Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide. Despite a high prevalence of smoking and respiratory symptoms, two recent population-based studies ...in Russia found a relatively low prevalence of obstructive lung function. Here, we investigated the prevalence of both obstructive lung disease and respiratory symptoms in a population-based study conducted in two Russian cities and compared the findings with a similar study from Norway conducted in the same time period.
The study population was a sub-sample of participants aged 40-69 years participating in the Know Your Heart (KYH) study in Russia in 2015-18 (n=1883) and in the 7th survey of the Tromsø Study (n=5271) carried out in Norway in 2015-16 (Tromsø 7) who participated in spirometry examinations. The main outcome was obstructive lung function (FEV
/FVC ratio< lower limit of normal on pre-bronchodilator spirometry examination) with and without respiratory symptoms (chronic cough and breathlessness). In those with obstructive lung function, awareness (known diagnosis) and management (use of medications, smoking cessation) were compared.
The age-standardized prevalence of obstructive lung function was similar among men in both studies (KYH 11.0% vs Tromsø 7 9.8%, p=0.21) and higher in the Norwegian (9.4%) than Russian (6.8%) women (p=0.006). In contrast, the prevalence of obstructive lung function plus respiratory symptoms was higher in Russian men (KYH 8.3% vs Tromsø 7 4.7%, p<0.001) but similar in women (KYH 5.9% vs Tromsø 7 6.4%, p=0.18). There was a much higher prevalence of respiratory symptoms in Russian than Norwegian participants of both sexes regardless of presence of obstructive lung function.
The prevalence of respiratory symptoms was strikingly high among Russian participants but this was not explained by a higher burden of obstructive lung function on spirometry testing in comparison with Norwegian participants. Further work is needed to understand the reasons and health implications of this high prevalence of cough and breathlessness.
Recorded molecular weights (MWs) for humic substances (HS) range from a few hundred to millions of daltons. For purposes of defining HS as a specific class of chemical compounds, it is of particular ...importance to ascertain if this broad range of MWs can be attributed to actual variability in molecular properties or is simply an artifact of the analytical techniques used to characterize HS. The main objectives of this study were (1) to establish if a preferential range of MWs exists for HS and (2) to determine any consistent MW properties of HS. To reach the goal, we have undertaken an approach to measure under standardized conditions the MW characteristics of a large set of HS from different natural environments. Seventy-seven humic materials were isolated from freshwater, soil, peat, and coal, such that each possessed a different fractional composition: humic acid (HA), fulvic acid (FA), and a nonfractionated mixture of HA and FA (HF). Size exclusion chromatography (SEC) was used as the analytical technique to determine molecular weight characteristics. The MW distributions were characterized by number (M n) and weight (M w) average MW, and by polydispersity. The complete range of M w values varied within 4.7−30.4 kDa. The maximum M w values were observed for peat HF and soil HA, whereas the smallest weights were measured for river water HF. Maximum values of polydispersity (3.5−4.4) were seen for peat HF and soil HA, while much lower values (1.6−3.1) were found for all preparations isolated with XAD-resins. Statistical evaluation showed consistent M w and M n variations with the HS source, while polydispersity was mostly a function of the isolation procedure used. A conclusion was made that HS have a preferential range of MW values that could characterize them as a specific class of chemical compounds.
Effects of 27 different humic materials on the toxicity of polycyclic aromatic hydrocarbons (PAH) were studied for crustacean Daphnia magna. Sources included isolated humic acids, fulvic acids, and ...their combination from soil, peat, and freshwater. The PAH used were pyrene, fluoranthene, and anthracene. The observed reduction in toxicity of PAH in the presence of humic substances (HS) was shown to be a result of the detoxification effect caused by the chemical binding of PAH to HS and of the direct effect of HS on D. magna. An approach was developed to quantify the detoxifying impact of humic materials related to their chemical binding to PAH with a use of the “constant of detoxification” or “toxicological partition coefficient” Koc D . The latter was proposed to determine by fitting the experimental relationships of the detoxification effect versus concentration of HS. The obtained Koc D values were well tracked by the corresponding partition coefficients determined by the fluorescence quenching technique (Koc fq ): Koc D = b × Koc fq , b (mean ± CI, n = 26, P = 95%) = 2.6 ± 0.3, 4.6 ± 0.6, and 6.0 ± 1.4 for pyrene, fluoranthene, and anthracene, respectively. The predictive relationships between the structure and detoxifying properties of humic materials in relation to PAH were developed. It was shown that the magnitude of the Koc D values correlated closely with the aromaticity of humic materials characterized with the 13C NMR descriptors (ΣCAr, ΣCAr/ΣCAlk) and atomic H/C ratio. The obtained relationships showed the highest detoxifying potential of the humic materials enriched with aromatics and allowed a conclusion on the chemical binding as the governing mechanism of the mitigating action of HS on the toxicity of PAH.
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