To T, Agha M, Dick P T, Feldman W
Population Health Sciences, Research Institute, Hospital for Sick Children, Department of Public Health Sciences, University of Toronto, Ontario, Canada.
Lancet. 1998 Dec 5;352(9143):1813-6. doi: 10.1016/S0140-6736(98)02392-7.
A decrease in risk of urinary-tract infection is one of the most commonly given reasons for circumcision of newborn boys. Previous studies have reported rates of UTI to be 10-20 times higher in uncircumcised than in circumcised boys. This population-based cohort study followed neonates in Ontario, Canada, prospectively to study the relation between circumcision and subsequent UTI risk.
Eligible boys were born to residents of Ontario between April 1, 1993, and March 31, 1994. We used hospital discharge data to follow up boys until March 31, 1996.
Of 69,100 eligible boys, 30,105 (43.6%) were circumcised and 38,995 (56.4%) uncircumcised. 888 boys circumcised after the first month of life were excluded. 29,217 uncircumcised boys were matched to the remaining circumcised boys by date of birth. The 1-year probabilities of hospital admission for UTI were 1.88 per 1000 person-years of observation (83 cases up to end of follow-up) in the circumcised cohort and 7.02 per 1000 person-years (247 cases up to end of follow-up) in the uncircumcised cohort (p<0.0001). The estimated relative risk of admission for UTI by first-year follow-up indicated a significantly higher risk for uncircumcised boys than for circumcised boys (3.7 [2.8-4.9]). 195 circumcisions would be needed to prevent one hospital admission for UTI in the first year of life.
Although our findings support the notion that circumcision may protect boys from UTI, the magnitude of this effect may be less than previously estimated.
降低尿路感染风险是男婴行包皮环切术最常见的理由之一。既往研究报道，未行包皮环切术的男童患尿路感染的几率比行包皮环切术的男童高10至20倍。这项基于人群的队列研究对加拿大安大略省的新生儿进行了前瞻性跟踪，以研究包皮环切术与后续尿路感染风险之间的关系。
符合条件的男童为1993年4月1日至1994年3月31日期间安大略省居民所生。我们利用医院出院数据对男童进行随访，直至1996年3月31日。
在69100名符合条件的男童中，30105名（43.6%）接受了包皮环切术，38995名（56.4%）未接受。出生后第一个月后接受包皮环切术的888名男童被排除。29217名未接受包皮环切术的男童按出生日期与其余接受包皮环切术的男童进行匹配。接受包皮环切术队列中，每1000人年观察期内尿路感染住院的1年概率为1.88（随访结束时83例），未接受包皮环切术队列中为每1000人年7.02（随访结束时247例）（p<0.0001）。第一年随访中尿路感染住院的估计相对风险表明，未接受包皮环切术的男童风险显著高于接受包皮环切术的男童（3.7[2.8-4.9]）。在生命的第一年，需要进行195次包皮环切术才能预防一次尿路感染住院。
尽管我们的研究结果支持包皮环切术可能保护男童免受尿路感染的观点，但这种效果的程度可能小于先前的估计。
