ASTHMA

Asthma

Asthma

Introduction

Globally, asthma incurs a large burden of disease, affecting an estimated 300 million persons. Only recently, however, has the condition been recognized and addressed at the international level through efforts such as the Global Initiative for Asthma (GINA). As more attention is given to asthma and its increasing rates, the global campaign to address this disease and its causes will become more effective and comprehensive.

On the medical spectrum, asthma also requires a “global” perspective, representing a unique intersection of many areas of health. It draws together the fields of pediatrics and adult medicine, affecting certain subgroups in each disproportionately. It lies at the crossroads between preventive medicine, acute care, and chronic disease management. Asthma treatments and technologies involve medical specialties from pulmonology to immunology to infectious disease. Furthermore, looking into the causes of this condition invokes conversations ranging from the social determinants of health and health inequities to environmental health, and toward the genetic susceptibilities underlying asthma (Toelle, 2002).

Factors Associated With Asthma

The causes and contributing factors to asthma are varied, and often hard to assess. These factors may be broadly defined on a molecular/genetic level, in the context of other health conditions, and through the lens of the social determinants of this condition.

As an inflammatory condition, it is not surprising that mast cells, eosinophils, and lymphocytes are implicated in the immunologic dysregulation that appears to underlie asthma. Drazen summarizes the pathogenesis of asthma as follows: B lymphocytes set off a cascade, via cytokines, that activate mast cells and eosinophils that cause the inflammation of airways , cellular infiltration into the airways (involving T lymphocytes and eosinophils), and further cytokine production. Currently, we do not know the root cause for this dysregulation, though some evidence suggests that an early-in-life shift imbalance between Th2 and Th1 cells is to blame. We also know that elevated IgE levels are associated with asthma. IgE is an antibody that is elevated in atopy, the term for conditions of hypersensitivity to environmental allergens (e.g., asthma, eczema, hay fever, rhinitis).

A further pathway by which predisposition to asthma is thought to occur is maternal smoking during pregnancy, which through cellular effects on the fetus's developing airways, leads to small airways relative to the size of the lung parenchyma, and might explain increased rates of asthma seen in children with fetal exposure to environmental tobacco smoke (ETS).

The genetics of asthma are complex, and the genes causing aggregation of asthma in families have yet to be identified. Current evidence suggests multiple genes and gene pathways to be involved in predisposing some to asthma, with hope that as these can be more clearly elucidated, gene-based therapies will become a possibility (Weitzman, 2005).

Global Burden Of Asthma

Experts agree that asthma is an underrecognized public health and global health condition. An estimated 1 in 250 deaths worldwide is attributable to asthma, while in terms of disability adjusted life-years (DALYs) lost, asthma is comparable to diabetes, accounting for approximately 15 million DALYs each year. As mentioned before, rates of asthma are hard to accurately assess and ...