181–190 of 259 posts
>'Prof Stratton said in these organs smoking seemed to be accelerating a natural mutational process, but how it did this was "mysterious and complex".' Wow, just wow. This is standard Armitage & Doll model that has been taught since the 1950s. Every time a cell divides there is some chance of a genetic error occurring. The more generations away from the zygote a cell is, the more genetic errors it will have accumulat…
>'Prof Stratton said in these organs smoking seemed to be accelerating a natural mutational process, but how it did this was "mysterious and complex".' Wow, just wow. This is standard Armitage & Doll model that has been taught since the 1950s. Every time a cell divides there is some chance of a genetic error occurring. The more generations away from the zygote a cell is, the more genetic errors it will have accumulat…
It would be unfair to assume Prof Stratton is unaware of this model, rather than simply tailoring a technical finding to a non-technical audience.
So, why do they sell cigarettes?
People vary in what gives them pleasure and in their valuation of the time/pleasure trade-off. Cigarettes are a tool for some people to move pleasure from the future to the present (i.e., shorter life/less future pleasure in exchange for more pleasure now); they adress intertemporal pleasure-flow needs for some, much as loans address intertemporal cashflow.
Earlier quoted context omitted.
The safest way possible to smoke tobacco is to grow it yourself. The small yields will limit you to smoking only a few time a month. You will want to taste that homegrown tobacco so you will most likely invest in a good old wooden pipe. This will make it so that you don't inhale the smoke into your lungs. You will however still be at risk of mouth and throat cancer.
How would using a pipe prevent you from inhaling the smoke? I have never used one (but I was always curious when I smoked) so maybe it's a silly question.
Earlier quoted context omitted.
The safest way possible to smoke tobacco is to grow it yourself. The small yields will limit you to smoking only a few time a month. You will want to taste that homegrown tobacco so you will most likely invest in a good old wooden pipe. This will make it so that you don't inhale the smoke into your lungs. You will however still be at risk of mouth and throat cancer.
There's a risk from radioactive elements in the tobacco, from the air which in turn is from the fertilizer used. Maybe growing it yourself doesn't change this risk?
So, why do they sell cigarettes?
Unless I am misunderstanding something, their figure 3 seems to be plotting effect size vs p-value... So all it would be showing is that they had more data from lung adenocarcinomas (ie sample size is larger for that cancer type). It isn't 100% clear to me if they shared the data used for that figure, but here are the frequencies each cancer type appeared in table S1: Acute myeloid leukaemia (AML) Bladder 202 399 Cer…
"Comparison of overall methylation between smokers and non-smokers was performed for all tobacco-associated cancer types for which there were available data from Illumina Infinium HumanMethylation450 BeadChip array, where each array contains 473,864 autosomal CpG probes. The examined data were downloaded from the original data source (Table S1)
[...]
distributions were subsequently compared between smokers and non-smokers using a two-sample Student’s t-test. Results were considered significant for Bonferroni threshold of 10-7."
So it is not like figure one from that Lew paper, because their effect size is not normalized to the inter-individual variance. This is a point in their favor.
However, the sample sizes do match up to those found in table S1 (which I posted above). From the data provided, we cannot tell whether that difference in p-values is solely due to sample size or not. They need to tell us the variance for each CpG/tissue combo as well.