Size matters

Cortese M, Riise T, Bjørnevik K, Myhr KM; Multiple Sclerosis Conscript Service Database Study Group. Body size and physical exercise, and the risk of multiple sclerosis. Mult Scler. 2017: 1352458517699289

BACKGROUND: Whether large body size increases multiple sclerosis (MS) risk in men is not well understood. Concurrently, physical exercise could be an independent protective factor.

OBJECTIVE: To prospectively investigate the association between body mass index (BMI) and aerobic fitness, indicators of body size and exercise, and MS risk in men.

METHODS: We performed a population-based nested case-control study within the historical cohort of all Norwegian men, born in 1950-1975, undergoing mandatory conscription at the age of 19 years. 1016 cases were identified through linkage to the Norwegian MS registry, while 19,230 controls were randomly selected from the cohort. We estimated the effect of BMI and fitness at conscription on MS risk.

RESULTS: Higher BMI (≥25 vs 18.5-<25 kg/m2) was significantly associated with increased MS risk (adjusted relative risk (RRadj) = 1.36, 95% confidence interval (CI): 1.05-1.76). We also found a significant inverse association between aerobic fitness (high vs low) and MS risk independent of BMI (RRadj = 0.69, 95% CI: 0.55-0.88, p-trend = 0.003), remaining similar when men with MS onset within 10 years from conscription were excluded ( p-trend = 0.03).

CONCLUSION: These findings add weight to evidence linking being overweight to an increased MS risk in men. Furthermore, they suggest that exercise may be an additional modifiable protective factor for MS.

We have been talking about whether tallness makes a difference in accumulation of disability....I'm sure profG has an answer for this, but this study could perhaps of done it, instead it talks about Body mass index which is a mixture of weight and height. It says if you have a higher BMI you are at an increased risk of developing MS, which is not the same as reporting whether BMI affects the course. In this study it indicates a higher BMI is associated with an increased risk of MS. Likewise the more fit you were the less likely you were to develop MS.  This aspect is a modifiable risk factor however one can put an argument that maybe rather than cause it could be effect, so people with MS, pre-diagnosis MS may be more likely to be less fit and perhaps more sedantry leading to weight gain. So size matters..small is best.