Emerging exposures of developmental toxicants.

PURPOSE OF REVIEW: The purpose of this review is to identify emerging developmental toxicants that are understudied in children's health. Exposures may arise from new products designed to improve utility, to reduce toxicity, or to replace undesirable chemicals. Exposures to less-toxic chemicals may also be significant if they are very commonly used, thereby generating widespread exposure. Sources of exposure include the workplace, personal, home, and office products; food, water, and air. RECENT FINDINGS: We describe eight exposure categories that contain numerous potential developmental toxicants. References are discussed if reported in PubMed during the past decade at least 10 times more frequently than in 1990-2000. Examples included phthalates, phenols, sunscreens, pesticides, halogenated flame retardants, perfluoroalkyl coatings, nanoparticles, e-cigarettes, and dietary polyphenols. Replacements are often close structural homologs of their precursors. We suggest biomonitoring as preferred means of exposure assessment to emerging chemicals. Some existing analytic methods would require minimal modification to measure these exposures, but others require toxicokinetic and analytic investigation. SUMMARY: A deliberate strategy for biomonitoring of emerging replacement chemicals is warranted, especially in view of concerns regarding developmental toxicity. To prevent adverse health effects, it is important to characterize such exposures before they become widely disseminated.

Underage E-Cigarette Purchasing and Vaping Progression Among Young Adults.

PURPOSE: Despite laws prohibiting sale of e-cigarettes to individuals aged less than 21 years, many underage young adults purchase e-cigarettes from retail stores, which may increase likelihood of continued use due to a greater access to vaping products and exposure to point-of-sale marketing. METHODS: Data are from a prospective cohort of young adults aged 18-20 years in Los Angeles who had ever used e-cigarettes at baseline (N = 1,029). We evaluated the association of underage e-cigarette purchasing behavior (owned and purchased vs. owned but never purchased vs. never owned an e-cigarette) with subsequent vaping frequency, intensity, and dependence symptoms one year later, adjusting for vaping behaviors prior to baseline; additional models evaluated whether associations differed by purchase location or product type. RESULTS: At baseline, 332 (32%) had purchased e-cigarettes while underage, 227 (22%) owned but never purchased e-cigarettes themselves, and 470 (46%) never owned an e-cigarette. Compared to never owning e-cigarettes, those who had purchased their own e-cigarettes vaped more days in the past month (rate ratio [RR] = 2.97; 95% confidence interval [CI]: 2.15-4.09), had more vaping episodes per day (RR: 2.58; 95% CI: 2.12-3.14), vaped more puffs per vaping episode (RR: 1.90; 95% CI: 1.61-2.23), and had greater odds of dependence (odds ratio: 3.68; 95% CI: 2.51-5.40); elevated estimates were also observed for those who owned but never purchased e-cigarettes (vs. never owned). Vaping dependence was greatest among participants who purchased JUULs or other pod-mods. DISCUSSION: Participants who purchased e-cigarettes underage subsequently vaped more intensely and had greater vaping dependence. Regulations that reduce underage retail access to e-cigarettes may help prevent vaping progression among those most at risk of dependence.

Adaptation Resources and Responses to Wildfire Smoke and Other Forms of Air Pollution in Low-Income Urban Settings: A Mixed-Methods Study.

Little is known about how low-income residents of urban communities engage their knowledge, attitudes, behaviors, and resources to mitigate the health impacts of wildfire smoke and other forms of air pollution. We interviewed 40 adults in Los Angeles, California, to explore their threat assessments of days of poor air quality, adaptation resources and behaviors, and the impacts of air pollution and wildfire smoke on physical and mental health. Participants resided in census tracts that were disproportionately burdened by air pollution and socioeconomic vulnerability. All participants reported experiencing days of poor air quality due primarily to wildfire smoke. Sixty percent received advanced warnings of days of poor air quality or routinely monitored air quality via cell phone apps or news broadcasts. Adaptation behaviors included remaining indoors, circulating indoor air, and wearing face masks when outdoors. Most (82.5%) of the participants reported some physical or mental health problem or symptom during days of poor air quality, but several indicated that symptom severity was mitigated by their adaptive behaviors. Although low-income residents perceive themselves to be at risk for the physical and mental health impacts of air pollution, they have also adapted to that risk with limited resources.

Motivations for E-cigarette use and associations with vaping frequency and smoking abstinence among adults who smoke cigarettes in the United States.

INTRODUCTION: In observational studies, vaping daily is positively associated with cigarette smoking abstinence, while non-daily vaping is associated with less smoking abstinence (versus no e-cigarette use). It remains unknown whether cigarette smokers who vape daily have different motivations for using e-cigarettes than those who vape non-daily. METHODS: Using latent class analysis and 10 self-reported reasons for vaping, we identified sub-groups of participants based on vaping motivations among 1544 adult (≥18 y) dual users of e-cigarettes and cigarettes at wave 4 of the Population Assessment of Tobacco and Health (2016-2018). We examined the association of motivation sub-groups with vaping frequency at wave 4, and subsequent cigarette smoking abstinence at wave 5 (2018-2019). Additional analyses examined the association of vaping frequency with smoking abstinence before and after adjustment for motivation sub-groups. RESULTS: Four distinct sub-groups of e-cigarette users emerged, including 54 % of participants who were "Vaping Enthusiasts", 20 % who vaped for "Convenience and Social Acceptability", 10 % classified as "Experimenters", and 16 % who vaped for "Quitting Smoking and Harm Reduction." The Convenience and Social Acceptability sub-group were less likely than "Vaping Enthusiasts" (AOR=0.29, 95 %CI[0.20-0.42]) and "Quitting Smoking and Harm Reduction" (AOR=0.41, 95 %CI[0.24-0.71]) classes to vape daily (versus non-daily). Sub-groups were not associated with smoking abstinence after one year. Adjustment for motivation sub-groups did not attenuate a positive association of daily vaping with smoking abstinence. CONCLUSIONS: Cigarette smokers who vaped for convenience and social acceptability were less frequent e-cigarette users than those with other vaping motivations. Vaping motivations were not associated with subsequent smoking abstinence.

Prospective association between e-cigarette use frequency patterns and cigarette smoking abstinence among adult cigarette smokers in the United States.

AIMS: To estimate the association of longitudinal patterns of e-cigarette use with cigarette smoking abstinence, after accounting for time-dependent confounding and selection bias. DESIGN: Secondary analysis of longitudinal national cohort data. Using marginal structural models and four waves of the population assessment of tobacco and health (wave 1, 2013-14; wave 2, 2014-15; wave 3, 2015-16; wave 4, 2016-18), we estimated the association of vaping frequency across waves 2 and 3 with 12-month sustained cigarette smoking abstinence at wave 4, adjusting for time-dependent confounders at waves 1 and 2 and selection bias due to drop-out with inverse probability of treatment and censoring weights. SETTING: United States. PARTICIPANTS/CASES: A total of 5699 adults (18+ years) who smoked cigarettes and did not vape at wave 1. MEASUREMENTS: The exposure was vaping frequency at waves 2 and 3 (non-use, non-daily use, daily use), representing nine possible combinations of vaping frequency across two waves. Non-use at both waves was the exposure reference group. The primary outcome was sustained 12-month cigarette smoking abstinence at wave 4. FINDINGS: Among 5699 adults who smoked cigarettes at wave 1, a total of 560 (9.8%) reported smoking abstinence at wave 4. Compared with nonuse at both waves, daily vaping at both waves [risk ratio (RR) = 3.82, 95% confidence interval (CI) = 2.59-5.64] and non-use at wave 2 followed by daily vaping at wave 3 (RR = 2.50, 95% CI = 1.66-3.77) were positively associated with smoking abstinence; non-daily vaping at both waves was inversely associated with smoking abstinence (RR = 0.28, 95% CI = 0.11-0.75). Results persisted after accounting for misclassification of e-cigarette use and cigarette smoking abstinence and after restricting to participants with plans to quit smoking. CONCLUSIONS: In a US cohort of adult smokers, longitudinal patterns of vaping frequency appear to predict smoking abstinence, even after accounting for several sources of systematic error. Consistent daily vaping is associated with increased chances of cigarette smoking abstinence, while consistent non-daily vaping is associated with decreased chances of smoking abstinence.

Vulnerable, Resilient, or Both? A Qualitative Study of Adaptation Resources and Behaviors to Heat Waves and Health Outcomes of Low-Income Residents of Urban Heat Islands.

Little is known of how low-income residents of urban heat islands engage their knowledge, attitudes, behaviors, and resources to mitigate the health impacts of heat waves. In this qualitative study, we conducted semi-structured interviews with 40 adults in two such neighborhoods in Los Angeles California to explore their adaptation resources and behaviors, the impacts of heat waves on physical and mental health, and threat assessments of future heat waves. Eighty percent of participants received advanced warning of heat waves from television news and social media. The most common resource was air conditioning (AC) units or fans. However, one-third of participants lacked AC, and many of those with AC engaged in limited use due primarily to the high cost of electricity. Adaptation behaviors include staying hydrated, remaining indoors or going to cooler locations, reducing energy usage, and consuming certain foods and drinks. Most of the participants reported some physical or mental health problem or symptom during heat waves, suggesting vulnerability to heat waves. Almost all participants asserted that heat waves were likely to increase in frequency and intensity with adverse health effects for vulnerable populations. Despite limited resources, low-income residents of urban heat islands utilize a wide range of behaviors to minimize the severity of health impacts, suggesting they are both vulnerable and resilient to heat waves.

Sexual minority tobacco use disparities across adolescence and the transition to young adulthood.

INTRODUCTION: Sexual minority (SM; e.g., lesbian, gay, bisexual) youth are disproportionately more likely to use tobacco than non-SM youth, yet there exist several critical gaps in knowledge. This study assessed (a) the timing of SM tobacco use disparities (e.g., during adolescence or early adulthood), (b) whether disparities generalize across different tobacco products, and (c) whether disparities differ by sex. METHODS: Data were from a 6-year prospective cohort of diverse high school students from Southern California who were followed into early adulthood (9 waves, 2013-2019). SM (vs. non-SM) differences in past 6-month use were assessed for: any tobacco products, cigarettes, e-cigarettes, other products (e.g., hookah), and multiple products. Disparities were modeled longitudinally across adolescence (high school) and the transition to early adulthood (end of high school to post-high school). Differences were tested by sex. RESULTS: Among females, SM disparities were evident for all outcomes during both adolescence and early adulthood; no differences were observed among males. For example, SM (vs. non-SM) females had higher odds of cigarette (aOR = 4.4 [3.0-6.5]) and e-cigarette (aOR = 1.7 [1.2-2.4]) use, averaged across adolescence. The timing of disparities varied by product. For example, cigarette use disparities emerged prior to high school and persisted through adolescence and young adulthood, while e-cigarette use disparities were present in early adolescence and young adulthood only. CONCLUSIONS: Young SM females are at especially high risk for tobacco use, across various tobacco products, throughout adolescence and young adulthood. Interventions must consider differences in the timing of disparities by product type.

Prevalence of Electronic Cigarette Dependence Among Youth and Its Association With Future Use.

Importance: Understanding the prevalence and symptoms of electronic cigarette (e-cigarette) dependence and its association with future e-cigarette use among youth may help to guide pediatric clinical services and health policy. Objectives: To examine the cross-sectional prevalence and symptom presentation of e-cigarette dependence and to determine whether e-cigarette dependence is associated with subsequent e-cigarette use patterns 6 months later among youth with baseline past-year e-cigarette use. Design, Setting, and Participants: This prospective cohort study used baseline and 6-month follow-up surveys among students in the 12th grade during the 2016 to 2017 school year who reported any past-year e-cigarette use. Surveys were conducted on site in 10 high schools in Los Angeles, California. Data were analyzed from March 2019 to December 2019. Main Outcomes and Measures: Self-reported checklist of 10 tobacco product dependence symptoms reflecting loss of control over use, craving or urge, or withdrawal symptoms while abstinent, completed at baseline and administered separately for e-cigarettes and combustible cigarettes. Reporting 1 or more symptoms indicated a positive screen for dependence. Vaping continuation, defined as any past 6-month vaping, and past 30-day nicotine vaping days (range, 0-30), sessions per vaping day (range, 0-20), and puffs per session (range, 0-20) at 6-month follow-up were assessed. Results: Among 3168 twelfth-grade students who completed the baseline survey, 444 youths (mean [SD] age, 17.48 [0.39] years; 217 [48.9%] female) reported past-year e-cigarette use. Among these, 52 youths (11.7%) reported at least 1 e-cigarette dependence symptom. Among youth who reported past-year dual e-cigarette and combustible cigarette use, combustible cigarette dependence, reported by 43 youths (29.7%), was more prevalent than e-cigarette dependence, which was reported by 24 youths (16.4%). The most common symptoms, craving, urge, and need to use, and least common symptoms, abstinence-related concentration and emotional problems, were similar in both combustible and e-cigarette dependence. The prevalence of e-cigarette dependence was higher among youth who reported vaping in the past month than among those who did not (41 youths [17.6%] vs 11 youths [5.2%]; P < .001) and among youth who used e-cigarettes with nicotine than among those who used e-cigarettes without nicotine (42 youths [15.2%] vs 10 youths [6.0%]; P = .004). After adjusting for baseline vaping and e-cigarette dependence risk propensity scores, baseline e-cigarette dependence symptom status was associated with vaping continuation (adjusted odds ratio, 2.30 [95% CI, 1.07-4.94]; P = .02) and past 30-day number of nicotine vaping days (adjusted rate ratio, 2.17 [95% CI, 1.44-3.28]; P < .001), vaping sessions per day (adjusted rate ratio, 2.41 [95% CI, 1.52-3.83]; P < .001), and puffs per session (adjusted rate ratio, 1.70 [95% CI, 1.09-2.66]; P = .02) at 6-month follow-up. Conclusions and Relevance: These findings suggest that e-cigarette dependence may be an expression of tobacco use disorder associated with future use persistence and escalation among youth. Electronic cigarette dependence may be a behavioral health consequence of adolescent vaping that warrants consideration in pediatric patient care and public health policy.

Digital media use and subsequent cannabis and tobacco product use initiation among adolescents.

BACKGROUND: Digital media engagement, such as browsing the internet or social media posting, may be associated with cannabis and tobacco product use initiation among adolescents. Whether certain digital media exposure confers greater - or reduced - risk for specific cannabis or tobacco products is unknown. METHODS: Adolescents completed surveys on digital media and substance use every 6 months from 2015 to 2017 (4 waves). Self-reported digital media use (14 items) was classified into six subcategories (e.g., "social media posting," "reading news/articles & browsing photos"). Random-effect repeated-measures regression models examined the association of exposure to each digital media subcategory with subsequent cannabis or tobacco product use initiation in the next 6 months, among baseline cannabis and tobacco never-users (n = 1841; n = 1558, respectively). RESULTS: High frequency digital media use (multiple times/day) of "social media posting" (vs. no high frequency use; OR = 1.95; 95%CI:1.20-3.17) and "checking in" (OR = 1.71; 95%CI:1.23-2.38) was associated with greater odds of any cannabis product use initiation 6 months later. "Reading news/articles & browsing photos" was associated with decreased odds of initiation (OR = 0.52; 95%CI:0.34-0.79). "Checking in" and "reading news/articles & browsing photos" were similarly associated with any tobacco use initiation. "Chatting and shopping" was associated with greater odds (OR = 4.63; 95%CI:1.53-14.06) of e-cigarette initiation, but not of other product use initiation. CONCLUSIONS: Some subcategories of digital media use conferred increased odds, others conferred reduced odds, and others were not associated with cannabis and tobacco use initiation. Research exploring mechanisms that put users of specific digital media at greater risk for substance use initiation is warranted.

Flavored E-cigarette Use and Progression of Vaping in Adolescents.

OBJECTIVES: Electronic cigarettes (e-cigarettes) are available in nontraditional flavors (eg, fruit and candy) that are banned in combustible cigarettes in the United States. Whether adolescent use of e-cigarettes in nontraditional flavors prospectively predicts continuation of vaping and progression to more frequent vaping is unknown. METHODS: High school students in Los Angeles, California, completed 5 semiannual surveys (2014-2017 [10th grade to 12th grade]). Among past-6-month e-cigarette users at survey waves 1 to 4 (N = 478), e-cigarette flavor (or flavors) used was coded into 2 mutually exclusive categories at each wave (use of ≥1 nontraditional flavors [fruit, candy, sweet or dessert, buttery, blends or combinations, and other] versus exclusive use of tobacco, menthol or mint, or flavorless). Flavor used during waves 1 to 4 was modeled as a time-varying, time-lagged regressor of vaping status and frequency outcomes 6 months later at waves 2 to 5. RESULTS: Across waves 1 to 4, there were 739 (93.8%) observations of nontraditional-flavor use and 49 (6.2%) observations of exclusive use of tobacco, mint or menthol, or flavorless e-cigarettes. Use of e-cigarettes in nontraditional flavors (versus only tobacco, mint or menthol, or flavorless) was positively associated with vaping continuation (64.3% vs 42.9%; adjusted odds ratio = 3.76 [95% confidence interval 1.20 to 10.31]) and past-30-day number of puffs per nicotine vaping episode (mean: 3.1 [SD 5.5] vs 1.5 [SD 3.8]; adjusted rate ratio = 2.41 [95% confidence interval 1.08 to 5.92]) 6 months later. Flavor used was not associated with the subsequent number of past-30-day vaping days or episodes per day. CONCLUSIONS: Adolescents who vaped e-cigarettes in nontraditional flavors, compared with those who exclusively vaped tobacco-flavored, mint- or menthol-flavored, or flavorless e-cigarettes, were more likely to continue vaping and take more puffs per vaping occasion 6 months later.

The association between contextual socioeconomic factors and prevalent asthma in a cohort of Southern California school children.

Spatial variation in childhood asthma and a recent increase in prevalence indicate that environmental factors play a significant role in the etiology of this important disease. Socioeconomic position (SEP) has been associated inversely and positively with childhood asthma. These contradictory results indicate a need for systematic research about SEP and asthma. Pathways have been suggested for effects of SEP on asthma at both the individual and community level. We examined the relationship of prevalent asthma to community-level indicators of SEP among 5762 children in 12 Southern California communities, using a multilevel random effects model. Estimates of community-level SEP were derived by summarizing census block group-level data using a novel method of weighting by the proportion of the block groups included in a community-specific bounding rectangle that contained 95% of local study subjects. Community characteristics included measures of male unemployment, household income, low education (i.e., no high school diploma) and poverty. There was a consistent inverse association between male unemployment and asthma across the inter-quartile range of community unemployment rates, indicating that asthma rates increase as community SEP increases. The results were robust to individual-level confounding, methods for summarizing census block group data to the community level, scale of analysis (i.e., community-level vs. neighborhood-level) and the modeling algorithm. The positive association between SEP and prevalent childhood asthma might be explained by differential access to medical care that remains unmeasured, by the hygiene hypothesis (e.g., lower SES may associate with higher protective exposures to endotoxin in early life), or by SEP acting as a proxy for unmeasured neighborhood characteristics.

Associations of Electronic Cigarette Nicotine Concentration With Subsequent Cigarette Smoking and Vaping Levels in Adolescents.

Importance: Research indicates that electronic cigarette (e-cigarette) use (vaping) among adolescents is associated with the initiation and progression of combustible cigarette smoking. The reasons for this association are unknown. Objective: To evaluate whether use of e-cigarettes with higher nicotine concentrations is associated with subsequent increases in the frequency and intensity of combustible cigarette smoking and vaping. Design, Setting, and Participants: In this prospective cohort study involving students from 10 high schools in the Los Angeles, California, metropolitan area, surveys were administered during 10th grade in the spring (baseline) and 11th grade in the fall (6-month follow-up) of 2015 to students who reported using e-cigarettes within the past 30 days and the nicotine concentration level they used at baseline. Exposures: Self-report of baseline e-cigarette nicotine concentration of none (0 mg/mL), low (1-5 mg/mL), medium (6-17 mg/mL), or high (≥18 mg/mL) typically used during the past 30 days. Main Outcomes and Measures: Frequency of combustible cigarette smoking and e-cigarette use within the past 30 days (0 days [none], 1-2 days [infrequent], or ≥3 days [frequent]) and daily intensity of smoking and vaping (number of cigarettes smoked per day, number of vaping episodes per day, and number of puffs per vaping episode) at the 6-month follow-up. Results: The analytic sample included 181 students (96 boys [53.0%] and 85 girls [47.0%]; mean [SD] age, 16.1 [0.4] years). Each successive increase in nicotine concentration (none to low, low to medium, and medium to high) vaped was associated with a 2.26 (95% CI, 1.28-3.98) increase in the odds of frequent (vs no) smoking and a 1.65 (95% CI, 1.09-2.51) increase in the odds of frequent (vs no) vaping at follow-up after adjustment for baseline frequency of smoking and vaping and other relevant covariates. Use of e-cigarettes with high (vs no) nicotine concentration was associated with a greater number of cigarettes smoked per day at follow-up (adjusted rate ratio [RR], 7.03; 95% CI, 6.11-7.95). An association with a significantly greater number of vaping episodes per day was found with use of low (adjusted RR, 3.32; 95% CI, 2.61-4.03), medium (adjusted RR, 3.32; 95% CI, 2.54-4.10), and high (adjusted RR, 2.44; 95% CI, 1.63-3.24) nicotine concentrations (vs no nicotine) at baseline. Similar results were found for the number of puffs per vaping episode for low (adjusted RR, 2.05; 95% CI, 1.41-2.70), medium (adjusted RR, 3.39; 95% CI, 2.66-4.11), and high (adjusted RR, 2.23; 95% CI, 1.42-3.03) nicotine concentrations. Conclusions and Relevance: The results of this study provide preliminary evidence that use of e-cigarettes with higher nicotine concentrations by youths may increase subsequent frequency and intensity of smoking and vaping.

Perceived stress and poly-tobacco product use across adolescence: Patterns of association and gender differences.

Perceived stress-an endophenotype indicative of the tendency to appraise stress as frequent, unpredictable and unmanageable-is associated with adolescent cigarette smoking. It is unclear whether this association: (1) extends to alternative tobacco products, like electronic cigarettes and hookah (tobacco water pipe), which are increasingly popular among youth, and (2) differs by gender. In this report, data were drawn from a population-based longitudinal cohort of youth in Southern California. Perceived stress was assessed at baseline (7th or 8th grade; 2010). Electronic cigarette, hookah, combustible cigarette, and cigar use were assessed at a 4-year follow-up (11th or 12th grade; 2014). After adjusting for confounders, polytomous logistic regressions showed that a standardized baseline perceived stress score (M = 0, SD = 1) predicted electronic cigarette, hookah, combustible cigarette, and cigar use and a poly-tobacco use index at the 4-year follow-up in the overall sample. Interactions between perceived stress and gender were also observed (Interaction Ps < 0.05), which demonstrated that the association of perceived stress with tobacco product use and poly-use were stronger in females (ORs for current use range: 1.47 to 1.72) than males (ORs range: 0.93 to 1.31). Adjusting for baseline perceived stress, the change in perceived stress from baseline to follow-up was also positively associated with use and poly-use of most tobacco products in females and in males to some extent. In the current era in which teen use of alternative tobacco products is increasingly common, adolescent tobacco use and poly-use research and prevention strategies should address gender-specific origins of tobacco product use risk and consider perceived stress and other emotional endophenotypes in such risk pathways.

Surface sampling for endotoxin assessment using electrostatic wiping cloths.

OBJECTIVES: Much of the cost of exposure assessment for studies of residential cohorts is in scheduling and travel time for field staff. One way to reduce costs is to simplify methods such that subjects can sample their own residence. Analysis of settled dust is being widely used for assessment of exposures to allergens, lead and pesticides and can also be used for endotoxins. While vacuum sampling is the most common surface sampling method, wipe sampling has the advantage that it can be readily performed by the resident when convenient and samples can then be mailed to researchers. Thus, we evaluated the feasibility of wipe sampling for endotoxin environmental assessment using electrostatic wipes with or without the use of disposable examination gloves. METHODS: Multiple lots of six types of commercial wipes and eight types of gloves were extracted and analyzed for endotoxin content using the kinetic chromogenic Limulus amebocyte lysate assay. Wipes were compared across brands, between lots, within lots, between pairs depending on proximity to cardboard packaging, and in wipe tests with or without gloves. Collected dust samples of known concentration were also tested in spiking assays for endotoxin recovery. RESULTS: The most striking finding was the high variability of endotoxin contamination of both wipes and gloves across brands and between various lots. The content of endotoxin in unused gloves ranged from <1.5 to 5810 endotoxin units (EU). The range for unused wipes was 3.6-87.8 EU. Surfaces of equal loading and area were sampled using three types of cloths that had low initial endotoxin contamination. The cloths were very good at collecting dust and endotoxin could be assayed from aqueous extracts of the wipes. Samples collected using cloths with bare washed hands yielded higher endotoxin loading per mass of collected dust versus samples collected wearing endotoxin-free gloves. This demonstrated additional endotoxin loading from the subject's hand. CONCLUSION: This study shows that wipe sampling while wearing medical gloves can be an effective method for collecting and assessing endotoxin on surfaces, so long as each lot of wipes and gloves have been tested and determined to be low in endotoxin.