HealthDay News — Older genetically predicted age at puberty is associated with reduced odds of multiple sclerosis (MS), although the correlation seems to be dependent on body mass index (BMI), according to a study published online March 20 in Neurology.
Adil Harroud, M.D., from McGill University in Montreal, and colleagues used 372 genetic variants strongly associated with age at menarche in a genome-wide association study (GWAS) involving 329,245 women. Because the genetic architecture of pubertal timing is highly correlated across sexes, these variants provide reliable insight into pubertal timing in men as well. The effect of pubertal timing on the risk for MS was examined using a GWAS with 14,802 cases with MS and 26,703 controls.
The researchers found that the odds of MS were reduced for a one-year increase in genetically predicted age at puberty (odds ratio, 0.92; 95 percent confidence interval, 0.86 to 0.99; P = 0.03). After accounting for effects on adult BMI, multivariable mendelian randomization analysis demonstrated a reduction in the correlation between age at puberty and MS susceptibility (odds ratio, 0.96; 95 percent confidence interval, 0.88 to 1.04; P = 0.36). When childhood BMI was incorporated, the results were similar.
“Higher genetically predicted age at puberty is protective against the development of MS,” the authors write. “The magnitude of this association appears to be dependent on obesity, suggesting that pathways specific to pubertal timing are less likely to be direct determinants of MS risk.”
Two authors disclosed financial ties to the pharmaceutical industry.