Genetic Predisposition to Obesity and Medicare Expenditures [pdf] | Hacker News Reader

Genetic Predisposition to Obesity and Medicare Expenditures [pdf]

gwern.net

47 pointsgwern33 comments

This feels like a short footstep into bad science-policy outcome. I don't for a minute doubt the science side has good numbers for it's weighted outcome probabilities. I think its going to be widely mis-used, mis-quoted and mis-understood.

Language in this area of health is a poison pen. Intentionality (you chose to drink the coke, you own the diabetes) and de-empathising (you were born fat and poor, I don't have to help you) are the two stand outs I hear a lot from people I know in the USA who have personal struggles with health costs, and consequences and mostly have conquered them. Down here in a world of public health, the genetic exposure risk is pretty directly about aboriginal and islander communities who are drowning in fetal alcohol syndrome, early onset diabetes, other diseases. This kind of report should (I think) help, but I suspect is going to hinder as it becomes a giant baseball bat in the policy debate.

> the genetic exposure risk is pretty directly about aboriginal and islander communities

Is it, though? Families and communities share much more than genes with each other, including big lifestyle choices. So we can't deduce that easily that genes are to blame.

There has been discovered partial link between biome and obesity. Likely it is not based on single gene but rather total sum of factors.

https://www.youtube.com/watch?v=uO6l6Bgo3-A #itc

After reading the first few comments two things stand out:

1. Genetic Predisposition is always a factor (basically for everything) and therefore has an impact on prices and ultimately "fairness" (whatever your definition). One can have basically the same argument about intelligence and salaries.

2. It is also never the only factor.

Once we start to acknowledge the above two facts, we can start discussing percentages

- To what extend does Generic Predisposition affect Obesity?

- What other factors exist that affect it similarly or more? (Gender, smoking, alcohol, white vs blue collar, leisure activities, marital status, salary, age ...)

Only after that we should discuss whether it's fair: It's highly unlikely that anyone is in the worst of all above categories and a simple cap on expenses (or a progressive negative tax) may help to soften the blow to those cases while still incentivizing everyone to live a healthier life.

Bad food habits, food choices, culture, and very low activity levels have far more significance to obesity than genetics. This is obvious if you just look at historical obesity rates, it was virtually non-existent a few decades ago.

But yes, the obese consume massive medical resources as any doctor or clinician will tell you. At some point you have to acknowledge this and find a way to adjust for that massive cost increase. Allow insurers to set premiums based on BMI, tax BMI, or have a tax credit for healthy BMI, tax junk food, all of the above, etc. Get creative, but you have to find a way to pay for the cost of being fat. Otherwise, obesity and the myriad related illnesses is going to bankrupt the entire US health system.

Also a culture of snacking and telling people they can't go hungry even for a minute.

When I was a kid (not so long ago!) I'd eat breakfast in the morning, something small like a sandwich for lunch at school and then dinner at home with the family. There was nothing in between or nothing in the house to eat in between. Leftovers from previous day maybe? Had to wait until mom prepared the dinner. No candy bars or a bags of nuts or crisps.

Now people just reach out and grab an extremely high-calorie snack at any time. It's a habit, a way of passing time.

Individuals make an easy target because there's an easy story to tell: that they have bad habits and little willpower. The problem is that this story is incomplete.

The US, at least, is a society which actively incentivizes the preconditions for obesity. The USDA's food pyramid (and now plate) promotes a high carb inflammation diet designed for US agriculture, not citizen health. School food programs (partially based on this) are not healthy and set the stage for later dietary behavior. Grains, meats, and dairy are subsidized by the government making them artificially cheap compared to whole fruits and vegetables. Unhealthy food is enshrined in culture and pushed through advertising. Food deserts are a reality for a large portion of the population.

A better strategy would be to target the problem closer to its source. Incentivize the production of healthier crops and healthier food products. This gives consumers lots of feedback on their choices--each time they go to a supermarket or a restaurant and see prices and nutritional information--as opposed to the occasional doctor visit where they learn just how bad the situation has become.

Ultimately, it's simply unfair the way we treat the sick when we've set them up for failure. Let's create a food-to-health system rather than a system that taunts and then punishes.

The general idea of broad lifestyle choices affecting insurance rates might be sound, but the specific idea of using BMI is ridiculous. It's off for tall people, short people, and very fit, athletic people (because it does not distinguish between mass from fat and mass from muscle).

Interestingly enough, I've heard that BMI mostly under-predicts problems. There are a lot more people at a higher body-fat percentage now than when BMI was developed, meaning that BMI assumes that the average person is leaner than they are.

I'm not sure I follow. BMI is a objective (if arguably problematic) measurement. How would changes in population demographics change it's predictive usefulness?

BMI is objective, but it is used as a crude proxy for amount of body fat. If the average amount of lean body mass for a given height changes, it would change the correlation between BMI and body fat percentage, which would make it a less accurate proxy for amount of body fat when comparing to old BMIs.

Why not just use body fat % measurements?

Primarily because they're hard to take accurately. Using calipers takes training; the bathroom scales which report body fat percentage are using an approximation based on conductivity which have varying results. BMI is quick, and I agree not a very good measure, particularly if only used on their own. For example, lean, muscular people can have BMI values which, outside of context, place them as morbidly obese. But, because they're expedient, they've continued to be used.

I see what you're getting at. I don't see this as being driven by a change in population over time; this is just bad interpretation. As I mention down thread (and I'm sure you're aware), body builders often have BMI values that fall into the "morbidly obese" range. This is just due to the measure itself, not a change in population averages.

Bodybuilders often have BMIs that wrongly predict their health outcomes. They know this, though, and it's pretty obvious that they're not actually overweight. The problem is the average person, because BMI will list them as incorrectly healthy.

If you're a "normal" weight, but 25% bodyfat, you're not in good shape. But you may think "oh, I'm okay" rather than "I really need to adjust".

It seems obvious to me that BMI will tend to error by understating the problem. That means that if average BMI is increasing, the problem is getting worse much more rapidly than you might think.

BMI's predictive usefulness is based on people looking like when it was developed (it's an index, so you have to choose values for "normal", "overweight", etc).

Back then, people in the "normal" band had more muscle and less fat than they do today. From what I understand, body-fat % is a much better metric for individual health outcomes, and BMI is a rough proxy to that. Taking two populations of the same BMI, one from say 40 years ago and one now, the one now will be fatter and less healthy.

The core problem is that BMI is a proxy for what you're actually trying to measure: body composition. Height and weight gets you there on average, if you make some assumptions about the average composition. If average composition gets worse, BMI becomes more inaccurate.

People are susceptible to suggestion and manipulation. As evidence consider that 40 years ago it would have been considered insane to suggest that k-12 teachers be armed. Opinions, and behaviors can be manipulated and a grand scale. Foods can be designed to increase likelihood of addiction. It is well known that everyone has a limited supply of willpower. Given all this it is not reasonable to put the blame solely on the individual.

But 40 years before that, it wasn't uncommon or abnormal for teachers to be armed. We need to get back to whatever glued society together 40 years ago.

My dad was on the rifle team in high school, carried a rifle to school and stored it in his locker during the day. Now you can get expelled for making a gun shape with your finger and thumb. I don't have any helpful conclusions to offer, I just find the situation puzzling.

The symptom is obvious: ivory tower professionals professing knowledge.

In rural communities, people were still bringing their hunting rifles to school (leaving them in their truck on the rack in the back window) up until and for some time after Columbine.

I even remember kids accidentally bringing their rifle maybe as late as 2001 or 2002. They were just asked to go home and drop it of, if anyone noticed.

I would wager that at those same schools today, a gun drawing or finger gesture of a gun would not get you expelled.

"It is well known that everyone has a limited supply of willpower."

Not sure about that : http://blogs.discovermagazine.com/neuroskeptic/2016/07/31/en...

but, then again.... : https://digest.bps.org.uk/2017/12/14/strongest-evidence-yet-...

I agree that poor lifestyle choices should be somehow disincentivized.

Leaving aside the fact that BMI isn't a great metric (as mentioned in another comment); we can probably come up with a better one.

80% of healthcare costs are driven by 15 conditions, which in turn are mostly affected by 8 behaviors [1]. I bet that the bulk of the cost is due to completely changeable lifestyle behaviors (diet, drinking, smoking, physical activity).

Alcohol and tobacco should be more heavily taxed (fast-food is trickier, as we need to make sure that there's healthy, equally-accessible food options out there). Education around healthy lifestyle choices should be more available, as well as gym memberships/fitness equipment/trainers. Sure they do cost money, but we're already paying so much through non-preventive healthcare.

Any other ideas how to disincentivized unhealthy lifestyle choices?

[1] http://www.aon.com/attachments/human-capital-consulting/2012...

Be careful what you ask for. High taxes on alcohol would be like Prohibition "lite". Smuggling and corruption would increase. Drinkers would go blind from poorly distilled moonshine.

Under the Affordable Care Act (aka Obamacare), employers can already charge employees more for health insurance if they don't meet BMI goals or participate in a weight reduction program.

https://www.healthaffairs.org/do/10.1377/hpb20130516.373854/...

>Bad food habits, food choices, culture, and very low activity levels

You say that as if you know for certain that none of those things are affected by genetics. Could it be that some people are genetically predisposed to higher levels of activity? It seems very likely to me that different people get varying amounts of endorphin released for similar levels of activity based on genetics.

Same goes for levels of satiation, levels of endorphin release when eating things like sugar.

I grew up in the same household, eating the same food as my brother. Why is it that he just doesn't care for sweet things, never has? And I have a massive sweet tooth. It's been the same since we were both skinny children. It's no wonder he is still skinny and I struggle with weight gain.

How exacty is obesity genetic when mass obesity is a recent phenomenon? Your bias shows when logic is absent.

Genetics and environment don't exist in isolation. As a totally made up example, maybe some people are more vulnerable to specific toxins (genetics) that are a by-product of plastic manufacturing (environment), and this causes increased appetite.

Simple. Some humans likely were always predisposed to obesity. But as a species, we have never had enough easy calories to get obese.

It doesn't matter if you have a genetic predisposition to alcoholism if you have never even had a chance to taste alcohol.

Is Americans' genetic makeup so different from the rest of the developed world? How bout West Virginians vs New Yorkers? I mean ffs WV has 38% obesity rate vs ~25 NY and they are less than 10hr drive from each one another, genetic my ass!

Help me understand your logic. You are saying that because two locations have two different rates of obesity, that means genetics plays no role in obesity?

Even if someone has the hypothetical sweet tooth gene, they are still going to be more likely to be obese in the poorer location that has less access to healthy food and less reason/necessity/possibility to walk everywhere.

> You are saying that because two locations have two different rates of obesity, that means genetics plays no role in obesity?

This really, really needs some explaining from GP. All evidence in the history of genetics tells us that if you put a population in relative isolation (say, West Virginia or one of the other deep south micro-societies which are predominantly economically insulated from one another with very little social mobility), adaptations and recessive traits become more prominent and pronounced and eventually speciation occurs.

Let me run this one by you: Put a bunch of poor people from Ireland and England (which were already isolated populations subsisting on a lean largely starch-based diet, which pushes selection pressures towards genetic adaptations that preserve starch-based energy) into a society-based island that is Appalachia, start applying very cheap garbage food made largely of factory starches and sugars by the train-car load since the late 1940's when the processed and packaged food industries needed an excuse to keep going after WWII, and social pressures like the reduction in need for dirty coal, mineral mining and manufacturing such that all that most of these people can afford to eat is the cheap processed stuff, and you wonder why previously rare diseases like obesity are so common among these people? You wonder why over time these adaptations may have had a chance to take hold as some of these individuals are able to diaspora or escape abject poverty and pass on their obsolete adaptations as we move forward into a post-food-scarcity society?

HackerNews is so filled with people who lack even the most basic sense of human empathy - I wish I could say I'm so surprised, but it's almost looked upon as a badge of honor by some of these people...

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