 2018; 18: 1097


    Even though Latinos have become a priority population for the promotion of physical activity in the United States, several widely used scales in physical activity promotion research have not been validated among this population, particularly in Spanish. This study aims to assess the validity and other psychometrics of the Self-Efficacy for Physical Activity scale among a sample of Spanish-speaking Latina women who participated in the Pasos Hacia La Salud intervention. We also explored alternatives for scale simplification.Data from 205 women corresponding to baseline, 6-month, and 12-month time points were analyzed. Internal consistency was assessed. A series of Spearman correlations, t-tests, linear regressions, and logistic regressions were used to assess the concurrent and predictive validity of the Self Efficacy for Physical Activity scale against both self-report and accelerometer-measured physical activity, using both continuous and categorical outcome data. Item Response Theory and factor analysis methods were used to explore alternatives to simplify the scale. Psychometric tests were repeated with the simplified scale.Cronbach's alpha for the original scale was .72, .76, and .78 for baseline, 6-month, and 12-month data respectively. All concurrent validity tests conducted with 6-month and 12-month data, but not with baseline data, were statistically significant. Self-efficacy at 6 months was also predictive of physical activity at 12 months for all tests except one. Based on plots of Option Characteristic Curves, a modified version of the scale was created. Psychometric results of the modified scale were similar to those of the original scale.This study confirmed the scale's reliability and validity, and revealed that the scale's accuracy improves when some response items are collapsed, which is an important finding for future research among populations with low literacy levels.

    View details for DOI 10.1186/s12889-018-5998-0

    View details for Web of Science ID 000444172000001

    View details for PubMedID 30185171

    View details for PubMedCentralID PMC6125999

  • Web-Based Physical Activity Intervention for Latina Adolescents: Feasibility, Acceptability, and Potential Efficacy of the Ninas Saludables Study JOURNAL OF MEDICAL INTERNET RESEARCH Larsen, B., Benitez, T., Cano, M., Dunsiger, S. S., Marcus, B. H., Mendoza-Vasconez, A., Sallis, J. F., Zive, M. 2018; 20 (5): e170


    Physical activity is markedly low in Latina adolescents, yet few physical activity interventions have been attempted in this population. Web-based interventions can incorporate theory-based components, be appealing to adolescents, and have potential for low-cost dissemination.This study aimed to assess the feasibility, acceptability, and potential efficacy of a Web-based physical activity intervention for Latina adolescents in a single-arm pilot trial.A total of 21 Latina adolescents (aged 12-18 years) who could read and write in English and were underactive (<90 min/week) participated in a 12-week, theory-informed Web-based physical activity intervention. The intervention website was modified from a previous Web-based intervention for Latina adults. Web content was individually tailored based on the responses to monthly questionnaires. Feasibility was measured by recruitment, retention, and adherence/engagement, and acceptability was measured by satisfaction surveys. Physical activity was measured at baseline and follow-up (12 weeks) using the 7-day physical activity recall (PAR) interview and accelerometers.Baseline activity as measured by the 7-day PAR and accelerometers was 24.7 (SD 26.11) and 24.8 (SD 38.3) min/week, respectively. At 12 weeks, 19 participants (90%, 19/21) returned. Adherence and engagement with materials were low, but 72% (15/21) of the participants indicated that they were satisfied with the intervention. Activity at 12 weeks increased by 58.8 (SD 11.33) min/week measured by the 7-day PAR (P<.001). Accelerometer-measured activity did not increase. Activities reported at follow-up were more varied than at baseline, including some activities measured poorly by accelerometers (eg, biking and swimming). Participants suggested simplifying the website and incorporating other technologies.Good retention and increases in self-reported activity suggest a promising approach to delivering a physical activity intervention to Latina adolescents. Incorporating other technologies, such as smartphone apps, could make the intervention more engaging, acceptable, and effective.

    View details for DOI 10.2196/jmir.9206

    View details for Web of Science ID 000431799100001

    View details for PubMedID 29743151

    View details for PubMedCentralID PMC5966649

  • Physical activity maintenance among Spanish-speaking Latinas in a randomized controlled trial of an Internet-based intervention JOURNAL OF BEHAVIORAL MEDICINE Hartman, S. J., Dunsiger, S. I., Bock, B. C., Larsen, B. A., Linke, S., Pekmezi, D., Marquez, B., Gans, K. M., Mendoza-Vasconez, A. S., Marcus, B. H. 2017; 40 (3): 392–402


    Spanish-speaking Latinas have some of the lowest rates of meeting physical activity guidelines in the U.S. and are at high risk for many related chronic diseases. The purpose of the current study was to examine the maintenance of a culturally and individually-tailored Internet-based physical activity intervention for Spanish-speaking Latinas. Inactive Latinas (N  =  205) were randomly assigned to a 6-month Tailored Physical Activity Internet Intervention or a Wellness Contact Control Internet Group, with a 6-month follow-up. Maintenance was measured by assessing group differences in minutes per week of self-reported and accelerometer measured moderate to vigorous physical activity (MVPA) at 12 months after baseline and changes in MVPA between the end of the active intervention (month 6) and the end of the study (month 12). Potential moderators of the intervention were also examined. Data were collected between 2011 and 2014, and were analyzed in 2015 at the University of California, San Diego. The Intervention Group engaged in significantly more minutes of MVPA per week than the Control Group at the end of the maintenance period for both self-reported (mean diff. = 30.68, SE = 11.27, p = .007) and accelerometer measured (mean diff. = 11.47, SE = 3.19, p = .01) MVPA. There were no significant between- or within-group changes in MVPA from month 6 to 12. Greater intervention effects were seen for those with lower BMI (BMI × intervention = -6.67, SE = 2.88, p = .02) and lower perceived places to walk to in their neighborhood (access × intervention = -43.25, SE = 19.07, p = .02), with a trend for less family support (social support × intervention = -3.49, SE = 2.05, p = .08). Acculturation, health literacy, and physical activity related psychosocial variables were not significant moderators of the intervention effect during the maintenance period. Findings from the current study support the efficacy of an Internet-delivered individually tailored intervention for maintenance of MVPA gains over time.

    View details for DOI 10.1007/s10865-016-9800-4

    View details for Web of Science ID 000400197500002

    View details for PubMedID 27752866

    View details for PubMedCentralID PMC5393970

  • Promoting Physical Activity among Underserved Populations CURRENT SPORTS MEDICINE REPORTS Mendoza-Vasconez, A. S., Linke, S., Munoz, M., Pekmezi, D., Ainsworth, C., Cano, M., Williams, V., Marcus, B. H., Larsen, B. A. 2016; 15 (4): 290–97


    Underserved populations, including racial/ethnic minorities, individuals with low socioeconomic status, and individuals with physical disabilities, are less likely to engage in sufficient moderate to vigorous physical activity (MVPA) and are thus at increased risk of morbidity and mortality. These populations face unique challenges to engaging in MVPA. Learning how to overcome these challenges is a necessary first step in achieving health equity through health promotion research. In this review of the literature, we discuss issues and strategies that have been used to promote MVPA among individuals from underserved populations, focusing on recruitment, intervention delivery, and the use of technology in interventions. Physical activity promotion research among these vulnerable populations is scarce. Nevertheless, there is preliminary evidence of efficacy in the use of certain recruitment and intervention strategies including tailoring, cultural adaptation, incorporation of new technologies, and multilevel and community-based approaches for physical activity promotion among different underserved populations.

    View details for Web of Science ID 000379753700013

    View details for PubMedID 27399827

    View details for PubMedCentralID PMC5371027

  • Pasos Hacia La Salud: a randomized controlled trial of an internet-delivered physical activity intervention for Latinas INTERNATIONAL JOURNAL OF BEHAVIORAL NUTRITION AND PHYSICAL ACTIVITY Marcus, B. H., Hartman, S. J., Larsen, B. A., Pekmezi, D., Dunsiger, S. I., Linke, S., Marquez, B., Gans, K. M., Bock, B. C., Mendoza-Vasconez, A. S., Noble, M. L., Rojas, C. 2016; 13: 62


    Internet access has grown markedly in Latinos during the past decade. However, there have been no Internet-based physical activity interventions designed for Latinos, despite large disparities in lifestyle-related conditions, such as obesity and diabetes, particularly in Latina women. The current study tested the efficacy of a 6-month culturally adapted, individually tailored, Spanish-language Internet-based physical activity intervention.Inactive Latinas (N = 205) were randomly assigned to the Tailored Physical Activity Internet Intervention or the Wellness Contact Control Internet Group. Participants in both groups received emails on a tapered schedule over 6 months to alert them to new content on the website. The primary outcome was minutes/week of moderate to vigorous physical activity (MVPA) at 6 months as measured by the 7-Day Physical Activity Recall; activity was also measured by accelerometers. Data were collected between 2011 and 2014 and analyzed in 2015 at the University of California, San Diego.Increases in minutes/week of MVPA were significantly greater in the Intervention Group compared to the Control Group (mean difference = 50.00, SE = 9.5, p < 0.01). Increases in objectively measured MVPA were also significantly larger in the Intervention Group (mean differences = 31.0, SE = 10.7, p < .01). The Intervention Group was also significantly more likely to meet national physical activity guidelines at 6 months (OR = 3.12, 95% CI 1.46-6.66, p < .05).Findings from the current study suggest that this Internet-delivered individually tailored intervention successfully increased MVPA in Latinas compared to a Wellness Contact Control Internet Group.NCT01834287.

    View details for DOI 10.1186/s12966-016-0385-7

    View details for Web of Science ID 000377079100001

    View details for PubMedID 27234302

    View details for PubMedCentralID PMC4884436

  • Adapting Technological Interventions to Meet the Needs of Priority Populations PROGRESS IN CARDIOVASCULAR DISEASES Linke, S. E., Larsen, B. A., Marquez, B., Mendoza-Vasconez, A., Marcus, B. H. 2016; 58 (6): 630–38


    Cardiovascular diseases (CVD) comprise the leading cause of mortality worldwide, accounting for 3 in 10 deaths. Individuals with certain risk factors, including tobacco use, obesity, low levels of physical activity, type 2 diabetes mellitus, racial/ethnic minority status and low socioeconomic status, experience higher rates of CVD and are, therefore, considered priority populations. Technological devices such as computers and smartphones are now routinely utilized in research studies aiming to prevent CVD and its risk factors, and they are also rampant in the public and private health sectors. Traditional health behavior interventions targeting these risk factors have been adapted for technology-based approaches. This review provides an overview of technology-based interventions conducted in these priority populations as well as the challenges and gaps to be addressed in future research. Researchers currently possess tremendous opportunities to engage in technology-based implementation and dissemination science to help spread evidence-based programs focusing on CVD risk factors in these and other priority populations.

    View details for DOI 10.1016/j.pcad.2016.03.001

    View details for Web of Science ID 000376552200008

    View details for PubMedID 26957186

  • Type II diabetes disparities in diverse women: the potential roles of body composition, diet and physical activity WOMENS HEALTH Crawford, M. A., Mendoza-Vasconez, A. S., Larsen, B. A. 2015; 11 (6): 913–27


    The rates of diabetes in the USA are rapidly increasing, and vary widely across different racial/ethnic groups. This paper explores the potential contribution of body composition, diet and physical activity in explaining diabetes disparities across women of different racial and ethnic backgrounds. For body composition, racial/ethnic groups differ widely by BMI, distribution of body mass and quantity and type of adipose tissue. Dietary patterns that vary across race/ethnicity include consumption of meat, added sugars, high-glycemic carbohydrates and fast food. Additionally, physical activity patterns of interest include aerobic versus muscle-strengthening exercises, and the purpose of physical activity (leisure, occupation, or transportation). Overall, these variables provide a partial picture of the source of these widening disparities, and could help guide future research in addressing and reducing diabetes disparities.

    View details for DOI 10.2217/whe.15.62

    View details for Web of Science ID 000213228000024

    View details for PubMedID 26648099

    View details for PubMedCentralID PMC4864180