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作者：Roxanne Nelson  
出處：WebMD醫學新聞

　　November 30, 2009 — 根據線上發表於11月20日美國國家癌症研究院期刊(Journal of the National Cancer Institute)的新研究，殯葬業的工人因為職業因素長期曝露於甲醛，與骨髓性白血病死亡率風險顯著增加有關。
　　
　　作者們並未觀察到與其他淋巴造血惡性腫瘤的任何關聯，與腦瘤的關聯也不清楚。
　　
　　根據該報告，從事防腐實務的年數與相關的甲醛曝露，和骨髓性白血病死亡率風險增加有統計上的顯著關聯(趨勢P值= .020)，且與甲醛曝露尖峰值增加有關(趨勢P值= .036)。
　　
　　從事防腐實務超過20年者的風險最大。
　　
　　【風險已知 因果關係尚未建立】
　　作者們指出，這類人員有多種專業，包括解剖者、病理學家以及殯葬業工人，都會經常接觸甲醛。以前的調查顯示，這幾類工作人員有相當多死於淋巴造血惡性腫瘤和腦癌。不過，雖然職業性甲醛曝露和白血病被視為強烈關聯，還無法確立因果關係。
　　
　　這篇最新的案例控制研究，是由阿姆斯特丹荷蘭癌症研究中心的資深統計學者Michael Hauptmann博士所領導。
　　
　　研究者比較所有在1960年1月1日至1986年1月1日間死亡的美國殯葬業工作者，死於淋巴造血惡性腫瘤者有168人、腦部腫瘤者有48人，與死於其他原因的配對控制組(n= 265人)比較 。
　　
　　研究者也訪談親屬和同業，以獲得有關甲醛曝露和終身工作實務的資訊。作者們指出，雖然近親一般不知道有關(家人)職場的細節，殯葬業倒是相當不同，因為許多殯儀館是家族擁有、經營，因此，通常是和近親一起工作，甚至和防腐者住在一起。
　　
　　【暴露增加導致風險較高】
　　作者們指出，防腐與骨髓性白血病風險最強、且統計上顯著相關(勝算比[OR]為11.2; 95%信心區間[CI]為1.3-95.6；P= .027)。他們也觀察到，從事防腐年數有統計上顯著趨勢(P= .020)，甲醛曝露尖峰值也是(P= .036)。比較27個從事防腐20年以上的人和其他從事年份較少者，從事防腐和骨髓性白血病之間有統計上的顯著關聯(OR為4.1；95% CI為1.6-10.7；P= .004)。
　　
　　作者們在從事防腐和腦瘤之間並未發現統計上的顯著風險，也未發現從事防腐年數之風險增加的實質證據。這些案例中有4人死於鼻咽癌，但是只有2人從事防腐，不過，這2人的平均曝露值相當於或高於控制組中曝露測量最高者的相對值。
　　
　　【需要後續研究】
　　他們寫道，白血病風險和特定防腐實務與曝露之關聯的後續研究，以及其他曝露於甲醛而增加白血病風險之職業的特定曝露研究，都有助於釐清及瞭解與甲醛相關的癌症風險。此研究有助於累積職業工作者之甲醛曝露風險增加與骨髓性白血病風險增加之關聯的證據。
　　
　　國家癌症研究中心的校內研究計畫資助本研究。作者們皆宣告沒有相關財務關係。
　　
　　J Natl Cancer Inst. 線上發表於2009年11月20日。


Formaldehyde Exposure Linked to Leukemia Risk in Funeral Workers

By Roxanne Nelson
Medscape Medical News

November 30, 2009 — Among people working in the funeral industry, long-term occupational exposure to formaldehyde was associated with a statistically significantly increased risk for mortality from myeloid leukemia, according to a new study published online November 20 in the Journal of the National Cancer Institute.

The authors did not observe any association with other lymphohematopoietic malignancies, and the association with brain cancer was unclear.

According to the report, the number of years of embalming practice and related formaldehyde exposure were associated with statistically significantly increased mortality from myeloid leukemia (P?for trend?= .020) and with increasing peak formaldehyde exposure (P?for trend?= .036).

The greatest risk was among those who practiced embalming for more than 20 years.

Risk Known, Causality Not Established

People working in a number of professions, including anatomists, pathologists, and funeral-industry workers, come in regular contact with formaldehyde, the authors point out. Previous surveys have shown an excess number of deaths attributed to lymphohematopoietic malignancies and brain cancer among individuals working in these professions. However, although the evidence associating occupational exposure to formaldehyde and leukemia is considered strong, it has remained insufficient to establish causality.

This latest study, led by Michael Hauptmann, PhD, a senior statistician at the Netherlands Cancer Institute in Amsterdam, was a case–control study.

The researchers compared all funeral-industry workers in the United States who died between January 1, 1960 and January 1, 1986 from lymphohematopoietic malignancies (n?= 168) or brain tumors (n?= 48) with deceased matched control subjects (n?= 265) who died from other causes.

Information on lifetime work practices and exposure to formaldehyde was obtained by interviews with relatives and coworkers. The authors point out that although close relatives generally do not know details about the workplace, the funeral industry is unusual in that many funeral homes are family owned and operated. Therefore, the next of kin often work and even live with the embalmer.

Increased Exposure Leads to Higher Risk

The authors noted that embalming was most strongly and statistically significantly associated with a risk for myeloid leukemia (odds ratio [OR], 11.2; 95% confidence interval [CI], 1.3 to 95.6; P?= .027). They also observed statistically significant trends with the number of years of embalming (P?= .020) and peak formaldehyde exposure (P?= .036). When the 27 case subjects who embalmed 20 or more years were compared with those who had embalmed for fewer years, there was a statistically significant association between embalming and risk for myeloid leukemia (OR, 4.1; 95% CI, 1.6 to 10.7; P?= .004).

The authors did not find a statistically significant risk between embalming and brain tumors, or any real evidence that the risk increased with the number of years performing embalming. There were 4 deaths among the case subjects from nasopharyngeal cancer, but only 2 of the individuals had performed embalming. However, the average exposure level of those 2 individuals was equal to or higher than the corresponding levels among exposed control subjects for most exposure metrics.

Further Studies Warranted

"Further studies of leukemia risk in relation to specific embalming practices and exposures, as well as similar specific exposure studies in other professional groups that are exposed to formaldehyde and that have an increased risk of leukemia, should help to clarify our understanding of cancer risks related to formaldehyde," they write. "This study adds to the accumulating evidence from studies of industrial workers that increased exposure to formaldehyde is associated with increased risk of myeloid leukemia."

The study was funded by the Intramural Research Program of the National Cancer Institute. The authors have disclosed no relevant financial relationships.

J Natl Cancer Inst. Published online November 20, 2009.