Wednesday, 12 October 2016

ClinicSpeak: calling all parents we have a problem

What can we do about the childhood obesity epidemic? For MSers this matters! #ClinicSpeak #MSResearch #MSBlog

The meta-analysis (combined results of several studies) shows that obesity in childhood, and adolescence, is a risk factor for developing MS. Obesity is a particular problem with girls. Why? I don't know but some people hypothesise that it is hormonal or linked to vitamin D. Fat alters the metabolism of oestrogen and also acts as a depot for vD, which is fat soluble vitamin (or hormone). Obese people have lower vD levels than non-obese people. The latter fits with the current dogma that low vD levels are a risk factor for MS - case closed. But the observation could also be due  to reverse causation; in other words whatever causes MS may also alter behaviour and metabolism in such a way that it results in obesity. 

Please note obese children and adolescents are less active and less likely to play outdoors. The latter may the real risk factor and not the obesity. Another interpretation is that childhood obesity is associated with excessive intake of processed carbohydrates (sugar), which may alter the microbiome (bacteria that live in the gut). We now know that the microbiome is part of our metagenome (genome including the commensal microbes that live in and on our bodies) and have been shown to regulate immune responses. Just may be obesity and its associated poor diet and microbiome results in dysfunctional immune regulation that then acts as a trigger for MS. 

What do we do about this problem? We need to continue to promote a healthy lifestyle in the general population and try to prevent, or reduce, the prevalence of obesity in childhood and adolescence. The figure below suggests that we as a society are failing in this task. At a professional level wWe can use this information to activate parents with MS to make sure their children are healthy and take steps to reduce childhood and adolescent obesity. May be we should add a station on our Digesting Science course about obesity (poor diet and inactivity) to make children of MSers, and MSers, themselves think about lifestyle and MS risk? The incidence of MS is soaring we can't simply watch the trend without doing something about it. The prevention of MS needs a holistic approach.

Prevalence of obesity (with 95% confidence limits) by year of measurement, school year, and sex (National Child Measurement Programme)

BACKGROUND AND AIM: Several epidemiological studies have reported the association between obesity and multiple sclerosis (MS).


METHODS: A literature search of the observational studies, published as original articles in English before December 2015, was performed using electronic databases.

RESULTS: Five observational studies were included, of which 3 were case-control studies and 2 were cohort studies. The pooled relative risk (RR) for overweight and obesity during childhood and adolescence compared with normal weight (body mass index = 18.5-24.9 kg/m2) was 1.44 (95% CI 1.22-1.70) and 2.01 (95% CI 1.63-2.48), respectively. In subgroup analyses, we found that excess body weight during childhood and adolescence increased the risk of MS in the female group (overweight: pooled RR = 1.62, 95% CI 1.35-1.94; obesity: pooled RR = 2.25, 95% CI 1.77-2.85), but not in the male group (overweight: pooled RR = 1.19, 95% CI 0.91-1.55; obesity: pooled RR = 1.22, 95% CI 0.79-1.90).

CONCLUSIONS:  Excess body weight during childhood and adolescence was associated with an increased risk of MS; severe obesity demonstrated a stronger risk. A statistically significant association was found in the female group, but not in the male group.

11 comments:

  1. I've been slim all my life, in fact borderline underweight much of the time, and physically very active, so clearly you don't need to be overweight to develop PPMS. But being overweight is a risk for many things (e.g. diabetes), so less sugar and more time outdoors would be good for children I would think.

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  2. Re: "The incidence of MS is soaring we can't simply watch the trend without doing something about it."

    Where is the data supporting this claim.

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    1. Dunn et al. Sex-Based Differences in Multiple Sclerosis (MS): Part II: Rising Incidence of Multiple Sclerosis in Women and the Vulnerability of Men to Progression of this Disease. Curr Top Behav Neurosci. 2015;26:57-86.

      It is well known that a number of autoimmune diseases including multiple sclerosis (MS) predominantly affect women and there has been much attention directed toward understanding why this is the case. Past research has revealed a number of sex differences in autoimmune responses that can account for the female bias in MS. However, much less is known about why the incidence of MS has increased exclusively in women over the past half century. The recency of this increase suggests that changing environmental or lifestyle factors are interacting with biological sex to increase MS risk predominantly in females.Indeed, a number of recent studies have identified sex-specific differences in the effect of environmental factors on MS incidence. The first part of this chapter will overview this evidence and will discuss the possible scenarios of how the environment may be interacting with autoimmune mechanisms to contribute to the preferential rise in MS incidence in women. Despite the strong female bias in MS incidence, culminating evidence from natural history studies, and imaging and pathology studies suggests that males who develop MS may exhibit a more rapid decline in disability and cognitive functioning than women. Very little is known about the biological basis of this more rapid deterioration, but some insights have been provided by studies in rodent models of demyelination/remyelination. The second part of this chapter will overview the evidence that males with relapsing-onset MS undergo a more rapid progression of disease than females and will discuss potential biological mechanisms that account for this sex difference.

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    2. Almost every country that is tracking incidence has seen a rise. The highest reported increase is in Iran where the ration of females:males is now 5:1. The increase in F:M sex ratio is a proxy of the rising incidence. Interestingly, in low prevalence regions such as South Africa, the Middle-East and Asia the increase is more interesting. Why?

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    3. Could F:M ratio in Iran be linked to women always being covered by clothes from head to foot so they have no sunshine on their skin?

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    4. That's something I've pondered about for a while since the Iranian revolution and the mandate on women to cover up since then.
      https://www.vitamindcouncil.org/vitamin-d-news/iranian-revolution-reason-for-irans-dramatic-increase-in-multiple-sclerosis/

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    5. Decreased maternal death, probably. MS is never a problem if you die on the childbed before 30.

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  3. I agree with this post. I was always on the overweight side as a teenager. I grew up in India and was the odd one out because of my excess weight. All the other kids were so thin. MS is so rare among Indians and I sometimes wonder if being overweight as a teenager was a cause.

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  4. I was an active and slim child/adolescent. The 7 years preceeding my first pregnancy were spent walking 10 miles a day, 5 days a week, till force policy placed me on light duties till the birth. Weight/allergies/ms became issues during and immediately after that pregnancy. Relapses started in earnest aged 46 at a time when my hormones would be beginning to change again.

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  5. I wasn't overweight and nor was my skinny (adopted/non blood relative) sister who a also has MS, but It's not hard to imagine that our body fat ratio was naturally higher than men. it is very interesting to consider hormones and fat percentage and vitamins. Hormones send my MS symptoms wild....what about hormones in the environment, oestrogen mimicking plasticides and oestrogen pill in water supplies for example?

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  6. Yesterday, the NMSS announced the funding of new MS research projects. Once project is looking at BMI and EBV (which should please Prof G):

    Brent Richards, M.D.
    Jewish General Hospital
    Montreal, Quebec
    Award: Research Grants
    Term: 10/1/2016-9/30/2018
    Funding: $128,000
    Title: The effect of obesity and EBV on the risk
    and progression of MS: A Mendelian randomization
    analysis

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