Exposure to MMVF in residential and commercial buildings: A literature review and quantitative synthesis.

Man-made vitreous fibers (MMVF) are a class of inorganic fibrous materials that include glass and mineral wools, continuous glass filaments, and refractory ceramic fibers valued for their insulative properties in high temperature applications. Potential health effects from occupational exposure to MMVF have been investigated since the 1970s, with focus on incidence of respiratory tract cancer among MMVF-exposed production workers. The general population may experience exposure to MMVF in residential and/or commercial buildings due to deterioration, construction, or other disruption of materials containing these fibers. Numerous studies have characterized potential exposures that may occur during material disruption or installation; however, fewer have aimed to measure background MMVF concentrations in residential and commercial spaces (i.e., non-production settings) to which the general population may be exposed. In this study, we reviewed and synthesized peer-reviewed studies that evaluated respirable MMVF exposure levels in non-production, indoor environments. Among studies that analyzed airborne respirable MMVF concentrations, 110-fold and 1.5-fold differences in estimated concentrations were observed for those studies utilizing phase contrast optical microscopy (PCOM) versus transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. A positive correlation was observed between respirable air concentrations of MMVF and total surface concentrations of MMVF in seldom-cleaned areas. Ultimately, available evidence suggests that both ambient air and surface concentrations of MMVF in indoor environments are consistently lower than exposure limits developed to prevent negative health outcomes among sensitive populations.

Systematic review of epidemiological studies evaluating the association between exposure to man-made vitreous fibers and non-malignant respiratory diseases.

This study aimed to systematically review and synthesize epidemiological evidence evaluating the association between occupational man-made vitreous fiber (MMVF) exposure and non-malignant respiratory disease (NMRD). We searched PubMed and Scopus databases to identify epidemiological studies evaluating the association between occupational MMVF exposure (limited to insulation wools) and at least 1 NMRD outcome published prior to January 2023. A total of 23 studies met our inclusion criteria. Studies of NMRD mortality among workers with MMVF exposure (n = 9) predominately reported null findings. Qualitative and quantitative synthesis of evidence from these studies suggests that MMVF exposure is not associated with elevated risk of NMRD mortality. The remaining 14 studies evaluated NMRD morbidity, specifically self-reported respiratory symptoms and/or subclinical measures of respiratory disease. Our review did not identify any consistent or compelling evidence of an association between MMVF exposure and any NMRD morbidity outcome; however, this body of evidence was largely limited by cross-sectional design, self-reported exposure and/or outcome ascertainment, incomplete statistical analysis and reporting, and questionable generalizability given that 13/14 studies were published over 20 years ago. We recommend that future studies aim to overcome the limitations of this literature to more accurately characterize the association between occupational MMVF exposure and NMRD morbidity.

Systematic review and meta-analysis of epidemiological literature evaluating the association between exposure to man-made vitreous fibers and respiratory tract cancers.

We conducted a systematic review and meta-analysis of epidemiological studies that evaluated occupational exposure to man-made vitreous fibers (MMVF) including glass, rock, and slag wools, and respiratory tract cancers (RTC) including cancers of the larynx, trachea, bronchus, and lung. The MEDLINE/PubMed and Web of Science databases were searched in order to identify epidemiological studies that evaluated the association between occupational MMVF exposure and RTCs. We performed random-effects meta-analyses of relevant studies identified by our literature search, and evaluated sources of between-study heterogeneity. The pooled relative risk (RR) of RTC among workers exposed to MMVFs was 1.09 (95% CI = 0.97, 1.22). The RR was closer to 1.0 when limiting the analysis to effect estimates from studies that accounted for the main a priori risk factors for RTC, asbestos exposure and smoking (RR = 1.03, 95% CI = 0.90, 1.18). Overall, our synthesis of the epidemiological literature suggests that occupational MMVF exposure is not associated with risk of RTC.

Associations of Endogenous Sex Hormones with Carotid Plaque Burden and Characteristics in Midlife Women.

CONTEXT: Endogenous sex hormones may be involved in the pathogenesis of cardiovascular disease (CVD) in women. Carotid plaque characteristics, such as echogenicity, an ultrasound measure that reflects plaque composition, may identify unstable plaques that are more likely to rupture, precipitating a CVD event. However, few studies have considered sex steroids in relation to carotid plaque and its characteristics. OBJECTIVE: To evaluate estrone (E1), estradiol (E2), testosterone (T), sex hormone binding globulin (SHBG), and free T (FT) in relation to carotid plaque in women. DESIGN, SETTING, AND PARTICIPANTS: In MsHeart, a cross-sectional study of 304 women aged 40 to 60 years, participants underwent a carotid artery ultrasound assessment. The current analysis included MsHeart participants with carotid plaque (n = 141, 46%). E1, E2, and T were assayed using liquid chromatography-tandem mass spectrometry; FT was estimated using ensemble allostery models. Regression models were adjusted for sociodemographic characteristics and CVD risk factors. MAIN OUTCOMES: Carotid plaque burden (number of plaques, total plaque area [TPA]) and characteristics (calcification, echogenicity) were determined using semi-automated software. RESULTS: SHBG was inversely related to TPA (odds ratio [OR] 0.39; 95% confidence interval [CI] 0.21, 0.74; multivariable) and higher FTs were associated with greater TPA (OR 2.89; 95% CI 1.31, 6.37; multivariable). Higher E1 was related to echogenicity (OR 2.31; 95% CI 1.26, 4.33; multivariable), characteristic of more stable plaque. CONCLUSIONS: SHBG and FT are related to TPA while E1 is related to plaque echogenicity, suggesting these hormones have different roles in the development of carotid plaque. Our findings highlight the importance of sex hormones in the development of carotid plaque in midlife women.