Migraine Headache and Air pollution (PM 2'5)

 1. Introduction

Over the past decade, many epidemiologic studies have demonstrated positive associations between ambient levels of airborne particulate matter (PM, generally measured as PM with an aerodynamic diameter ≤10 µm [PM10]) and daily mortality [1,2,3,4,5] and hospital admissions or emergency room (ER) visits for cardiovascular and respiratory morbidity [6,7,8]. The evidence on adverse effects of PM air pollution on public health has led to more stringent standards for levels of PM in outdoor air in the USA and in other countries [9].

While previous studies have primarily used PM10 as an exposure indicator, fine particles (defined as PM with an aerodynamic diameter less than 2.5 µm; PM2.5) have become a greater health and regulatory concern due to 

epidemiologic studies suggesting that PM2.5 might have greater toxicity than larger particles [10,11,12]. It is now generally accepted that PM2.5 are more harmful to health effect than larger particles (PM10) because PM2.5 offer a larger surface area and hence potentially larger concentrations of adsorbed or condensed 

toxic air pollutants per unit mass [13,14].

Relatively few epidemiologic studies (mainly focused on severe events such as mortality, hospitalizations, and ED visits) have been undertaken which address 

specifically the health effects of PM2.5, as only a few cities have monitored PM2.5 [15]. Very few have investigated the relationship between PM2.5 levels and general practitioner visits where most patients contact occur but 

concentrated on respiratory diseases [16,17,18,19,20]; other symptoms have rarely been investigated [21].

Migraine headache is a common clinic problem,

 an important cause of morbidity in mordern society [22]. Migraines represent an enormous public health concern. 

In United States, about 18% of women and 6% of 

men report migraines [23], and annual costs attributed to migtaines have been estimated to approximate $17 billion [24]. In Taiwan, a population-based survey reported that 14.4% of women and 4.5% of men reported suffering from migraine headache [25]. In addition, it was estimated that migraines account for more than 3.7 million lost working days at an estimated lost labor cost of 0.47 billion (Taiwan Dollars) yearly [26].

There are many self-reported triggers for migraines including weather, food, stress, fatigue, menstruation, and infection [27,28]. The association between air pollution or other environmental factors and migraine has not been accepted widely by clinicians [29]. A few studies have suggested that PM2.5 levels may be linked to migraine [30,31,32,33]. However, these results require confirmation and also further explorationas using larger datasets.

This study was undertaken to examine the association between PM2.5 levels and clinic visits 

for migraine among people residing in 

Taipei city, the biggest metropolitan city of Taiwan, 

over the six year period from 2006–2011, using a case-crossover design.

Taipei City

This study examined daily variations in clinic visits for migraine in relation to PM2.5 levels in Taipei for the 6-year period from 2006 through 2011. Taipei is the largest metropolitan city in Taiwan with a population 

of about 2.64 million and is located in northern 

Taiwan. The major air pollution source is

 automobile exhaust emission. Taipei has a subtropical climate, with an annual average temperature of 23 °C (the months with a mean temperature below 23 °C are from November through April and May through October are the months with a mean temperature above 23 °C).

Ref

Int J Environ Res Public Health. 2015 Apr 29;12(5):4697–4708. doi: 10.3390/ijerph120504697

Association between Fine Particulate Air Pollution and Daily Clinic Visits for Migraine in a Subtropical City: Taipei, Taiwan

Chih-Cheng Chen 1, Shang-Shyue Tsai 2, Chun-Yuh Yang 3,4