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Allergy in the population
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Below are résumés of several Danish and international population studies on allergies to chemical substances. Changes in the prevalence of the different forms of allergies are shown among eczema patients.
See the most recent figures
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Danish studies
Adults
In 1990 and again in 1998 a random sample of people living in Glostrup was examined for allergies to chemical substances. In 1990, the investigation included 567 people in the age range of 15–41 years; in 1998, the investigation included 312 people, also in the age range of 15–41 years. All participants completed a questionnaire and were allergy tested.
Glostrup was chosen for the study as the population was representative of the general Danish population regarding distribution of the sexes and age, and occupation, apart from work in the fishing industry.
In 1990, the study showed that 15.9% of the participants were allergic to one or more chemical substance(s); and in 1998, the figure was 18.6%. The figures here, and in the following, show the percentages of people who have tested positive for allergy to the named chemical.
Nickel allergy
In the 1990 study, 6.7% of the participants were allergic to nickel: 11.1% of the women and 2.2% of the men, with considerable differences among the women between the different age groups. The differences were due to younger women being more exposed to nickel through ear-piercing and wearing inexpensive jewellery.
Read more about nickel allergy
| The prevalence of nickel allergy in a random population sample from 1990, distributed over sex and age |
| Age |
Men (n=279)
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Women (n=288)
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Total
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| 15-34 yrs |
2,4 %
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19,6 %
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12,2 %
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| 35-49 yrs |
1,1 %
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7,9 %
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4,6 %
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| 50-69 yrs |
3,0 %
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2,7 %
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2,9 %
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| Total |
2,2 %
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11,1 %
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6,7 %
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The 1998 study covered only those in the 15–41 age group and time comparisons are therefore possible for that group only. Nickel allergy was the most frequent allergy in both 1990 and 1998, with little difference between the two studies.
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Comparisons between the 1990 and the 1998 studies.
The prevalence of nickel allergy in a random population sample distributed over sex in the age group 15–41 yrs
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Men
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Women
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| 1990 |
2,2 %
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16,9 %
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| 1998 |
2,1 %
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17,2 %
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Perfume allergy
In the 1990 study, perfume allergy* was found in a total of 1.1% of the random population sample: 1.1% in men and 1.0% in women.
The 1998 study covered only those in the 15–41 age group and time comparisons are therefore possible for that group only. There was an increase in the prevalence of perfume allergy between the two studies among both men and women.
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Comparisons between the 1990 and the 1998 studies.
The prevalence of perfume allergy* in a random population sample distributed over sex in the age group 15–41 yrs
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Men
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Woman
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| 1990 |
0,0 %
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0,6 %
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| 1998 |
1,0 %
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3,2 %
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| *) Perfume allergy based on a test with a mixture of eight fragrances (Fragrance mix). This is a minimum figure, inasmuch as it covers only a selection of the chemicals that can provoke perfume allergy. |
The same result was found in a study of eczema patients in Denmark who were allergy tested by Danish dermatologists in 1986 and 1998.
Read more about perfume allergy
Allergies to the ingredients in cosmetics
In the 1990 study, 3.2% of men and 4.2% of women were allergic to one or more selected chemical(s) that can be found in cosmetics. Hair dye, perfume, adhesives and preservatives were included.
The 1998 study covered only those in the 15–41 age group and time comparisons are therefore possible for that group only. The study showed an increasing prevalence of allergy to chemicals in cosmetics – more than twice that found in the 1990 study.
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Comparisons between the 1990 and the 1998 studies.
The prevalence of allergy cause by cosmetics* in a random population sample distributed over sex in the age group 15–41 yrs
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Men
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Women
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| 1990 |
0,7 %
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3,9 %
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| 1998 |
2,1 %
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8,3 %
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The figures for both perfume and cosmetic allergy are minimum figures, inasmuch as they cover only a selection of the allergenic chemicals found in perfume/cosmetics.
References:
Nielsen NH, Menné T. Allergic contact sensitization in an unselected Danish population. Acta Derm Venereol 1992;72:456-460
Nielsen NH, Menné T. Sensibilisation de contact aux constitutants des cosmetique dans unde population Danoise non sélectionée. Ann Dermatol Venereol 1993 :120 :33-36
Nielsen NH et al. Allergic contact sensitization in an adult Danish population: two cross-sectional surveys eight years apart. Acta Derm Venereol 2001:81:31-34
New studies
A new population-based study of allergies is currently underway in Glostrup. The study began in 2006 and has 5000 participants; the first results are expected in 2009. The study is run by the Research Centre for Prevention and Health and the National Allergy Research Centre in partnership.
Schoolchildren study in Odense
From 1995 to 1996 a study was run including 1501 eighth-grade school children (i.e., children aged between 12 and 16 years) from 40 schools in Odense County. The children completed a questionnaire and 1146 underwent an allergy test. Allergies to one or more chemical substance(s) were found in 15.2%, of which 19.5% were girls and 10.3% were boys. The study showed that nickel allergy was the most frequent form of allergy followed by perfume allergy, both in girls and in boys.
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The prevalence of nickel allergy and perfume allergy* among schoolchildren in Odense in 1995/96
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Boys n=526
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Girls n=620
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Total
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| Nickel allergy |
2,5 %
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13,7 %
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8,6 %
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| Perfume allergy |
2,1 %
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1,6 %
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1,8 %
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| *) Perfume allergy based on a test with a mixture of eight fragrances (Fragrance mix). This is a minimum figure, inasmuch as it covers only a selection of the chemicals that can provoke perfume allergy. |
Reference:
Mortz CG et al. Contact allergy and allergic contact dermatitis in adolescents: prevalence measures and associations. Acta Derm Venereol 2002:82:352-358
Children/adolescents
Nickel allergy among Danish schoolgirls with pierced ears before and after nickel legislation.
In 1991, legislation was introduced in Denmark to limit exposure to nickel from fastenings and jewellery, including body-piercing jewellery.
A study was run including 200 schoolgirls aged 10–14 years from 12 secondary schools and 237 girls aged 17–22 years from high schools/colleges, all recruited from the Copenhagen area. The findings revealed a far greater prevalence of nickel allergy among participants who had had their ears pierced before, rather than after, the nickel legislation came into effect.
It is also noteworthy that there was no nickel allergy among those in the youngest group of girls who had not had their ears pierced. It is expected that nickel allergy will be less frequent in the future; however, the allergy emerges early in life and remains detectable in allergy tests for many years, so it will be some time before the full effect of the legislation can be registered.
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Pierced before 1992
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Pierced after 1992
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Not pierced
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Secondary school
(10-14 yrs)
n=200
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15,4 %
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4,4 %
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0 %
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High school
(17-22 yrs)
n=237
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26,9 %
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12,4 %
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5,3 %
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Reference:
Jensen CS, Lisby S, Baadsgaard O, Volund A, Menné T. Decrease in nickel sensitization in a Danish schoolgirl population with ears pierced after implementation of a nickel-exposure regulation. British Journal of Dermatology 2002 Apr; 146(4):636-42
International studies
Adults
A study from Germany in 1997/98 allergy tested 1141 people aged 25–74 years recruited from the background population in Augsberg. The participants were selected on the basis of a questionnaire and a blood test; half the participants had a form of type 1 allergy (e.g., pollen/dust-mite allergy) and half had had asthma, hay fever, or skin irritation. Subsequently, the prevalence of allergies was estimated. Perfume allergy and nickel allergy were the most prevalent allergies with perfume allergy in 11.4% and nickel allergy in 9.9% of the participants.
The prevalence of perfume allergy was far greater than expected, seen in relation to that found in Danish studies. This could be due to the selection of people tested and that the selection was not sufficiently adjusted for.
Reference:
Schäfer T et al. Epidemiology of contact allergy in adults. Allergy 2001:56:1192-1196
In another German study the prevalence of contact allergy in Germany was estimated based on the sales and use of allergy tests and the prevalence of allergies in allergy-tested eczema patients. The estimation method was the same as that used to estimate the prevalence of disease based on the sales of medicine. Between 4% and 16% of the German population was estimated to be allergic to one or more chemical substance(s). Nickel allergy and perfume allergy were the most prevalent allergies, and it is estimated that between 1.9 and 4.5 million people in Germany are allergic to nickel and that between 1.4 and 3.4 million are allergic to perfume.
Reference:
Schnuch A. et al. Epidemiology of contact allergy: an estimation of morbidity employing the clinical epide-miology and drug-utilization research (CE-DUR) approach. Contact Dermatitis 2002:47:32-39
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