Allergies in Asia: are we facing an allergy epidemic?

Prevalence of food allergies in South Asia

OBJECTIVE

To evaluate the published medical literature on the prevalence and types of food allergies in South Asia.

DATA SOURCES

A PubMed search was performed using the keywords India and food allergy, Asia and food allergy, and South Asia and food allergy for any period. Articles cited in selected studies were reviewed for their appropriateness of inclusion into this review.

STUDY SELECTIONS

Publications were included that were original research and fit the topic of food allergy and South Asia. South Asia is defined as region inclusive of India, Pakistan, Bangladesh, and Sri Lanka.

RESULTS

A total of 169 articles were initially identified, and 47 were reviewed in detail for inclusion in this review. The primary focus was placed on 10 studies that consisted of case reports of newly reported or documented food allergy, survey studies that investigated food allergy prevalence in specific demographics, and prospective and cross-sectional studies with case controls, all of which investigated food allergy prevalence by allergy testing in a selected population.

CONCLUSION

The medical literature on the prevalence and types of food allergy in South Asia indicates that there is a variety of unusual and unique allergens and an overall low incidence of food allergy. There is also an association of increased food allergy prevalence in individuals who live in metropolitan regions or who migrate to communities that have adopted westernization.

Is atopy in early childhood a risk factor for ADHD and ASD? a longitudinal study

OBJECTIVE

Previous studies have found a temporal concordance in the increased prevalence of atopic diathesis/atopic diseases, attention-deficit hyperactivity disorder (ADHD), and autistic spectrum disorder (ASD) worldwide. But, the temporal association among these 3 distinct diseases is unknown.

METHOD

14,812 atopic subjects diagnosed with any atopic disease (asthma, atopic dermatitis, allergic rhinitis, or allergic conjunctivitis) before the age of 3 (atopic cohort) and 6944 non-atopic subjects with no lifetime atopic disease (non-atopic cohort), born between 1997 and 2000, were enrolled and followed to December 31, 2010 to identify the development of ADHD and ASD.

RESULTS

The presence of any atopic disease in early childhood increased the risk of developing ADHD (hazard ratio [HR]: 1.97) and ASD (HR: 3.40) in later life. Greater numbers of atopic comorbidities (4 comorbidities: ADHD: HR: 2.53; ASD: HR: 4.29) were significantly related to a greater risk of developing ADHD and ASD.

DISCUSSION

Atopic diathesis in early childhood elevated the risk of developing ADHD and ASD in later life, with the dose-dependent relationship of more atopic comorbidities with a greater likelihood of ADHD and ASD.