Why did I get CLL? Clearing up confusion between correlation and causation

[AussieNeil]

Following our CLL diagnosis, one of our first questions is why me? What did I do, or not do, that caused me to get CLL? Many of us have shared what we think caused us to develop CLL/SLL, but in reality, unlike some other blood cancers, there is little firm evidence of exposure of any specific carcinogens being strongly linked with the subsequent development of CLL.

Quite often, we read of studies reporting correlations between diet and other lifestyle factors and specific cancers or other health conditions. But just because two quantities are correlated does not necessarily mean that one is directly causing the other to change. Correlation does not imply causation, just like cloudy weather does not imply rainfall, even though the reverse is true.

theconversation.com/clearin...

Why correlation does not imply causation?

towardsdatascience.com/why-...

Photo: Living near high-voltage power lines raises children's risk of leukemia by 69%, a British study shows.

That doesn't prove that power lines cause the deadly blood cancer, the study's authors are quick to point out. Despite 30 years of research, scientists still can't come up with a plausible reason why the weak magnetic fields near power lines might cause leukemia.

:

What is puzzling is that the magnetic field from power lines is only 1% of the earth's magnetic field, which surrounds us all," Dickinson tells WebMD. "Your fridge or vacuum generates a magnetic field of about the same strength. In England and Wales, only 5% of the exposure to magnetic fields comes from high voltage pylons. So if this is a hazard, people with appliances should be just as concerned.

webmd.com/cancer/lymphoma/n...

One interesting proposal suggested to explain the increased risk of childhood leukaemia seen for children living near high voltage power lines, is that the pylons and lines lower the desirability of living in the neighbourhood. The resulting lower cost of housing, means that those living there are less able to afford better quality food, health care and so on.

This is an unlocked post, discoverable via Internet Search:

healthunlocked.com/cllsuppo...

Neil

[AdrianUK]

Another great example is the well reports finding that people who drink diet fizzy drinks are more likely to be obese. Scientists have even come up with explanations about how maybe the artificial sweetener tricks the body into producing insulin and so getting fat. But what is perhaps more likely is either that people who drink diet fizzy drinks are also more likely to eat other unhealthy fattening and sweat food (so the association is “indirect” or perhaps even more likely that people who appreciate that they are fat are more likely to choose to drink diet drinks with the goal of losing weight. Ie they drink because they are fat rather than are fat because they drink! This is called “reverse causation”.

One of the best ways of getting round the problem of what are often called cross sectional studies where you look at a population only once is huge prospective studies where you watch the population for a long time in which case you could test if people who drink diet drinks do indeed get fatter over time!

Also the better studies try to look at huge numbers of variables (in the prior example they would look at issues like poverty and other markers of desirable homes) and try to establish more accurately which factors are more strongly associated together and which disappear if you make allowances for another factor.

Here by the way is a link for those interested in more on this. healthknowledge.org.uk/publ...

[AussieNeil Partner Administrator in reply to AdrianUK]

Thanks Adrian.

Very nice epidemiology reference, that is specifically relevant to our concerns.

[Psmithuk in reply to AdrianUK]

I agree with you about fizzy drinks, Adrian. I usually try to turn these sort of explanations round, like you have in your first paragraph, to discover another way to suggest the result. I do get so tired of the silly conclusions we read daily in the paper.

Cx (the cynic!).

[blowinginthewind in reply to Psmithuk]

I am a cynic too.

[JigFettler Volunteer in reply to AdrianUK]

Nice link Adrian! Jig

[Havemercy]

I only know that my father had CLL. My consultant said that there can be a genetic link.

[AussieNeil Partner Administrator in reply to Havemercy]

Your consultant is right. Familial CLL is thought to be responsible for about 10% of cases and the blood relative might have another blood cancer. Yet even with parents with Cll, that doesn't mean that there is a certainty that children will develop a blood cancer. Unfortunately, it's rather difficult to choose your parents.

[JigFettler Volunteer]

This is a really important issue - and can be tricky to understand.

And indeed the opposite is true - I mean: If a treatment is taken and an improvement in a symptom occurs - they may not be linked, or even related. It may be a coincidence.

I am reminded:

Why is it that men who wear a tie to work - have a reduced incidence of heart attack?

(Apologies for the absence of a link to the study - I am relying on my memory and cant recall it - and I am off birding for the day - hope to see some Gannets. Otherwise I would have more time and do my research!)

Thank you Neil - this knowledge strengthens our arm when keep our medical advisers alert!

Jig

[AussieNeil Partner Administrator in reply to JigFettler]

Without cheating, I might anticipate that men who wear a tie to work are in more senior, better paid positions. Hence they would have a greater opportunity for a healthier lifestyle - more able to pay for better quality food, health services and so on. I initially thought that they might actually have a greater risk of heart attacks, as those not wearing ties are more likely to be more physically active at work, but as a society, we have increasingly removed physical labour from our work environment.

Neil

[JigFettler Volunteer in reply to AussieNeil]

Exactly right Neil!

Jig

[Hidden in reply to JigFettler]

Gannets! Nice

[blowinginthewind]

I once challenged the causation of T2 diabetes and obesity. We are always told that if we are fat we will get diabetes - sometimes in those words. I put it to a doctor that perhaps people who carry the genes for diabetes will tend towards obesity because their metabolism isn't functioning as well it could because of the diabetes gene. I got a fairly sensible result, that this was something that may be true, but hadn't been tested.

[AussieNeil Partner Administrator]

Other than curiosity and wanting to spare others the same fate, knowing why we developed CLL is far less important than how we will deal with it. I like Dr. Ilana Yurkiewicz's approach, a fellow in hematology and oncology at Stanford (Calif.) University.

'When they inevitably ask “how did I get this?” and I answer, what I’m really saying is this: I don’t care what you did, or didn’t do, or how we got here. But we are here, and so I am here with you, and from now on the only place we care about is here and now, the only direction forward.'

mdedge.com/hematology-oncol...

Neil

[vog292]

There is a potential genetic propensity for CLL .

[DamnIHaveCLL]

I’m still pretty annoyed at my body for getting CLL. Been eating copious amounts of broccoli for years...time for more steaks.

[J_88 in reply to DamnIHaveCLL]

I didn't change my diet when diagnosed, nor will i ever. Its not like the CLL will go away if i start eating better.

[Hidden in reply to DamnIHaveCLL]

I have been eating mostly organic vegetable diet since I was young, always interested in nutrition and making sure I was eating right.

[Sierrastar in reply to DamnIHaveCLL]

Don’t you know it should’ve been kale?

[scarletnoir]

This is an interesting discussion - I have a dilettante's level interest in epistemology!

FWIW, I am sceptical about the idea that the magnetic fields surrounding power lines 'cause' CLL or anything else health related - though they do cause interference on my car radio (AM medium wave) when I drive past them.

However, IF there is an effect, I can suggest a way in which the weaker fields associated with power cables differ from the stronger Earth's field - as far as I know, the Earth's field does not change polarity except once every 01. to 50 million years, so in a human time scale we can say that the polarity is constant (intensity can and does vary in both short and long time scales).

So - we could posit that the effect, if it exists, may be down to the alternating nature of the magnetic field - with power being generated at 50Hz in the UK, this means that the direction, or polarity, of the magnetic field goes through 50 cycles per second. Could this alternating and continuously varying field (in strength and direction) cause health problems? I doubt it - but who knows.

(This link has nothing medical, but describes the need for a constant frequency across a grid:

drax.com/energy-policy/need... )

[AussieNeil Partner Administrator in reply to scarletnoir]

Better not use electric blankets or throw rugs then! Note also that the energy in an electromagnetic field is proportional to frequency and 50 cycles (60 in some places) is very, very low. FM and TV electromagnetic fields are over 1,000 times higher and those used for mobile phones at least 10,000 times higher. Visible light is about 10,000,000,000,000 times higher. What's more light from the sun provides about 1,000 watts of heating at midday per square metre, yet we have to go even higher in frequency to ultraviolet before we can get burned.

Neil

[scarletnoir in reply to AussieNeil]

Quite so - I said that I was a sceptic!

[CycleWonder in reply to scarletnoir]

So one could compare the rate of the US incidence of CLL for those living near power lines versus that of the UK. I suspect there will be no difference but it is an interesting observation!

Several years ago many utilities in the US were installing smart meters which used radio waves to communicate. A few complained that they got headaches from the radio waves. Of course, we observed one complainer using a cell phone.

[scarletnoir in reply to CycleWonder]

Yes, indeed. Back in the day, people suffered from 'superstitions'. Nowadays, we seem to live in a post-fact world, where some people (far too many IMO) seem to think that if they believe something, then it must be true!☹️

[maggiesgrandmom]

LOL! I never used an electric blanket till I got CLL and had to go to bed with shivers every night for months (before treatment)!

[Sierrastar in reply to maggiesgrandmom]

The best thing to do is retire under a hot lover.

[scarletnoir in reply to Sierrastar]

I thought we'd run out of those circa 1970!

en.wikipedia.org/wiki/Last_...

[Gisygirl]

I have wondered "why me?" as well. I surveyed some cousins after I was first diagnosed and cannot find anyone with blood cancer...now, as far as other cancers- yes..in the family- Mom and Dad, a grandfather, 2 cousins that I know of. At least the Imbruvica seems to be managing it well and I am living normally.

[Sierrastar in reply to Gisygirl]

I have surveyed all my family and no one has any type of cancer. I always knew I was special. Elizabeth.

[Dago12345]

We have done research with my family and no one has CLL. I assume I contacted it when I was in the military. After exposure to certain chemicals and weed killers there

[AussieNeil Partner Administrator in reply to Dago12345]

Agent orange?

[Dago12345 in reply to AussieNeil]

I was in rate after Vietnam and stationed at Wright Patterson where they stored agent orange

[AussieNeil Partner Administrator in reply to Dago12345]

Indeed, the US government recognises the link between any service personnel exposed to Agent Orange and them subsequently developing CLL and will pay for their health care.

en.m.wikipedia.org/wiki/Age... That's thought to be due to the carcinogenic dioxin, TCDD, produced during the manufacture of the herbicide 2,4,5-T. Improvements in manufacturing process control greatly reduced the degree of contamination but it still wasn't enough for 2,4,5 -T to be safely used.

Neil

[AussieNeil Partner Administrator]

Interest in using Metformin to reduce the risk of developing cancer has been mentioned previously in this community, so of relevance to this post on correlation and the difficulties of establishing causation, I was interested to read the following:

Men with diabetes may appear to be at lower risk for prostate cancer because they are less likely to get a biopsy when they have elevated prostate-specific antigen (PSA), a large cohort study suggested.

:

As shown in their study online in JAMA Network Open, there were no differences in prostate cancer detection at biopsy in men with diabetes, regardless of the PSA level that triggered the biopsy. "This study's findings do not support the hypothesis that the inverse association between diabetes and prostate cancer is mediated through antidiabetic medications lowering PSA levels to mask prostate cancer," the researchers said. "They do suggest potential detection bias due to fewer biopsies among men receiving antidiabetic medications, which may explain the lower prostate cancer risk in men with diabetes."

Previous studies have reported several potential links between diabetes and prostate cancer, including a lower incidence, a higher risk of aggressive cancer, and poorer prognosis in men with diabetes. The reasons for the apparent lower incidence are unclear, but one suggestion has been that antidiabetic medications may be protective. Metformin, for example, has been suggested to be protective in the early stages of prostate cancer due to its antineoplastic properties, the study authors noted.

medpagetoday.com/endocrinol...

Neil