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BEDREHELSE-Bedre helse og livskvalitet

The reset hypothesis - fact or fiction? Are the favorable effects of breastfeeding on cardiometabolic risk factors mediated via weight loss?

Alternative title: Nullstillingshypotesen - fakta eller fiksjon? Er de positive effektene av amming på kardiometabolske risikofaktorer mediert via vekttap?

Awarded: NOK 8.7 mill.

Project Number:

301029

Application Type:

Project Period:

2020 - 2026

Location:

Cardiovascular disease (CVD) is the main cause of death in women in rich societies. Women who have borne children have increased risk for CVD later in life and the risk increases with the number of children. During pregnancy, concentrations of cholesterol and fasting insulin are increased. Lactating women show greater improvements in metabolic risk factors than non-lactating women. A possible role for lactation in resetting maternal metabolism, called The reset hypothesis, has been proposed. It is possible that the effect of lactation on the "good cholesterol", HDL and fasting insulin decreases the risk of CVD and type 2 diabetes. It is unclear if these improvements are mediated by weight loss and the hypothesis has never been experimentally tested. The aim of this clinical trial is to determine if lactation produces weight loss and improved risk factors for CVD beyond those of weight loss from diet intervention. Using a 2x2 factorial design, pregnant women are randomized to a) breastfeeding promotion intervention (BPI); b) diet intervention to achieve a 6 kg weight loss in 12 wk, c) both interventions or d) no intervention. Possible interaction between treatments will be evaluated. Measurements will be performed at 2 wk (baseline), 6 and 15 mo postpartum. Underlying biological mechanisms of treatment effects will be evaluated using genome transcripts. A health economic analysis will be performed. This study will help clarify how to reduce risk for CVD in women who have borne children.

Cardiovascular disease (CVD) is the main cause of death in women in rich societies. Reproduction may increase this risk; parous women have increased risk for CVD later in life. Pregnancy is a hyperlipidemic, insulin-resistant state. A possible role for lactation in resetting maternal metabolism, called "The reset hypothesis", has been proposed. Lactating women show greater improvements in metabolic risk factors than non-lactating women. It is unclear if these improvements are mediated by weight loss and the hypothesis has never been experimentally tested. We have initiated an experimental intervention study with a 2x2 factorial design in which pregnant women are randomized to a) breastfeeding promotion intervention (BPI: breastfeeding to recommended levels (4-6 mo exclusive and continued partial 1 y postpartum)); b) diet intervention to achieve a 6 kg weight loss in 12 wk, c) both interventions or d) no intervention. We will test if BPI produces significant weight loss and/or improvements in body composition, blood lipid profile, glucose metabolism and blood pressure postpartum. Possible interaction between treatments will be evaluated. Measurements will be performed at 2 wk (baseline), 6 and 15 mo postpartum. Underlying biological mechanisms of treatment effects will be evaluated using genome transcripts. A health economic analysis will be performed. If resetting exists, i.e. a metabolic effect of breastfeeding beyond that of weight reduction, BPI is an inexpensive and readily available method for reducing risk for metabolic disease in women. This study will also clarify if weight loss through diet intervention can compensate for the increased risk in women who are unable or unwilling to breastfeed.

Funding scheme:

BEDREHELSE-Bedre helse og livskvalitet