Ahlgren Martin, Wohlfahrt Jan, Olsen Lina W, Sørensen Thorkild I A, Melbye Mads
Department of Epidemiology Research, Statens Serum Institute, Copenhagen, Denmark.
Cancer. 2007 Jul 15;110(2):412-9. doi: 10.1002/cncr.22773.
It is well established that prenatal biologic processes are important for the development of some childhood cancers, whereas less is known regarding their influence on adult cancer risk. High birth weight has been associated with risk of breast cancer, whereas studies of other specific cancers and all cancers together have been less conclusive.
The authors established a cohort of more than 200,000 men and women who were born between 1936 and 1975. Birth weights were obtained from school health records and information concerning cancer from the Danish Cancer Registry. Follow-up was performed between April 1, 1968 and December 31, 2003. During 6,975,553 person-years of follow-up, a total of 12,540 primary invasive cancers were diagnosed.
Analyses of site-specific cancers revealed that the majority of cancers had a positive linear association with birth weight. Departures from a positive linear association were found to be statistically significant for cancers of the pancreas and bladder, which demonstrated a V-shaped association, and testicular cancer, which demonstrated an inverse association with birth weight. Excluding these 3 exceptions, the trends for the individual cancer sites were not heterogeneous, and the overall trend was a relative risk of 1.07 (95% confidence interval, 1.03-1.11) per 1000-g increase in birth weight. This trend was the same in men and women and in all age groups.
A 7% increase in cancer risk was observed per 1000-g increase in birth weight. Few cancers demonstrated a nonlinear association with birth weight, and testicular cancer was found to be negatively associated with birth weight. The authors hypothesized that the biologic explanation behind the association between birth weight and cancer at different sites should be sought in a common pathway.
产前生物学过程对某些儿童癌症的发展很重要，这一点已得到充分证实，而关于它们对成人癌症风险的影响则知之甚少。高出生体重与乳腺癌风险相关，而对其他特定癌症和所有癌症的综合研究结果则不太明确。
作者建立了一个由20多万名出生于1936年至1975年之间的男性和女性组成的队列。出生体重数据来自学校健康记录，癌症信息来自丹麦癌症登记处。随访时间为1968年4月1日至2003年12月31日。在6975553人年的随访期间，共诊断出12540例原发性浸润性癌症。
对特定部位癌症的分析显示，大多数癌症与出生体重呈正线性关联。发现胰腺癌和膀胱癌呈V形关联，睾丸癌与出生体重呈负相关，这三种癌症与正线性关联的偏差具有统计学意义。排除这3个例外情况后，各个癌症部位的趋势并非异质性，总体趋势是出生体重每增加1000克，相对风险为1.07（95%置信区间为1.03 - 1.11）。这种趋势在男性和女性以及所有年龄组中都是相同的。
出生体重每增加1000克，癌症风险增加7%。很少有癌症与出生体重呈非线性关联，并且发现睾丸癌与出生体重呈负相关。作者推测，出生体重与不同部位癌症之间关联背后的生物学解释应在一条共同途径中寻找。
