Menarche increases relapse risk in pediatric multiple sclerosis.

BACKGROUND

Multiple sclerosis (MS) predominantly affects women with a sex ratio of 3:1 in contrast with a 1:1 sex ratio seen in pre-pubertal onset. Thus, puberty may influence MS risk differentially in males and females. How puberty may be associated with MS clinical features and disease course remains unknown.

OBJECTIVE

The objective of this paper is to determine the association of menarche with disease course in girls with MS.

METHODS

This is a longitudinal retrospective study from the UCSF Regional Pediatric MS Center database. We categorized patients by time of disease onset: pre-menarche, peri-menarche and post-menarche. Poisson regression models were used for within-subject relapse analyses offset by follow-up time.

RESULTS

Seventy-six girls were included (pre-menarche onset = 17; peri-menarche onset = 9; post-menarche onset = 50). Age of menarche was similar in all groups (Kruskal-Wallis p = 0.19). Relapse rate was the same in all three groups during the first two years of follow-up. In girls with follow-up overlapping at least two time periods, within-subject analyses showed increased relapses during the peri-menarche compared to post-menarche period (adjusted IRR = 8.5, 95% CI 2.5-28.7, p = 0.001).

CONCLUSION

Pubertal status may influence MS course at least in female patients. Understanding how puberty influences MS clinical features may offer new insights into important factors regulating disease processes.