Severe childhood obesity linked to increased risk of Multiple Sclerosis

A new study from Sweden has found that severe obesity in childhood and adolescence more than triples the risk of developing Multiple Sclerosis (MS) later in life, even when lifestyle changes are implemented to reduce body fat.

The nationwide study, published in the International Journal of Obesity, analysed data from the Swedish Childhood Obesity Treatment Register, which included 21,652 individuals aged 2–19 who received treatment for obesity. Their data were compared with a control group of 102,187 age- and sex-matched individuals from the general population. Researchers identified MS diagnoses through the Swedish National Patient Register, excluding individuals diagnosed before age 15 or those with genetic disorders linked to obesity.

Although the absolute risk of developing MS remained low, the study found that 0.13 per cent of people with childhood obesity developed the disease compared to 0.06 per cent in the general population. This equated to a 2.3 times higher risk of MS for those who experienced obesity in early life. The findings emphasise the importance of preventing severe obesity in children as a potential means of reducing future MS risk.

Obesity is known to be associated with chronic low-grade inflammation, which can contribute to metabolic disorders such as type 2 diabetes and cardiovascular disease. Researchers believe this persistent inflammatory state may also play a role in increasing the risk of MS.

The study further explored how different factors, such as age, sex, and obesity severity, affect the likelihood of developing MS. The increased risk was observed regardless of whether obesity occurred in childhood (ages 2–9.9) or adolescence (ages 10–19). However, obesity severity played a crucial role. Those with moderate-risk obesity (BMI between 35 and 39.9) were 3.1 times more likely to develop MS, suggesting a dose-response relationship between body fat levels and disease risk.

Importantly, the study found that early lifestyle modifications to reduce body fat did not decrease the risk of MS in later years. Participants received behavioural interventions but no pharmacological treatments, and modest weight loss over time was not linked to a lower likelihood of developing MS.

“In the present study, modest weight loss after lifestyle behavioural treatment was not associated with increased risk of MS several years later,” the researchers concluded. “Nevertheless, since obesity itself remains a significant factor contributing to MS risk, prevention of high-degree obesity in childhood and adolescence is warranted.”