Human Lung Responses to Respiratory Pathogens

University of Iowa

Status and phase: Completed; Phase 2; Phase 1

Conditions: Respiratory Infection

Treatments: Dietary Supplement: Vitamin D3 (cholecalciferol); Dietary Supplement: Placebo Sugar Pill

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT01967628

DMID 06-0003

N01AI30040-11-0-0 (U.S. NIH Grant/Contract)

Details and patient eligibility

About

For most individuals, the lung has a remarkable ability to deal with exposure to a variety of inhaled bacteria. Some individuals, however, do have recurrent bacterial infections, usually in the form of acute or chronic bronchitis and, in some instances, pneumonia. The reasons for this variability in bacterial infections between otherwise healthy subjects, between types of lung disease, and within the same type of lung disease are poorly understood.

Variability in susceptibility to bacterial infections is partially explained by differences in exposure to infectious agents, genetic susceptibility and innate (or early) immune responses. It is of interest that the incidence and severity of bacterial infections is greatest during the winter months. Other than viral infections, there are few variables that change with season. Vitamin D is one known immune modulator with a seasonal periodicity. The hypothesis of this study is that levels of vitamin D are an important determinant of the innate defense of the lung against inhaled bacteria. The investigators further postulate that vitamin D has effects on the innate immune function of both alveolar macrophages and lung epithelial cells.

Enrollment: 98 patients

Sex: All

Ages: 18 to 60 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

Signed informed consent form Age 18 - 60 Healthy nonsmoker, healthy smoker Forced expiratory volume in 1 second (for smokers) > 60% predicted.

Exclusion criteria

• Pregnant or breastfeeding
• Medications (with the exception of hormonal birth control, thyroid medication or prespecified over the counter medications), including multi-vitamins and any preparation that contains vitamin D
• Asthma
• Heart disease
• Diabetes
• Previous positive tuberculin skin test, or previous diagnosis of tuberculosis
• Recent respiratory tract infection
• History of multiple bouts of pneumonia
• Allergies to caines, atropine, or a history of adverse reaction to narcotics
• Other factors that increase the risk of bronchoscopy
• Evidence of acute bronchitis within the past 2 weeks

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Single Group Assignment

Masking: Triple Blind

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98 participants in 2 patient groups, including a placebo group

Vitamin D3 (cholecalciferol)

Experimental group

Description:

Vitamin D3 (1000 international units) daily for 3 months.

Treatment:

Dietary Supplement: Vitamin D3 (cholecalciferol)

Sugar capsule

Placebo Comparator group

Description:

Placebo comparator made of sugar in a capsule

Treatment:

Dietary Supplement: Placebo Sugar Pill