People diagnosed with multiple sclerosis (MS) during childhood take longer than older MS patients to reach the stage where they become irreversibly disabled, but this point arrives at a younger age.

The finding comes from a study reported in this week's New England Journal of Medicine.

By evaluating data for close to 18,000 patients in the European Database for Multiple Sclerosis, Dr. Christian Confavreux of the University of Lyon and colleagues identified 394 patients diagnosed with MS between 1976 and 2003 at the age of 16 years or younger.

The researchers compared the time elapsed for older and younger patients before they became unable to walk without support and no further than 100 meters -- indicating a score of 6 on a standard assessment scale.

This was reached after an average of 28.9 years in younger patients compared with 19.7 years in adults. Their corresponding ages were 42.2 and 54.8, respectively, on average.

"Efforts to improve therapy for MS have focused on the population with adult-onset disease," Confavreux's team writes. "Patients with childhood-onset MS clearly deserve similar attention."