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)|
Liu et al. Excess Body Weight during Childhood and Adolescence Is Associated with the Risk of Multiple Sclerosis: A Meta-Analysis. Neuroepidemiology. 2016 Oct 11;47(2):103-108.
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.