Predicting nutrition and environmental factors associated with female reproductive disorders using a knowledge graph and random forests.

OBJECTIVE: Female reproductive disorders (FRDs) are common health conditions that may present with significant symptoms. Diet and environment are potential areas for FRD interventions. We utilized a knowledge graph (KG) method to predict factors associated with common FRDs (for example, endometriosis, ovarian cyst, and uterine fibroids). MATERIALS AND METHODS: We harmonized survey data from the Personalized Environment and Genes Study (PEGS) on internal and external environmental exposures and health conditions with biomedical ontology content. We merged the harmonized data and ontologies with supplemental nutrient and agricultural chemical data to create a KG. We analyzed the KG by embedding edges and applying a random forest for edge prediction to identify variables potentially associated with FRDs. We also conducted logistic regression analysis for comparison. RESULTS: Across 9765 PEGS respondents, the KG analysis resulted in 8535 significant or suggestive predicted links between FRDs and chemicals, phenotypes, and diseases. Amongst these links, 32 were exact matches when compared with the logistic regression results, including comorbidities, medications, foods, and occupational exposures. DISCUSSION: Mechanistic underpinnings of predicted links documented in the literature may support some of our findings. Our KG methods are useful for predicting possible associations in large, survey-based datasets with added information on directionality and magnitude of effect from logistic regression. These results should not be construed as causal but can support hypothesis generation. CONCLUSION: This investigation enabled the generation of hypotheses on a variety of potential links between FRDs and exposures. Future investigations should prospectively evaluate the variables hypothesized to impact FRDs.

Questionnaire-based exposome-wide association studies for common diseases in the Personalized Environment and Genes Study.

The exposome collectively refers to all exposures, beginning in utero and continuing throughout life, and comprises not only standard environmental exposures such as point source pollution and ozone levels but also exposures from diet, medication, lifestyle factors, stress, and occupation. The exposome interacts with individual genetic and epigenetic characteristics to affect human health and disease, but large-scale studies that characterize the exposome and its relationships with human disease are limited. To address this gap, we used extensive questionnaire data from the diverse North Carolina-based Personalized Environment and Genes Study (PEGS, n = 9, 429) to evaluate exposure associations in relation to common diseases. We performed an exposome-wide association study (ExWAS) to examine single exposure models and their associations with 11 common complex diseases, namely allergic rhinitis, asthma, bone loss, fibroids, high cholesterol, hypertension, iron-deficient anemia, ovarian cysts, lower GI polyps, migraines, and type 2 diabetes. Across diseases, we found associations with lifestyle factors and socioeconomic status as well as asbestos, various dust types, biohazardous material, and textile-related exposures. We also found disease-specific associations such as fishing with lead weights and migraines. To differentiate between a replicated result and a novel finding, we used an AI-based literature search and database tool that allowed us to examine the current literature. We found both replicated findings, especially for lifestyle factors such as sleep and smoking across diseases, and novel findings, especially for occupational exposures and multiple diseases.

Contributions of common genetic variants to constitutional delay of puberty and idiopathic hypogonadotropic hypogonadism.

CONTEXT: Constitutional delay of puberty (CDP) is highly heritable, but the genetic basis for CDP is largely unknown. Idiopathic hypogonadotropic hypogonadism (IHH) can be caused by rare genetic variants, but in about half of cases, no rare-variant cause is found. OBJECTIVE: To determine whether common genetic variants that influence pubertal timing contribute to CDP and IHH. DESIGN: Case-control study. PARTICIPANTS: 80 individuals with CDP; 301 with normosmic IHH, and 348 with Kallmann syndrome; control genotyping data from unrelated studies. MAIN OUTCOME MEASURES: Polygenic scores (PGS) based on genome-wide association studies for timing of male pubertal hallmarks and age at menarche (AAM). RESULTS: The CDP cohort had higher PGS for male pubertal hallmarks and for AAM compared to controls (for male hallmarks, Cohen's d = 0.85, p = 1 × 10-16; for AAM, d = 0.67, p = 1 × 10-10). The normosmic IHH cohort also had higher PGS for male hallmarks compared to controls, but the difference was smaller (male hallmarks d = 0.20, p = 0.003; AAM d = 0.10, p = 0.055). No differences were seen for the KS cohort compared to controls (male hallmarks d = 0.04, p = 0.45; AAM d = -0.03, p = 0.86). CONCLUSIONS: Common genetic variants that influence pubertal timing in the general population contribute strongly to the genetics of CDP, weakly to normosmic IHH, and potentially not at all to KS. These findings demonstrate that the common-variant genetics of CDP and normosmic IHH are largely but not entirely distinct.

Interactive data sharing for multiple questionnaire-based exposome-wide association studies and exposome correlations in the Personalized Environment and Genes Study.

The correlations among individual exposures in the exposome, which refers to all exposures an individual encounters throughout life, are important for understanding the landscape of how exposures co-occur, and how this impacts health and disease. Exposome-wide association studies (ExWAS), which are analogous to genome-wide association studies (GWAS), are increasingly being used to elucidate links between the exposome and disease. Despite increased interest in the exposome, tools and publications that characterize exposure correlations and their relationships with human disease are limited, and there is a lack of data and results sharing in resources like the GWAS catalog. To address these gaps, we developed the PEGS Explorer web application to explore exposure correlations in data from the diverse North Carolina-based Personalized Environment and Genes Study (PEGS) that were rigorously calculated to account for differing data types and previously published results from ExWAS. Through globe visualizations, PEGS Explorer allows users to explore correlations between exposures found to be associated with complex diseases. The exposome data used for analysis includes not only standard environmental exposures such as point source pollution and ozone levels but also exposures from diet, medication, lifestyle factors, stress, and occupation. The web application addresses the lack of accessible data and results sharing, a major challenge in the field, and enables users to put results in context, generate hypotheses, and, importantly, replicate findings in other cohorts. PEGS Explorer will be updated with additional results as they become available, ensuring it is an up-to-date resource in exposome science.

Public support for tobacco endgame policies in South Korea: Findings from the 2020 International Tobacco Control Korea Survey.

BACKGROUND: Strong public support can increase the likelihood of adopting tobacco control policies. We assessed support for six commercial tobacco endgame policies in South Korea: limiting the nicotine in cigarettes, banning all additives in cigarettes, restricting the number of places where cigarettes are sold, and banning the manufacture and sales of cigarettes (unconditionally, with the provision of cessation support and with alternative tobacco products available). METHODS: Data were obtained from 4740 adults who completed the 2020 International Tobacco Control Korea Survey. Participants were categorised based on their nicotine use: (1) did not use any products, (2) vaped and/or used heated tobacco products (HTPs) but did not smoke cigarettes, (3) smoked cigarettes only and (4) smoked cigarettes and vaped and/or used HTPs. Attitudes towards the policies were classified as supportive, undecided or opposed. Weighted multinomial logistic regression models assessed support levels according to nicotine use. RESULTS: Support was highest for limiting the nicotine content in cigarettes (68.4%; 95% CI 64.6% to 72.3%) and restricting the number of retailers (68.1%; 95% CI 64.5% to 71.7%), and lowest for banning cigarette sales if alternative products are made available (45.0%; 95% CI 40.9% to 49.1%). People who did not use any products were most likely to support endgame policies, except for banning cigarette sales with alternatives available. The proportion of undecided participants exceeded 10% (range 13%-25%) for all policies. CONCLUSION: There is a strong public support for tobacco endgame policies in South Korea. Further research should prioritise the development of strategies to ensure the effective implementation of highly supported policies.

Illicit cigarette purchasing after implementation of menthol cigarette bans in Canada: findings from the 2016-2018 ITC Four Country Smoking and Vaping Surveys.

OBJECTIVE: To examine the impact of menthol cigarette bans on use and purchasing of illicit cigarettes among menthol and non-menthol smokers in seven Canadian provinces. METHODS: Data from 1098 non-menthol smokers and 138 menthol smokers in Canada who completed the ITC Four Country Smoking and Vaping Survey in 2016 (pre-ban) and 2018 (post-ban). Brand validation analysis was conducted to (1) compare self-reported use of menthols versus actual use of menthols as regular brand, and verify self-reported purchasing of menthols among pre-ban menthol smokers at post-ban; and (2) assess pre-post ban changes in purchasing of illicit cigarettes from First Nations reserves among non-menthol smokers and menthol smokers. RESULTS: Among the subset of 138 pre-ban menthol smokers, 36 (19.5%) reported smoking menthols at post-ban. Brand validation analyses showed that 19 (9.0%) were actually using a non-menthol brand; of the 17 (10.5%) who were actually using a menthol brand, 13 (7.9%) bought a menthol brand at last purchase, and 4 (2.6%) bought a non-menthol brand. Among the full sample of smokers who purchased cigarettes from First Nations reserves at both pre-ban and post-ban, there was no change in purchasing of menthols (n=9 menthol smokers; 51.2% vs 51.2%, p=1.00), non-menthols (n=1024 non-menthol smokers; 9.1% vs 8.7%, p=0.69) or all cigarettes (menthol+non-menthol) (n=1086 smokers; 9.7% vs 9.2%, p=0.56). CONCLUSIONS: Actual rates of brand-verified menthol smoking were substantially lower than self-reported rates at post-ban. After Canada's menthol ban, there was no increase in illicit purchasing of menthol or non-menthol cigarettes from First Nations reserves.

Optimising a product standard for banning menthol and other flavours in tobacco products.

In this paper, we highlight key issues that policymakers should consider when developing a product standard banning menthol and other flavours in tobacco products based on research evidence and experiences learnt from other countries. A flavour product standard may be optimised by (1) having a clear and comprehensive definition of flavour that includes a complete ban on additives that have flavour properties and/or evoke sensory/cooling effects (ie, menthol analogues and synthetic coolants that stimulate the cooling receptor of the brain) rather than only as a 'characterising flavour' and (2) applying the standard to all tobacco product categories as well as all components or parts of the tobacco product (ie, the tobacco, filter, wrapper or paper), including separate flavourings that can be added to the product.

Application of machine learning and artificial intelligence in the diagnosis and classification of polycystic ovarian syndrome: a systematic review.

Introduction: Polycystic Ovarian Syndrome (PCOS) is the most common endocrinopathy in women of reproductive age and remains widely underdiagnosed leading to significant morbidity. Artificial intelligence (AI) and machine learning (ML) hold promise in improving diagnostics. Thus, we performed a systematic review of literature to identify the utility of AI/ML in the diagnosis or classification of PCOS. Methods: We applied a search strategy using the following databases MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, the Web of Science, and the IEEE Xplore Digital Library using relevant keywords. Eligible studies were identified, and results were extracted for their synthesis from inception until January 1, 2022. Results: 135 studies were screened and ultimately, 31 studies were included in this study. Data sources used by the AI/ML interventions included clinical data, electronic health records, and genetic and proteomic data. Ten studies (32%) employed standardized criteria (NIH, Rotterdam, or Revised International PCOS classification), while 17 (55%) used clinical information with/without imaging. The most common AI techniques employed were support vector machine (42% studies), K-nearest neighbor (26%), and regression models (23%) were the commonest AI/ML. Receiver operating curves (ROC) were employed to compare AI/ML with clinical diagnosis. Area under the ROC ranged from 73% to 100% (n=7 studies), diagnostic accuracy from 89% to 100% (n=4 studies), sensitivity from 41% to 100% (n=10 studies), specificity from 75% to 100% (n=10 studies), positive predictive value (PPV) from 68% to 95% (n=4 studies), and negative predictive value (NPV) from 94% to 99% (n=2 studies). Conclusion: Artificial intelligence and machine learning provide a high diagnostic and classification performance in detecting PCOS, thereby providing an avenue for early diagnosis of this disorder. However, AI-based studies should use standardized PCOS diagnostic criteria to enhance the clinical applicability of AI/ML in PCOS and improve adherence to methodological and reporting guidelines for maximum diagnostic utility. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42022295287.

Illicit purchasing and use of flavour accessories after the European Union menthol cigarette ban: findings from the 2020-21 ITC Netherlands Surveys.

BACKGROUND: The 2020 European Union (EU) menthol cigarette ban increased quitting among pre-ban menthol smokers in the Netherlands, but some reported continuing to smoke menthol cigarettes. This study examined three possible explanations for post-ban menthol use-(i) illicit purchasing, (ii) use of flavour accessories and (iii) use of non-menthol replacement brands marketed for menthol smokers. METHODS: Data were from the ITC Netherlands Cohort Surveys among adult smokers before the menthol ban (Wave 1: February-March 2020, N = 2067) and after the ban (Wave 2: September-November 2020, N = 1752; Wave 3: June-July 2021, N = 1721). Bivariate, logistic regression and generalized estimating equation model analyses were conducted on weighted data. RESULTS: Illicit purchasing remained low from pre-ban (2.4%, 95% CI: 1.8-3.2, Wave 1) to post-ban (1.7%, 1.2-2.5%, Wave 3), with no difference between menthol and non-menthol smokers from Wave 1 to Wave 3. About 4.4% of post-ban menthol smokers last purchased their usual brand outside of the EU and 3.6% from the internet; 42.5% of post-ban menthol smokers and 4.4% of smokers overall reported using flavour accessories, with greater odds among those aged 25-39 years vs. 55+ (aOR = 3.16, P = 0.002). Approximately 70% of post-ban smokers who reported using a menthol brand were actually using a non-menthol replacement brand. CONCLUSIONS: There was no increase in illicit purchasing or of smuggling outside the EU among menthol and non-menthol smokers in the Netherlands 1 year after the EU menthol cigarette ban. Use of flavour accessories and non-menthol replacement brands best explain post-ban menthol use, suggesting the need to ban accessories and ensure industry compliance.

Predicting nutrition and environmental factors associated with female reproductive disorders using a knowledge graph and random forests.

Objective: Female reproductive disorders (FRDs) are common health conditions that may present with significant symptoms. Diet and environment are potential areas for FRD interventions. We utilized a knowledge graph (KG) method to predict factors associated with common FRDs (e.g., endometriosis, ovarian cyst, and uterine fibroids). Materials and Methods: We harmonized survey data from the Personalized Environment and Genes Study on internal and external environmental exposures and health conditions with biomedical ontology content. We merged the harmonized data and ontologies with supplemental nutrient and agricultural chemical data to create a KG. We analyzed the KG by embedding edges and applying a random forest for edge prediction to identify variables potentially associated with FRDs. We also conducted logistic regression analysis for comparison. Results: Across 9765 PEGS respondents, the KG analysis resulted in 8535 significant predicted links between FRDs and chemicals, phenotypes, and diseases. Amongst these links, 32 were exact matches when compared with the logistic regression results, including comorbidities, medications, foods, and occupational exposures. Discussion: Mechanistic underpinnings of predicted links documented in the literature may support some of our findings. Our KG methods are useful for predicting possible associations in large, survey-based datasets with added information on directionality and magnitude of effect from logistic regression. These results should not be construed as causal, but can support hypothesis generation. Conclusion: This investigation enabled the generation of hypotheses on a variety of potential links between FRDs and exposures. Future investigations should prospectively evaluate the variables hypothesized to impact FRDs.

Race/ethnicity-stratified fine-mapping of the MHC locus reveals genetic variants associated with late-onset asthma.

Introduction: Asthma is a chronic disease of the airways that impairs normal breathing. The etiology of asthma is complex and involves multiple factors, including the environment and genetics, especially the distinct genetic architecture associated with ancestry. Compared to early-onset asthma, little is known about genetic predisposition to late-onset asthma. We investigated the race/ethnicity-specific relationship among genetic variants within the major histocompatibility complex (MHC) region and late-onset asthma in a North Carolina-based multiracial cohort of adults. Methods: We stratified all analyses by self-reported race (i.e., White and Black) and adjusted all regression models for age, sex, and ancestry. We conducted association tests within the MHC region and performed fine-mapping analyses conditioned on the race/ethnicity-specific lead variant using whole-genome sequencing (WGS) data. We applied computational methods to infer human leukocyte antigen (HLA) alleles and residues at amino acid positions. We replicated findings in the UK Biobank. Results: The lead signals, rs9265901 on the 5' end of HLA-B, rs55888430 on HLA-DOB, and rs117953947 on HCG17, were significantly associated with late-onset asthma in all, White, and Black participants, respectively (OR = 1.73, 95%CI: 1.31 to 2.14, p = 3.62 × 10-5; OR = 3.05, 95%CI: 1.86 to 4.98, p = 8.85 × 10-6; OR = 19.5, 95%CI: 4.37 to 87.2, p = 9.97 × 10-5, respectively). For the HLA analysis, HLA-B*40:02 and HLA-DRB1*04:05, HLA-B*40:02, HLA-C*04:01, and HLA-DRB1*04:05, and HLA-DRB1*03:01 and HLA-DQB1 were significantly associated with late-onset asthma in all, White, and Black participants. Conclusion: Multiple genetic variants within the MHC region were significantly associated with late-onset asthma, and the associations were significantly different by race/ethnicity group.

Prevalence of Deleterious Variants in MC3R in Patients With Constitutional Delay of Growth and Puberty.

CONTEXT: The melanocortin 3 receptor (MC3R) has recently emerged as a critical regulator of pubertal timing, linear growth, and the acquisition of lean mass in humans and mice. In population-based studies, heterozygous carriers of deleterious variants in MC3R report a later onset of puberty than noncarriers. However, the frequency of such variants in patients who present with clinical disorders of pubertal development is currently unknown. OBJECTIVE: This work aimed to determine whether deleterious MC3R variants are more frequently found in patients clinically presenting with constitutional delay of growth and puberty (CDGP) or normosmic idiopathic hypogonadotropic hypogonadism (nIHH). METHODS: We examined the sequence of MC3R in 362 adolescents with a clinical diagnosis of CDGP and 657 patients with nIHH, experimentally characterized the signaling properties of all nonsynonymous variants found and compared their frequency to that in 5774 controls from a population-based cohort. Additionally, we established the relative frequency of predicted deleterious variants in individuals with self-reported delayed vs normally timed menarche/voice-breaking in the UK Biobank cohort. RESULTS: MC3R loss-of-function variants were infrequent but overrepresented in patients with CDGP (8/362 [2.2%]; OR = 4.17; P = .001). There was no strong evidence of overrepresentation in patients with nIHH (4/657 [0.6%]; OR = 1.15; P = .779). In 246 328 women from the UK Biobank, predicted deleterious variants were more frequently found in those self-reporting delayed (aged ≥16 years) vs normal age at menarche (OR = 1.66; P = 3.90E-07). CONCLUSION: We have found evidence that functionally damaging variants in MC3R are overrepresented in individuals with CDGP but are not a common cause of this phenotype.

The Thyroid Hormone Axis and Female Reproduction.

Thyroid function affects multiple sites of the female hypothalamic-pituitary gonadal (HPG) axis. Disruption of thyroid function has been linked to reproductive dysfunction in women and is associated with menstrual irregularity, infertility, poor pregnancy outcomes, and gynecological conditions such as premature ovarian insufficiency and polycystic ovarian syndrome. Thus, the complex molecular interplay between hormones involved in thyroid and reproductive functions is further compounded by the association of certain common autoimmune states with disorders of the thyroid and the HPG axes. Furthermore, in prepartum and intrapartum states, even relatively minor disruptions have been shown to adversely impact maternal and fetal outcomes, with some differences of opinion in the management of these conditions. In this review, we provide readers with a foundational understanding of the physiology and pathophysiology of thyroid hormone interactions with the female HPG axis. We also share clinical insights into the management of thyroid dysfunction in reproductive-aged women.

Support for pictorial health warning labels on cigarette packages in the United States among adults who currently smoke or quit smoking: Findings from the ITC US Smoking and Vaping Surveys.

INTRODUCTION: In March 2020, the US Food and Drug Administration (FDA) finalized new pictorial health warnings (PHWs), covering 50% of the front and back of the pack; however, legal challenges from cigarette manufacturers have prevented the new warnings from being implemented. About 70% of adults in the general US population support PHWs. This study assessed support for PHWs in 2016, 2018 and 2020 among US adults (aged ≥18 years) who currently smoke or formerly smoked cigarettes. We also assessed factors related to support. METHODS: Respondents included adults who currently or formerly smoked cigarettes and participated in at least one wave of the US ITC Smoking and Vaping Surveys: Wave 1 (2016, n=2557); Wave 2 (2018, n=2685); and Wave 3 (2020, n=1112). We assessed changes in support for PHWs between 2016 and 2020, and assessed factors related to support (support vs oppose/don't know). Analyses were conducted on weighted data. RESULTS: Overall, 38.0% of respondents supported PHWs in 2016, with a significant increase to 44.7% in 2018 (p<0.001), and leveling off to 45.0% in 2020 (2018 vs 2020, p=0.91). Support was highest among former smokers and lowest among daily smokers in all three survey years. Support for PHWs at all survey years was significantly higher among those who formerly smoked, were younger (aged 18-39 vs ≥40 years), those who identified as Black (vs White), and planned to quit smoking (vs not planning to quit). There were no differences by income level, education level, or sex. CONCLUSIONS: Nearly half of US adults who smoke cigarettes or quit smoking supported PHWs in 2020, with support being higher among younger adults, ethnic minorities, and those who formerly smoked. Support increased between 2016 and 2018, but not between 2018 and 2020. Similar to other studies, fewer current and former smokers supported PHWs compared to the US adult general population.

Inflammasome-independent NLRP3 function enforces ATM activity in response to genotoxic stress.

NLRP3 is a pattern recognition receptor with a well-documented role in inducing inflammasome assembly in response to cellular stress. Deregulation of its activity leads to many inflammatory disorders including gouty arthritis, Alzheimer disease, and cancer. Whereas its role in the context of cancer has been mostly explored in the immune compartment, whether NLRP3 exerts functions unrelated to immunity in cancer development remains unexplored. Here, we demonstrate that NLRP3 interacts with the ATM kinase to control the activation of the DNA damage response, independently of its inflammasome activity. NLRP3 down-regulation in both broncho- and mammary human epithelial cells significantly impairs ATM pathway activation, leading to lower p53 activation, and provides cells with the ability to resist apoptosis induced by acute genotoxic stress. Interestingly, NLRP3 expression is down-regulated in non-small cell lung cancers and breast cancers, and its expression positively correlates with patient overall survival. Our findings identify a novel non-immune function for NLRP3 in maintaining genome integrity and strengthen the concept of a functional link between innate immunity and DNA damage sensing pathways to maintain cell integrity.

Heterozygous mutations in SOX2 may cause idiopathic hypogonadotropic hypogonadism via dominant-negative mechanisms.

Pathogenic SRY-box transcription factor 2 (SOX2) variants typically cause severe ocular defects within a SOX2 disorder spectrum that includes hypogonadotropic hypogonadism. We examined exome-sequencing data from a large, well-phenotyped cohort of patients with idiopathic hypogonadotropic hypogonadism (IHH) for pathogenic SOX2 variants to investigate the underlying pathogenic SOX2 spectrum and its associated phenotypes. We identified 8 IHH individuals harboring heterozygous pathogenic SOX2 variants with variable ocular phenotypes. These variant proteins were tested in vitro to determine whether a causal relationship between IHH and SOX2 exists. We found that Sox2 was highly expressed in the hypothalamus of adult mice and colocalized with kisspeptin 1 (KISS1) expression in the anteroventral periventricular nucleus of adult female mice. In vitro, shRNA suppression of mouse SOX2 protein in Kiss-expressing cell lines increased the levels of human kisspeptin luciferase (hKiss-luc) transcription, while SOX2 overexpression repressed hKiss-luc transcription. Further, 4 of the identified SOX2 variants prevented this SOX2-mediated repression of hKiss-luc. Together, these data suggest that pathogenic SOX2 variants contribute to both anosmic and normosmic forms of IHH, attesting to hypothalamic defects in the SOX2 disorder spectrum. Our study describes potentially novel mechanisms contributing to SOX2-related disease and highlights the necessity of SOX2 screening in IHH genetic evaluation irrespective of associated ocular defects.

Evaluating the impact of plain packaging among Canadian smokers: findings from the 2018 and 2020 ITC Smoking and Vaping Surveys.

BACKGROUND: In February 2020, Canada implemented plain packaging without any changes to the size and content of health warning labels (HWLs), which were last updated in 2012 (pictorial HWLs on 75% of the pack front and back). This pre-post evaluation study assessed the impact of plain packaging in Canada on: (1) pack appeal; (2) HWL effectiveness; and (3) support for plain packaging. Additionally, a quasi-experimental design was used to assess the Canadian results relative to two comparator countries: Australia, where plain packaging (with new larger HWLs) was implemented in 2012, and the United States (USA), where plain packaging has not been implemented and the same text warnings have appeared on cigarette packs since 1985. METHODS: Data are from adult smokers who participated in the 2018 and/or 2020 International Tobacco Control Smoking and Vaping Surveys in Canada (n=4600), Australia (n=1834) and the USA (n=3046). Online surveys were conducted before (February to July 2018) and after (February to June 2020) the implementation of plain packaging in Canada. Adjusted regression analyses were conducted on weighted data. RESULTS: Plain packaging was associated with a significant increase in the percentage of Canadian smokers who did not like the look of their cigarette pack (2018: 28.6% vs 2020: 44.7%, p<0.001), whereas no change in pack appeal was observed among smokers in Australia and the USA over the same period. Plain packaging was not associated with changes in HWL effectiveness in Canada. Support for plain packaging increased significantly among Canadian smokers (2018: 25.6% vs 2020: 33.7%, p<0.001). CONCLUSIONS: Plain packaging in Canada substantially reduced pack appeal and increased support for the policy among adult smokers; however, there was no increase in the effectiveness of Canada's 8-year-old HWLs. The impact of plain packaging on health warning effectiveness may depend on the design of the warnings and length of time since implementation.