Breastfeeding linked to reduced risk of heart disease

“Breastfeeding is good for mothers as well as babies and slashes their risk of dying from heart disease, a study has found”

The print edition of the Daily Mail has reported on new research, claiming it shows that breastfeeding cuts the risk of mothers dying from heart disease and developing various cardiovascular diseases.

This isn’t what the research found. The research found a link between breastfeeding and a reduced risk of these conditions, but not that breastfeeding caused the reductions in risk.

The study authors combined the results of eight papers on the topic in what’s called a meta-analysis, finding that women who breastfed were 11 to 14% less likely to develop a range of cardiovascular diseases, and 17% less likely to die of cardiovascular disease, than mothers who did not breastfeed.  

Breastfeeding itself may explain some of that reduced risk, but the relationship could also be explained by other, unrelated factors.

Professor of Metabolic Medicine at the University of Glasgow Naveed Sattar responded to the research through the Science Media Centre, saying: “The top line results are not surprising given i) women who chose to breast feed will have several other lifestyle habits that reduce heart disease risks compared to women who chose not to, and many of these factors are not easily accounted for in the research methods; and ii) breast feeding can help women lose weight and long term weight trajectories are highly relevant to heart disease, cancers and type 2 diabetes, all of which occur less in women who chose to breast feed.  

“So there may be both direct and indirect reasons for why women who chose to breast feed are at lower risk of heart disease or stroke.”

The research was also reported by The Times, which at one point also suggested a causal relationship, saying that “breastfeeding appears to cut the risk of developing cardiovascular disease by 11 per cent”. However, its headline accurately reflected the research, reading: “Breastfeeding linked to lower heart disease risk for mothers”.

MailOnline also suggested a causal relationship in its reporting of the study, headlining its article: “Breast is best... for mum too! Breastfeeding cuts heart disease AND stroke risk by up to 15% later in life, study of 1.2m mothers finds.” 

Newspapers inappropriately reporting causal links from studies which actually found a correlation are a frequent source of health misinformation. 

For example, in November, Full Fact wrote about another story from the Daily Mail claiming going to bed at a certain time cuts your risk of heart disease by 25%. The Mail subsequently corrected its article. The same month we wrote about incorrect reporting that tea and coffee lower the risk of dementia and stroke, when the authors of the research said they could not establish a causal relationship.

In December, the Telegraph claimed a study showed gum disease increases the risk of mental health, though the authors acknowledged their research could not confirm causality or the direction of causality. 

They acknowledged the potential for a causal relationship in the other direction, saying: “Individuals under increased stress may reduce health promoting behaviours (eg, optimal oral hygiene practices).”