Daily Low-Dose Aspirin, Round 2

(For Round 1, see this comment from last year.)

NYT: Studies Link Daily Doses of Aspirin to Reduced Risk of Cancer

One of the new studies examined patient data from dozens of large, long-term randomized controlled trials involving tens of thousands of men and women. Researchers at the University of Oxford found that after three years of daily aspirin use, the risk of developing cancer was reduced by almost 25 percent when compared with a control group not taking aspirin. After five years, the risk of dying of cancer was reduced by 37 percent among those taking aspirin.

A second paper that analyzed five large randomized controlled studies in Britain found that over six and a half years on average, daily aspirin use reduced the risk of metastatic cancer by 36 percent and the risk of adenocarcinomas — common solid cancers including colon, lung and prostate cancer — by 46 percent.

The article is worth reading in its entirety, but here's an especially interesting paragraph:

The new studies, however, also found that the risk of bleeding in aspirin users diminished over time, and that the risk of death from brain bleeds was actually lower in the aspirin users than in the comparison group.

The evidence still isn't perfect, but the purpose of rationality is making good decisions with limited information. I am a healthy 28-year-old and these studies make me even more confident that taking daily low-dose aspirin is the right thing for me to do.

On a related note, if society were more rational, I wouldn't have to be sad reading paragraphs like this one:

Some cancer doctors commended the new research, saying said that despite the limitations of the analyses, no other long-term clinical trials of aspirin and cancer are likely to be done because of the enormous expense involved and the fact that aspirin is a cheap generic drug.

Or these ones from A Cheap Drug Is Found to Save Bleeding Victims, published on the same day:

For months, a simple generic drug has been saving lives on America’s battlefields by slowing the bleeding of even gravely wounded soldiers.

Even better, it is cheap. But its very inexpensiveness has slowed its entry into American emergency rooms, where it might save the lives of bleeding victims of car crashes, shootings and stabbings — up to 4,000 Americans a year, according to a recent study.

Because there is so little profit in it, the companies that make it do not champion it.

(For Round 1, see this comment from last year.)

NYT: Studies Link Daily Doses of Aspirin to Reduced Risk of Cancer

One of the new studies examined patient data from dozens of large, long-term randomized controlled trials involving tens of thousands of men and women. Researchers at the University of Oxford found that after three years of daily aspirin use, the risk of developing cancer was reduced by almost 25 percent when compared with a control group not taking aspirin. After five years, the risk of dying of cancer was reduced by 37 percent among those taking aspirin.

A second paper that analyzed five large randomized controlled studies in Britain found that over six and a half years on average, daily aspirin use reduced the risk of metastatic cancer by 36 percent and the risk of adenocarcinomas — common solid cancers including colon, lung and prostate cancer — by 46 percent.

The article is worth reading in its entirety, but here's an especially interesting paragraph:

The new studies, however, also found that the risk of bleeding in aspirin users diminished over time, and that the risk of death from brain bleeds was actually lower in the aspirin users than in the comparison group.

On a related note, if society were more rational, I wouldn't have to be sad reading paragraphs like this one:

Some cancer doctors commended the new research, saying said that despite the limitations of the analyses, no other long-term clinical trials of aspirin and cancer are likely to be done because of the enormous expense involved and the fact that aspirin is a cheap generic drug.

Or these ones from A Cheap Drug Is Found to Save Bleeding Victims, published on the same day:

For months, a simple generic drug has been saving lives on America’s battlefields by slowing the bleeding of even gravely wounded soldiers.

Even better, it is cheap. But its very inexpensiveness has slowed its entry into American emergency rooms, where it might save the lives of bleeding victims of car crashes, shootings and stabbings — up to 4,000 Americans a year, according to a recent study.

Because there is so little profit in it, the companies that make it do not champion it.

It appears that the evolutionarily unprecedented high omega-6 and low omega-3 intake in the modern western diet causes excessive series-2 prostaglandin and thromboxane (TXA2) formation, and resulting inflammation and cardiovascular effects- and low dose aspirin is an attempt to combat this. Why not fix the problem at it's source?

Reducing omega-6 oils in your diet and increasing omega-3 should have a similar effect, but with more proven safety and effectiveness: nearly all humans did this until industrial seed oils became popular in the last few decades (see this video series from biochemist Dr. Bill Lands for more details http://youtu.be/dgU3cNppzO0 ).

Aspirin works primarily by suppressing production of thromboxane and inflammatory series-2 prostaglandins from omega-6 fats, by inactivating the cyclooxygenase enzymes (COX-1, and COX-2). Omega-3 fats also competitively inhibit this same enzyme, by competing with omega-6 fats to be metabolized into less inflammatory series-1 and series-3 prostaglandins.

There are other important benefits of fixing the omega 3/6 ratio in your diet as well- their ratio is reflected in tissue lipid membranes, and likely influences the proper function of these membranes. Continuing on a high omega-6 diet and trying to counter-act this with aspirin seems less than ideal.

It would be interesting to see some data showing the effectiveness of low dose aspirin in countries that already have a healthy omega 3/6 ratio (such as Greenland or Japan). I would be very surprised if it still has the same benefit in such a group.

As a person who has a nearly 1/1 omega-6 to long chain omega-3 ratio in my diet (I regularly eat fatty cold water fish and avoid seed oils), I wouldn't consider low dose aspirin to be a prudent risk adverse decision unless I saw data showing it's benefits reproduced in others with a similar intake ratio.

I retracted this, because I have learned a lot more about this issue in the last year. I am still undecided on aspirin, however I no longer think that the mechanisms mentioned above are the only important roles aspirin plays. I am also no longer convinced that omega-3 offers a health benefit, and that omega-6 restriction alone may be superior to replacing omega-6 with omega-3.

0Lumifer13y

If you look at the Rothwell paper linked above by gwern, there's one Japanese study there - JPAD (Ogawa H, Nakayama M, Morimoto T, et al. Japanese Primary Prevention of Atherosclerosis With Aspirin for Diabetes (JPAD) Trial Investigators. Low-dose aspirin for primary prevention of atherosclerotic events in patients with type 2 diabetes: a randomized controlled trial. JAMA 2008; 300: 2134–41). Looking at the graphs, JPAD effectively showed zero effect of aspirin. I think this supports your thesis.

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Daily Low-Dose Aspirin, Round 2

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Daily Low-Dose Aspirin, Round 2

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