I found a piece of interesting news on the website of New York Times. [1]This news reveals the potential association between childhood obesity and school lunch. The research was conducted among the children who study in Southeastern Michigan schools. The result indicates that, the children who consumed school lunch on daily basis have 29% more risk of developing obese problem than the children who ate home-made lunch. The research also explore the link between watching TV or video games and obesity issue. The long time spending on watching TV and video games could also contribute to the increase in risk of obesity.
Afterward, I searched the original article related to this piece of news. [2] I think asking questions is a good way to learn the health articles, so, I will pose some questions below to understand this article.
What is the exposure and disease?
Answer: The exposure in this research is the school lunch consumption, and watching TV or video games. The disease is obesity.
What are the measured and unmeasured confounders?
Answer: The measured confounders: The age, gender, ethnics/racial factors, height, weight, blood pressure, serum cholesterol, glucose, total cholesterol, high-density lipoprotein, physiologic characteristics, dietary characteristics, physical activity, sedentary activities, lipid profile and heart rate.
The unmeasured confounders: Genetic information,the BMI and other obesity indicators of parents, stress level, emotional status, disease history, medicine and treatment in the recent period and family income. In addition, besides lunch, we also need to know what type of food these students consumed for supper and breakfast, and what they often eat as the snack. If a student ate home-made food for lunch, but had dinner at KFC regularly, he/she may have the obesity problem. We need to collect the comprehensive information about subjectives' eating habit, not just for the lunch.
These unmeasured confounders may result in the outcome bias. The confounders could influence on both exposure and disease. If a study has too many unmeasured confounders, we would cast doubt on the causality exists between exposure and disease.
What is the study design and how do we know?
Answer: This research is a case- control study because the researchers firstly determined the group of obese (case) and the group of non obese ( control), and then collect the data regarding to the exposure ( eating habits) in each group, to calculate the proportion of the cases (and controls) were exposed and not exposed. Since this study is a case-control study, the researcher calculate the odds ratio to interpret the data.
What are the strengths and weaknesses of the study design?
Answer:
Strengths : This study collect the information of many variables, thus, it decreases the outcome bias by considering many confounders. In addition, the two groups were similar with respect to the age, gender. The similarity may diminish the bias come from the effect of gender and age. Also, this study is cheap and quick.It is not time-consuming and money-consuming.
Weaknesses: Firstly, as mentioned above, this study has many unmeasured confounders. These confounders may lead to bias. Secondly, since it is a case-control study, this research may has the "recall bias". It is possible that the children cannot recall their diet items and amount very clearly, thus causes bias in data. Third, the genetic factors could also lead to obesity. However, in this study, researchers did not collect any data about genetic information. Fourth, the objectives only come from the Midwest communities, and all the subjectives are participants in the health program. This process may cause the "selection bias". The restriction of sample selection might result in the restriction of conclusion.The conclusion can not be generalized to the broad population. Finally, the researchers used the questionnaire to get the data. Because the objectives are children, they may do not answer the questions very seriously. Also, they may lack the health literacy of understanding the question. All of these could lead to the data bias.
Do you agree with the author's interpretation of the findings?
Answer: In general, the outcome of this finding is reliable. So, I agree with the interpretation that the school lunch and watching TV or video games are related to the childhood obesity. However, I think the investigation of school lunch is also very important. If the school lunch is high-calories and low-nutrition, the interpretation of this research may be more persuasive.
Was this responsibly reported in the Internet article?
Answer: Yes, I think the article should be reported on the Internet. Because the research is basically valid, the conclusion of this article should be learned by the general public. In addition, this article will not lead to negative effect to life. After reading this article, more children may bring lunch from home, it would not be a bad thing for the health of children.
What is your impression of this article?
Answer: In general, I think the finding of this article is convictive. Before reading this article, I have known that the school lunch may result in obesity. According to my experience, I gained more pounds when I ate the school lunch. As a contrast, I became slimmer if I ate the home-made food. So, I believe the conclusion of this article. However, it would not be a surprise for me.
Would this change your behavior?
Answer: Yes, this article will remind me the healthy eating behavior. I will try to eat at home and eat in a health way, in order to control my weight.
Should you be alarmed?
Answer: Since the objectives of this research are children, the conclusion may can not be generalized to me. I will tell this finding to my brothers.
What is the value of this article?
Answer: This article may stimulate more researchers to explore the association of obesity and school lunch in other groups, such as the college students. Such researches may help us to deal with the obesity issue.
References:
1.http://www.nytimes.com/2011/02/08/health/research/08childhood.html
2. http://proxy.mul.missouri.edu:2159/science?_ob=ArticleURL&_udi=B6W9H-51NNFHD-12&_user=3419478&_coverDate=12%2F31%2F2010&_rdoc=1&_fmt=full&_orig=gateway&_origin=gateway&_cdi=6683&_sort=d&_docanchor=&view=c&_acct=C000049994&_version=1&_urlVersion=0&_userid=3419478&md5=937b9ae14f722ec7e1ee03d2f288b7dc&searchtype=a&artImgPref=F
3. Gordis, Leon, Case-Control Studies and Other Study Designs, Epidemiology, fourth edition, 2008, 169-177.
Tuesday, March 1, 2011
Saturday, February 12, 2011
Epidemiology is connected to our everyday life!
In our everyday life,we come into contact with so many things.We take showers(contact with water), we eat (contact with food), we breathe (contact with air), we talk to others (perhaps contact with their saliva), we shake hands with new friends (contact with people) and so on.
All of these things may carry the harmful agent that could lead us to be infected with certain diseases. We live in the environment forever, so, we can not stay in a totally separate space to avoid getting infection. Communication is a very important component in life; we can not be isolated from this world. Thus, the risk of getting infectious disease always exists around us. All we can do is to learn more about the epidemiology and try our best to protect our families and ourselves.
All of these things may carry the harmful agent that could lead us to be infected with certain diseases. We live in the environment forever, so, we can not stay in a totally separate space to avoid getting infection. Communication is a very important component in life; we can not be isolated from this world. Thus, the risk of getting infectious disease always exists around us. All we can do is to learn more about the epidemiology and try our best to protect our families and ourselves.
Epidemiology Examples
avian influenza:
In 1997,the first case of avian influenza virus infecting humans occurred in HongKong. Originally, Avian influenza is flu infection among birds. The infection of humans gave us an alert.People who work with poultry , travellers who go to infected countries, health care workers who come into contact with avian influenza have a higher chance of getting infected than a normal person.
The avian flu virus could survive in the environment for a long time. People could be infected by touching the contaminated surface.What is more,the birds who recover from the disease still can shed the virus for a long period of time.
The cases of human infection of H5N1 has been reported in many areas across the world.It poses the threat of disease outbreak. We heard reported cases in Africa,Asia,Pacific,Europe and Indonesia and Vietnam.
The disease could cause death among humans, it is horrible!So,we have to pay much attention to this disease.
The symptoms include: cough, diarrhea, difficulty in breathing, fever,headache, malaise and so forth.
Citation : http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004522
Hepatitis B:
The irritation and swelling of the liver caused by infection with hepatitis B virus.
Reference: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001324
Picture citation: http://image.baidu.com/i?ct=503316480&z=&tn=baiduimagedetail&word=renqun&in=25895&cl=2&lm=-1&pn=39&rn=1&di=18501671551&ln=2000&fr=&fmq=&ic=&s=&se=&sme=0&tab=&width=&height=&face=&is=&istype=
Picture citation: http://image.baidu.com/i?ct=503316480&z=0&tn=baiduimagedetail&word=%B8%CE%B5%C4%CE%BB%D6%C3&in=25933&cl=2&lm=-1&pn=0&rn=1&di=42885866568&ln=2000&fr=&fmq=&ic=&s=&se=&sme=0&tab=&width=&height=&face=&is=&istype=2#pn0&-1
In china, the general population are very sensitive for the hepatitis B. Lots of people hold fear for hepatitis B as it can be infectious to humans. Also, the hepatitis B virus is spread widely in China. In average,one of ten Chinese carries this virus.This fact cause the public alienate the hepatitis B patients.And the patients often experience discrimination in many circumstances. For instance, they may be rejected by the employer since they are dangerous to others. People would isolate them to keep safe.
It is true that the hepatitis virus could be transmitted by blood, urine, fluid, saliva, semen and milk. Humans can get infection through sexual transmission, close contact, blood exposure. A positive strategy to prevent hepatitis is to inject the vaccine.
While, we should not isolate or discriminate the hepatitis patients, we must give enough respect and care to them. If we are educated about hepatitis, we will understand how to reduce our risk of infection.
Severe acute respiratory syndrome(SARS):
SARS is a serious form of pneumonia due to SARS virus infection.
Reference: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004460
When I was in high school, I experienced the outbreak of infectious disease--SARS.
Early in the outbreak of SARS cases in China, we did not understand the importance of this disease. As a high school student, I even did not hear any reports about SARS. I knew SARS can be transmitted among humans, and lots of people died of SARS. The Chinese public agency tried to control the outbread, but the effectiveness was not satisfactory. They took actions to keep the travellers from leaving,in order to avoid the virus spreading to other cities. My mom was travelling in another city at that time,she was forced to stay at that city for about two weeks. After a long period of time,the situation eventually improved.
However,until recently,I can still see the report of worldwide SARS cases.I think we need to create more effective weapons to cope with this disease.
The avian flu virus could survive in the environment for a long time. People could be infected by touching the contaminated surface.What is more,the birds who recover from the disease still can shed the virus for a long period of time.
The cases of human infection of H5N1 has been reported in many areas across the world.It poses the threat of disease outbreak. We heard reported cases in Africa,Asia,Pacific,Europe and Indonesia and Vietnam.
The disease could cause death among humans, it is horrible!So,we have to pay much attention to this disease.
The symptoms include: cough, diarrhea, difficulty in breathing, fever,headache, malaise and so forth.
Citation : http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004522
Hepatitis B:
The irritation and swelling of the liver caused by infection with hepatitis B virus.
Reference: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001324
It is true that the hepatitis virus could be transmitted by blood, urine, fluid, saliva, semen and milk. Humans can get infection through sexual transmission, close contact, blood exposure. A positive strategy to prevent hepatitis is to inject the vaccine.
While, we should not isolate or discriminate the hepatitis patients, we must give enough respect and care to them. If we are educated about hepatitis, we will understand how to reduce our risk of infection.
Severe acute respiratory syndrome(SARS):
SARS is a serious form of pneumonia due to SARS virus infection.
Reference: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004460
When I was in high school, I experienced the outbreak of infectious disease--SARS.
Early in the outbreak of SARS cases in China, we did not understand the importance of this disease. As a high school student, I even did not hear any reports about SARS. I knew SARS can be transmitted among humans, and lots of people died of SARS. The Chinese public agency tried to control the outbread, but the effectiveness was not satisfactory. They took actions to keep the travellers from leaving,in order to avoid the virus spreading to other cities. My mom was travelling in another city at that time,she was forced to stay at that city for about two weeks. After a long period of time,the situation eventually improved.
However,until recently,I can still see the report of worldwide SARS cases.I think we need to create more effective weapons to cope with this disease.
If you are an epidemiologist……
Imagine if you are an epidemiologist,and you noticed many infectious disease cases in the past days.What will you do?
The correct process should be :
First,collect the data of people involved in cases. The case means the health-related event, such as the outbreak of flu. We need to find the common characteristics of these people. The characteristics may be the genetic factors or the environmental factors. Are they special in origin? Are they exposed to certain environmental hazard? Did they have something in common, like eat some contaminated food or participate in a big event?
Then,we need to know about the modes of transmission.
Reference: Leon Gordis(2008),Epidemiology (4th edition),19.
As the graph shows,the disease can be transmitted in several ways. Health professionals would work to reduce the chances of the disease spreading.
Example: A person gets the flu, and the people around him are healthy. Suddenly, this person sneezes on others. So, the virus could be transmitted to others by this unintended event.(Gordis)
One of the most concerning aspects of infectious disease is that harms can be spread from very few people to large groups of people. So, it is very important to avoid further transmission of the disease.
References:
Leon Gordis(2008),Epidemiology (4th edition),3-19.
The correct process should be :
First,collect the data of people involved in cases. The case means the health-related event, such as the outbreak of flu. We need to find the common characteristics of these people. The characteristics may be the genetic factors or the environmental factors. Are they special in origin? Are they exposed to certain environmental hazard? Did they have something in common, like eat some contaminated food or participate in a big event?
Then,we need to know about the modes of transmission.
Reference: Leon Gordis(2008),Epidemiology (4th edition),19.Example: A person gets the flu, and the people around him are healthy. Suddenly, this person sneezes on others. So, the virus could be transmitted to others by this unintended event.(Gordis)
One of the most concerning aspects of infectious disease is that harms can be spread from very few people to large groups of people. So, it is very important to avoid further transmission of the disease.
References:
Leon Gordis(2008),Epidemiology (4th edition),3-19.
What is epidemiology???
Key words: disease, illness, population, distribution, factors.
Epidemiology is defined as the study of disease and illness distribution in certain populations.
In epidemiology, we need to collect the information about cases, in order to discover the potential factors of the disease and illness.
More definitions of epidemiolgy: webpage link
The epidemiologists analyze when, who and how of disease occur in specific populations. Given the knowledge of the disease patterns, epidemiologists try to control the outbreak of the disease and prevent health problems developing among large populations.
Epidemiology is defined as the study of disease and illness distribution in certain populations.
In epidemiology, we need to collect the information about cases, in order to discover the potential factors of the disease and illness.
More definitions of epidemiolgy: webpage link
The epidemiologists analyze when, who and how of disease occur in specific populations. Given the knowledge of the disease patterns, epidemiologists try to control the outbreak of the disease and prevent health problems developing among large populations.
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