Cnattingius Sven, Lundberg Frida, Sandin Sven, Grönberg Henrik, Iliadou Anastasia
Department of Medicine, Karolinska Institutet at Karolinska University Hospital Solna, Stockholm, Sweden.
Cancer Epidemiol Biomarkers Prev. 2009 Sep;18(9):2422-6. doi: 10.1158/1055-9965.EPI-09-0366. Epub 2009 Aug 18.
Prostate cancer has a strong hereditary component, but it has been proposed that hormonal influences in utero may contribute to offspring risk. We investigated the associations between birth characteristics and the risk of prostate cancer in twins, and whether possible associations could be confounded by familial factors, such as shared environment and common genes.
All like-sexed male twins in the Swedish Twin Registry, born from 1926 to 1958 and alive in 1973, were eligible. Data were obtained from birth records, and 11,420 male twins with reliable birth weight data were included in the final study population. Hazard ratios with 95% confidence intervals (CI) from Cox regression models were used to estimate associations between birth characteristics and risk of prostate cancer. Paired analysis was done to account for potential confounding by familial factors.
Compared with twins with a birth weight of 2,500 to 2,999 g, the hazard ratio (95% CI) for twins with a higher birth weight (>or=3,000 g) corresponded to 1.22 (0.94-1.57). In analyses within twin pairs, in which both twins had a birth weight of >or=2,500 g, a 500 g increase in birth weight was associated with an increased risk of prostate cancer within dizygotic twin pairs (odds ratio, 1.41; 95% CI, 1.02-1.57), but not within monozygotic twin pairs (odds ratio, 1.06; 95% CI, 0.61-1.84).
High birth weight is associated with an increased risk of prostate cancer. The difference in risk within dizygotic and monozygotic twin pairs may be due to genetic factors playing an important role in this association.
前列腺癌具有很强的遗传因素，但有人提出子宫内的激素影响可能会增加后代患癌风险。我们研究了出生特征与双胞胎患前列腺癌风险之间的关联，以及这种可能的关联是否会受到家族因素（如共同环境和共同基因）的混淆。
瑞典双胞胎登记处中所有1926年至1958年出生且1973年仍在世的同性男性双胞胎均符合条件。数据来自出生记录，最终研究人群纳入了11420名有可靠出生体重数据的男性双胞胎。采用Cox回归模型的风险比及95%置信区间（CI）来估计出生特征与前列腺癌风险之间的关联。进行配对分析以考虑家族因素可能造成的混淆。
与出生体重在2500至2999克的双胞胎相比，出生体重较高（≥3000克）的双胞胎的风险比（95%CI）为1.22（0.94 - 1.57）。在双胞胎对的分析中，当双胞胎双方出生体重均≥2500克时，出生体重增加500克与异卵双胞胎对中前列腺癌风险增加相关（优势比，1.41；95%CI，1.02 - 1.57），但在同卵双胞胎对中则不然（优势比，1.06；95%CI，0.61 - 1.84）。
出生体重高与前列腺癌风险增加相关。异卵和同卵双胞胎对之间的风险差异可能是由于遗传因素在这种关联中起重要作用。
