Economic influences I believe
The answer is homocysteine. <span>Having high levels of homocysteine in the body, it can lead to coronary artery disease. It is also connected with the formation of blood clots that could lead to a stroke or heart attack.</span>
There are many websites you can visit however, the following link is a good one. https://www.cancer.gov/about-cancer/understanding/what-is-cancer
I think this says that self esteem is a bigger issue in schools than it used to be. a lot of teens have a low self esteem due to bullying and teasing in school. most of the higher self esteem children are the ones who think they are better than everyone else and they usually end up having a bad attitude towards other people which causes them to have very few friends.