免费日韩片_欧美成人精品一区二区男人小说_国产乱码一区二区三区四区_国产精品国产三级国产aⅴ入口_成人看的污污超级黄网站免费_欧美一级在线免费观看_成人午夜免费无码福利片_国产乱人伦偷精品视频色欲_aaa少妇高潮大片免费看_国产精品1234_亚洲精品国产suv一区88_中文字字幕在线中文无码_精品亚洲区_午夜九九九_国产av国片精品jk制服丝袜_色综合亚洲_亚洲成av人片无码bt种子下载_欧美色就色_精品少妇的一区二区三区四区_男人用嘴添女人下身免费视频

Download

Frequent blood donation is not harmful to your health, a new study confirms.

"No one should worry that giving blood causes cancer," Dr Gustaf Edgren of the Karolinska Institutet in Stockholm, the study's lead author, told Reuters Health. "If anything, blood donation may actually be good for you."

People who donate blood show lower cancer and mortality rates than their non-donating peers, Edgren and his colleagues note in their report, published in the Journal of the National Cancer Association, but the fact that blood donors tend to be healthier overall could mask any ill effects of frequent donation.

There are also several mechanisms by which frequent blood donation could theoretically affect health, Edgren noted in an interview. For one, drawing blood causes the body to ramp up production of blood cells in the bone marrow. This accelerated cell division, or "mitotic stress," could increase the likelihood of malignancy in blood-forming tissues.

Giving blood has also been shown to result in immune system changes, and some have suggested these immunologic effects could be associated with cancer.

On the positive side, excess iron stores have been tied to heart disease and certain types of cancer, so people who have their blood drawn regularly may be depleting these stores and thus improving their health.

To better understand how repeated blood donations affect health, Edgren and his team looked at data from Swedish and Danish blood banks and transfusion clinics containing records of individuals who donated blood at least once between 1968 and 2002, a total of 1,110,212 people.

The investigators found no relationship between how frequently a person gave blood and their risk of cancer. However, among male donors, the risk of liver, lung, colon, stomach and throat cancer declined as the frequency of donations increased, which suggests that iron depletion may reduce cancer risk.

Even a small excess risk of cancer associated with blood donation would be "a very serious matter," Edgren noted, because so many people donate blood.

However, he added, "we've more or less made very clear that there is no excess risk of cancer associated with frequent blood donation."

Questions:

1. What does Dr Gustaf Edgren’s study show about the rates of cancer and mortality around people who donate blood?

2. How does frequent blood donation affect one’s health?

3. Does the frequency of blood donation affect one’s risk of cancer?

Answers:

1.The rates are lower than those who don’t donate blood.

2.It forces the body to ramp up the production of red blood cells in the bone marrow.

3.No.

（英語點津  Celene 編輯）

About the broadcaster:

Bernice Chan is a foreign expert at China Daily Website. Originally from Vancouver, Canada, Bernice has written for newspapers and magazines in Hong Kong and most recently worked as a broadcaster for the Canadian Broadcasting Corporation, producing current affairs shows and documentaries.