Quantifying the mediating effect of body mass index on the relation between a Mediterranean diet and development of maternal pregnancy complications: the Australian longitudinal study on women's health

Schoenaker, Danielle A. J. M., Soedamah-Muthu, Sabita S. and Mishra, Gita D. (2016) Quantifying the mediating effect of body mass index on the relation between a Mediterranean diet and development of maternal pregnancy complications: the Australian longitudinal study on women's health. American Journal of Clinical Nutrition, 104 3: 638-645. doi:10.3945/ajcn.116.133884


Author Schoenaker, Danielle A. J. M.
Soedamah-Muthu, Sabita S.
Mishra, Gita D.
Title Quantifying the mediating effect of body mass index on the relation between a Mediterranean diet and development of maternal pregnancy complications: the Australian longitudinal study on women's health
Journal name American Journal of Clinical Nutrition   Check publisher's open access policy
ISSN 0002-9165
1938-3207
Publication date 2016-07-27
Year available 2016
Sub-type Article (original research)
DOI 10.3945/ajcn.116.133884
Open Access Status Not Open Access
Volume 104
Issue 3
Start page 638
End page 645
Total pages 8
Place of publication Bethesda, MD, United States
Publisher American Society for Nutrition
Collection year 2017
Language eng
Formatted abstract
Background: The contribution of body mass index (BMI) to the observed associations between dietary patterns and risk of gestational diabetes mellitus (GDM) and hypertensive disorders of pregnancy (HDP) remains unclear.

Objective: The objective of this study was to formally quantify the mediating effect of prepregnancy BMI in these associations.

Design: Women (aged 25–30 y) participating in the Australian Longitudinal Study on Women’s Health were not pregnant at baseline in 2003 and reported ≥1 pregnancy up to 2012. GDM and HDP diagnoses were self-reported for each pregnancy and validated in a subset. A Mediterranean diet score was created by use of a baseline-validated food-frequency questionnaire and dichotomized to reflect low adherence (<25th percentile) and higher adherence (≥25th percentile). A causal inference framework for mediation analysis was used to estimate total, natural direct, and natural indirect effects of the prepregnancy Mediterranean diet on incident GDM and HDP and proportions mediated through prepregnancy BMI.

Results: In 3378 women without a history of diabetes, 240 (7.1%) developed GDM. HDP was reported in 273 (8.6%) of 3167 women with no history of hypertension. Low adherence to the Mediterranean diet was associated with higher risk of GDM (OR: 1.35; 95% CI: 1.02, 1.60) and HDP (OR: 1.41; 95% CI: 1.18, 1.56), after adjustment for education, parity, polycystic ovary syndrome, energy intake, and physical activity. Proportions mediated through prepregnancy BMI (per 1-kg/m2 increase) were 32% and 22% for GDM and HDP, respectively.

Conclusion: These findings suggest that prepregnancy BMI as a single mediator contributes substantially to the total effects of the prepregnancy Mediterranean diet on GDM and HDP risk.
Keyword Mediterranean diet
Body mass index
Gestational diabetes
Gestational hypertension
Mediation
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Public Health Publications
 
Versions
Version Filter Type
Citation counts: Scopus Citation Count Cited 0 times in Scopus Article
Google Scholar Search Google Scholar
Created: Thu, 11 Aug 2016, 10:41:28 EST by Danielle Schoenaker on behalf of School of Public Health