Background

The extent to which fecal incontinence is associated with obstetrical history or pelvic floor injuries is still a controversial and unresolved issue. One crucial first step toward answering this question is the need to study fecal incontinence in nonpregnant, nulliparous women.

Objective

The aim of this study was to present detailed, descriptive measures of the accidental leakage of liquid or solid stool and gas in a randomly selected, large national cohort of nonpregnant, nulliparous women aged 25 to 64 years.

Study Design

The Swedish Total Population Register identified the source population. Four independent, age-stratified, simple random samples in a total of 20,000 nulliparous women aged 25 to 64 years were drawn from 625,810 eligible women. Information was collected in 2014 using postal and web-based questionnaires. The 40-item questionnaire included questions about the presence and frequency of the leakage of solid and liquid stool and gas, which provided the basis for the generic terms fecal and anal incontinence. Statistical analyses of the differences between the groups were performed using the Fisher’s exact test for dichotomous variables and the Mann-Whitney U-test for continuous variables. The trend between >2 ordered categories of dichotomous variables was analyzed with Mantel-Haenszel statistics. When analyzing the trend between multiple ordered vs nonordered categorical variables, the Kruskal-Wallis test was used. The age-related probability and risk increase per 10 years for incontinence parameters was calculated from logistic regression models adjusted for body mass index.

Results

The study population was 9197 women, and the response rate was 52.2%, ranging from 44.7% in women aged 25 to 34 years to 62.4% among those from 55 to 64 years. All the types of incontinence, except severe isolated gas incontinence, increased with age up to 64 years. The estimated probability of fecal incontinence was 8.8% at age 25 years and 17.6% at age 64. The leakage of liquid stool was dominant, occurring in 93.1% (95% confidence interval, 91.4–94.5) of the women with fecal incontinence, whereas leakage of solid stool occurred in 33.9% (95% confidence interval, 31.1–36.7), of which approximately 80% also had concomitant leakage of liquid stool. The leakage of liquid stool increased markedly up to age 65, whereas the increase in the isolated leakage of solid stool was negligible across all ages (overall <0.4%). Liquid and solid stool, separate or in combination, co-occurred with gas in approximately 80%. The distribution pattern of the different types of leakage, single or combined, was similar in all the age groups. Both age and body mass index (kg/m²) were risk factors for fecal incontinence (P<.0001), with an interaction effect of P=.16.

Conclusion

Abnormal stool consistency has been identified as the strongest risk factor for accidental bowel leakage. The same pattern characterized by a dominance of liquid stool and gas leakage, prevalent concomitant leakage of solid and liquid stool, and a negligible rate of isolated leakage of solid feces was observed across all ages. The low rates of isolated leakage of solid stool support the impression that dysfunction of the continence mechanism of the pelvic floor had a negligible role for bowel incontinence, which is essential information for comparison with women with birth-related injuries.

中文翻译：

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25至64岁非妊娠初产妇女大便失禁——一项随机选择的全国队列患病率研究

 背景

大便失禁与产科病史或盆底损伤的关联程度仍然是一个有争议且尚未解决的问题。回答这个问题的关键第一步是需要研究非怀孕、未产妇的大便失禁。

 客观的

本研究的目的是对随机选择的全国范围内 25 至 64 岁未怀孕、未生育妇女群体中的液体或固体粪便和气体意外泄漏提供详细的描述性措施。

 研究设计

瑞典总人口登记册确定了来源人口。从 625,810 名符合条件的女性中抽取了 4 个独立、按年龄分层的简单随机样本，共 20,000 名年龄在 25 至 64 岁之间的未生育女性。 2014 年通过邮寄和网络调查问卷收集信息。这份包含 40 项的调查问卷包括有关固体、液体粪便和气体泄漏的存在和频率的问题，这为大便失禁和肛门失禁的通用术语提供了基础。使用二分变量的 Fisher 精确检验和连续变量的 Mann-Whitney U检验进行组间差异的统计分析。使用 Mantel-Haenszel 统计分析了二分变量的 >2 有序类别之间的趋势。在分析多个有序与无序分类变量之间的趋势时，使用了 Kruskal-Wallis 检验。失禁参数每 10 年与年龄相关的概率和风险增加是根据体重指数调整后的逻辑回归模型计算得出的。

 结果

研究对象为 9197 名女性，应答率为 52.2%，其中 25 至 34 岁女性的应答率为 44.7%，55 至 64 岁女性的应答率为 62.4%。除严重的孤立性气体失禁外，所有类型的失禁均随着年龄的增长而增加，直至 64 岁。 25 岁时大便失禁的估计概率为 8.8%，64 岁时大便失禁的概率为 17.6%。大便失禁的女性中，93.1%（95% 置信区间，91.4-94.5）的女性以液体粪便渗漏为主，而33.9% 发生固体粪便渗漏（95% 置信区间，31.1-36.7），其中约 80% 还伴有液体粪便渗漏。直到 65 岁，液体粪便的渗漏量显着增加，而固体粪便的孤立渗漏量的增加在所有年龄段都可以忽略不计（总体<0.4%）。液体和固体粪便，无论是单独的还是混合的，大约 80% 与气体同时出现。不同类型渗漏（单一或组合）的分布模式在所有年龄组中均相似。年龄和体重指数（kg/m ² ）都是大便失禁的危险因素（ P <.0001），交互作用为P =0.16。

 结论

大便稠度异常已被确定为意外肠漏的最强危险因素。在所有年龄段中都观察到相同的模式，其特征是液体粪便和气体泄漏占主导地位，固体粪便和液体粪便同时泄漏，以及固体粪便的孤立泄漏率可以忽略不计。孤立的固体粪便渗漏率较低，这支持了这样一种印象，即盆底节制机制功能障碍对肠失禁的影响可以忽略不计，这是与患有出生相关损伤的妇女进行比较的重要信息。