Could vitamin D deficiency in young girls contribute to early onset of menstruation? 
A study conducted by the University of Michigan School of Public Health suggests this may be the case. Blood vitamin D levels were measured in 242 girls between the ages of 5 and 12 in Bogota, Colombia. The girls were then followed for 30 months.
“Compared to girls in the vitamin D-sufficient group who first menstruated at the age 12.6 years, those in the vitamin D-deficient group started menstruating at11.8 years. (Epidemiologist Eduardo)Villamor says that although 10 months may seem like a small gap, the difference is momentous because at that age, a young girl’s body may undergo many changes rapidly.”
The findings are significant because of other research suggesting links between early onset of menarche, or first menstruation, before the age of 12 and serious health concerns later in life such as cardiovascular disease and breast cancer. Vitamin D deficiency is also associated with poor bone health and osteoporosis.
This study showing an association between vitamin D deficiency and early menarche raises many questions. Should mothers be asking their doctors to test their daughters vitamin D levels? How might vitamin D supplementation prevent future health concerns now associated with early menarche? What blood level for vitamin D is optimal?
Grassroots Health, a non-profit advocacy organization promoting optimal vitamin D levels for the prevention of disease and maintenance of good health, has recently launched a study on breast cancer prevention with vitamin D. The group also has an initiative called D*Action involving a consortium of scientists, institutions and individuals committed to solving what they consider to be a worldwide vitamin D deficiency epidemic.
Might the girls in Colombia lead the way for vitamin D supplementation to begin at a young age to protect the bones, breast and hearts of the next generation?
I have written to Dr. Villamor to ask where and whether these data are published. Here is what I asked:
What mechanism(s) are you postulating to explain your observation of a younger age at menarche in girls with lower levels of vitamin D? Many variables are associated with an earlier first period, for example, lower birth weight, lower socioeconomic status, greater prepubertal weight gain, emotional and sexual abuse and many other stressors. I need to see the full regression model in order to understand it.
Also, I think it is important to say that all children need to meet the Insitite of Medicine’s vitamin D guidelines which means to get at least 600 IU per day (and that it is safe in 9-12 year olds in amounts up to 3,000 IU/day). That message should have been given along with this new information as a public health message–surely you don’t want every mother of a little girl going out to ask their doctor to order a 250hydroxyvitamin D level! Better to tell them how much vitamin D they need and how much is safe.
Thank you,
Sincerely,
Dr. Jerilynn C. Prior