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- Carstens, Adam, 1975-, et al.
(author)
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Differential clustering of faecal and mucosa-associated microbiota in healthy individuals
- 2018
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In: Journal of Digestive Diseases. - : Wiley-Blackwell Publishing Asia. - 1751-2972 .- 1751-2980. ; 19:12, s. 745-752
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Journal article (peer-reviewed)abstract
- BACKGROUND: Faecal samples are often used to characterise gut microbiota, since they are easily collected. However, whether or not the faecal microbiota differ from the mucosa-associated microbiota remains largely unknown. This may be specifically relevant in conditions that are characterised by complex mucosal microbe-host interactions, such as Crohn's disease. We aimed to determine the degree of agreement between faecal and mucosal microbiota profiles in healthy individuals, using two commonly used collection procedures.MATERIAL AND METHODS: The gut microbiota composition of faecal samples (sent at ambient temperature before storage at -70°C) and of colonic biopsies (obtained at endoscopy and immediately stored at -70°C) was determined by sequencing the 16S rRNA gene. Thirty-one randomly selected healthy individuals from the population-based colonoscopy (Popcol) study were included.RESULTS: Faecal samples were characterised by a reduced degree of richness (p<0.0001) and diversity (p=0.016), and also differences in several phyla, including a lower relative abundance of Proteobacteria (p<0.0001) and Verrucomicrobia (p=0.008) than in biopsies. Only 3 of 30 individuals had a similar faecal and mucosal microbiota profile, based on weighted UniFrac analysis. A difference in Crohn's disease dysbiosis-associated bacteria was observed, including a lower relative abundance of Faecalibacterium (p=0.004) and a higher relative abundance of Ruminococcus (p=0.001) in faeces than in biopsies.CONCLUSIONS: Analysis of faecal samples that have been transported at ambient temperature does not adequately reflect the colonic mucosa-associated microbiota in healthy individuals. These findings have implications for the interpretation of the previous literature, and may be specifically relevant to studies on Crohn's disease.
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| 2. |
- Montgomery, Scott, et al.
(author)
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Mortality following unemployment during an economic downturn : Swedish register-based cohort study
- 2013
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In: BMJ Open. - : BMJ. - 2044-6055. ; 3:7, s. e003031-
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Journal article (peer-reviewed)abstract
- Objective To investigate if unemployment during an economic downturn is associated with mortality, even among men with markers of better health (higher cognitive function scores and qualifications), and to assess whether the associations vary by age at unemployment. Design Longitudinal register-based cohort study. Setting Study entry was in 1990 and 2001 when Sweden was entering periods of significant economic contraction. Participants A representative sample of men from the general population (n=234782) born between 1952 and 1956 who participated in military conscription examinations. Men in receipt of disability or sickness benefit at study entry were excluded. Main outcome measure All-cause mortality. Results Unemployment compared with employment in 1991 (ages 34-38years) produced adjusted HRs (with 95% CIs) for all-cause mortality (3651 deaths) during follow-up to 2001 and after stratification by education of 2.35 (1.99 to 2.76) for compulsory education, 2.25 (1.97 to 2.58) for up to 3years postcompulsory education and 1.90 (1.40 to 2.57) for more than 3years postcompulsory education. When unemployment was compared with employment in 2001 (ages 45-49years) with follow-up to 2010, the pattern of mortality risk (4271 deaths) stratified by education was reversed, producing adjusted HRs of 2.81 (2.47 to 3.21) for compulsory education, 2.87 (2.58 to 3.19) for up to 3years postcompulsory education and 3.44 (2.78 to 4.25) for more than 3years postcompulsory education. Interaction testing confirmed effect modification by age/period (p=0.003). The degree of gradient reversal was slightly less pronounced after stratification by cognitive function but produced a similar pattern of results (p=0.004). Conclusions Unemployment at older ages is associated with greater mortality risk than at younger ages, with the greatest relative increase in risk among men with markers of better health, suggesting the greater vulnerability of all older workers to unemployment-associated exposures.
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