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PurposeTo evaluate the association between lifetime personal cigarette smoking and young-onset breast cancer (YOBC; diagnosed

PURPOSE: The etiology of young-onset breast cancer (BC) is poorly understood, despite its greater likelihood of being hormone receptor-negative with a worse prognosis and persistent racial and socioeconomic inequities. We conducted a population-based case-control study of BC among young Black and White women and here discuss the theory that informed our study, exposures collected, study methods, and operational results. METHODS: Cases were non-Hispanic Black (NHB) and White (NHW) women age 20-49 years with invasive BC in metropolitan Detroit and Los Angeles County SEER registries 2010-2015. Controls were identified through area-based sampling from the U.S. census and frequency matched to cases on study site, race, and age. An eco-social theory of health informed life-course exposures collected from in-person interviews, including socioeconomic, reproductive, and energy balance factors. Measured anthropometry, blood (or saliva), and among cases SEER tumor characteristics and tumor tissue (from a subset of cases) were also collected. RESULTS: Of 5,309 identified potentially eligible cases, 2,720 sampled participants were screened and 1,812 completed interviews (682 NHB, 1140 NHW; response rate (RR): 60%). Of 24,612 sampled control households 18,612 were rostered, 2,716 participants were sampled and screened, and 1,381 completed interviews (665 NHB, 716 NHW; RR: 53%). Ninety-nine% of participants completed the main interview, 82% provided blood or saliva (75% blood only), and SEER tumor characteristics (including ER, PR and HER2 status) were obtained from 96% of cases. CONCLUSIONS: Results from the successfully established YWHHS should expand our understanding of young-onset BC etiology overall and by tumor type and identify sources of racial and socioeconomic inequities in BC.

Abstract: Previous studies have found that tobacco exposure is associated with an increased risk of premenopausal breast cancer (BC) overall and some studies suggest that risk is only increased for Luminal A BC. Few studies have described the association between tobacco exposure and BC risk with characterization of the human epidermal growth factor receptor 2 (HER2) subtype. This analysis explored associations between smoking over the life course and BC risk overall and by BC subtype among a socioeconomically diverse population of young non-Hispanic (NH) Black and White women. Data were examined from a population-based case-control study in women under 50 years of age, the Young Women’s Health History Study. In total, 1,812 women with invasive BC (1,130 NH White, 682 NH Black) and an area-based sample of 1,381 (716 NH White, 665 NH Black) control women, frequency matched to cases by five-year age group, study site and self-reported race were identified from the Los Angeles County and Metropolitan Detroit SEER registry areas. Lifetime smoking histories were collected from in-person interviews. Sample-weighted logistic regression analysis was conducted to estimate the association between lifetime cigarette smoking status (never versus ever smoker) and BC risk adjusted for known BC risk factors and study site. Multinomial logistic regression analysis was conducted for analyses by BC subtype. Heterogeneity in the odds ratio (OR) estimates by BC subtype and cross-product interaction terms of smoking status by race and by household percent poverty (HHP) were evaluated by the Wald test. In adjusted models, BC risk overall was not significantly associated with ever smoking at least 1 cigarette a day for 6 months or more (OR 1.18; 95% confidence interval (CI) 0.97- 1.43). By BC subtype, ever smokers displayed a statistically significant 30% increase in Luminal A BC risk compared to never smokers (OR 1.30; 95% CI 1.03-1.64) and a 90% increased risk of HER2-type BC (OR 1.90; 95% CI 1.17-3.08). Smoking was not associated with risk of Luminal B or Triple Negative BC. Associations between ever smoking and BC risk significantly differed by BC subtype (Pheterogeneity=0.02). Statistical interactions by race or by HHP were not observed. However, we noted that in stratified models the association between smoking and risk for HER2-type BC was higher among NH White compared to NH Black women and among women with HHP ≥150% compared to HHP

Abstract: The etiology of breast cancer (BC) among young women is not well understood. Recent studies have suggested that tobacco exposure is associated with an increased risk of BC but few studies have evaluated risk among women under age 50 or racial and socioeconomic disparities in risk. We hypothesized that racial and socioeconomic differences in age at smoking initiation and lifetime cigarette smoking contribute to disparities in BC risk among young women. Data were examined from a population-based case-control study in women under 50 years of age, the Young Women’s Health History Study. In total, 1,812 women with invasive BC (1,130 Non-Hispanic (NH) White, 682 NH Black) and an area-based sample of 1,381 control women (716 NH White, 665 NH Black), frequency matched to cases by five-year age group, study site and race were identified and interviewed from the Los Angeles County and Metropolitan Detroit SEER registry areas. Lifetime smoking history (including age at initiation, duration, and frequency) were collected from structured in-person interviews. Survey-weighted multivariable logistic regression was used to evaluate the association between lifetime cigarette smoking and BC risk adjusted for matching and known BC risk factors. Additionally, cross-product interaction terms of smoking exposure by race and by socioeconomic position (SEP; based on household percent poverty) were evaluated by Wald’s test. Among controls, 36.5% reported ever smoking at least 1 cigarette a day for at least 6 months in their lifetime with White women compared to Black women (38.3% vs. 32.3%) and women of lower SEP (

BACKGROUND: The incremental shuttle walk test (ISWT) provides an indirect approach for predicting cardiorespiratory fitness (predicted peak oxygen consumption [VO2peak]) that may offer a cost-effective and efficient surrogate for laboratory-based measures of fitness. A pediatric ISWT prediction equation has evidence for validity in otherwise healthy children, but there is no validity evidence in children with pediatric-onset multiple sclerosis (POMS). OBJECTIVES: To evaluate the agreement between predicted VO2peak from an ISWT and measured VO2peak from a gold standard, maximal cycle ergometer exercise test with expired gas analysis. METHODS: Between 2020 and 2023, patients aged 11 to 21 years with a diagnosis of POMS were recruited as part of an ongoing exercise trial from 1 of 3 North American pediatric centers located in either Canada or the United States. Participants provided informed consent and were then provided with materials required for setting up the ISWT remotely, to be performed while on a scripted video call (Zoom for Healthcare) with a research coordinator. The ISWT followed standardized procedures and was externally paced, with increases in walking up to 12 levels. The total distance covered in meters was the final score from the ISWT and transformed into predicted VO2peak based on 20.94 + 0.2*walking distance. Additionally, participants took part in cardiorespiratory fitness testing involving an 8- to 10-minute test on a cycle ergometer, with work rate increasing in increments of 10 to 20 watts per minute until volitional exhaustion. VO2peak was directly determined using analysis of expired gases. Correlational analysis and intraclass correlation coefficients (ICCs) evaluated the agreement between predicted VO2peak based on the ISWT and measured VO2peak using JASP (version 18.3). RESULTS: Twenty-eight patients (19 female participants) with POMS (body mass index, 25; Expanded Disability Status Scale score, 0) completed both tests. The mean predicted VO2peak (SD) was 36 mL/kg/ min (4), whereas the mean measured VO2peak was 30 mL/kg/min (7.7). The predicted VO2peak was strongly associated with measured VO2peak (Spearman ρ = 0.6; 95% CI, 0.2-0.8; P < .01). The agreement between predicted and measured VO2peak was fair based on an ICC of 0.57 (95% CI, 0.1-0.9). The ISWT overestimated VO2peak (mean difference, -6.9 mL/kg/min; 95% CI, -10 to 4). CONCLUSIONS: Predicted VO2peak from a remotely administered ISWT associates strongly with laboratory measurement of cardiorespiratory fitness in children with POMS. We believe future research should refine the prediction equation for improving its accuracy in children with MS and examine whether this approach is sensitive for capturing effects of exercise interventions in this cohort. [ABSTRACT FROM AUTHOR]