Study: Higher BMI Could Raise MS Risk

A new study found that patients with a genetically increased body mass index (BMI) have a higher risk of developing multiple sclerosis (MS).

The authors of this research point out that observational studies have reported a connection between obesity—as measured by elevated BMI—in early adulthood and the risk of MS, but note that "bias potentially introduced by confounding and reverse causation may have influenced these findings." Thus, the researchers performed Mendelian randomization (MR) analyses to evaluate whether genetically increased BMI is linked to a greater risk of MS.
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A team led by McGill University researchers employed a 2-sample MR approach, using summary statistics from the Genetic Investigation of Anthropometric Traits (GIANT) consortium and the International MS Genetics Consortium (IMSGC), the largest genome-wide association studies for BMI and MS, respectively. The mean standard deviation for BMI across cohorts was 4.70.

The results "suggest that increased BMI influences MS susceptibility," according to the researchers, who saw a 41% increase in the odds of developing MS for every 1 standard deviation increase in genetically determined BMI.

"Genetically elevated BMI is associated with risk of MS, providing evidence for a causal role for obesity in MS etiology," the authors concluded, noting that genetic factors contributing to the development of MS did not play a role in determining BMI. "While obesity has been associated with many late-life outcomes, these findings suggest an important consequence of childhood and/or early adulthood obesity."

—Mark McGraw

Reference

Mokry L, Ross S, Timpson MJ, Sawcer S, Smith GD, Richards JB. Obesity and multiple sclerosis: a Mendelian randomization study. PLoS Med. doi:http://dx.doi.org/10.1371/journal.pmed.1002053.