Exhaled carbon monoxide and its associations with smoking, indoor household air pollution and chronic respiratory diseases among 512 000 Chinese adults

Background Exhaled carbon monoxide (COex) level is positively associated with tobacco smoking and exposure to smoke from biomass/coal burning. Relatively little is known about its determinants in China despite the population having a high prevalence of smoking and use of biomass/coal. Methods The China Kadoorie Biobank includes 512 000 participants aged 30-79 years recruited from 10 diverse regions. We used linear regression and logistic regression methods to assess the associations of COex level with smoking, exposures to indoor household air pollution and prevalent chronic respiratory conditions among never smokers, both overall and by seasons, regions and smoking status. Results The overall COex level (ppm) was much higher in current smokers than in never smokers (men: 11.5 vs 3.7; women: 9.3 vs 3.2). Among current smokers, it was higher among those who smoked more and inhaled more deeply. Among never smokers, mean COex was positively associated with levels of exposures to passive smoking and to biomass/coal burning, especially in rural areas and during winter. The odds ratios (OR) and 95% confidence interval (CI) of air flow obstruction (FEV 1 /FVC ratio <0.7) for never smokers with COex at 7-14 and 514 ppm, compared with those having COex <7, were 1.38 (1.31-1.45) and 1.65 (1.52-1.80), respectively (P trend <0.001). Prevalence of other self-reported chronic respiratory conditions was also higher among people with elevated COex (P <0.05). This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. Conclusion In adult Chinese, COex can be used as a biomarker for assessing current smoking and overall exposure to indoor household air pollution in combination with questionnaires

Advances in Susceptibility Genetics of Intervertebral Degenerative Disc Disease

<p>The traditional view that the etiology of lumbar disc herniation is primarily due to age, gender, occupation, smoking and exposure to vehicular vibration dominated much of the last century. Recent research indicates that heredity may be largely responsible for the degeneration as well as herniation of intervertebral discs. Since 1998, genetic influences have been confirmed by the identification of several genes forms associated with disc degeneration. These researches are paving the way for a better understanding of the biologic mechanisms. Now, many researchers unanimously agree that lumbar disc herniation appears to be similar to other complex diseases, whose etiology has both environmental and hereditary influence, each with a part of contribution and relative risk. Then addressing the etiological of lumbar disc herniation, it is important to integrate heredity with the environment factors. For the purpose of this review, we have limited our discussion to several susceptibility genes associated with disc degeneration.</p

Characteristics of microscopic pore-throat structure of tight oil reservoirs in Sichuan Basin measured by rate-controlled mercury injection

Based on the results of rate-controlled mercury-injection experiments, the microscopic pore-throat structure characteristics of tight sandstone in Sha-1 Section and tight limestone in Da’anzhai Section of Sichuan Basin were quantitatively characterized. The results show that the pore radius distribution characteristics of tight oil reservoirs are similar. The main distribution is between 100~190 μm, and the average pore radius is 160 μm. While the distribution of the throat radius of tight sandstone and limestone is quite different, the distribution of the throat of sandstone samples is relatively concentrated, and the distribution of the throat of limestone samples is relatively sparse. There is a good positive correlation between the average throat radius and permeability, but the correlation between fractal dimension and permeability is not obvious. This indicates that the permeability is mainly affected by the radius of the throat. The pore-throat ratio in tight oil reservoirs is relatively large, and the resistance to seepage is greater during development. Therefore, during the development of tight oil, measures should be taken to increase the radius of the throat, reduce the ratio of pore radius to pore-throat radius, and improve the seepage capacity of the reservoir, thereby improving the development of tight oil