건강과 대안 » 발암

[육식/발암] 적색육 및 가공육과 결장-직장암 상관관계 밝혀져

건강과대안 — Thu, 11 Mar 2010 12:50:27 +0000

고기와 결장-직장암 위험 : 미국 국립암연구소(NCI) 연구팀 잠재적 연관관계 연구결과 발표

미국 국립암연구소(NCI)의 과학자들이 적색육 및 가공육(red and processed meat)의 소비와 결장-직장암의 위험성에 관한 생물학적 기전에 대한 조사 연구 결과를 발표했다는 소식입니다.

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Meat And Colorectal Cancer Risk: Scientists Suggest Potential Mechanisms

출처 : Medical News Today Article Date: 10 Mar 2010 – 9:00 PST
http://www.medicalnewstoday.com/articles/181874.php

Scientists in the US who undertook a large study to investigate what biological mechanisms might be behind the already established link between colorectal cancer and consumption of red and processed meat, confirmed that such a link exists and suggested the main players are three compounds: heme iron, nitrate/nitrite, and heterocyclic amines.

You can read a paper on the research behind these findings in the published online first 9 March issue of Cancer Research. Most of the research team members, including corresponding author Dr Amanda J Cross, were from the Division of Cancer Epidemiology and Genetics, at the US National Cancer Institute (NCI) in Rockville, Maryland.

The authors noted that although the link between consumption of red and processed meat and colorectal cancer has been demonstrated in several studies, few have explored the underlying mechanisms.

Cross and colleagues undertook a large prospective study that counted colorectal cancer cases in a cohort of over 300,000 men and women who filled in detailed questionnaires about the types of meat they consumed and how it was cooked.

In their analysis they linked the questionnaire data to information kept in scientific databases about the levels of compounds present in meat cooked at different temperatures. The compounds they were interested in were heme iron, nitrate, nitrite and certain mutagens. (Mutagens are compounds that can alter DNA or other genetic material, thus increasing the rate of rogue cell production which can trigger cancer).

In their analysis the researchers arranged the cohort data in “quintiles”. That is they grouped it into five bands: the bottom quintile contained the data on those who ate the least meat and the top quintile contained data on those who ate the most.

They then compared the hazard ratios (HR) of the top quintile with the bottom quintile: thus working out how much extra risk of developing colorectal cancer was represented in the 20 per cent of the cohort that ate the most meat compared to the 20 per cent that ate the least.

The results showed that:

After 7 years of follow up, there were 2,719 cases of colorectal cancer in the cohort.
Comparing the top quintile (the 20 per cent that ate the most meat) with the bottom quintile (the 20 per cent that ate the least meat) for both red and processed meat showed a significantly higher risk of developing colorectal cancer.
The HR for red meat was 1.24 (24 per cent higher risk) and for processed meat it was 1.16 (16 per cent higher risk).
The potential mechanisms for this that showed statistical significance were intakes of heme iron (HR 1.13), nitrate from processed meats (HR 1.16) and heterocyclic amines (HR 1.19).
In general, the elevated risk was higher for rectal cancer than colon cancer, with the exception of two heterocyclic amines (MeIQx and DiMeIQx), which were only linked to colon cancer.

The researchers concluded that they found:

“A positive association for red and processed meat intake and colorectal cancer; heme iron, nitrate/nitrite, and heterocyclic amines from meat may explain these associations.”

Studies have shown that cooking certain meats at high temperatures produces chemicals that are not present in meats that are uncooked.

Some of these chemicals, such as heterocyclic amines, form when muscle meat is cooked (eg from beef, pork, fowl and fish). HCAs are made when creatine (a chemical found in muscle tissue) combines with amino acids at high temperature.

According to the NCI, scientists have found 17 different heterocyclic amines in cooked muscle meat that may pose a cancer risk in humans.

“A Large Prospective Study of Meat Consumption and Colorectal Cancer Risk: An Investigation of Potential Mechanisms Underlying this Association.
Amanda J. Cross, Leah M. Ferrucci, Adam Risch, Barry I. Graubard, Mary H. Ward, Yikyung Park, Albert R. Hollenbeck, Arthur Schatzkin, and Rashmi Sinha.
Cancer Research, Published online first on March 9, 2010
DOI:10.1158/0008-5472.CAN-09-3929

Additional sources: NCI.

Written by: Catharine Paddock, PhD

[전자파] 휴대전화가 뇌종양을 일으킨다는 보고서… 논란

건강과대안 — Thu, 07 Jan 2010 11:02:16 +0000

전자파 감시단체인 Powerwatch와 EMR 정책연구원이 2009년 8월 “휴대전화와 뇌 종양 : 우려되는 15가지 이유, 과학, 편견(정보조작), 인터폰의 밝혀지지 않은 진실”이라는 보고서를 발표했습니다.

휴대전화 사용이 뇌종양, 안구종양, 침샘종양, 고환암, 림프종 이상과 백혈병 등을 유발한다는 사실이 과학적으로 밝혀진 적도 있습니다.

WHO를 비롯한 국가 및 공공 의료기관들은 위해성에 관한 결정적인 증거를 확보하지 못했다는 이유로 휴대전화의 사용에 대해 어떠한 제제도 가하지 않고 있습니다만… 앞으로 휴대전화의 건강상 위해와 안전성에 관한 논란은 더욱 가속화되리라 예상합니다.

산업의학 전공자들과 전자기기의 안전성에 관심 있는 전문가들의 많은 연구와 관심이 필요한 사안이라 생각합니다.

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Once again: Do cell phones cause brain tumors?
출처 : [CNET] August 26, 2009 7:12 AM PDT
http://news.cnet.com/8301-27083_3-10318075-247.html

A collaborative of international electromagnetic radiation (EMR) watchdogs, including Powerwatch and the EMR Policy Institute, sent a paper to government leaders and media Tuesday detailing several design flaws in a major but oft-delayed telecom-funded Interphone study.

Now consumers get to wonder yet again whether the message behind the paper, “Cellphones and Brain Tumors: 15 Reasons for Concern, Science, Spin and the Truth Behind Interphone,” is legitimate or the result of overzealous conspiracy theorists.

The paper’s main conclusions are: There is a “significant” risk of brain tumors from cell phone use; EMR exposure limits that have been used by governments and supported by industry are based on the false premise that EMR has no biological effects except for heating; and design flaws of the Interphone study include selection bias, insufficient latency time to expect a tumor diagnosis, unrealistic definition of what makes a “regular” cell phone user, exclusion of children and young adults from the study, exclusion of many types of brain tumors, and exclusion of people who had died or were too ill to be interviewed as the result of brain tumors.

Read the full report here (PDF), as well as CNET’s cell phone radiation level chart (a few Motorola models top the list, with several Samsungs coming in lowest).

The paper’s primary author, L. Lloyd Morgan (a retired electronics engineer and member of the Bioelectromagnetics Society), is backed by endorsers (mostly scientists) from 14 countries when he cautions that cell phone use might lead to an increased risk of more than just brain tumors:

Exposure to cell phone radiation is the largest human health experiment ever undertaken, without informed consent, and has some four billion participants enrolled. Science has shown increased risk of brain tumors from use of cell phones, as well as increased risk of eye cancer, salivary gland tumors, testicular cancer, non-Hodgkin’s lymphoma and leukemia. The public must be informed.

The World Health Organization does not seem terribly worried about the effects of cell phone use on health: “None of the recent reviews have concluded that exposure to the RF fields from mobile phones or their base stations causes any adverse health consequence.” But this statement–last updated nine years ago–relies on precisely the kind of data these watchdogs suggest is flawed.

Several other studies, many of which are referenced in the book “Cancer Biology,” including one of 195,775 workers manufacturing and testing cell phones, indicate no association between EMR exposure and brain or other nervous system cancers. But again, this book was published in 1995; time for an update?

Yesterday’s announcement also calls into question the wide use of wireless technologies beyond cell phones. If GSM cell phones are dangerous in the 1.8GHz band, does that render Wi-Fi, at 2.4GHz and 5GHz frequency bands, even worse? These are questions that need to be addressed, preferably by researchers who do not receive their funding from the telecommunications industry.

Elizabeth Armstrong Moore is a freelance journalist based in Portland, Ore. She has contributed to Wired magazine, The Christian Science Monitor, and public radio. Her semi-obscure hobbies include unicycling, slacklining, hula-hooping, scuba diving, billiards, Sudoku, Magic the Gathering, and classical piano. She is a member of the CNET Blog Network and is not an employee of CNET.