Do Statins Cause Motor Neuron Diseases, Such as ALS?

A study report­ed in April 2018 has made the news because it sug­gests that tak­ing a statin drug might increase your risk of get­ting a motor neu­ron dis­ease.  Statin drugs are used to reduce the amount of cho­les­terol in your blood, to pre­vent heart attacks and strokes. Motor neu­ron dis­eases include amy­otroph­ic lat­er­al scle­ro­sis (ALS).  ALS is also known as Lou Gehrig’s dis­ease, because that famous base­ball play­er had it. Physi­cist Stephen Hawk­ing also had a form of ALS. Motor neu­ron dis­eases are a big deal, but so are heart attacks and strokes. So should you wor­ry about this study? I don’t wor­ry about it, for the fol­low­ing rea­sons:

  • If you eat a healthy diet, you almost cer­tain­ly won’t need pills to low­er your cho­les­terol. So you could avoid even the the­o­ret­i­cal risks of the side effects of the pills.
  • Even if the statins do increase your risk of com­ing down with a motor neu­ron dis­ease, the motor neu­ron dis­eases were rare to start with and are still rare, even though so many peo­ple are tak­ing statins.

The deci­sion of whether to take a statin drug should be based on your per­son­al risk fac­tors and the like­ly ben­e­fits. There are a few peo­ple who do have extreme­ly high cho­les­terol for genet­ic rea­sons, even if they eat a good diet. They might ben­e­fit from a statin drug. For them, the high risks of dying of a heart attack or an ischemic stroke would prob­a­bly out­weigh the risks of devel­op­ing a motor neu­ron dis­ease.

What is Motor Neuron Disease?

The motor neu­rons are the nerve cells in the cir­cuits that cause your mus­cles to move. The motor neu­rons in your brain are called upper motor neu­rons. The ones in your spinal cord are called low­er motor neu­rons. Motor neu­ron dis­eases destroy your abil­i­ty to con­trol your mus­cles. You slow­ly lose your abil­i­ty to use your arms and legs. Even­tu­al­ly, you lose the abil­i­ty to talk, swal­low, and even breathe.

Amy­otroph­ic lat­er­al scle­ro­sis is one of the most famous motor neu­ron dis­eases. It is often called Lou Gehrig’s dis­ease because it killed Lou Gehrig, who played base­ball for the New York Yan­kees. He was called “The Iron Horse” because he played in 2,130 con­sec­u­tive games, often while injured. How­ev­er, he had to retire from base­ball in 1939 after he got amy­otroph­ic lat­er­al scle­ro­sis. He died of the dis­ease in 1941.

The most famous recent per­son with a motor neu­ron dis­ease was physi­cist Stephen Hawk­ing. Hawk­ing man­aged to live with the dis­ease for 51 years.

High Cholesterol Is Dangerous

The pur­pose of the statin drugs is to reduce the amount of cho­les­terol in the blood­stream. If you don’t have high blood cho­les­terol, then you will not have ath­er­o­scle­ro­sis. If you have ath­er­o­scle­ro­sis, you may go on to have a heart attack or stroke. Heart attacks are our num­ber 1 cause of death and dis­abil­i­ty, and strokes are num­ber 3.

In oth­er words, your total cho­les­terol has to be high for you to get ath­er­o­scle­ro­sis, but not every­one who has high cho­les­terol will get ath­er­o­scle­ro­sis. Also, not every­one with ath­er­o­scle­ro­sis will die of a heart attack or an ischemic stroke. Nev­er­the­less, if you keep your total cho­les­terol stays below 150 mg/dL, you become prac­ti­cal­ly immune to heart attack, and your risk of ischemic stroke also drops sharply.

How Diet Affects Cholesterol Levels

The best way to keep your total cho­les­terol this low is to eat a low-fat, zero-cho­les­terol, high-fiber diet. Our liv­er makes cho­les­terol to help us digest fat. This cho­les­terol is then absorbed back into the sys­tem and recy­cled. Foods from ani­mal sources (meat, fish, dairy prod­ucts, and eggs) also con­tain cho­les­terol. So when human beings eat a fat­ty diet and a lot of cho­les­terol-rich foods, their blood cho­les­terol can get very high. Dietary fiber is sup­posed to bind to cho­les­terol and car­ry it out of the body. So low-fiber diets make high cho­les­terol worse.

Human beings are at risk for ath­er­o­scle­ro­sis because our bod­ies were real­ly built for a low-cho­les­terol diet. So even if we eat a low-fat, zero cho­les­terol diet, our cho­les­terol nev­er gets too low. How­ev­er, if we eat a fat­ty, cho­les­terol-rich diet, our total cho­les­terol can get too high. As a result, we can end up with cho­les­terol crys­tals in our gall­blad­ders (gall­stones). We can also end up with cho­les­terol deposits inside our arter­ies. The cho­les­terol builds up there because arte­r­i­al walls are poor­ly drained by the lym­phat­ic sys­tem. The coro­nary arter­ies (the arter­ies that serve the heart mus­cle) have par­tic­u­lar­ly bad lym­phat­ic drainage. That’s why so many Amer­i­cans end up with clog­ging of the arter­ies.

Near­ly every­one could keep their total cho­les­terol with­in the heart-attack-proof zone (<150 mg/dL) if they ate a low-fat, high-fiber, pure­ly plant-based (veg­an) diet. Yet many peo­ple are unwill­ing to do that. So for that rea­son, researchers devel­oped cho­les­terol-low­er­ing drugs. The statins keep the liv­er from mak­ing one of the ingre­di­ents that it needs for mak­ing cho­les­terol.  How­ev­er, it is bet­ter to eat a healthy diet, rather than to use pills to cov­er up the effects of a bad diet.

I explain all this in my book Where Do Goril­las Get Their Pro­tein? What We Real­ly Know About Diet and Health:

Where Do Gorillas Get Their Protein book cover

How Drug Safety Is Evaluated

If you invent a new drug, you have to do stud­ies to show that the drug works and is rea­son­ably safe. Oth­er­wise, nation­al gov­ern­ments won’t let you sell that drug with­in their coun­try.  Unfor­tu­nate­ly, those stud­ies gen­er­al­ly com­pare the drug to a place­bo (inac­tive pill), rather than to a dietary treat­ment, even if the most rea­son­able treat­ment is dietary.

In phase 3 of the drug devel­op­ment process, the drug spon­sor has to run some large stud­ies. Those stud­ies must show that the drug actu­al­ly works and that it is rea­son­ably safe. How­ev­er, those stud­ies are too small to reveal rare side effects. They are too short to reveal the side effects of long-term use. For that rea­son, the U.S. Food and Drug Admin­is­tra­tion (FDA) keeps look­ing for safe­ty prob­lems, for as long as the drug is on the mar­ket.  In par­tic­u­lar, the FDA main­tains the FDA Adverse Events Report­ing Sys­tem (FAERS). FAERS is a data­base of reports of bad things that hap­pened to peo­ple who have tak­en a par­tic­u­lar drug. This data­base is use­ful for uncov­er­ing “sig­nals” that a drug might be caus­ing a prob­lem. Sci­en­tists need to do oth­er kinds of stud­ies to con­firm whether those sig­nals reflect some­thing real.

Do Statins Cause Motor Neuron Disease?

For at least 10 years, sci­en­tists have wor­ried that statins might be caus­ing motor neu­ron dis­eases. Lab­o­ra­to­ry stud­ies had shown that statins could harm spinal nerve cells that were being grown in a lab­o­ra­to­ry dish. This arti­cle dis­cuss­es how the FDA  began look­ing for evi­dence of whether statins were  harm­ing the spinal cord in liv­ing peo­ple.  In Octo­ber 2012, the review of the evi­dence exist­ing at that time showed no rela­tion­ship between statins and motor neu­ron dis­eases. How­ev­er, the Golomb study sug­gests that peo­ple who are tak­ing statins, espe­cial­ly the fat-sol­u­ble statins, prob­a­bly do have a high­er risk of motor neu­ron dis­ease.

The peo­ple tak­ing the water-sol­u­ble statins had about a 10-fold increase in the odds of hav­ing a motor neu­ron dis­ease. The peo­ple tak­ing fat-sol­u­ble statins had a 100-fold greater odds of hav­ing a motor neu­ron dis­ease. Why they had greater odds in that study was not clear. Per­haps the statins real­ly are caus­ing the dis­ease or mak­ing it progress faster. On the oth­er hand, high cho­les­terol might pro­tect peo­ple from get­ting the dis­ease. Or there may be some odd rea­son why the motor neu­ron dis­eases in peo­ple tak­ing statins were sim­ply more like­ly to be report­ed. The answers are still not clear. How­ev­er, this study might encour­age doc­tors to avoid pre­scrib­ing some statin drugs for peo­ple who have a fam­i­ly his­to­ry of a motor neu­ron dis­ease or who already have a neu­ro­log­i­cal prob­lem.

Is This a Big Increase in Risk?

This increase in odds sounds alarm­ing. How­ev­er, you should put it in per­spec­tive. The inci­dence of motor neu­ron dis­eases is rough­ly 2 cas­es per 100,000 peo­ple. A 10-fold increase would trans­late to 20 cas­es per 100,000 peo­ple. A 100-fold increase would trans­late to 200 cas­es per 100,000 peo­ple. So a big increase in the risk of a very rare dis­ease does not nec­es­sar­i­ly mean a big risk for that dis­ease.

If a block­buster drug real­ly does dra­mat­i­cal­ly increase the risk of a rare dis­ease, that rare dis­ease would sud­den­ly become much more com­mon.  For exam­ple, cig­a­rette smok­ing was uncom­mon before World War I. Lung can­cer was rare until the 1930s. Then, lung can­cer sud­den­ly became com­mon. Most of the cas­es were in men who had tak­en up smok­ing dur­ing the war. Ulti­mate­ly, sci­en­tists found con­vinc­ing evi­dence that cig­a­rette smok­ing real­ly does cause lung can­cer. In con­trast, the research today is not try­ing to explain the mas­sive out­break of what was once a rare dis­ease. Instead, they are try­ing to see whether a rare dis­ease is more com­mon among peo­ple who took a par­tic­u­lar drug.

Some­times there are out­breaks of motor neu­ron dis­ease. For exam­ple, an out­break in the East African coun­try of Tan­za­nia was found to be due to poor­ly processed cas­sa­va root, which was high in cyanide. The world’s high­est rate of ALS was among the native peo­ple of Guam. Their high risk of ALS was due to a tox­in from an algae. This tox­in was in par­tic­u­lar­ly high con­cen­tra­tions in fruit bats.

If statins real­ly do increase your risk of get­ting a motor neu­ron dis­ease, then the inci­dence of those dis­eases would have gone up in the Unit­ed States after the statin drugs became com­mon­ly pre­scribed. The motor neu­ron dis­eases did become slight­ly more com­mon from the 1950s to the 1980s. This increase was due to the aging of the pop­u­la­tion. More peo­ple were liv­ing long enough to get these dis­eases. For­tu­nate­ly, despite the wide­spread use of statins, motor neu­ron dis­eases are still rare.

Pho­to by rchdj10

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