Obesity in early adolescence poses a risk for multiple sclerosis (MS) regardless of sex, and an earlier age at puberty also contributes to MS onset at younger ages, especially in overweight teenagers, a study reports.
These findings were in the study, “Distinct effects of obesity and puberty on risk and age at onset of pediatric MS,” published in the journal Annals of Clinical and Translational Neurology.
Recent research has indicated that both increased body mass index (BMI), a weight-to-height ratio, and the onset of puberty can contribute to MS risk. Furthermore, an increase of pediatric MS is seen in more girls that boys beginning around age 11, suggesting puberty is a pivotal time for MS initiation.
Scientists compiled information on children under age 18 from 14 different pediatric MS centers across the U.S. In total, they analyzed 254 cases of pediatric MS, and recruited 420 teenagers without an autoimmune disease as controls, being treated at these centers. The study data is part of a larger National Institutes of Health investigation (R01NS071463, PI Waubant).
More girls were in the MS group (63%) than were in the control group (49%), and the analysis corrected for differences in race and ethnicity. Factors analyzed were BMI as an indicator of healthy or excessive weight, sexual maturity (including genitalia, breast and pubic hair development, known as Tanner stages), and age at first menstrual cycle.
A higher BMI was recorded in both boys and girls with MS than in teens serving as controls; excessive weight or obesity was observed in 54% of MS girls compared to 33% of the controls, and in 48% of boys with MS compared to 34% in the control group. These results are consistent with previous research.
“Markers of sexual maturity, particularly in association with increased BMI, were associated with younger age at onset in both boys and girls, while obesity alone was associated with increased risk of MS in both boys and girls,” the researchers wrote.
Likewise, only 20% of girls, ages 12–16, in the MS group had not yet reached puberty (defined as a first menstrual period or menarche) at disease onset. A higher BMI was also linked to a younger age at menstruation start. The researchers suggest that a complex relationships exists between menarcheal age and obesity regarding age at MS onset, and recommend further research to determine hormonal patterns.
“Higher BMI in early adolescence is a risk factor for MS in girls and boys. Earlier age at sexual maturity contributes to earlier age at MS onset, particularly in association with obesity,” the researchers concluded. “[These findings are] of significant concern given the growing rates of pediatric obesity worldwide.”