All Publications

  • Nicotine Dependence from Different E-Cigarette Devices and Combustible Cigarettes among US Adolescent and Young Adult Users. International journal of environmental research and public health Lin, C., Gaiha, S. M., Halpern-Felsher, B. 2022; 19 (10)


    E-cigarettes, the most popular tobacco product among adolescents, vary widely in design and nicotine composition; thus, different devices may have different addictive potential. However, few studies examine levels of nicotine dependence across devices among adolescent and young adult (AYA) e-cigarette users. To assess the extent of nicotine dependence among US AYA (ages 13-24) by e-cigarette device type, we conducted a large, national, cross-sectional survey (n = 4351) and used the Hooked on Nicotine Checklist (HONC) to assess levels of nicotine dependence among those who had used disposable, pod-based, and/or mods/other e-cigarette devices in the past 30 days. We also examined HONC scores among those who had used combustible cigarettes in the past 30 days, whether with or without using e-cigarettes. Patterns of nicotine dependence were comparable across those who had used a combustible cigarette and/or e-cigarette in the past 30 days, with 91.4% of combustible cigarette users, 80.7% of disposable e-cigarette users, 83.1% of pod-based e-cigarette users, and 82.5% of mods/other e-cigarette users showing signs of nicotine dependence, as measured by endorsing at least one HONC symptom. This pattern persisted when analyses were restricted to e-cigarette only users, with more than 70% of all e-cigarette only past-30-day users endorsing at least one HONC symptom, across all types of devices. A thorough understanding of the extent and presentation of nicotine dependence among AYA will help researchers, public health officials, and clinicians recognize and manage AYA nicotine dependence.

    View details for DOI 10.3390/ijerph19105846

    View details for PubMedID 35627381

  • Use Patterns, Flavors, Brands, and Ingredients of Nonnicotine e-Cigarettes Among Adolescents, Young Adults, and Adults in the United States. JAMA network open Gaiha, S. M., Lin, C., Lempert, L. K., Halpern-Felsher, B. 2022; 5 (5): e2216194


    Importance: Nonnicotine e-cigarettes contain chemicals, flavorants, and solvents that have known health harms and/or have not been proven safe for inhalation.Objective: To evaluate nonnicotine e-cigarette use patterns, including common flavors, brands, and ingredients.Design, Setting, and Participants: This cross-sectional study included a convenience sample of US residents aged 13 to 40 years who completed an online survey in November and December 2021. Quota sampling was used for an equal proportion of participants aged 13 to 17 years, 18 to 20 years, and 21 to 40 years, balanced for sex, race, and ethnicity per the latest US Census.Main Outcomes and Measures: Nonnicotine e-cigarette use (ever, past 30- and past 7-day, number of times used, time taken to finish); co-use with nicotine e-cigarettes; age at first try; and flavors, brands, and ingredients used.Results: Overall, 6131 participants (mean [SD] age, 21.9 [6.8] years; range, 13-40 years; 3454 [56.3%] identifying as female) completed the survey (55.1% completion rate). Among all participants, 1590 (25.9%) had ever used a nonnicotine e-cigarette, 1021 (16.7%) used one in the past 30 days, and 760 (12.4%) used one in the past 7 days. By age group, 227 of 1630 participants aged 13 to 17 years (13.9%), 497 of 2033 participants aged 18 to 20 years (24.4%), 399 of 1041 participants aged 21 to 24 years (38.3%), and 467 of 1427 participants aged 25 to 40 years (32.7%) had ever used nonnicotine e-cigarettes. Among 1590 participants who had ever used a nonnicotine e-cigarette, 549 (34.5%) had used one more than 10 times; 1017 (63.9%) finished 1 nonnicotine e-cigarette in less than 1 week. Co-use of nonnicotine with nicotine e-cigarettes was reported by 1155 participants (18.8%), 1363 (22.2%) exclusively used nicotine e-cigarettes, and 431 (7.0%) exclusively used nonnicotine e-cigarettes. Most-used flavors were sweet, dessert, or candy (578 [36.3%]); fruit (532 [33.4%]); and mint or menthol (321 [20.2%]); similar flavor patterns were observed for the top 2 flavors among those who used nonnicotine e-cigarettes in the past 30 days, followed by combinations of coffee, alcohol, flower, plant, and mint or menthol flavors by age group. Participants most reported using tetrahydrocannabinol (587 [36.9%]), cannabidiol (537 [33.7%]), melatonin (438 [27.5%]), caffeine (428 [26.9%]), and essential oils (364 [22.9%]) in their nonnicotine e-cigarettes.Conclusions and Relevance: In this study of adolescents, young adults, and adults, a sizeable proportion reported having used nonnicotine e-cigarettes and co-using them with nicotine e-cigarettes. Surveillance studies should further assess nonnicotine e-cigarette use patterns and regulations, and prevention should be developed to address youth appeal, unsubstantiated health claims, and possible health harms.

    View details for DOI 10.1001/jamanetworkopen.2022.16194

    View details for PubMedID 35612852

  • Entice With Procedures, Inspire With Primary Care: A Preclerkship Pipeline Course. PRiMER (Leawood, Kan.) Lin, C., Zheng, J., Shivakumar, V., Schillinger, E., Rydel, T. A., Montacute, T. 2021; 5: 22


    Background and Objectives: The growing demand for primary care clinicians in the United States continues to outstrip their dwindling supply. Many allopathic medical schools, including Stanford University School of Medicine, are not adequately meeting this shortage. We sought to develop a preclerkship elective to increase the visibility and desirability of primary care at our institution.Methods: A novel 9-week preclerkship elective titled "Primary Care Defined: Perspectives and Procedures," was designed as a series of procedural workshops followed by interactive sessions with local primary care clinicians. A total of 36 medical and physician assistant students were enrolled. We administered a questionnaire pre- and postcourse to evaluate the impact of the elective on learner interest and attitudes toward primary care.Results: Twenty-four enrolled and 10 nonenrolled learners completed the questionnaire both pre- and postcourse. A one-way analysis of covariance controlling for gender, program (medical doctor versus physician assistant), and precourse responses demonstrated that enrollees had a significantly increased interest in primary care compared to nonenrollees after the course (F 1,32=9.22, P=.005). Enrollees also more positively rated their attitudes toward compensation, scope of practice, and job fulfillment than nonenrollees. Both groups had high levels of agreement on statements concerning patient-physician interactions and the importance of primary care to the health care system.Conclusion: The design and content of this elective offers a framework for other institutions looking to promote the value of primary care specialties, particularly family medicine. Creating opportunities for experiential learning and early student-faculty engagement may encourage preclerkship learners to consider a career in primary care.

    View details for DOI 10.22454/PRiMER.2021.782026

    View details for PubMedID 34286225

  • Longitudinal trends in e-cigarette devices used by Californian youth, 2014-2018. Addictive behaviors Lin, C., Baiocchi, M., Halpern-Felsher, B. 2020; 108: 106459


    The rate of adolescent and young adult (AYA) e-cigarette usage has increased in recent years, possibly due to the introduction of sleek new e-cigarette devices such as JUUL. This study analyzed data from 400 California AYA to examine trends in e-cigarette usage by device type (disposables, large-size rechargeables, vape/hookah pens, JUUL/pod-based). Participants were asked about their ever, past 30-day, and past 7-day use of e-cigarettes; their usual e-cigarette device used; and co-use of devices in seven surveys administered approximately biannually from 2014 to 2018. During this time period, total e-cigarette ever-usage in our cohort increased linearly from 14.1% to 46.2% (ptrend<0.001). JUUL/pod-based e-cigarette ever-usage increased from 14.9% to 22.5% in just six months in 2018. Furthermore, a majority of new e-cigarette users at the time of the survey endorsed using JUUL/pod-based devices (58.3% in Wave 6, 73.0% in Wave 7). With newer device options, AYA were also increasingly less likely to endorse older models such as disposables (19.1% to 6.9% from 2014 to 2018, ptrend<0.01) and rechargeables (69.1% to 26.2% from 2014 to 2018, ptrend<0.001) as their usual e-cigarette device. Participants who used JUUL/pod-based only as their usual device were more likely to endorse using only JUUL/pod-based devices during follow-up survey (70%), and none switched to a new device completely. Overall, this study provides a snapshot of how AYA's e-cigarette preferences appear to respond to new devices entering the market.

    View details for DOI 10.1016/j.addbeh.2020.106459

    View details for PubMedID 32388394

  • Pre-diagnostic circulating insulin-like growth factor-I and bladder cancer risk in the European Prospective Investigation into Cancer and Nutrition INTERNATIONAL JOURNAL OF CANCER Lin, C., Travis, R. C., Appleby, P. N., Tipper, S., Weiderpass, E., Chang-Claude, J., Gram, I. T., Kaaks, R., Kiemeney, L. A., Ljungberg, B., Tumino, R., Tjonneland, A., Roswall, N., Overvad, K., Boutron-Ruault, M., Manciniveri, F., Severi, G., Trichopoulou, A., Masala, G., Sacerdote, C., Agnoli, C., Panico, S., Bueno-de-Mesquita, B., Peeters, P. H., Salamanca-Fernandez, E., Chirlaque, M., Ardanaz, E., Dorronsoro, M., Menendez, V., Lujan-Barroso, L., Liedberg, F., Freisling, H., Gunter, M., Aune, D., Cross, A. J., Riboli, E., Key, T. J., Perez-Cornago, A. 2018; 143 (10): 2351–58


    Previous in vitro and case-control studies have found an association between the insulin-like growth factor (IGF)-axis and bladder cancer risk. Circulating concentrations of IGF-I have also been found to be associated with an increased risk of several cancer types; however, the relationship between pre-diagnostic circulating IGF-I concentrations and bladder cancer has never been studied prospectively. We investigated the association of pre-diagnostic plasma concentrations of IGF-I with risk of overall bladder cancer and urothelial cell carcinoma (UCC) in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. A total of 843 men and women diagnosed with bladder cancer between 1992 and 2005 were matched with 843 controls by recruitment centre, sex, age at recruitment, date of blood collection, duration of follow-up, time of day and fasting status at blood collection using an incidence density sampling protocol. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression with adjustment for smoking status. No association was found between pre-diagnostic circulating IGF-I concentration and overall bladder cancer risk (adjusted OR for highest versus lowest fourth: 0.91, 95% CI: 0.66-1.24, ptrend = 0.40) or UCC (n of cases = 776; 0.91, 0.65-1.26, ptrend = 0.40). There was no significant evidence of heterogeneity in the association of IGF-I with bladder cancer risk by tumour aggressiveness, sex, smoking status, or by time between blood collection and diagnosis (pheterogeneity > 0.05 for all). This first prospective study indicates no evidence of an association between plasma IGF-I concentrations and bladder cancer risk.

    View details for DOI 10.1002/ijc.31650

    View details for Web of Science ID 000450113100003

    View details for PubMedID 29971779

    View details for PubMedCentralID PMC6220964

  • Macrophage Blockade Using CSF1R Inhibitors Reverses the Vascular Leakage Underlying Malignant Ascites in Late-Stage Epithelial Ovarian Cancer CANCER RESEARCH Moughon, D. L., He, H., Schokrpur, S., Jiang, Z. K., Yaqoob, M., David, J., Lin, C., Iruela-Arispe, M. L., Dorigo, O., Wu, L. 2015; 75 (22): 4742-4752


    Malignant ascites is a common complication in the late stages of epithelial ovarian cancer (EOC) that greatly diminishes the quality of life of patients. Malignant ascites is a known consequence of vascular dysfunction, but current approved treatments are not effective in preventing fluid accumulation. In this study, we investigated an alternative strategy of targeting macrophage functions to reverse the vascular pathology of malignant ascites using fluid from human patients and an immunocompetent murine model (ID8) of EOC that mirrors human disease by developing progressive vascular disorganization and leakiness culminating in massive ascites. We demonstrate that the macrophage content in ascites fluid from human patients and the ID8 model directly correlates with vascular permeability. To further substantiate macrophages' role in the pathogenesis of malignant ascites, we blocked macrophage function in ID8 mice using a colony-stimulating factor 1 receptor kinase inhibitor (GW2580). Administration of GW2580 in the late stages of disease resulted in reduced infiltration of protumorigenic (M2) macrophages and dramatically decreased ascites volume. Moreover, the disorganized peritoneal vasculature became normalized and sera from GW2580-treated ascites protected against endothelial permeability. Therefore, our findings suggest that macrophage-targeted treatment may be a promising strategy toward a safe and effective means to control malignant ascites of EOC.

    View details for DOI 10.1158/0008-5472.CAN-14-3373

    View details for PubMedID 26471360