All posts by Rayena McLaughlin

Puberty: The New Normal


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.


Dr. Mina Class Assignment

Dr. Minas presentation was really interesting to me. I just wanted to share my response to the assignment for that class period. I would love to hear feedback on whether or not you agree with me!

1.   I would like the students to read the nature draft paper (if anyone wants the     supplementary model stuff they can email me) and write down a few comments for why this paper should and should not be published in very high profile journal like Nature – as though they are reviewing the paper for publication. Note that this is instead of your normal synopsis – so bring a printed copy of this to turn in.

I really liked how under each results section the authors clearly identified why they were doing that test. Most papers simply state how the results support or refute the hypothesis. There is no mention as to why, initially, the experimenters decided to do that specific test in the first place. I prefer this layout because it made the results easier to follow. The figures were very helpful; specifically Figure 2. It really helped with visualization and it was not confusing. Many papers that we have read for this class had very complicated figures/tables that were hard to follow. The one thing that I think could be changed, in regards to the structure of the paper, is the order of the sections. I found it odd that the materials and methods sections came last. Personally, I prefer for the materials and methods section to come earlier in the paper. The take-away message of this paper is that flu vaccines do seem to cause higher rates of bacterial infections, but this negative effect does not outweigh the positive that vaccines do for the public.

2. Read the two news articles regarding the mBio paper and compare and contrast them.

The Greenmed info paper used the data from the paper to support anti-vaccine campaigns.  I do not feel this was the original intention of the paper. It was very biased. The authors used evidence from the paper to totally persuade people to not get vaccinated. The science now article stated the evidence from the paper, but it did not force an opinion on the public. It presents the evidence in a way that the public can use to come to an informed decision about vaccinations.  I also like how this article mentions Mina’s future research that could support or refute his original hypothesis. The first article did not credit the fact that this data is not collected in humans as of yet.

3.   I would also like them to consider the research as though they are the director of the CDC:

  • Is this research worth doing
  • Is it the CDC’s responsibility to report the results
  • What are the tradeoff’s that would ultimately be made and possible downstream effects of the CDC reporting these results, vs. the private sector.

 I do think that this research is worth doing. The public should be fully informed of the risks so that they can come to their own educated decision.  I do think that the private sector of healthcare might get backlash. Many people may start to oppose vaccinations, but that is not up to other to decide. Everyone is entitled to their own opinion. Also, if Mina’s suggestions about higher rates of infections due to lower vaccination rates does hold true, the implications could be worse than expected if many people decide against vaccinations. It is the CDC’s duty to report this information to the public. Immunizations are the major weapon of public health so is only fair that all the information is available to the public.

The link between Vaccines and Polio Eradication in India!

Dr. Mina was a guest lecturer to our class soon after India announced the eradication of polio! Many interesting questions came up in discussion that class period. The question that interested me the most was, ” What impacts will this data have on the anti-vaccination campaign?” . I think we can all agree that individuals against vaccination will definitely use Dr. Mina’s research to support their claims.

I think an important part of acquiring data like this is to make sure that the public is properly educated. I think that the greenmed article we read for class improperly relayed the data to the public. The data was used out of context in order to strengthen a personal argument. This is one reason why I do not agree with the CDC’s decision to no longer support Dr. Mina’s research. The CDC, as a highly respected health organization, has a duty to properly educate the public about new information regarding vaccines. After that, it is the personal opinion of the individual to take a stance in regard to vaccines.

In this blog post I just wanted to provide some information on how polio eradication was achieved in India. Vaccinations were a huge part in this achievement:

Polio is a highly contagious virus that affects the nervous system (WHO). The virus is spread through contaminated water which is pretty abundant in impoverished areas of India. Polio has been a challenge to eradicate in India because of many reasons such as a high population density, poor sanitation, and low rates of routine immunizations (Gates Foundation).  India has been well on its way to the eradication of polio for some time now. A small child, Rukhsar Khatoon, was India’s last reported polio case in January of 2011 (CNN Health). The surveillance of polio proved to be a very important step in India’s eradication process (WHO). The surveillance strategy helped to pin point which populations had a greater risk of polio (WHO). The National Polio Surveillance Project was started in 1997 (WHO). They started by supporting early detection as well as testing stool samples of children who had recently become paralyzed (WHO). Later, environmental surveillance proved to be one of the missing links in the surveillance system (WHO).

Immunization efforts were also a big part of India’s success story! Innovative ideas on how to keep the polio vaccine refrigerated were a major part in the success of immunization (CNN health). There are many parts of India without electricity which presented a major issue in attempting to vaccinate rural villages (CNN health). The solution to this problem was refrigerators powered by kerosene (CNN health). Another major issue with vaccination in India was the lack of trust people had in the polio vaccine. Many people believed that the polio vaccine was a government conspiracy that presented adverse side effects, this lead people to refuse polio vaccination (CNN health). Infertility and even death were some of the rumored side effects of the vaccine. Prominent religious figures and government officials played a major role in gaining the trust of the public to try the vaccine (CNN health). This is a great example of how respected individuals/organizations have a huge influence of the opinions of people.The eradication of polio in India required stead fast dedication from all parties involved.



The Role of Human Movement in the Transmission of Vector-Borne Pathogens

This paper highlights how human movement greatly affects the transmission of vector-borne diseases; specifically dengue.  This paper also notes that the behavior of vectors also plays an important role in disease transmission.  Vector behavior can range from activity (nocturnal) to the biting patterns of the vector. The fact that vectors may be attracted to certain hosts over others also must be taken into account. I think the strength of this paper is the model used to support the data. The model is termed ‘the activity space model’. Spatial arrangement can be broad (international) and local. This model focuses on the few places that individuals spend most of their time (local). The big idea is to use human habitual behaviors to track the places they spend the most time. These individual movements are broken down into spatial and temporal scales. From this model authors concluded that movements with greater spatial arrangements usually involve more time, but not always. The most important thing that the model shows is which movements actually are important when looking at rates of transmission versus those that do not really contribute to transmission. I did find all the different equations a little confusing.  Overall, the data from this paper can help better disease prevention programs.

Diabetes and Evolution

Although obesity is an unfavorable trait, there is evidence that in the past storing fat was quite beneficial. The body was apt to store fat to prepare for long periods of famine in our ancient history. This thrifty gene hypothesis was originally proposed by James Neel. Obesity leads to many health complications, one of the most common being Diabetes.

There are a high percentage of Native American populations that have Type 2 Diabetes. Unnatural Causes: Bad Sugar, a documentary,  delves into the many ways that other factors have contributed to the genetic predisposition of Diabetes in the Pima Indian population of Arizona. Many of these factors happen to be political/economic issues. For instances, the Coolage dam diverted water from the Gila River (major water source in the Pima community) away from the reservation.  The Pima Indians were left with little water resources for their crops and for survival, making them one of the poorest populations in America at the time. This severely affected the Pima economically and culturally. They had to learn to survive without water and adequate food.  Many of the Pima died from starvation during this time of famine. Within 30 years of building the dam there were more than 500 cases of diabetes among the Pima Indians. This supports the thrifty genotype hypothesis. Their bodies were used to not receiving adequate nutrition so the body evolved to hold onto more fat than usual for survival. After a while the government provided food subsidies, but they were not healthy options. The Pima community did not have markets where fresh produce was abundant so they had to rely on processed food that had low nutritional value, provided by the American governemtn. This resulted in even higher rates of diabetes in the population today.

I think that the story of the Pima community in Arizona is a good example of our class discussion on how the human genome evolves simultaneously with our environment and culture.  There is evidence that many minority groups, such as African Americans, that have experienced extreme hard ship in history have high rates of diabetes as well.