Adolescent use of electronic vapor products , including electronic cigarettes, vaporizers, and vape pens—with and without nicotine—is an emergent public health epidemic in the U.S.Vaping nicotine during adolescence is associated with increased risk for cigarette smoking initiation and co-use of alcohol, cannabis, and other substances.Vape products not containing nicotine may also have negative health effects, although these effects are not well understood.For example, evidence suggests that vape cartridges with THC may be related to recent outbreaks of severe lung injury in the U.S5 and flavored e-liquid found in vape products with and without THC contain health harming toxins.Since 2011, past 30-day prevalence of adolescent vaping has increased steadily, peaking in 2019 at approximately 30%.Although adolescent vaping prevalence dropped to approximately 20% in 2020, it remains high.Given the potential negative health consequences associated with vaping, adolescent vaping prevention must be a public health priority. Ideally, prevention efforts will target the most vulnerable, however, there is a limited evidence base regarding differences in vulnerability across adolescent groups. One group that may be at high risk for vaping is transgender adolescents. By transgender, we mean adolescents whose gender identity is not aligned with their sex assigned at birth, and by cisgender, we mean adolescents whose gender identity aligns with their sex assigned a birth. Although limited,vertical grow research with nationally-representative and population-based surveys finds transgender adolescents are more likely to smoke combustible cigarettes and vape than their cisgender peers.
Vaping and smoking disparities among transgender people have been explained by the gender minority stress model. The model posits that chronic exposure to multilevel gender minority-related prejudice and discrimination predisposes transgender and other gender minority people to excess stress and in turn, negative health outcomes and health disparities.Indeed, past research has found tobacco- and substance use related disparities among transgender adolescents may be related to violence and victimization, community norms favoring substance use, and targeting of LGBTQ people by tobacco and alcohol companies.While examinations of gender identity disparities in adolescent tobacco use—vaping in particular—are uncommon,even less is known about how these disparities vary by race/ethnicity, i.e., disparities at the intersection of gender identity and race/ethnicity. Indeed, vaping among transgender adolescents of color may differ significantly from their non-Latinx white peers given exposure to multiple and intersecting individual, interpersonal, and structural level forms of racism and cisgenderism. These intersecting, multiplicative experiences of racism and cisgenderism, and resultant stress and coping can be understood through the lens of intersectionality. A theoretical framework rooted in Black feminist thought, intersectionality examines relationships between macro-level interlocking systems of power and individual-level experiences and behaviors across multiple social positions .
As a tool, intersectionality provides a lens through which researchers can elucidate and explain population health disparities across multiple axes of social positions, centering the notion that “social categories are not independent and unidimensional but rather multiple, interdependent, and mutually constitutive” .Given a dearth of evidence on vaping and vaping disparities among transgender adolescents of color, the present study examines the prevalence of adolescent vaping at the intersections of gender identity and race/ethnicity in a population-based sample of adolescents in California secondary schools. We tested the hypothesis that gender identity and race/ethnicity interact such that transgender adolescents of color would evidence greater frequency of vaping compared to cisgender white adolescents . This information may provide a starting point for advancing understanding of vaping disparities among transgender adolescents of diverse races/ethnicities and informing vaping prevention and control initiatives. Data for this study come from the California Healthy Kids Survey collected in 2017-2018 and 2018-2019. One of the largest of its kind in the U.S., the CHKS is administered via paper/pencil or electronically to adolescents in California schools on a variety of health domains, including tobacco and substance use, and sociodemographics, including gender identity, ethnicity, and race. School districts receiving subsidies from the California Department of Education are required to administer the CHKS at least biennially in 7th and 9th grades and strongly encouraged to administer it in 5th and 11th grades. Districts not receiving subsidies participate voluntarily. Parents/guardians provide active, written consent for children in 5th grade and passive consent for children in 7th grade and above to participate.
Student participation is voluntary and anonymous.24 For years 2017-2018 and 2018-2019, approximately 75% of California school districts administered the survey at least once , 39% of which administered it twice .Our main independent variables were gender identity and race/ethnicity. Gender identity was measured with the question, “Some people describe themselves as transgender when their sex at birth does not match the way they think or feel about their gender. Are you transgender?”. We categorized participants into three gender identity categories based on their response to the question: Cisgender , Transgender , and Unsure of Gender Identity . We categorized race/ethnicity based on participant responses to two separate questions: “Are you of Hispanic or Latino origin” , and “What is your race?” . Participants who indicated a Hispanic or Latino ethnicity were categorized as “Latinx” 26 regardless of the race they endorsed. Participants who did not indicate a Latinx identity were categorized as non-Latinx white , non-Latinx Black or African American , non-Latinx Asian , non-Latinx American Indian or Alaskan Native , non-Latinx Native Hawaiian or Pacific Islander , and non-Latinx multiracial . Our outcome variable was number of days vaped in the past 30-days, i.e., vaping frequency, measured with the item: “During the past 30 days, on how many days did you use electronic cigarettes, e-cigarettes, or other vaping device such as juul, e-hookah, hookah pens, or vape pens? ”. Past research on adolescent vaping has tended to examine vaping as a binary outcome . To allow for greater detail in modeling frequency, we re-categorized this variable on an integer ordinal scale of 0 days , 1 day , 2-9 days , and 10 or more days vaping in the past 30-days. Based on prior research finding differential patterns in vaping or other tobacco product use among adolescents by specific sociodemographic factors,we included the following potential confounders in analyses: grade, parental education, and sexual orientation. We coded grade into four categories to capture typical groupings in the U.S. context and aid model convergence: 6th -8 th , 9th -10th , 11th -12th , and other/non-traditional. Of note, the majority of adolescents participating in the CHKS are in grades 7th, 9th, and 11th; however a small proportion of students participating in the 2017-18 or 2018-19 survey indicated that they were in 6th, 8th, 10th, or 12th grade which may mean they completed the survey during a class that is primarily open to students in grades 7th, 9th , or 11th, or that their school administered the survey to all grades. We coded parental education into five categories: did not graduate from high school,vertical outdoor farming graduated from high school, attended some college, graduate college, or “don’t know”, and sexual orientation into six categories: heterosexual/straight, gay/lesbian, bisexual, not sure, other , or declined to answer. Our analytical goal was to test the hypothesis that disparities in vaping frequency would be magnified among transgender adolescents of color relative to cisgender white adolescents. We pooled data from the CHKS 2017-2018 and 2018-2019 waves to increase sample size in smaller racial/ethnic and gender identity subcategories and to ensure that the maximum number of schools across the state could be included in the analysis given most schools participate biennially as opposed to annually. We restricted analyses to data from adolescents in grades 6th and above , as the 5th grade survey does not ask about gender identity or substance use . We excluded data from 26 schools that did not collect gender identity .
Compared to adolescents attending schools that collected gender identity, adolescents attending schools that did not collect gender identity were less likely to report any past 30-day vaping , and more likely to identify as white and report their parents graduated from college . We further excluded observations collected via a shortened version of the survey which lacked items on substance use . Per recommendations from the survey administrator WestEd, we then excluded observations considered implausible or impossible responses and/or endorsement of an item indicating that some or all survey items were answered dishonestly . We chose not to impute missing data on the outcome or main independent variables and thus excluded 12.8% of the observations in the remaining sample . Finally, we excluded missing data on covariates due to the small proportion of missing. Our final analytic sample included 953,445 observations . First, we examined gender identity and race/ethnicity differences in sociodemographic characteristics via descriptive statistics, and calculated bivariate chi-squares accounting for school clustering. Next, we calculated prevalence estimates of vaping frequency by gender identity stratified by race/ethnicity. Because our outcome variable met the proportional odds assumption for our independent variables , we used generalized linear mixed models for an ordinal outcome to examine bivariate odds ratios and multi-variable adjusted odds ratios and 95% confidence intervals estimating associations of gender identity and race/ethnicity with vaping. To examine the joint relationship between gender identity and race/ethnicity in vaping frequency,we formally tested gender identity-byrace/ethnicity statistical interaction , adjusting for covariates. Because we aimed to examine the relationship between two independent variables and an outcome,we estimated two models: one quantifying relationships between gender identity and vaping within race/ethnicity strata and another quantifying relationships between race/ethnicity and vaping within gender identity strata. Generalized linear mixed models included random intercepts at level two to account for correlations among adolescents nested in schools. Models were fitted by maximum likelihood with Laplace approximation in SAS version 9.4. The San Diego State University Institutional Review Board deemed our analysis of publicly available, de-identified data, exempt from review. Most adolescents in the analytic sample were cisgender ; 0.92% were transgender, and 1.73% were unsure of their gender identity. Table 1 provides sociodemographic characteristics of the sample overall and by gender identity. Participants were diverse in terms of their race/ethnicity, with Latinx adolescents making up more than half of the sample , followed by white , Asian , multiracial , Black , Native Hawaiian or Pacific Islander , and American Indian or Alaskan Native adolescents. Chi-square tests revealed statistically significant associations between independent variables and grade, parental education, and sexual orientation . The prevalence of any past 30-day vaping for the full sample was 8.6%. As a point of comparison, the prevalence of any past 30-day combustible cigarette smoking was 1.7% for the full sample. Table 2 presents the distributions of vaping frequency in the past 30-days by gender identity and bivariate associations between gender identity and vaping frequency, each within race/ethnicity strata. For each race/ethnicity stratum, transgender adolescents evidenced greater odds of more days vaping relative to their cisgender peers . Associations for adolescents unsure of their gender identity were less consistent, with only Latinx, Asian, and Black adolescents evidencing greater odds of more days vaping than their cisgender peers of the same race/ethnicity . All race/ethnicity by gender identity interactions were significant for transgender adolescents of color relative to cisgender white adolescents , and four out of six interactions were significant for adolescents of color unsure of their gender identity relative to cisgender white adolescents . Thus, AORs and 95% CIs of vaping in relation to gender identity within race/ethnicity strata, and race/ethnicity within gender identity strata are presented in Tables 3 and 4, respectively. Table 3 presents the AORs of vaping frequency for transgender adolescents and adolescents unsure of their gender identity relative to their cisgender peers of the same race/ethnicity. Transgender adolescents evidenced greater odds of more frequent vaping in the past 30-days compared to cisgender adolescents across each race/ethnicity stratum . AORs ranged from 1.20 among transgender white adolescents to 6.05 among transgender Black adolescents relative to their cisgender peers of the same race/ethnicity. Compared to cisgender adolescents of the same race/ethnicity, Asian, Latinx, and Black adolescents unsure of their gender identity evidenced 1.34, 1.43, and 3.28 times greater odds of more frequent vaping, respectively. In contrast, white adolescents unsure of their gender identity evidenced lower odds than cisgender white adolescents. Table 4 presents the AORs of vaping frequency for Latinx, American Indian or Alaskan Native, Asian, Black, Native Hawaiian or Pacific Islander, and multiracial adolescents for each gender identity stratum relative to white adolescents of the same gender identity. Cisgender Latinx, Asian, Black, and multiracial adolescents evidenced lower odds of more frequent vaping relative to cisgender white adolescents.