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The relation between past exposure to fine particulate air pollution and prevalent anxiety: observational cohort study

BMJ 2015; 350 doi: https://doi.org/10.1136/bmj.h1111 (Published 24 March 2015) Cite this as: BMJ 2015;350:h1111

Re: The relation between past exposure to fine particulate air pollution and prevalent anxiety: observational cohort study

Power et al.’s fascinating paper found that exposure to fine particulate matter appears to correlate with a tendency towards symptoms of anxiety (1). They point out that factors that might contribute to this include oxidative stress and systemic inflammation. Some other recent papers point to an additional possible mechanism. The gut ecosystem appears to influence mood, including anxiety (2, 3). Gut microbiota have a multitude of physiological effects on the host including possibly regulating the serotonergic system and influencing the levels of brain-derived neurotropic factor (BDNF) (4, 5, 6, 7, 8). The gut ecosystem is believed to nudge the host epigenome (9). The gut ecosystem is impacted by various environmental factors possibly including particulate matter and other aspects of modern society (10, 11, 12). More research is needed on the physiological implications of the impact of environmental factors, including particulate matter, on the gut ecosystem.

About the author: www.CeliaMRoss.com

(1) Power MC, Kioumourtzoglou MA, Okereke OI, Laden F, Weisskopf MG. The relation between past exposure to fine particulate air pollution and prevalent anxiety: observational cohort study. BMJ. 2015 Mar 24;350:h1111.

(2) Luna RA, Foster JA. Gut brain axis: diet microbiota interactions and implications for modulation of anxiety and depression. Curr Opin Biotechnol. 2015 Apr;32:35-41.

(3) Crumeyolle-Arias M, Jaglin M, Bruneau A, et al. Absence of the gut microbiota enhances anxiety-like behavior and neuroendocrine response to acute stress in rats. Psychoneuroendocrinology. 2014 Apr;42:207-17.

(4) Yano JM, Yu K, Donaldson GP, et al. Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis. Cell. 2015 Apr 9;161(2):264-76.

(5) O’Mahony SM, Clark G, Borre YE, Dinan TG, Cryan JF. Serotonin, tryptophan metabolism and the brain-gut-microbiome axis. Behav Brain Res. 2015 Jan 15;277:32-48.

(6) Clarke G, Stilling RM, Kennedy PJ, et al. Minireview: Gut microbiota: the neglected endocrine organ. Mol Endocrinol. 2014 Aug;28(8):1221-38.

(7) Carabotti M, Scirocco A, Maselli MA, Severi C. The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Ann Gastroenterol. 2015 Apr-Jun;28(2):203-209.

(8) Bercik P, Denou E, Collins J, et al. The intestinal microbiota affect central levels of brain-derived neurotropic factor and behavior in mice. Gastroenterology. 2011 Aug;141(2):599-609, 609.e1-3.

(9) Shenderov BA. Gut indigenous microbiota and epigenetics. Microb Ecol Health Dis. 2012 Mar 28;23.

(10) Kish L, Hotte N, Kaplan GG, et al. Environmental particulate matter induces murine intestinal inflammatory responses and alters the gut microbiome. PLoS One. 2013 Apr 24;8(4):e62220.

(11) Salim SY, Kaplan GG, Madsen KL. Air pollution effects on the gut microbiota: a link between exposure and inflammatory disease. Gut Microbes. 2014 Mar-Apr;5(2):215-9.

(12) Kelsen JR, Wu GD. The gut microbiota, environment and diseases of modern society. Gut Microbes. 2012 Jul-Aug;3(4):374-82.

Competing interests: I write about health issues.

16 April 2015
Celia M. Ross
writer
Wilmington Delaware, USA