Abdominal adiposity intensifies the negative effects of ambient air pollution on lung function in Korean men

Abstract

BACKGROUND: Some studies have provided the possibility that adipose tissue may mediate air pollution-induced lung dysfunction. Studies using quantified fat mass data are needed to understand the biological mechanisms between adipocyte and air pollution in lung function. We aimed to investigate whether abdominal adiposity measured by computed tomography (CT) modifies the effects of air pollution on lung function in Korean men. METHODS: A total of 1876 men who visited one of two health checkup centers were recruited for this study. Adiposity traits such as visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and total adipose tissue (TAT) areas were measured by CT. We used the annual mean concentrations of ambient air pollutants including nitrogen dioxide (NO 2 ) and particulate matter with an aerodynamic diameter ⩽ 10 μm (PM 10 ). RESULTS: Interquartile range (IQR) increase in annual mean concentration of NO 2 was significantly associated with a 2.5% lower forced expiratory volume in 1 s (FEV 1 ) and 2.9% lower forced vital capacity (FVC) (both P o0.05). The decrease in lung function was more strongly associated with adiposity traits than with body mass index. In a stratified analysis of adiposity, compared with subjects with low-VAT area (VAT ⩽ 200 cm 2 ), those with high-VAT area (VAT4200 cm 2 ) showed a rapid decrease in FEV 1 with each IQR increase in PM 10 (β = -0.0812; 95% confidence interval (CI) = -0.1590, -0.0035) and NO 2 (β = -0.0979; 95% CI = -0.1611, -0.0346). In the high-VAT group, each IQR increase in NO 2 content was significantly associated with a 10.6% decrease (β = -0.1056; 95% CI = -0.1770, -0.0343) in FVC. SAT and TAT areas showed similar patterns. CONCLUSIONS: We report the first finding that abdominal adiposity intensifies the inverse relationship between air pollution and lung function.

Is obesity the missing link between COVID-19 severity and air pollution?

“…(2020) . Moreover, if it is largely accepted that air pollution may contribute to the pathogenesis of pulmonary diseases, some studies have also highlighted that the expansion of adipose tissue, namely visceral fat, is strongly associated with air pollution-induced lung dysfunction ( Elliot et al., 2019 ; Conti et al., 2018 ; Kim et al., 2017 ; Yang et al., 2019 ), and this is not surprising considering that both fat excess and air pollution-derived lung injury have been linked to increased local and systemic inflammation ( Zhang et al., 2016 ; Bastard et al., 2000 ). In this regard, it has been observed in Asian men that obesity may exhibit a synergistic effect on the relationship between prolonged exposure to air pollutants and worse pulmonary function, suggesting that excessive fat, especially the abdominal one, may intensify the adverse effects of air pollutants on lung function ( Kim et al., 2017 ).…”

“…Moreover, if it is largely accepted that air pollution may contribute to the pathogenesis of pulmonary diseases, some studies have also highlighted that the expansion of adipose tissue, namely visceral fat, is strongly associated with air pollution-induced lung dysfunction ( Elliot et al., 2019 ; Conti et al., 2018 ; Kim et al., 2017 ; Yang et al., 2019 ), and this is not surprising considering that both fat excess and air pollution-derived lung injury have been linked to increased local and systemic inflammation ( Zhang et al., 2016 ; Bastard et al., 2000 ). In this regard, it has been observed in Asian men that obesity may exhibit a synergistic effect on the relationship between prolonged exposure to air pollutants and worse pulmonary function, suggesting that excessive fat, especially the abdominal one, may intensify the adverse effects of air pollutants on lung function ( Kim et al., 2017 ). Another link between air pollution, obesity and COVID-19 severity may be Vitamin D deficiency; obesity is closely associated with low vitamin D levels, as higher body mass index leads to lower vitamin concentrations ( Barrea et al., 2017 ) and, in light of its largely known and beneficial immunomodulating actions, Vitamin D deficiency may represent an independent risk factor for COVID-19 severity ( Muscogiuri et al., 2020b ; Grant et al., 2020 ).…”

White and brown adipose tissue functionality is impaired by fine particulate matter (PM2.5) exposure

“…Growing evidence suggests that PM 2.5 inhalation negatively influences both white and brown adipose tissue (WAT and BAT, respectively) [ 12 , 13 ]. In addition, the development of dysfunction in both the adipose tissues is associated with the worsening of health conditions in humans and animals undergoing chronic PM exposure [ 12 , 14 – 28 ].…”

Effects of abdominal visceral fat compared with those of subcutaneous fat on the association between PM10 and hypertension in Korean men: A cross-sectional study

“…We considered the first cut-off value for VAT at 100 cm 2 , which has been reported as a reasonable criterion for screening for obesity-related cardiovascular disorders 21,22 . In addition, to define the high visceral obesity group, the second cut-off point for VAT was applied at 200 cm 2 , twice the screening cut-off level (VAT = 100 cm 2 ) 23 . Therefore, we classified into three groups according to VAT level: low-VAT group (VAT ≤ 100 cm 2 ), intermediate VAT group (100 cm 2 < VAT ≤ 200 cm 2 ), and high-VAT group (VAT > 200 cm 2 ).…”