Statistical analysis masquerading as science

This week the BBC posted this article.

‘Good fat’ cuts heart risk by a fifth, study shows
Replacing saturated fats with healthier options can cut the risk of heart disease by a fifth, a US study says.
So what is a “study”? Is it some statistical analysis, or some empirical research? Well it turns out this is just number crunching. But the way it is reported makes it seem like some doctors and/or scientists have carried out some research.
Five minutes on google will find plenty of people who have already highlighted the problems with this kind of approach and this report in particular. Definitely the best I’ve seen is this analysis by Ned Kock.
So what I thought I would post about today, was an actual piece of science by the same author Dariush Mozaffarian. In this study  they actually carried out  coronary angiographyies on 235 women.
Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women1–3. Dariush Mozaffarian, Eric B Rimm, and David M Herrington
Here are some take-outs from the study, which you can read in full here.
“Among postmenopausal women with established CHD, greater saturated fat intake was associated with less progression of coronary atherosclerosis over an average follow-up of 3 y, whereas polyunsaturated fat and carbohydrate intakes were associated with greater progression. To our knowledge, this is the first study that evaluated the associations between dietary macronutrients and atherosclerotic progression in women. Although the findings do not establish causality, the associations were independent of a variety of other risk factors, including age, diabetes, smoking, body mass index, physical activity, prior MI or PTCA, and other dietary habits. Thus, known clinical risk actors do not appear to account for the observed relations.
The inverse association between saturated fat intake and atherosclerotic progression was unexpected. However, this finding should perhaps be less surprising. Ecologic and animal experimental studies showed positive relations between saturated fat intake and CHD risk (8). However, cohort studies and clinical trials in humans have been far less consistent (9 –12)…..
…..Polyunsaturated fat intake was not associated with atherosclerotic progression when replacing carbohydrate or protein but was positively associated when replacing other fats, especially saturated fat….
…Our findings also suggest that carbohydrate intake may increase atherosclerotic progression, especially when refined carbohydrates replace saturated or monounsaturated fats.”
This report (by the same author) clearly shows that in all the women studied (they all had CHD to some extent) the primary difference among those studied was that the more saturated fat they eat, the less diseased their arteries were. There was a smaller positive link between high polyunsaturated fat consumption (although it did not draw a distinction between natural polyunsaturated oils in nuts and fish and high unstable processed vegetable oils) and reduced amounts of atherosclerosis. And the study clearly showed that the more carbs the women ate the worse the atherosclerosis was.

About thegymmonkey

I'm a fitness junkie,interested in injury rehab and get back into competition. View all posts by thegymmonkey

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