Effects of Dietary Supplements on Response to Air Pollution
This study will determine if a comprehensive antioxidant/anti-inflammatory dietary supplement pack can offer protection against a decline in lung function and increase in inflammation and oxidative stress following acute exposure to particulate matter air pollution with a diameter <2.5 µm (PM2.5).
The investigators hypothesis is a follows: Compared to an appropriate control, supplementation with a comprehensive antioxidant/anti-inflammatory dietary supplement pack for 18 weeks will: 1) reduce the decline in lung function following acute exposure to naturally occurring elevations in PM2.5 levels as measured by exhaled nitric oxide levels and forced vital lung capacity; and 2) reduce changes in pro-inflammatory cytokines following acute exposure to naturally occurring elevations in PM2.5 levels as measured by plasma levels of C-reactive protein.
|Inflammation||Dietary Supplement: Placebo Dietary Supplement: Antioxidant, anti-inflammatory dietary supplement|
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
|Official Title:||Effect of an Antioxidant and Anti-inflammatory Dietary Supplement Pack on the Adverse Physiological Actions Associated With Acute PM2.5 Exposure|
- Forced vital lung capacity (FVC) [ Time Frame: Six times over 3 months to coincide with high and low PM2.5 exposure ]
- Forced expiratory volume in first second (FEV1) [ Time Frame: Six times over 3 months to coincide with high and low PM2.5 exposure ]
- Fractional exhaled nitric oxide (FeNO) [ Time Frame: Six times over 3 months to coincide with high and low PM2.5 exposure ]
- C-reactive protein [ Time Frame: Six times over 3 months to coincide with high and low PM2.5 exposure ]
|Study Start Date:||November 2011|
|Study Completion Date:||June 2012|
|Primary Completion Date:||March 2012 (Final data collection date for primary outcome measure)|
Placebo Comparator: Placebo dietary supplements
Visually identical inactive dietary supplement pack
Dietary Supplement: Placebo
7-pill placebo dietary packed visually identical to active dietary supplement
Experimental: Active dietary supplements
Combination of antioxidants, minerals, fish oil, proflavanol and vitamin D
Dietary Supplement: Antioxidant, anti-inflammatory dietary supplement
A combination of dietary supplements including: β-carotene, vitamin C, vitamin D3, vitamin E, vitamin K, thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, biotin, pantothenic acid, calcium, iodine, magnesium, zinc, selenium, copper, manganese, chromium, molybdenum, boron, silicon, vanadium, eicosapentaenoic acid, docosahexaenoic acid, olive extract, mixed tocopherols, bioflavonoids, inositol, choline, N-acetyl L-cysteine, bromelain, coenzyme Q10, turmeric extract, lutein, lycopene, broccoli concentrate, grape seed extract
The study will be conducted in Cache County, UT. Surrounded by tall mountains (2513-3042 m), and subject to frequent winter atmospheric inversions characterized by stagnant air that traps and concentrates pollutants, Cache Valley, home to 120,000 inhabitants, is particularly susceptible to high particulate air pollution during the winter months.
A total of 70 individuals (with the goal of completing 60) between the ages of 45-80 will be recruited from Cache County, UT. Eligible participants will be randomly assigned to one of two treatment arms (Placebo Dietary Supplements, Active Dietary Supplements) in a manner to provide balanced assignment between the two arms with respect to age, sex and baseline exhaled nitric oxide levels.
Participants assigned to the Placebo or Active arms will be provided with sealed envelopes or bottles containing dietary supplements (or matched placebos) along with instructions as to when to consume the supplements. Participants will be instructed to consume their supplements twice a day with meals containing a small amount of fat (at least 3 grams) in order to optimize the absorption of fat soluble nutrients. They will also be instructed to consume the supplements with liquids in order to enhance absorption and to minimize GI upset and choking potential. Participants will be asked to maintain their typical diet for the 18 weeks of the study.
Routine Clinic Visits are scheduled at two week intervals for the length of the study (with accommodations made for Holiday schedules). During these visits, participants will: 1) receive a sufficient supply of supplements to last until the next routine clinic visit; 2) return any unused supplements; 3) be provided an opportunity to describe any adverse events/reactions to the supplements; 4) describe any health issues experienced since the previous exam; and 5) have their weight and blood pressure assessed.
Endpoint Clinic Visits are scheduled to coincide with low and high PM2.5 exposure. Starting on Jan 2, participants will be notified of a potential endpoint assessment day when the PM2.5 levels are predicted by the Utah Department of Environmental Quality, Division of Air Quality, to rise above 30 µg/m3 (peak event) or fall below 8 µg/m3 (baseline event). Endpoint visits will take place 24 hrs following these peak and baseline events. Based on historical patterns, we anticipate at least three peak events, with corresponding baseline assessments, during the intervention time period. For purposes of analysis, each peak event will be paired with the nearest baseline event so that both events are captured at a similar time after initiation of the intervention.
At each endpoint clinic visit, participants will undergo assessments of lung function and systemic inflammation. Blood samples will be obtained for potential future analysis of additional markers of systemic inflammation and plasma antioxidant capacity.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01488656
|Principal Investigator:||Michael Lefevre, PhD||Utah State University|