The role of vitamin D in asthma and the effect of supplementation

Oude Avenhuis, M. (2016) The role of vitamin D in asthma and the effect of supplementation. Bachelor's Thesis, Biology.

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Abstract

Vitamin D deficiency is a global public health issue and has been associated with an increased incidence and severity of many diseases including diseases of the respiratory system. Due to westernized lifestyles, with spending more time indoors, there has been an increase in asthma and allergy as a result of vitamin D deficiency. Asthma is a chronic inflammatory disease of the lungs and the number one chronic disease in children. The vitamin D receptor (VDR) is expressed in cells involved in the immune/inflammation system in the human body, which provides the biological basis for the role of vitamin D in inflammatory diseases. In this thesis, the effect of vitamin D deficiency on asthma onset, pathophysiology and exacerbation will be discussed as well as the effect of therapy with vitamin D supplementation. Gupta et al. measured serum 25(OH)D levels from children with moderate and steroid resistant asthma, and non-asthmatic children. They discovered that serum 25(OH)D levels were lowest in children with steroid resistant asthma. Damera et al. demonstrated that 1,25(OH)2D can inhibit ASM cell proliferation in both normal and asthmatic subjects by preventing cell cycle progression. Birth cohort studies have shown that lower maternal dietary intake of vitamin D during pregnancy can be related to an increased risk of wheeze and development of asthma in children. Children from a mother with serum 25(OH)D concentrations of > 75 nmol/L had an increased risk of asthma at nine years of age, reported Gale et al. Higher levels of vitamin D are associated with fewer asthma exacerbations in asthmatic children between 6 and 14 years old. An inverse correlation in asthmatic children between corticosteroid use and vitamin D levels was stated by Searing and colleagues. Studies have revealed that stimulation of ASM cells with VDR ligand, 1,25(OH)2D, control the expression of the genes coding for glucose-6-phosphate dehydrogenase and 1β-hydroxysteroid dehydrogenase type 1 enzyme, which are both responsible for corticosteroid activation. Vitamin D supplementation in infancy has been associated with increased atopy and allergic rhinitis in adulthood. Increasing 25(OH)D levels were associated with increasing risk of allergic rhinitis among adults in NHANES III. The conflicting data indicate the need to demonstrate the effect of vitamin D on the prevention and control of allergic diseases. Much of the data support the hypothesis that higher vitamin D levels lead to better asthma outcomes. However, vitamin D deficiency is often an indirect marker of other confounding factors such as physical activity, making it hard to determine a causal association between vitamin D status and asthma.

Item Type:	Thesis (Bachelor's Thesis)
Degree programme:	Biology
Thesis type:	Bachelor's Thesis
Language:	English
Date Deposited:	15 Feb 2018 08:10
Last Modified:	15 Feb 2018 08:10
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/13641

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