THE RELATIONSHIP BETWEEN VITAMIN D STATUSES AND YOUNG ADULT WOMEN ASTHMA

INTRODUCTION

Although the role of vitamin D in bone health is well known, recent studies have described new, nonskeletal roles for vitamin D in human health, including a role in preventing chronic diseases such as cardiovascular disease, diabetes and cancer. (Wang, 2008; Mohr, 2008; Holick, 2004a; Holick, 2004b)

In addition to these chronic diseases, vitamin D status may also be linked to asthma, although this area of research is relatively new (Black, 2005, Burns 2006, Camargo, 2007). Asthma is a common chronic lung disease that involves inflammation of the pulmonary airways and bronchial hyper-responsiveness, which manifests as lower airway obstruction (Expert Panel Report 3, 2007). Asthma is a common disease worldwide and affects 22 million people in the United States alone. Although the overall mortality rate for asthma has declined and asthma-related hospitalizations have remained constant since 1995 (Centers for Disease Control and Prevention asthma surveillance data; Moorman 2007), asthma nonetheless contributes substantially to morbidity. Children and African Americans are especially affected by asthma; the prevalence of asthma is twice as high in these groups as in other groups (Centers for Disease Control and Prevention asthma surveillance data; Moorman 2007). The cost of treating asthma continues to be a large burden in health care costs for both adults and children.

The prevalence of asthma increased throughout the late 1980s in developed countries, leading to many hypotheses that attempted to explain this increase. One hypothesis, the ―hygiene hypothesis, suggested that declining family size reduced exposure to infectious pathogens in early childhood, and higher standards of cleanliness, compromise development of immune function which then increases susceptibility to allergic diseases (Strachan, 1989), including asthma. Although this phenomenon may account for some of the increase in asthma prevalence, it does not completely explain the asthma epidemic. Other factors, including urban poverty (Platts-Mills, 2001), obesity (Ford, 2005) and dietary components also appear to play a role (Raviv, 2010).

Litonjua and Weiss (2007) recently offered a new hypothesis to explain the asthma epidemic. They hypothesized that vitamin D status influences asthma risk, although they had direct evidence of a relationship only among pregnant women and their offspring. Whether vitamin D status is associated with adult asthma remains unclear. The main goal of the current project is to assess the relationship between vitamin D status and asthma in young adult women.