BackgroundSeveral components of dairy products have been linked to earlier
menarche.Methods/FindingsThis study assessed whether positive associations exist between childhood
milk consumption and age at menarche or the likelihood of early menarche
(<12 yrs) in a U.S sample. Data derive from the National Health and
Nutrition Examination Survey (NHANES) 1999–2004. Two samples were
utilized: 2657 women age 20–49 yrs and 1008 girls age 9–12 yrs.
In regression analysis, a weak negative relationship was found between
frequency of milk consumption at 5–12 yrs and age at menarche (daily
milk intake β = −0.32,
P<0.10; “sometimes/variable milk intake”
β = −0.38, P<0.06, each
compared to intake rarely/never). Cox regression yielded no greater risk of
early menarche among those who drank milk “sometimes/varied” or
daily vs. never/rarely (HR: 1.20, P<0.42, HR: 1.25,
P<0.23, respectively). Among the 9–12 yr olds,
Cox regression indicated that neither total dairy kcal, calcium and protein,
nor daily milk intake in the past 30 days contributed to early menarche.
Girls in the middle tertile of milk intake had a marginally lower risk of
early menarche than those in the highest tertile (HR: 0.6,
P<0.06). Those in the lowest tertiles of dairy fat
intake had a greater risk of early menarche than those in the highest (HR:
1.5, P<0.05, HR: 1.6, P<0.07, lowest
and middle tertile, respectively), while those with the lowest calcium
intake had a lower risk of early menarche (HR: 0.6,
P<0.05) than those in the highest tertile. These
relationships remained after adjusting for overweight or overweight and
height percentile; both increased the risk of earlier menarche. Blacks were
more likely than Whites to reach menarche early (HR: 1.7,
P<0.03), but not after controlling for overweight.ConclusionsThere is some evidence that greater milk intake is associated with an
increased risk of early menarche, or a lower age at menarche.