Maybe Birth Control Pills Would Be OK

Talking to Hart about hormonal birth control, migraine and stroke risk got me wondering what my risk really is. If it is low, multiplying the number by eight isn’t that big of a deal. Kersti explains this well in her comment on the post:

[T]he problem with statistics is that they’re misleading. 8 times more likely… 8 times what? You need to find out what the baseline actually is, and you need to find it out for your own ethnicity, gender, circumstances before you know if this is a problem. If for example the baseline is 10% then 8 times is pretty ghastly, however, if the baseline is 0.01% then you’re still at 8 times 99.92% likely to NOT get one.

I’m kind of embarrassed I didn’t think this through before I wrote the post. I’m always urging readers to think critically. No matter how much I recommend caution, I too fall into the trap of fear. “Stroke? Eight times more likely? No way!” is how I reacted yesterday.

According to the American Heart Association’s stroke risk factors, I’m at very little risk. That’s reassuring. I’ll talk with the doctor on Monday and see what she recommends.

Check out the this BBC article on understanding — and critically evaluating — statistics, which Kersti suggested.

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Migraine Linked to Blood Clots in Veins

People with migraine may be more likely to develop blood clots in their veins than those without, according to a study published today. Called venous thrombosis or thromboembolism, the blood clots can lead to strokes. Researchers speculate this is why people with migraine have a greater risk of stroke.

Studies of stroke and migraine implicate only people who have visual auras with their migraines. I wonder what migraine types the blood clot study participants had.

From Science Daily:

Of the [574] participants, 111 people had migraine. A total of 21 people with migraine also had one or more instances of venous thrombosis, or 19 percent. In comparison, 35 people without migraine had the condition, or 8 percent.

Researchers do not know why migraine and venous thrombosis are linked. One theory is that the blood of people with migraine may be more prone to clotting.

The study also found that people with migraine are not more likely to have hardening or narrowing of the arteries, which is contrary to a current theory.