Hiding unhealthy heart outcomes in a low-fat diet trial: the Women’s Health Initiative Randomized Controlled Dietary Modification Trial finds that postmenopausal women with established coronary heart disease were at increased risk of an adverse outcome if they consumed a low-fat ‘heart-healthy’ diet
doi.org
The Women’s Health Initiative Randomized Controlled Dietary Modification Trial (WHIRCDMT) was designed to test whether the US Department of Agriculture’s 1977 Dietary Guidelines for Americans protects against coronary heart disease (CHD) and other chronic diseases. The only significant finding in the original 2006 WHIRCDMT publication was that postmenopausal women with CHD randomised to a low-fat ‘heart-healthy’ diet in 1993 were at 26% greater risk of developing additional CHD events compared with women with CHD eating the control diet. A 2017 WHIRCDMT publication includes data for an additional 5 years of follow-up. It finds that CHD risk in this subgroup of postmenopausal women had increased further to 47%–61%. The authors present three post-hoc rationalisations to explain why this finding is ‘inadmissible’: (1) only women in this subgroup were less likely to adhere to the prescribed dietary intervention; (2) their failure to follow the intervention diet increased their CHD risk; and (3) only these women were more likely to not have received cholesterol-lowering drugs. These rationalisations appear spurious. Rather these findings are better explained as a direct consequence of postmenopausal women with features of insulin resistance (IR) eating a low-fat high-carbohydrate diet for 13 years. All the worst clinical features of IR, including type 2 diabetes mellitus (T2DM) in some, can be ‘reversed’ by the prescription of a high-fat low-carbohydrate diet. The Women’s Health Study has recently reported that T2DM (10.71-fold increased risk) and other markers of IR including metabolic syndrome (6.09-fold increased risk) were the most powerful predictors of future CHD development in women; blood low-density lipoprotein-cholesterol concentration was a poor predictor (1.38-fold increased risk). These studies challenge the prescription of the low-fat high-carbohydrate heart-healthy diet, at least in postmenopausal women with IR, especially T2DM. According to the medical principle of ‘first do no harm’, this practice is now shown to be not evidence-based, making it scientifically unjustifiable, perhaps unethical.

https://doi.org/10.1136/openhrt-2021-001680

Hiding unhealthy heart outcomes in a low-fat diet trial: the Women’s Health Initiative Randomized Controlled Dietary Modification Trial finds that postmenopausal women with established coronary heart disease were at increased risk of an adverse outcome if they consumed a low-fat ‘heart-healthy’ diet

The Women’s Health Initiative Randomized Controlled Dietary Modification Trial (WHIRCDMT) was designed to test whether the US Department of Agriculture’s 1977 Dietary Guidelines for Americans protects against coronary heart disease (CHD) and other chronic diseases. The only significant finding in the original 2006 WHIRCDMT publication was that postmenopausal women with CHD randomised to a low-fat ‘heart-healthy’ diet in 1993 were at 26% greater risk of developing additional CHD events compared with women with CHD eating the control diet. A 2017 WHIRCDMT publication includes data for an additional 5 years of follow-up. It finds that CHD risk in this subgroup of postmenopausal women had increased further to 47%-61%. The authors present three post-hoc rationalisations to explain why this finding is ‘inadmissible’: (1) only women in this subgroup were less likely to adhere to the prescribed dietary intervention; (2) their failure to follow the intervention diet increased their CHD risk; and (3) only these women were more likely to not have received cholesterol-lowering drugs. These rationalisations appear spurious. Rather these findings are better explained as a direct consequence of postmenopausal women with features of insulin resistance (IR) eating a low-fat high-carbohydrate diet for 13 years. All the worst clinical features of IR, including type 2 diabetes mellitus (T2DM) in some, can be ‘reversed’ by the prescription of a high-fat low-carbohydrate diet. The Women’s Health Study has recently reported that T2DM (10.71-fold increased risk) and other markers of IR including metabolic syndrome (6.09-fold increased risk) were the most powerful predictors of future CHD development in women; blood low-density lipoprotein-cholesterol concentration was a poor predictor (1.38-fold increased risk). These studies challenge the prescription of the low-fat high-carbohydrate heart-healthy diet, at least in postmenopausal women with IR, especially T2DM. According to the medical principle of ‘first do no harm’, this practice is now shown to be not evidence-based, making it scientifically unjustifiable, perhaps unethical.

Apologies, I had to butcher the title, it was too long for lemmy.

  • jetOPMAEnglish
    1·
    1 day ago

    This paper is quite literally fire, at the academic scale.

    Notes -

    The dietary intervention effectively lowered dietary fat intake and was associated with a reduction in blood cholesterol concentrations.

    The intervention group

    an ‘intensive behavioral modification program involved 18 group sessions in the first year and quarterly maintenance sessions thereafter, led by specially trained and certified nutritionists’. In addition, ‘group activities were supplemented during the intervention period by individual interviews…targeted-message campaigns, and personalized feedback on fat intake’

    postmenopausal women randomised to the intervention diet were at 47%–61% increased risk of developing additional CHD complications during a further 5 years of follow-up.

    Wow, a 50% relative risk increase for the low fat intervention.

    his iconic study definitively establishes that the prescription of the low-fat ‘heart- healthy’ diet to post-menopausal women with established CHD, because they are likely to be insulin-resistant, is scientifically unjustifiable and potentially unethical.

    Very strong language for a paper.

    postmenopausal women who entered the trial with established CHD and who were randomised to the intervention diet in 1993 were at 26% increased risk of an adverse outcome compared with those women with CHD who continued eating their usual ‘high’-fat control diet. This was the sole outcome that reached statistical significance

    Post-hoc rationalisations to explain why findings of harm are ‘uninterpretable’

    I believe Dr. Noaks just called someone a little bitch. Saying study group 1 was fully compliant, but study 2 group wasn’t compliant - based solely on getting a signal you couldn’t ignore… bold

    the ERA trial predict that those eating less fats and especially less saturated fats and more carbohydrates (and more polyunsaturated fats if they so chose) would experience a more rapid progression of coronary artery narrowing

    By excluding women for whom the diet has now been shown to be harmful, the authors were able to conclude that ‘reduction in dietary fat with corresponding increase in vegetables, fruit, and grains led to benefits related to breast cancer, CHD and diabetes, without adverse effects, among healthy post-menopausal US women

    This statement fails to warn that this same diet produced measurable harm in unhealthy women with established CHD in 1993

    As can be see in Figure 3 - All markers for insulin resistance had a significantly higher hazard ratio then LDL-cholesterol. Therefor reducing LDL is the wrong target (it’s insulin resistance).

    figure 3

    Why did only the healthiest postmenopausal women in the WHIRCDMT receive some benefit from eating the heart-healthy intervention diet?

    … It’s possible the positive responders to the low fat intervention were insulin sensitive and remained insulin sensitive throughout the study…

    Thoughts:

    This demonstrates why its important to read papers, not just abstracts, people will stick to agendas, funding sources, and personal beliefs even in the face of contrary raw data.

    As discussed in https://hackertalks.com/post/5676721, researcher bias and how data is sliced is almost as important as the data itself. It’s critical that science datasets are always published and open for peer analysis!