Headaches

There are many different kinds of headaches. 90% of all occurring headaches are migraines or tension headaches and not attributable to any other primary disease. In Germany, 50% of men and over 60% of women reported having had headaches over the last 12 months (migraines: 5-10% males and 15-24% females). Up to the age of twelve, around 90% of children have already had some experience with headaches. This is of special interest because childhood migraine might lead to migraine in adult age.

Triggering factors are assumed to be:

• Nutrition (missed meals, insufficient fluid intake, incompatible foods e.g. chocolate, alcohol, aspartame, or glutamate)
• Hormonal factors (oral contraceptives, hormone replacement therapy)
• Stress (especially long lasting)
• Fatigue, exhaustion (lack of sleep, apnea)
• Lack of or excess physical exercise)

In children, psychosocial stress can be of importance: family problems, dealing with headaches, lack of or too little relaxation, lack of friends and social contacts, excessive TV viewing and computer games.

Spending time in a room with “bad air” can trigger headaches in some people. Pollutants that can be present in indoor air and might cause headaches are:

• Tobacco Smoke: Already in the 1990s a significant epidemiological link between passive indoor or secondhand smoke and headaches was found and proven in large studies from Norway and the USA.
• Carbon monoxide (CO):CO is a gas with known neurotoxic properties and released during the burning of fossil fuels. According to diagnostic criteria mild headaches do occur at CO-Hb blood concentration levels of 10-20%. A concentration level of 10% is equal to a concentration of about 70 ppm in indoor air (at equilibrium). Some authors assume that even lower concentration levels might lead to headaches depending on the duration of exposure.
• Carbon dioxide (CO₂): Carbon dioxide is a gas exhaled by human beings and therefore concentration levels rise relatively quickly in rooms where people congregate. In epidemiological studies, significant correlations between symptoms of headache and fatigue and the CO₂ concentration in indoor air have been found.
• Volatile organic compounds (VOC): VOC are among the most important substances that can be found in indoor air. Well-known are the BTXS (benzene, toluene, xylene and styrene) and terpenes. VOCs are widely used in products such as paints and varnishes, waxes, solvents and cleaning products, and thus transported into indoor air. Since some of these compounds have neurotoxic effects, they can be considered as a trigger factor for headaches.

When thinking about the heavily polluted air in some regions of the world this could indeed be a good reason to become stressed and acquire a headache but okay - this is a different matter. Whether typical outdoor pollutants like fine dust (particulate matter), nitrogen oxides and sulfur dioxides in the concentrations measured in Europe actually cause headaches cannot be answered from existing environmental epidemiological studies. The results of these studies were found to be contradictory.

Researchers agree that there are major research gaps regarding the causes of headaches, however, there are some good reasons:

• Most studies do not observe subjects over a long period of time, so that the interaction between the triggering factors and other diseases cannot be sufficiently investigated.
• Often people are included in the research who have other diseases or severe chronic headaches because they are easily accessible. Only about 50% of migraine sufferers and many less with chronic headaches try to get adequate medical care.

These difficulties apply especially to studies investigating the connection between environmental pollutants in indoor and outdoor air and headaches. Often such studies have the additional problem of an unsuitable exposure assessment. Nevertheless, it might be worthwhile examining the role of environmental factors because even if a factor only slightly influences the severity, the duration or the frequencies of headaches, the individual lifetime benefit can be substantial.

Regardless of the results of epidemiological studies, there are good reasons to provide clean air for people suffering from headaches. As pollutants present in indoor air can cause headaches, it is important to ensure for sufficient ventilation or airing. Whether the concentrations of outdoor air pollutants measured in Germany contribute to headaches has not been proven so far. Spending time outdoors in the clean and fresh air is not only good for the prevention of headaches but also for general health.