Low Vitamin D and Early Puberty

Having low levels of vitamin D has been associated with a host of health problems. Researchers now believe this deficiency could have a life-long impact on girls.

The University of Michigan School of Public Health (U-M SPH) has found a link between low blood vitamin D levels in young girls and early menstruation. Early menstruation has already been implicated in a number of health problems for adolescent girls and women later in life - including breast cancer.

Ask your doctor about vitamin D tests.

Researchers took blood tests and measured vitamin D levels in 242 girls from Bogota, Colombia, aged 5-12. These youngsters were followed for 30 months.

They found 57 percent of the girls who had low levels of vitamin D started menstruating during the study, compared to 23 percent of girls who had adequate levels.

The deficient girls reached menarche (first menstruation) at roughly 11.8 years old, compared to the other girls who were about age 12.6 years old.

This 10-month difference is substantial, according to epidemiologist Eduardo Villamor, associate professor in the U-M SPH, because of all that's going on in a young girl's body at the time.

Early menstruation increases the risks of psychosocial and behavioral problems in teenagers. And girls who start their periods earlier are also at greater risks as adults of developing heart disease and cancer - especially breast cancer.

Villamor says that worldwide girls are reaching menarche at younger ages. Environmental causes are suspected since there haven't been measurable genetics changes, he says.

Finding what's at the root of this declining age trend may help identify interventions that could prevent premature menarche, he concludes.

Villamor says that the study only suggests a link between vitamin D levels and menarche, but doesn't establish a causal relationship. More study is needed to see if changing vitamin D levels changes the age of menarche.

Research findings are considered preliminary before they are published in peer-reviewed journals.