Cremin I, Mushati P, Hallett T, Mupambireyi Z, Nyamukapa C, Garnett G P, Gregson S
Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
Sex Transm Infect. 2009 Apr;85 Suppl 1(Suppl_1):i34-40. doi: 10.1136/sti.2008.033431.
To identify reporting biases and to determine the influence of inconsistent reporting on observed trends in the timing of age at first sex and age at marriage.
Longitudinal data from three rounds of a population-based cohort in eastern Zimbabwe were analysed. Reports of age at first sex and age at marriage from 6837 individuals attending multiple rounds were classified according to consistency. Survival analysis was used to identify trends in the timing of first sex and marriage.
In this population, women initiate sex and enter marriage at younger ages than men but spend much less time between first sex and marriage. Among those surveyed between 1998 and 2005, median ages at first sex and first marriage were 18.5 years and 21.4 years for men and 18.2 years and 18.5 years, respectively, for women aged 15-54 years. High levels of reports of both age at first sex and age at marriage among those attending multiple surveys were found to be unreliable. Excluding reports identified as unreliable from these analyses did not alter the observed trends in either age at first sex or age at marriage. Tracing birth cohorts as they aged revealed reporting biases, particularly among the youngest cohorts. Comparisons by birth cohorts, which span a period of >40 years, indicate that median age at first sex has remained constant over time for women but has declined gradually for men.
Although many reports of age at first sex and age at marriage were found to be unreliable, inclusion of such reports did not result in artificial generation or suppression of trends.
识别报告偏倚，并确定不一致报告对首次性行为年龄和结婚年龄观测趋势的影响。
对来自津巴布韦东部一项基于人群队列的三轮纵向数据进行分析。根据一致性对参加多轮调查的6837人的首次性行为年龄和结婚年龄报告进行分类。采用生存分析来确定首次性行为和结婚时间的趋势。
在该人群中，女性开始性行为和结婚的年龄比男性小，但首次性行为和结婚之间的间隔时间要短得多。在1998年至2005年接受调查的人群中，15 - 54岁男性的首次性行为和首次结婚的中位年龄分别为18.5岁和21.4岁，女性分别为18.2岁和18.5岁。在参加多次调查的人群中，首次性行为年龄和结婚年龄的高水平报告都被发现不可靠。从这些分析中排除被确定为不可靠的报告并没有改变首次性行为年龄或结婚年龄的观测趋势。追踪出生队列随着年龄增长的情况发现了报告偏倚，特别是在最年轻的队列中。跨越40多年的出生队列比较表明，女性首次性行为的中位年龄随时间保持不变，而男性则逐渐下降。
尽管发现许多首次性行为年龄和结婚年龄的报告不可靠，但纳入这些报告并未导致趋势的人为生成或抑制。
