Air Pollution & Migraine

0:00 Welcome to our presentation tonight
0:03 we’re really excited to have Miss Andrea
0:06 port and Dr Christine leay with us we
0:10 are a federally registered charity
0:12 supporting the five million Canadians
0:14 living with migraine and headache
0:16 disorders our mission is to improve the
0:19 lives of people with migraine and
0:21 headache disorders through our five
0:22 pillars advocacy awareness education
0:26 research and
0:27 support um just a quick side note that
0:30 our remaining Q2 webinars are posted on
0:32 our events page and we’ve launched our
0:35 annual move for migraine uh campaign so
0:38 please you can also check that out on
0:39 our website as
0:41 well and so now to introduce our
0:44 presenters we have Dr Christine leay
0:46 joining us tonight Dr leay is a
0:49 professor of Neurology at the University
0:51 of Toronto and is the founding director
0:53 of the heada program at UF holding the
0:56 Deborah Ivy Christian Brill chair for
0:58 neurology research in addition to
1:00 building the headache program training
1:02 fellows as well as a very busy patient
1:05 Practice Dr Le is actively involved in
1:08 research teaching and advocacy serving
1:10 as the chair of the American migraine
1:12 foundation and as a board member for
1:14 both the American and Canadian headache
1:17 societies tonight we also have Miss
1:20 Andrea Port PhD student she is a PhD
1:24 student in epidemiology at the
1:26 University of Toronto her research
1:28 passion lies in deciphering the impact
1:31 of environmental exposures on
1:32 neurological Health under the mentorship
1:35 of Dr Peter Smith Andrea’s doctoral
1:37 research focuses on the Innovative use
1:39 of mobile app data to unravel links
1:42 between air pollution and
1:47 migraine and with that I’m going to turn
1:49 it over to our presenters well let’s get
1:53 started then thank you so much for uh
1:55 that introduction it’s really an honor
1:57 for Christine and I to be here and uh
2:00 nothing makes migraine researchers
2:01 happier than having a chance to share
2:04 our research with uh the findings who
2:06 are living with this
2:07 condition um so just to give you an
2:12 overview um I’m going to start by
2:14 talking a little bit about why we were
2:16 interested in studying air pollution
2:18 with relation to migraine uh air
2:20 pollution as a migraine
2:23 trigger uh why we carried out this
2:25 particular review that I’m going to talk
2:28 about uh what we found and some of the
2:31 limitations practical
2:33 implications uh future directions that
2:36 we’re working on and finally
2:40 acknowledgements so why study air
2:43 pollution with relation to migraine well
2:45 to start with we know that patients and
2:47 clinicians have questions about
2:48 environmental exposures like weather and
2:50 air pollution that we don’t have answers
2:53 to yet um and also as you can see from
2:56 this in this poster from the World
2:58 Health Organization it’s something that
2:59 we’re almost all exposed to so if you
3:02 think about 92% of people in the world
3:05 breathing um unsafe air then a small
3:10 increase in migraine attacks per
3:12 exposure could be a very large number in
3:14 the end especially when you also
3:16 consider that more than a billion people
3:17 worldwide are living with
3:20 migraine um and there are also things
3:22 that we can do to prepare for or to
3:24 reduce air pollution exposure that we’ll
3:26 talk about more later
3:32 so in terms of how we think air
3:34 pollution causes migraine um we used to
3:37 really um I know growing up I thought of
3:40 air pollution as something that hurts
3:42 your lungs and your heart uh and now we
3:45 know that air pollution actually impacts
3:47 multiple systems in the body so the
3:49 pollutants I’m going to talk about today
3:51 are particulate matter um sulfur dioxide
3:56 ozone carbon monoxide and nitrogen Di
4:00 oxide and we have this beautiful image
4:04 that was published in Katherine alford’s
4:06 scientist article in 2019 uh and it
4:10 shows three different ways that it’s
4:12 believed that air pollution can reach
4:14 the brain or affect the brain uh so the
4:17 first way is uh through the old factory
4:20 nerves uh which are the nerves at the
4:22 back of your nose that help you smell
4:25 and uh it turns out that some pollutants
4:27 can travel right along those into the
4:29 brain
4:30 bra uh secondly sort of the more
4:33 traditional way that I definitely
4:35 thought about air pollution um is absorb
4:37 through the lungs and they can then
4:40 either cross the bloodb brain barrier or
4:42 just trigger changes in the blood that
4:44 impact the
4:46 brain and finally um another route that
4:49 I had never thought about before I
4:51 started this research um and learning
4:53 about it is uh reaching the the gut
4:57 through swallowed air um and then air
4:59 pollutant may be absorbed into the
5:01 bloodstream or they may impact the gut
5:05 microbiome uh the biological mechanism
5:08 or biological connection
5:10 between um air pollution and migraine
5:14 we’re actually learning more about
5:16 recently uh so there’s some work that’s
5:18 been done at Southern Medical University
5:20 in guandong Province China and yay and
5:24 others have looked at rats that were
5:27 exposed to nitrogen dioxide
5:30 and they looked at the gene expression
5:33 in the rat’s trigeminal nerves which are
5:35 the nerves that run from the back of the
5:37 head um to the sides of the face that
5:39 are associated with migraine in humans
5:41 and migraine like behavior in
5:44 rats and what this group found is that
5:46 following exposures to nitrogen dioxide
5:50 there are actually changes in gene
5:51 expression in the in a migraine related
5:55 pain and inflammation pathway which is
5:57 the same pathway that anti-cgrp
5:59 and trip tan migraine medications
6:02 block Andrea I think the slide didn’t
6:04 move um oh
6:08 yeah what slide are you seeing now the H
6:11 Catherine um offer’s
6:14 drawing let
6:16 me okay you got okay thanks Christine um
6:22 so sources of air pollutants are
6:25 Transportation uh industry Agriculture
6:28 and energy are some of the main source
6:30 um for example nitrogen dioxide sulfur
6:33 dioxide and carbon
6:35 monoxide um major sources of those are
6:38 burning fossil fuels and then nitrogen
6:41 dioxide actually goes on to react in the
6:43 air to create
6:45 ozone uh particulate matter is kind of a
6:48 funny one because it’s not actually
6:49 chemically defined um so it can be any
6:53 tiny Airborne dust any tiny Airborne
6:56 particles from Sand and dust to fuel
7:00 related medical particles in the air uh
7:03 so major sources of particulate matter
7:05 are roads fossil fuels construction and
7:09 agriculture now that being said all
7:12 these pollutants normally occur in
7:14 mixtures um and the concentration in the
7:17 air can can vary depending on the Wind
7:20 sunlight the temperature uh which is
7:23 important for This research because we
7:25 know that some of these weather factors
7:26 can also impact migraine so we need to
7:29 take weather into consideration in uh
7:32 these
7:36 studies so we carried out this
7:38 systematic review to see what work has
7:40 already been done and to find out if the
7:43 results in different studies and
7:44 different locations agree with one
7:46 another uh interestingly a number of
7:49 these studies to date have actually been
7:50 done in Canada or with Canadian
7:54 researchers so this slide’s uh an
7:58 overview of how we narrow down our
8:00 search and I’ll explain it without
8:01 getting into too much
8:03 detail so we started out by searching
8:06 broadly through different scientific
8:08 search engines and we came up with 124
8:12 different articles that might be related
8:13 to air pollution and migraine in that
8:15 search looking through the citations and
8:19 the references in those search searches
8:21 or in those articles and also um with
8:25 weekly updates we found another six
8:27 articles
8:29 uh once we’d found all those my friend
8:32 and colleague Christa and I read all the
8:35 abstracts and ruled out studies that
8:37 either weren’t related to migraine um or
8:41 um didn’t quantify air pollution or
8:43 migraine or were sub analyses of
8:45 different papers that were going to be
8:47 included and in the end we had 12
8:50 studies to include in the
8:52 review we then assessed the research
8:55 quality for those 12 studies us using
8:57 the World Health Organization air
8:59 quality assessment risk of bias domains
9:03 instrument and we extracted data and
9:05 looked at the results from the
9:12 studies so this figure is a summary of
9:16 our risk of bias assessment and you can
9:18 see from all the green on this side of
9:22 the um figure that there was generally
9:25 high quality in the methodology of the
9:27 studies one limitation that we B ped
9:29 into around this point is that uh there
9:32 were a wide variety of pollutants and of
9:35 ranges of exposures a wide variety of
9:37 outcomes which were mostly clinic or ER
9:40 visits um but also prescriptions and
9:43 diagnosis of migraine and also a wide
9:46 variety of study methods so because of
9:49 all those differences we didn’t try to
9:51 combine the results and come up with
9:53 sort of a True Result um but instead
9:57 looked at the results Side by side to
9:59 see if um they agree with one
10:07 another so this is our summary of
10:09 results from studies that examine the
10:11 association between nitrogen dioxide and
10:14 migraine
10:15 outcomes and as you can see there are uh
10:20 different ranges of exposures in the
10:22 different studies which is mostly that’s
10:24 related to being in different
10:26 locations uh there also a wide variety
10:28 of migraine related outcomes um
10:31 including Ed as an emergency department
10:34 or emergency room visits uh Diaries uh
10:38 neurology visits and
10:41 prescriptions um now interestingly
10:43 despite all that variety uh overall most
10:47 of the estimates were positive or we say
10:50 above 1.0 which suggests that there may
10:53 be an association between exposure to
10:55 nitrogen dioxide and new migraine or
10:58 migraine attack on S
11:00 uh the numbers here to the right of the
11:03 estimates in Brackets are the 95%
11:05 confidence
11:07 intervals um these basically mean that
11:09 the authors expect that if they repeated
11:12 their studies the estimates would fall
11:14 between these numbers 95 out of 100
11:17 repetitions um so it’s a measure of
11:20 certainty and as you can see in these
11:23 results about half of the confidence
11:25 intervals include the null value of 1.0
11:28 meaning that there is some uncertainty
11:30 in uh this
11:33 work so overall when we looked at the
11:37 different pollutants that have been
11:39 examined we found that the strongest and
11:41 most consistent associations were with
11:43 nitrogen dioxide and migraine that was
11:45 followed by particulate matter and ozone
11:48 whereas it was less clear or there were
11:50 simply less to go on um for carbon
11:53 monoxide or sulfur
11:56 dioxide um and since August when this
11:59 this was published uh or when our review
12:01 was published there have actually been
12:02 two new studies and one new systematic
12:04 review uh and those studies and the
12:06 review broadly agree with the results of
12:09 our review uh one of the
12:13 studies is this work by dong and others
12:17 uh their team used data from a big
12:19 resource called the UK
12:21 biobank um and they linked the incidents
12:26 of new migraine uh to air
12:30 pollution and they actually estimated
12:32 that about 14% of new migraine cases
12:35 that developed in the higher pollution
12:38 uh environments or areas in the UK were
12:40 attributable to combined exposure to
12:42 particulate matter nitrogen dioxide and
12:45 nitrous
12:48 oxides wh I just oh no I didn’t skip
12:51 okay
12:52 good so uh practically um what can we do
12:57 uh with this new information uh
12:59 personally if we’re living with migraine
13:03 uh we might want to try to reduce the
13:05 potential impact of air pollution on our
13:07 lives uh which sounds great but as we
13:10 all know breathing is not optional um so
13:14 there are some things you can do uh for
13:16 example active choosing active transport
13:18 uh choosing streets with less car tra
13:20 traffic to walk on uh using air
13:24 purifiers um and you can also we can
13:26 also prepare for exposures um and and
13:29 take preventives or take preventive
13:31 measures like we do for other
13:33 unavoidable migraine
13:35 triggers um but really the big
13:37 improvements in air quality come from
13:40 policy
13:41 change um there is good news on that
13:44 front uh as you can see from this poster
13:48 from the World Health Organization in
13:49 the Americas our exposures are actually
13:51 declining due to policy
13:53 changes and um the pollutants that we’re
13:57 looking at here um
13:59 are either are or piggyback with
14:02 greenhouse gases so the fact that
14:05 current and pending policies put Canada
14:07 on track to cut emissions of greenhouse
14:09 gases to 35% below 2005 Levels by 2030
14:14 is potentially really good news I mean
14:16 it’s already really good news but this
14:18 could be another reason it’s good
14:23 news uh so as I mentioned big air
14:26 quality improvements come from policy
14:28 change that means means that voting and
14:30 advocacy are important consumer choices
14:32 are important um we have this uh
14:36 infographic that describes some of the
14:38 solutions so uh air quality can be
14:41 improved by investing in energy
14:43 efficient power generation improving
14:46 domestic industry and municipal waste
14:49 management um making Greener and more
14:51 compact cities with energy efficient
14:54 buildings reducing agricultural waste
14:57 incineration forest fires and and
14:59 certain AGR forestry
15:01 activities providing universal access to
15:04 clean affordable fuels and Technologies
15:06 for cooking Heating and lighting and
15:08 building safe and affordable public
15:10 transport systems and pedestrian and
15:12 cycle friendly
15:14 networks so in conclusion uh it
15:17 increasingly looks likely that air
15:20 pollution triggers a portion of migraine
15:22 diagnoses and
15:23 events uh so along with known benefits
15:26 to the planet and respiratory and
15:28 cardiovas ular Health it’s possible that
15:30 ongoing reductions in pollution may help
15:32 some of the millions of Canadians who
15:35 are living with
15:39 migraine we do have some future plans
15:42 along these um related to this project
15:45 on the go
15:47 so um since a major source of
15:50 information on air pollution and
15:51 migraine to date has been on has used ER
15:54 visits we want to learn more about why
15:56 folks visit ER for migraine and what
15:59 barriers they
16:01 experience uh we had a survey sent out
16:03 this past fall and there were hundreds
16:06 of responses including many from the
16:08 migraine Canada Community um so thank
16:11 you and the results from that work are
16:15 going to be presented in May at the
16:16 Canadian neurological Sciences
16:18 Federation conf conference sorry
16:20 Congress in
16:23 Toronto uh as well we have a study
16:26 ongoing to determine and any to
16:29 determine potential associations between
16:31 air pollution and migraine in Ontario
16:34 using daily air pollution data from
16:36 environment and climate change Canada
16:38 which uh will give us better location PR
16:41 Precision than previous Studies have had
16:43 available and also Daily reported
16:46 migraine events from research consent
16:48 research consenting smartphone app users
16:50 via our collaborators at migraine
16:53 buddy uh and this res this work will be
16:57 presented in August at The Intern
16:58 National Society for environmental
17:00 epidemiology
17:01 conference and we hope uh to end up with
17:05 a more precise estimate of how
17:06 individual and mixed pollutants can
17:09 interact with
17:12 migraine here are my references that are
17:15 available if anybody would like them and
17:19 with that we’d just like to say thanks
17:21 to everyone who’s here to migrant Canada
17:24 and the migrant Canada Canada Community
17:27 uh it’s such a Wonder ful opportunity um
17:30 and honor for us to be able to share
17:32 what we’ve learned uh I’d like to thank
17:35 the research team so Christa for going
17:38 through all those titles and abstracts
17:40 and combing through the data with me um
17:43 my fantastic PhD committee uh Christine
17:46 Lei eria and Hong Chen and my supervisor
17:50 Peter Smith who’s given me the freedom
17:53 and support to explore these
17:55 questions as well as the dalana school
17:58 of public health and the Del School of
18:00 Public Health Data science
18:02 interdisciplinary research cluster at
18:05 University of Toronto uh their financial
18:07 support makes this work possible as well