Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12613000301763
Ethics application status
Not yet submitted
Date submitted
15/03/2013
Date registered
19/03/2013
Date last updated
26/02/2019
Date data sharing statement initially provided
26/02/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Dietary modification for asthma control in pregnancy.
Scientific title
Effects of dietary modification to improve asthma control in pregnant women with asthma.
Secondary ID [1] 282072 0
NIL
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Asthma 288561 0
Pregnancy 288562 0
Condition category
Condition code
Respiratory 288891 288891 0 0
Asthma
Reproductive Health and Childbirth 288892 288892 0 0
Other reproductive health and childbirth disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
At ~12 weeks gestation, asthmatic women will be recruited to participate in the 12 week intervention study, with an initial 4 week run-in period. At this initial visit, women will have the study procedures explained and have their asthma assessed (by a respiratory nurse). At 14 weeks gestation, the run-in period will commence in which all women will be provided asthma management, education and advice (by a respiratory nurse). It is important that the women in the study receive this, as previous data obtained from Lyell McEwin Hospital indicate that 16% of pregnant women have asthma and it is often poorly controlled, leading to high exacerbation rates. These procedures will also occur at week 16 and at week 18, in which the women will then be randomized into a control or intervention group.

The intervention group will be advised to consume increased consumption of foods containing antioxidants (i.e. at least 5 servings of vegetables/day, at least 2 servings of fruit/day) as well as antioxidant-rich nuts and wholegrains. The intervention group will receive a booklet on the current Australian Guide to Healthy Eating for pregnancy in which the desirable number of servings of food groups are outlined. Participants will be counselled and provided with a list of foods containing antioxidant-rich foods, and will be asked to identify which types of fruits and vegetables they are most likely to purchase and consume over the 12 weeks. They will also be given meal/snack suggestions to assist compliance.

Every 2 weeks during the intervention (i.e. weeks 20, 22, 26 and 28), women will be phoned by the registered nutritionist who will provide additional dietary counselling and support regarding the consumption of antioxidant-rich foods and will be questioned on their fruit and vegetable intake. Telephone calls will last approximately 15 minutes. Mid-way through the intervertion (i.e. ~24 weeks gestation), women will come to Lyell McEwin Hospital to also have this dietary counseling, along with further assessments.
Intervention code [1] 286669 0
Lifestyle
Intervention code [2] 286750 0
Prevention
Comparator / control treatment
The control group will receive standard care which includes a booklet on “healthy eating during pregnancy and lactation”. No other dietary education will be provided to this group.
Control group
Active

Outcomes
Primary outcome [1] 289019 0
Asthma control score, using the validated ACQ6 questionnaire.
Timepoint [1] 289019 0
Assessed every 2 weeks during the 12 week study (i.e. at ~18, 20, 22, 24, 26 and 30 weeks gestation).
Secondary outcome [1] 301582 0
Plasma circulating concentrations of antioxidants
Timepoint [1] 301582 0
Measured at the beginning and at the end of the 12 week study.
Secondary outcome [2] 301583 0
Markers of oxidative stress (plasma 8-F2 isoprostanes)
Timepoint [2] 301583 0
Measured at the beginning and at the end of the 12 week study.
Secondary outcome [3] 301584 0
Exhaled nitric oxide (FENO: direct measure of airway inflammation)
Timepoint [3] 301584 0
Measured at the beginning and at the end of the 12 week study.
Secondary outcome [4] 301585 0
Time to, and number of, exacerbations: Asthma exacerbations during pregnancy (moderate and severe exacerbations) defined as events for which the participant sought medical attention (i.e. an unscheduled visit to a doctor, presentation to the emergency department room or admission to hospital, or when oral corticosteroids were used for treatment of asthma).
Timepoint [4] 301585 0
Measured at the beginning and at the end of the 12 week study.

Eligibility
Key inclusion criteria
Pregnant women with mild or moderate/severe asthma and currently using inhaled corticosteroids, >18 years of age, and poor diet quality (less than 1 serving/day fruit and less than 2 servings/day vegetable, determined from Food Frequency Questionnaire).
Minimum age
18 Years
Maximum age
No limit
Sex
Females
Can healthy volunteers participate?
No
Key exclusion criteria
Recent (past month) respiratory tract infection, intermittent asthma, current smoker, use of antioxidant supplements, or previous pregnancy complications including growth restriction, still birth or preterm delivery.

Study design
Purpose of the study
Educational / counselling / training
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
At ~12 weeks gestation, asthmatic women will be recruited to participate in the 12 week intervention study, with an initial 4 week run-in period. At this initial visit, women will have the study procedures explained and have their asthma assessed. At 14 weeks gestation, the run-in period will commence in which women will be provided asthma management, education and advice. At week 18 of gestation (after the run-in) the women will be randomized into a control or intervention group.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
A telephone randomization service with balanced variable blocks, prepared by an independent investigator, will be used. Stratification will be by parity and pre-pregnancy asthma severity. During the randomization call, eligibility will be checked and information collected to enable stratification and assist in follow-up.
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis
All statistics will be performed using SPSS version 20.0 (SPSS, Inc., Chicago, IL, USA). Frequencies and descriptives of the study population will be reported as mean (SD) or between groups as mean (+/-SEM). Prior to hypothesis testing, the distribution of the data will be examined for normality. Any skewed data will be natural log transformed. Outcome comparisons will be made according to the treatment allocation at randomization on an ‘intention to treat’ basis. Both adjusted and unadjusted analyses will be carried out. Continuous variables with repeated measurements (i.e. ACQ6 score, blood results) will be analysed using a generalized linear mixed model with a random intercept for individuals to account for repeated measurements. Planned sub-analyses will be undertaken to assess the effects of asthma severity, asthma control, FEV1, FENO, on the primary and secondary outcomes. All tests will be conducted two-sided, and a P-value P<0.05 will be considered statistically significant.

Recruitment
Recruitment status
Withdrawn
Reason for early stopping/withdrawal
Lack of funding/staff/facilities
Date of first participant enrolment
Anticipated
3/06/2013
Actual
Date of last participant enrolment
Anticipated
5/01/2015
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
104
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
SA
Recruitment hospital [1] 729 0
Lyell McEwin Hospital - Elizabeth Vale
Recruitment postcode(s) [1] 6527 0
5112 - Elizabeth Vale

Funding & Sponsors
Funding source category [1] 286847 0
Self funded/Unfunded
Name [1] 286847 0
Country [1] 286847 0
Australia
Primary sponsor type
University
Name
The University of Adelaide
Address
The Robinson Institute
Level 2, Lyell McEwin Hospital
Haydown Road
Elizabeth Vale, SA, 5112
Country
Australia
Secondary sponsor category [1] 285639 0
None
Name [1] 285639 0
NA
Address [1] 285639 0
NA
Country [1] 285639 0

Ethics approval
Ethics application status
Not yet submitted
Ethics committee name [1] 288927 0
Human Research Ethics Committee (TQEH/LMH/MH)
Ethics committee address [1] 288927 0
Basil Hetzel Institute
The Queen Elizabeth Hospital
28 Woodville Road
Woodville South, SA, 5011
Ethics committee country [1] 288927 0
Australia
Date submitted for ethics approval [1] 288927 0
22/04/2013
Approval date [1] 288927 0
Ethics approval number [1] 288927 0

Summary
Brief summary
Asthma is the most common serious medical problem to complicate pregnancies worldwide, with a prevalence between 8-13%, and affecting around 12% of pregnant women in Australia or 36,000 pregnancies each year. The health expenditure on asthma is significant and the economic burden of asthma is high. A recent meta-analysis demonstrated clear associations between asthma in pregnancies and adverse perinatal outcomes, with a 22-54% increased risk for low birth weight, small-for-gestational age, preterm delivery and pre-eclampsia. Previous work the laboratory also indicates asthma exacerbation contributes to poor outcomes including preterm delivery, growth restriction and stillbirth, and occurs in up to 55% of pregnancies. Oxidative stress is a potential mechanism driving the increased incidence of asthma exacerbation in pregnancy. Oxidative stress and inflammation manifest during pregnancy; however asthma in pregnancies further intensifies oxidative stress. We have previously identified that there are altered pathways regarding oxidant and antioxidant status in pregnant women with asthma, and consumption of antioxidant rich foods are beneficial for asthma control in non-pregnant adults with asthma. It has not been investigated whether antioxidant-rich foods can improve the elevated oxidative stress that occurs with asthma in pregnancies, thereby improving asthma control.
We will reverse this oxidative burden through intervening with antioxidant-rich foods. We propose that 12 weeks of increased consumption of fruits, vegetables and wholegrains will modify the maternal biochemical profile of pregnancies complicated by asthma such that markers of oxidative stress will decrease and levels of antioxidants will increase. This novel approach will counteract the added oxidative stress caused by asthma during pregnancy and subsequently improve asthma control. No dietary guidelines exist for asthma management during pregnancy. Outcomes from our study will provide an avenue for which the development of new asthma management strategies can be devised.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 38306 0
Dr Jessica Grieger
Address 38306 0
School of Paediatrics and Reproductive Health
The University of Adelaide
The Robinsons Institute
Level 2
Lyell McEwin Hospital
Haydown Rd, Elizabeth Vale, SA, 5112
Country 38306 0
Australia
Phone 38306 0
+61 8 8133 2132
Fax 38306 0
Email 38306 0
jessica.grieger@adelaide.edu.au
Contact person for public queries
Name 38307 0
A/Prof Vicki Clifton
Address 38307 0
School of Paediatrics and Reproductive Health
The University of Adelaide
The Robinsons Institute
Level 2
Lyell McEwin Hospital
Haydown Rd, Elizabeth Vale, SA, 5112
Country 38307 0
Australia
Phone 38307 0
+61 8 8133 2133
Fax 38307 0
Email 38307 0
vicki.clifton@adelaide.edu.au
Contact person for scientific queries
Name 38308 0
A/Prof Vicki Clifton
Address 38308 0
School of Paediatrics and Reproductive Health
The University of Adelaide
The Robinsons Institute
Level 2
Lyell McEwin Hospital
Haydown Rd, Elizabeth Vale, SA, 5112
Country 38308 0
Australia
Phone 38308 0
+61 8 8133 2133
Fax 38308 0
Email 38308 0
vicki.clifton@adelaide.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.