XML Feed for RxPG News   Add RxPG News Headlines to My Yahoo!   Javascript Syndication for RxPG News

Research Health World General
 
  Home
 
 Latest Research
 Cancer
 Psychiatry
 Genetics
 Surgery
 Aging
 Ophthalmology
 Gynaecology
 Neurosciences
 Pharmacology
 Cardiology
 Obstetrics
 Infectious Diseases
 Respiratory Medicine
 Pathology
 Endocrinology
 Immunology
  Autoimmune Diseases
  Immunosupressants
  Monoclonal Antibodies
 Nephrology
 Gastroenterology
 Biotechnology
 Radiology
 Dermatology
 Microbiology
 Haematology
 Dental
 ENT
 Environment
 Embryology
 Orthopedics
 Metabolism
 Anaethesia
 Paediatrics
 Public Health
 Urology
 Musculoskeletal
 Clinical Trials
 Physiology
 Biochemistry
 Cytology
 Traumatology
 Rheumatology
 
 Medical News
 Health
 Opinion
 Healthcare
 Professionals
 Launch
 Awards & Prizes
 
 Careers
 Medical
 Nursing
 Dental
 
 Special Topics
 Euthanasia
 Ethics
 Evolution
 Odd Medical News
 Feature
 
 World News
 Tsunami
 Epidemics
 Climate
 Business
 
 India
Search

Last Updated: Nov 18, 2006 - 12:32:53 PM

Matthias Wjst and colleagues

Immunology Channel
subscribe to Immunology newsletter

Latest Research : Immunology

   DISCUSS   |   EMAIL   |   PRINT
Investigating spatial & temporal distribution of risk factors in allergy
Oct 7, 2005 - 6:44:00 PM, Reviewed by: Dr.

In this study, Wjst and colleagues tried to further understand the effects of latitude and birth date on the prevalence of allergy defined by markers such as allergic rhinitis, sensitization to grass or dust, and total IgE levels. They distributed a questionnaire to 20– to 44–year-old individuals in 54 centers across Europe, North Africa, India, North America, Australia, and New Zealand. Altogether, data from 200,682 participants were analyzed.

 
The prevalence of asthma and allergy, defined as immunologically mediated hypersensitivity, is increasing. It is estimated that more than 20% of the world's population has IgE-mediated allergic diseases. The scale of the clinical problem is immense. The World Health Organization estimates that asthma affects nearly 150 million people worldwide, and more than 180,000 deaths each year are due to asthma. Approximately US$20 billion is spent globally each year on allergic rhinitis, including medications, time off work, and clinician consultations. The cost of allergy drugs alone is estimated to be US$8 billion per annum.

While allergy prevalence is increasing, the causal risk factors are still unknown. Matthias Wjst and colleagues investigated whether the spatial (latitude) and temporal (birth month) distribution of risk factors might offer insight into the mechanism of disease.

Previous studies have already shown that birth month is a risk factor associated with allergy; as the authors point out, birth month, used as a proxy for early allergen exposure, might be associated with upper respiratory infections during winter months. Studies have also associated geographical latitude with allergy. But some experts have noted that latitude, a proxy for ultraviolet solar exposure, might also reflect climatic differences, genetic influences, or even cultural differences in the raising of children.

In this study, Wjst and colleagues tried to further understand the effects of latitude and birth date on the prevalence of allergy defined by markers such as allergic rhinitis, sensitization to grass or dust, and total IgE levels. They distributed a questionnaire to 20– to 44–year-old individuals in 54 centers across Europe, North Africa, India, North America, Australia, and New Zealand. Altogether, data from 200,682 participants were analyzed.

The median prevalence of allergic rhinitis was 22%, but with a substantial variation across centers. They found allergic rhinitis decreased with geographical latitude, but there were many exceptions. There was no increase in prevalence during certain winters, and no altered risk by birth month, except borderline reduced risks in September or October. Altogether, the authors concluded that there was no major risk by being born in a particular month or during a particular season. There may be relevant birth month effects in single centers, but a global effect was questionable.

Previous research on the effect of birth month has also shown mixed results: differing studies have found associations that were positive, negative, or simply unclear.

But the authors noted that one difference of their study compared with others was the higher age of the subjects—interviewees were born between 1945 and 1973—and suggested that it might be possible that there are more marked symptoms in children that were being lost in adulthood.

Most previous studies have shown an association with allergic sensitization, indicating subclinical effects that gained importance only when occurring in combination with additional risk factors. One of the main advantages of this study—a standardized allergen test protocol—might, thus, be a disadvantage since the effects of local allergens might have been missed. Another methodological restriction might have been the use of self-reported “hay fever.” This term may be used in a different way across Europe, said the authors.

Data on the geographical distribution of allergic diseases are rare, and, hence, this study is valuable. However, a previous meta-analysis has shown negative association of latitude and symptoms of allergic rhinitis, with a −0.05% decrease per degree. In this study, symptoms of allergic rhinitis decreased with geographical latitude on a worldwide scale, but not when the analysis was restricted to Europe alone. One intriguing possibility, which needs further work, is that a risk factor within language borders might be more relevant than geographical latitude alone in determining the distribution of allergic diseases.
 

- (2005) Teasing Out the Effects of Latitude and Birth Date on Allergy. PLoS Med 2(10): e375
 

PDF of the Source Article at PLoS Medicine

 
Subscribe to Immunology Newsletter
E-mail Address:

 

DOI: 10.1371/journal.pmed.0020375

Published: October 4, 2005

Copyright: © 2005 Public Library of Science. This is an open-access article distributed under the terms of the Creative Commons Attribution License.

PLoS Medicine is an open-access journal published by the nonprofit organization Public Library of Science.


Related Immunology News

Pregnant women with lupus are at higher risk for complications
Molecular 'signature' protects cells from viruses
Discovery in the evolution of the immune system absorbing cells
Leeds University study shows eculizumab may be an effective therapy for PNH
Research Reveals Inner Workings of Immune System �Thermostat�
CD23 Protein in Stool Samples may Indicate Food Allergy
Molecular signals triggering maturation of natural killer cells uncovered
New method to analyse the Major Histocompatibility Complex (MHC) of the human genome
Front Line Immune Cells Mature in Four Stages - Study
Caspase-12 gene that shuts down immune system is found in 20% of people of African descent


For any corrections of factual information, to contact the editors or to send any medical news or health news press releases, use feedback form

Top of Page

 

© Copyright 2004 onwards by RxPG Medical Solutions Private Limited
Contact Us