Nickel in ambient particulate matter and respiratory or cardiovascular outcomes: A critical review.

Exposure to ambient particulate matter (PM) has been associated with respiratory and cardiovascular outcomes, and nickel has been more frequently associated with these outcomes than other metal constituents of ambient PM. Because of this, we evaluated whether the evidence to date supports causal relationships between exposure to nickel in ambient PM and respiratory or cardiovascular outcomes. We critically reviewed 38 studies in human populations published between 2012 and 2022. Although a large variety of respiratory and cardiovascular outcomes were examined, data were sparse for many. As a result, we focused our evaluation on seven respiratory outcomes and three cardiovascular outcomes that were each examined in ≥3 studies. Of these health outcomes, exposure to nickel in ambient PM has been statistically significantly associated with respiratory mortality, respiratory emergency hospital visits, asthma, lung function (i.e., forced expiratory volume in 1 s, forced vital capacity), cardiovascular mortality, and ischemic heart disease mortality. Studies of the health outcomes of focus are subject to multiple methodological limitations, primarily ecological fallacy (short-term exposure studies), exposure measurement error, confounding, model misspecification, and multiple comparisons issue. While some statistically significant associations were reported, they were not strong, precise, or consistent. Statistically significant findings for long-term exposure to nickel in PM were largely reported in studies that could not establish temporality, despite their cohort study design. Statistically significant findings for short-term exposure to nickel in PM were largely reported in studies that could establish temporality, although this cannot inform causal inference at the individual level due to the aggregate level data used. The biological plausibility of the associations is only supported at high concentrations not relevant to ambient exposures. Overall, the literature to date does not provide adequate support for a causal relationship between nickel in ambient PM and respiratory or cardiovascular outcomes.

Gas cooking and respiratory outcomes in children: A systematic review.

The most recent meta-analysis of gas cooking and respiratory outcomes in children was conducted by Lin et al. [93] in 2013. Since then, a number of epidemiology studies have been published on this topic. We conducted the first systematic review of this epidemiology literature that includes an in-depth evaluation of study heterogeneity and study quality, neither of which was systematically evaluated in earlier reviews. We reviewed a total of 66 relevant studies, including those in the Lin et al. [93] meta-analysis. Most of the studies are cross-sectional by design, precluding causal inference. Only a few are cohort studies that could establish temporality and they have largely reported null results. There is large variability across studies in terms of study region, age of children, gas cooking exposure definition, and asthma or wheeze outcome definition, precluding clear interpretations of meta-analysis estimates such as those reported in Lin et al. [93]. Further, our systematic study quality evaluation reveals that a large proportion of the studies to date are subject to multiple sources of bias and inaccuracy, primarily due to self-reported gas cooking exposure or respiratory outcomes, insufficient adjustment for key confounders (e.g., environmental tobacco smoke, family history of asthma or allergies, socioeconomic status or home environment), and unestablished temporality. We conclude that the epidemiology literature is limited by high heterogeneity and low study quality and, therefore, it does not provide sufficient evidence regarding causal relationships between gas cooking or indoor NO2 and asthma or wheeze. We caution against over-interpreting the quantitative evidence synthesis estimates from meta-analyses of these studies.

Systematic review of the potential carcinogenicity of bisphenol A in humans.

Bisphenol A (BPA) is a synthetic chemical to which humans are exposed through a variety of environmental sources. We have conducted a comprehensive, systematic review of 29 epidemiology studies and 27 experimental animal studies, published through May 2022, evaluating the potential carcinogenicity of BPA to contribute to the understanding of whether BPA is carcinogenic in humans. We conducted this review according to best practices for systematic reviews and incorporating established frameworks for study quality evaluation and evidence integration. The epidemiology studies have many limitations that increase the risk of biased results, but overall, the studies do not provide clear and consistent evidence for an association between BPA exposure and the development of any type of cancer. The experimental animal studies also do not provide strong and consistent evidence that BPA is associated with the induction of any malignant tumor type. Some of the proposed mechanisms for BPA carcinogenicity are biologically plausible, but the relevance to human exposures is not clear. We conclude that there is inadequate evidence to support a causal relationship between BPA exposure and human carcinogenicity, based on inadequate evidence in humans, as well as evidence from experimental animal studies that suggests a causal relationship is not likely.

Feasibility of Patient Navigation-Based Smoking Cessation Program in Cancer Patients.

Continued smoking after a cancer diagnosis is causally associated with increased risks of all-cause and cancer-specific mortality, and of smoking-related second primary cancers. Patient navigation provides individualized assistance to address barriers to smoking cessation treatment and represents a promising bridge to smoking cessation in persons with cancer who smoke cigarettes. We conducted a single-arm interventional cohort study of current smokers identified through prospective health record screening and recruited from Penn State Cancer Institute outpatient clinics. Consented participants received two telephone intervention sessions and gain-framed messaging-based smoking cessation educational materials designed for persons with cancer. The primary study outcome was the feasibility of the patient navigation-based intervention; the secondary outcome was the engagement in smoking cessation treatment at the two-month follow-up. Of 1168 unique screened Cancer Institute patients, 134 (11.5%) were identified as current cigarette smokers. Among 67 patients approached at outpatient clinics, 24 (35.8%) were interested in participating, 12 (17.9%) were enrolled, eight (11.9%) completed the intervention sessions and study assessments, and six engaged in smoking cessation treatment. The participants expressed satisfaction with the intervention sessions (median = 8.5, scale 0-10). The low recruitment rates preclude patient navigation as a feasible method for connecting cancer patients to smoking cessation treatment resources.

Changes in Flavor Preference in a Cohort of Long-Term Electronic Cigarette Users.

Rationale: The use of electronic cigarettes (e-cigarettes) has rapidly increased in the United States, and thousands of e-cigarette flavors are available. However, there remains a dearth of evidence on e-cigarette flavor use patterns among older e-cigarette users.Objectives: This longitudinal study examined changes in flavor use patterns in long-term e-cigarette users, assessed self-reported adverse reactions, and evaluated users' anticipated reactions to possible U.S. Food and Drug Administration e-cigarette flavor regulatory scenarios.Methods: The study population was 383 adult participants who completed two online e-cigarette surveys in 2012-2014 (baseline survey) and in 2017-2019 (follow-up survey). In both surveys, participants were asked, "Thinking about your preferred liquid, what is the name of this liquid flavor?" and to list all flavors used in the past 30 days. Flavor preference was classified using the Penn State Three-Step Flavor Classification method. Participants reported adverse events (open-ended description) with the associated flavor. Regulatory scenarios were presented, and participants selected perceived actions from among a list of 15 options.Results: Participants' age averaged 44 ± 12 years; 86% were exclusive e-cigarette users, and 13% reported "poly-use" (i.e., e-cigarette and other tobacco product use). E-cigarette flavor preference migration occurred in all demographic groups: only 36-44% maintained a preference for their original flavor. Preference for tobacco and menthol or mint decreased over time (40% baseline vs. 22% follow-up); preference for fruit remained stable (23% baseline and follow-up), but chocolate/candy or other sweets preference significantly increased (16% baseline vs. 29% follow-up), and other flavors increased slightly. Migration to sweet flavors was more noticeable in younger adults (18-45 yr); exclusive e-cigarette users preferred sweet flavors more commonly than poly-users did (31% vs. 19%). Flavor-associated adverse reactions, mainly respiratory irritations, were reported by 26 (6.9%) participants. Nearly 50% of the participants reported that they would "find a way" to buy their preferred flavor or add flavoring agents themselves if nontobacco flavors were banned.Conclusions: Flavor migration toward sweet flavors occurred in long-term e-cigarette users, a trend most pronounced in younger and exclusive e-cigarette users. The anticipated maintenance of access to flavors despite regulation suggests an element of e-cigarette-related dependence that requires further evaluation. This information could help clinicians understand the health impacts of e-cigarette flavors, develop appropriate strategies for smoking cessation, and inform the U.S. Food and Drug Administration to plan future regulation of e-cigarette flavors.

Changes in E-Cigarette Use Behaviors and Dependence in Long-term E-Cigarette Users.

INTRODUCTION: Little is known about the effects of long-term e-cigarette use, particularly the risks of relapse to cigarette smoking or increased dependence. METHODS: In a 2012-2014 baseline online e-cigarette survey, 1,863 respondents consented to participate in future research. A follow-up online survey was conducted in 2017-2018 to assess changes in e-cigarette use behaviors and e-cigarette-related dependence. For both surveys, exclusive e-cigarette use was defined as only using e-cigarettes in the past 7 days, and poly use was defined as using both e-cigarettes and other tobacco or nicotine products in the past 7 days. The Penn State Electronic Cigarette Dependence Index (PSECDI) score was calculated for each study subject and was used to evaluate e-cigarette dependence. Paired t-tests or Pearson correlation coefficients were used to examine changes in e-cigarette use behaviors or PSECDI scores between baseline and follow-up. Baseline and follow-up survey data were analyzed in January 2019. RESULTS: A total of 494 subjects provided complete data on both surveys. At baseline, 402 subjects (81.4%) were exclusive e-cigarette users, and 71 subjects (14.4%) were poly users. Among baseline exclusive e-cigarette users, the majority (88.3%) continued using e-cigarettes exclusively, but 37 users (9.2%) became poly users and 1 returned to cigarette smoking at follow-up. Among baseline poly users, 60.6% became exclusive e-cigarette users at follow-up. The mean PSECDI score remained similar over time (8.4 at baseline vs 8.3 at follow-up). CONCLUSIONS: Findings suggest that the risk of relapse to cigarette smoking is low, and e-cigarette-related dependence remains stable in long-term e-cigarette users.