Neha Kamat’s presentation on menopause was very interesting to me! It really got me thinking about what factors may affect the age of onset for puberty. Studies have shown that girls around the world seem to be entering puberty a lot sooner. In the 1990’s African American girls were developing breasts at age 9 and Caucasian girls were developing breast at around 9.5 years old. Today, girls are entering puberty about 4 months earlier than in 1997. So what could be the cause? There are many hypotheses in the science community about why this is happening.

A very popular hypothesis, that does not constitute a lot of solid evidence, is that there are an increased amount of hormones in the food we eat. Meat and dairy are thought to be the main food groups with a high rate of hormones.  The hormone BPA in plastic food packaging has also been labeled as a culprit.

The well rounded obesity hypothesis has the most supporting evidence. There is a link between percentage of body fat and the onset age of puberty. A higher rate of body fat is believed to produce more estrogen, causing a faster onset of puberty. There have also been studies that suggest there is a noticeable difference in the age of puberty and ethnicity. African Americans and Hispanic girls tend to start puberty before Caucasian females. Although,  change in the onset of puberty has been recorded in most ethnicity’s, including Caucasians.

One thing this class has taught me is that changes in genotype/phenotype are usually do to a combination of factors! Puberty is not an exception to the rule.  The main culprit is probably many changes in the local environment. These environmental factors range from economics to climate conditions. There is even evidence that the prenatal environment may have effects on the onset of puberty! It is hard to narrow down exactly what could be the main cause of this pattern.

Other researchers suggest that people are not properly diagnosing the onset of puberty, “The appearance of acne and pubic hair is common even in infants and toddlers. It goes away. We need to be careful about how we identify the true onset of puberty”, warns Dr. Lawrence Silverman. Recently, boys have also been starting puberty earlier than usual. Not much research has been done because it is harder to pinpoint the onset of puberty in boys. Girls have clearly physical responses to puberty such as breast budding and menarche.

This is a topic that is worthwhile to research because studies show that girls who enter puberty earlier in life have higher rates of breast and uterine cancer. Data provided from this research may provide answers to a lot of questions around risk factors for cancer. Early development in girls has also been linked with poor self-esteem, eating disorders, and depression, as well as cigarette and alcohol use and earlier sexual activity.

The reason why girls of certain ethnicities are more susceptible to this change still remains a question today.

CITATIONS:

http://www.cnn.com/2013/11/01/health/early-puberty-girls/

http://www.cnn.com/2010/HEALTH/08/09/girls.starting.puberty.early/

http://news.discovery.com/human/videos/why-girls-are-entering-puberty-sooner-than-ever-video.htm