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Latitude, birth date, and allergy.

Wjst M, Dharmage S, André E, Norback D, Raherison C, Villani S, Manfreda J, Sunyer J, Jarvis D, Burney P, Svanes C - PLoS Med. (2005)

Bottom Line: Also, no altered risk by birth month was found, except borderline reduced risks in September and October.Effect estimates obtained by a multivariate analysis of total and specific IgE values in 18,085 individuals also excluded major birth month effects and confirmed the independent effect of language grouping.Although there might be effects of climate or environmental UV exposure by latitude, influences within language groups seem to be more important, reflecting so far unknown genetic or cultural risk factors.

View Article: PubMed Central - PubMed

Affiliation: Gruppe Molekulare Epidemiologie, Institut für Epidemiologie, Forschungszentrum für Umwelt und Gesundheit, Munich, Germany. m@wjst.de

ABSTRACT

Background: The space and time distribution of risk factors for allergic diseases may provide insights into disease mechanisms. Allergy is believed to vary by month of birth, but multinational studies taking into account latitude have not been conducted.

Methods and findings: A questionnaire was distributed in 54 centres to a representative sample of 20- to 44-y-old men and women mainly in Europe but also including regions in North Africa, India, North America, Australia, and New Zealand. Data from 200,682 participants were analyzed. The median prevalence of allergic rhinitis was 22%, with a substantial variation across centres. Overall, allergic rhinitis decreased with geographical latitude, but there were many exceptions. No increase in prevalence during certain winters could be observed. Also, no altered risk by birth month was found, except borderline reduced risks in September and October. Effect estimates obtained by a multivariate analysis of total and specific IgE values in 18,085 individuals also excluded major birth month effects and confirmed the independent effect of language grouping.

Conclusion: Neither time point of first exposure to certain allergens nor early infections during winter months seems to be a major factor for adult allergy. Although there might be effects of climate or environmental UV exposure by latitude, influences within language groups seem to be more important, reflecting so far unknown genetic or cultural risk factors.

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World Map and European Map of Study Centres
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pmed-0020294-g001: World Map and European Map of Study Centres

Mentions: Geographical latitude was obtained from the route planning software Mapsonic (http://www.viamichelin.com, where GPS degrees were obtained for a random inner city point and were included as a continuous variable as well as dichotomized into quartile groups. Non-European locations were taken from The World Gazetteer (http://www.world-gazetteer.com) or Encarta (http://encarta.msn.com). For Figures 1 and 2, the original latitude values are used, while for all regression models only the absolute latitude values are taken. If primary language was not self evident, the CIA's World Factbook (http://www.cia.gov/cia/publications/factbook/fields/2098.html) was used as a reference. The city of Montreal was classified as English, although English/French bilingual questionnaires were used. Additional data included in this study are obtained from http://rimmer.ngdc.noaa.gov/mgg/coast/getcoast.html, http://www.polleninfo.org, and http://www.dssresearch.com/toolkit/spcalc/power_p2.asp.


Latitude, birth date, and allergy.

Wjst M, Dharmage S, André E, Norback D, Raherison C, Villani S, Manfreda J, Sunyer J, Jarvis D, Burney P, Svanes C - PLoS Med. (2005)

World Map and European Map of Study Centres
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1240049&req=5

pmed-0020294-g001: World Map and European Map of Study Centres
Mentions: Geographical latitude was obtained from the route planning software Mapsonic (http://www.viamichelin.com, where GPS degrees were obtained for a random inner city point and were included as a continuous variable as well as dichotomized into quartile groups. Non-European locations were taken from The World Gazetteer (http://www.world-gazetteer.com) or Encarta (http://encarta.msn.com). For Figures 1 and 2, the original latitude values are used, while for all regression models only the absolute latitude values are taken. If primary language was not self evident, the CIA's World Factbook (http://www.cia.gov/cia/publications/factbook/fields/2098.html) was used as a reference. The city of Montreal was classified as English, although English/French bilingual questionnaires were used. Additional data included in this study are obtained from http://rimmer.ngdc.noaa.gov/mgg/coast/getcoast.html, http://www.polleninfo.org, and http://www.dssresearch.com/toolkit/spcalc/power_p2.asp.

Bottom Line: Also, no altered risk by birth month was found, except borderline reduced risks in September and October.Effect estimates obtained by a multivariate analysis of total and specific IgE values in 18,085 individuals also excluded major birth month effects and confirmed the independent effect of language grouping.Although there might be effects of climate or environmental UV exposure by latitude, influences within language groups seem to be more important, reflecting so far unknown genetic or cultural risk factors.

View Article: PubMed Central - PubMed

Affiliation: Gruppe Molekulare Epidemiologie, Institut für Epidemiologie, Forschungszentrum für Umwelt und Gesundheit, Munich, Germany. m@wjst.de

ABSTRACT

Background: The space and time distribution of risk factors for allergic diseases may provide insights into disease mechanisms. Allergy is believed to vary by month of birth, but multinational studies taking into account latitude have not been conducted.

Methods and findings: A questionnaire was distributed in 54 centres to a representative sample of 20- to 44-y-old men and women mainly in Europe but also including regions in North Africa, India, North America, Australia, and New Zealand. Data from 200,682 participants were analyzed. The median prevalence of allergic rhinitis was 22%, with a substantial variation across centres. Overall, allergic rhinitis decreased with geographical latitude, but there were many exceptions. No increase in prevalence during certain winters could be observed. Also, no altered risk by birth month was found, except borderline reduced risks in September and October. Effect estimates obtained by a multivariate analysis of total and specific IgE values in 18,085 individuals also excluded major birth month effects and confirmed the independent effect of language grouping.

Conclusion: Neither time point of first exposure to certain allergens nor early infections during winter months seems to be a major factor for adult allergy. Although there might be effects of climate or environmental UV exposure by latitude, influences within language groups seem to be more important, reflecting so far unknown genetic or cultural risk factors.

Show MeSH
Related in: MedlinePlus