Meta analysis of the Week.

Zhang P, Wang R, Li Z, Wang Y, Gao C, Lv X, Song Y, Li B. The risk of smoking on multiple sclerosis: a meta-analysis based on 20,626 cases from case-control and cohort studies. PeerJ. 2016;4:e1797. 

Background. Multiple sclerosis (MS) has become a disease that represents a tremendous burden on patients, families, and societies. The exact etiology of MS is still unclear, but it is believed that a combination of genetic and environmental factors contribute to this disease. Although some meta-analyses on the association between smoking and MS have been previously published, a number of new studies with larger population data have published since then. Consequently, these additional critical articles need to be taken into consideration. Method. We reviewed articles by searching in PubMed and EMBASE. Both conservative and non-conservative models were used to investigate the association between smoking and the susceptibility to MS. We also explored the effect of smoking on the susceptibility to MS in strata of different genders and smoking habits. The association between passive smoking and MS was also explored. Results.The results of this study suggest that smoking is a risk factor for MS (conservative model: odds ratio (OR) 1.55, 95% CI [1.48-1.62], p < 0.001; non-conservative model: 1.57, 95% CI [1.50-1.64], p < 0.001). Smoking appears to increase the risk of MS more in men than in women and in current smokers more than in past smokers. People who exposed to passive smoking have higher risk of MS than those unexposed. Conclusion.This study demonstrated that exposure to smoking is an important risk factor for MS. People will benefit from smoking cessation, and policymakers should pay attention to the association between smoking and MS.

ProfG described loosing his mojo and one of the issues is maintaining enthusiasm about posting. This is certainly a time drain, and is not helped by not having good quality information to post on.

Many of you are not interested in animal work. That is fine by me because to explain things properly takes a lot of time. However, how many times do you want to hear the same thing?

That is what science is…an Idea and then repetition.

Here is a good example

This is the risk of smoking and risk of MS. 

This is yet another meta analysis and it says smoking is a risk factor for MS. How many times do we need to say this?

Well it helps if you don’t smoke and make sure your kids don’t start smoke, it will be alot better for their pockets and their health.

However, who doesn’t say smoking is bad for you. If you look at the figure above and if you are to the left of 1 then smoking decreases your risk and to the right of one, it shows increases your risk increase slightly.

Here we have 25 studies and they all point to the same thing…how many more papers will we have on this subject…A few more I suspect, but let’s face it this is no longer an experiment you know what you are going to get.

If you do an experiment for Pharma they want a positive control…i.e. a drug that works in the system being tested. This is not very 3Rs of animal use because it is not an experiment. You know what is going to happen, if the test drug doesn’t work it doesn’t work and if you are that concerned you can repeat the negative result, so who cares about the positive control as long as the experiment performs properly i.e., it has some quality control in it. We see many experiments EAE where there is such QC. One time the control group scores say = one the next experiment the control group = four. If we don’t get the same score in our control groups thent there is a QC issue, which makes you cautious about any result. If the drug works who cares about a positive control.

Likewise the number of papers I see, where they have a negative control so the animals don’t get disease…is frankly in most cases an unethical waste of animals.

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  • Hi!

    A big question about smoking. I've read articles both in respect to risk of MS and risk of exacerbations apparently associated with smoking.

    In your humble opinion(s) as researchers, realizing none of it is necessarily advisable is this increased risk due to carcinogens? Nicotine?

    I ask for two reasons:

    1. Many people are using these vape's E-cigarettes which generally are delivering nicotine and at least claim, little else.

    2. In medicinal marijuana and smoking thereof CBD's appear beneficial in many health respects. THC at least in high concentrations has from the small amount of research come forward suggested damage is done within the brain. Atop this, older studies suggest that smoking marijuana has more carcinogens than tobacco.

    Realizing with cannabinoids, several delivery mechanisms have come forth and more are in trials and presumably more to come. These are the obvious best mechanisms of delivery .vs. incineration and intake. Its been known for years that bringing the levels of heat into the lungs is not a smart pursuit.

    I realize one needs measure the pro's / con's.

  • I always suspected that secondhand smoke was much worse than active smoking.
    I inhaled the smoke of countless cigarettes from my dad, and then my boyfriend because inevitavmente you end up inhaling more when you have smokers who do not respect the environment of others. Until both stop smoking…

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