matt (hbergeronx) wrote,

moderate alcohol consumption and cancer- should I be worried?

A report in JAMA today ( correlating moderate alcohol consumption and breast cancer incidence seems to suggest that abstinence from alcohol might have the effect of reducing your risk of breast cancer. Indeed, from some of the interviews (e.g. there's a hint that alcohol may induce or amplify estrogenic effects on breast cancer. The question in your mind should be, is this good science, and should I be listening to it?

In my opinion, no, and no. I mean, it is good science, that's excessively harsh- it's just a bad report on it, trying to find a result in a miniscule effect. It does find some interesting things, but I think they are obvious things that aren't getting reported. That binge drinking isn't good for you. That long term heavy alcohol use isn't good for you. No shit! Really?

A quick read of the paper seems to suggest that they didn't control for cigarette consumption, which is often correlated with alcohol consumption, and other matrix effects. Furthermore, the effect was vanishingly small. The 95% confidence interval on the increased risk (relative to 1.0, the control group) ranges from 1.06 to 1.24. Depending on the model they looked at, some 95% confidence intervals dropped below 1.0. Compare that with the 95% confidence interval of a recent study of breast cancer risk and smoking among women who have a particular type of genetic polymorphism ( Here the 95% interval is 1.3-14.8 for women who smoked for 2 years. While smoking is not well correlated with breast cancer risk in the general population, it doesn't take much of a leap to recognize that it is a risk factor that should be controlled for in studies. 

In fact, you will often see 95% confidence intervals in studies linking tobacco product use range to the double digits, and average risk is in the high single digits, because that is a well known fact: there are carcinogens in cigarette smoke that can cause cancer. This has been experimentally verified over and over and over again, and not just in terms of vague epidemiological risk. You can watch it cause cancer before your eyes in the lab. You can see the impact on the body in exhibits like BodyWorlds. In short, if you smoke, quit now. 

But this leads to another point: do you know your genotype for NAT2? ER? PR? Of course not, because it's highly unlikely that among my peers you have the interest in spending money or time learning about some egghead concept like genetics. In fact, it's most common for people to bury their head in the sand- "I don't want to know my future". But just because there is a risk, doesn't mean you should close your eyes. You don't do so when driving near a cliff.

You don't have to be super smart or have big bucks to militiate for a better future. You just have to ask why. Why in a country so advanced technologically, do we still believe that our future is decided largely by luck, fate or prayer? Why do we elect scores of science-deniers into the leadership positions in this world? 

You have to expect more. Expect more from your teachers, who need to learn the technologies that are going to give the next generation more hope, more of a chance to solve the problems of premature cancer and aging. Expect more of your children, who should be excited and hopeful, and deeply desire true knowledge, not just the "facts" of yesterday or the accumulation of shiny things. Expect more of your friends, who should be hungry for the occasional debate on these issues. Expect more of your doctors, who need to be proactive for your health instead of reactive and always agents of bad news. And, expect more of your leaders, to funnel more money into education, learning at all ages; rather than bankers, warmakers, and rich people's tax returns. And expect more from your scientists, who need to find better ways to communicate.

There are those of us who are working late hours, devoting our time and money to digest and understand the scientific revolution and try to give you hope in the face of fear, knowledge in the face of ignorance, and trust in the face of uncertainty. We don't always get it right, and it might seem some days like you are getting lots of mixed messages. It is true that in science like in all fields, one is generally rewarded for having results, not for the measure of the impact of those results. Don't be led by fear- ask what you can do. In this study on breast cancer and smoking, the editorial comment on the study ( says it best:

"These findings raise an important clinical question: should postmenopausal women stop drinking to reduce their risk of breast cancer? For some women the increase in risk of breast cancer may be considered substantial enough that cessation would seem prudent. However, there are no data to provide assurance that giving up alcohol will reduce breast cancer risk. " - Steven A. Narod, MD

That, in bold. That's what you should be retweeting, not "women are at risk if they drink". Freedom, not fear. The occasional drink is highly unlikely to kill you, and might just help. Just be smart about it, and don't worry if you fall off the wagon. 

One thing that I think you can do is begin to ask, what might I be able to learn to help change my odds? What can I do? In most cases, the advice is simplistic: eat less, eat healthy, don't smoke, dont be a glutton or a lush. But for those of you who want to pass beyond health 101, you might begin to look at things like what genotypes you have, because not everyone is the same. For example, if you've got the genotype for being tall and thin, or short and curvy, celebrate that! But too, the genes which control the proteins that make you taller or more curvy or a redhead are, on balance (mostly) not ironclad destiny, and neither are genes like NAT2. Some of us might benefit from more cardio. Some of us just need long, slow walks. We need to learn more, read the genome and research, to find out.

Your body is a machine- you don't put the same oil in every car, and what's a good fat added to the recipe for someone is a loss of a good carb for another. There are a lot of questions which don't have black and white answers for everyone because (newsflash!) we have evolved apart over time, and different families of people are different. We're not a panmictic, homogenous blend of all peoples, because that's boring and not the best survival strategy. It is written on your body- all you have to do is look. Some women will be PR+, and have more risk. Some will be PR-, and don't have to worry so much. Each of us gets a random mix from our parents, and learning all of the billions of things we bring to a union in childbirth is the legacy and birthright of the post-human-genome generation.

We don't, as scientists, know what we are going to find in the human genome, and it may take centuries to learn even a small fraction of everything there is to be learned there. But the journey started at the turn of the millenium. The words are there, written down, in G, C, T and A, of this we are absolutely certain. Start demanding of your elected officials why they don't put more money and effort into learning more about this language, so that we can begin to really make headway. Respect people who ask the hard questions, and seek the answers. 

And, instead of binge drinking, buy a scientist a glass of their favorite poison and start a good, meaningful conversation. If they are wise about genetics, buy a second round, keep them talking. We have hopeful wonders to reveal to you! Get excited!

Tags: cancer, genetics

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