Predictors of compliance with higher dose omega-3 fatty acid supplementation during pregnancy and implications for the risk of prematurity: exploratory analysis of the ORIP randomised trial
Files
(Published version)
Date
2023
Authors
Sullivan, T.R.
Yelland, L.N.
Gibson, R.A.
Thakkar, S.K.
Huang, F.
Best, K.P.
Devaraj, S.
Zolezzi, I.S.
Makrides, M.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
BMJ Open, 2023; 13(9):e076507-1-e076507-8
Statement of Responsibility
Thomas R Sullivan, Lisa N Yelland, Robert A Gibson, Sagar K Thakkar, Fang Huang, Karen P Best, Surabhi Devaraj, Irma Silva Zolezzi, Maria Makrides
Conference Name
Abstract
Background: Intention-to-treat analyses of the Omega‐3 to Reduce the Incidence of Prematurity (ORIP) trial found that omega-3 (n-3) fatty acid supplementation reduces the risk of prematurity in the subgroup of women with a singleton pregnancy and low n-3 status early in pregnancy, but not overall. However, results may have been influenced by less-than-optimal compliance. Objectives: To identify predictors of compliance with n-3 supplementation and determine treatment effects among compliers. Design: Exploratory analyses of a multicentre-blinded randomised trial. Setting: 6 tertiary care centres in Australia. Participants: 5328 singleton pregnancies. Interventions: Daily capsules containing 900 mg n-3 long-chain polyunsaturated fatty acids or vegetable oil, consumed from before 20 weeks gestation until 34 weeks gestation. Outcome measures: Early preterm (<34 weeks gestation) and preterm birth (<37 weeks gestation). Women were considered compliant if they reported missing less than a third of their allocated capsules in the previous week during a mid-pregnancy appointment. Results: Among 2654 singleton pregnancies in the n-3 intervention group, 1727 (65%) were deemed compliant with supplementation. Maternal characteristics associated with compliance included age, years of full-time education, consuming alcohol but not smoking in the 3 months leading up to pregnancy, fewer previous births and taking dietary supplements at enrolment. Based on complier average causal effects, n-3 supplementation reduced the risk of preterm birth in compliers (relative risk=0.76; 95% CI 0.60 to 0.97), but not early preterm birth (relative risk=0.80; 95% CI 0.44 to 1.46). Consistent with intention-to-treat analyses, the lack of an overall effect on early preterm birth in compliers appeared to be due to beneficial effects in women with low n-3 status at enrolment but not women with replete status. Conclusions: Results in compliers were similar to those from intention-to-treat analyses, suggesting that non-compliance was not a major factor in explaining outcomes from the ORIP trial. Trial registration number: ACTRN12613001142729.
School/Discipline
Dissertation Note
Provenance
Description
Access Status
Rights
© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.