Background Different definitions of constipation have been used to estimate its prevalence in the community but this creates difficulties when comparing results from various studies. This study explores the impact of different definitions on prevalence estimates in the same population and compares the performance of simple definitions with the Rome III criteria. Methods The prevalence of constipation in a large nationally representative sample of community-dwelling adults was estimated using five simple definitions of constipation and compared with definitions based on the Rome III criteria. The sensitivity, specificity, and positive and negative predictive values, were calculated for each definition using the Rome III criteria as the gold standards for chronic and sub-chronic constipation. Results Prevalence estimates for the five simple definitions ranged from 9.4 to 58.9%, while the prevalence estimates using the Rome III criteria were 24.0% (95%CI: 22.1, 25.9) for chronic constipation and 39.6% (95%CI: 37.5, 41.7) for sub-chronic constipation. None of the simple definitions were adequate compared to the Rome III criteria. Self-reported constipation over the past 12 months had the highest sensitivity (91.1%, 95%CI: 88.8, 93.4) and negative predictive value (94.5%, 95%CI: 93.1, 96.1) compared to the Rome III criteria for chronic constipation but an unacceptably low specificity (51.3%, 95%CI: 48.8, 53.8) and positive predictive value (37.1%, 95%CI: 34.4, 39.9). Conclusions The definition used to identify constipation within a population has a considerable impact on the prevalence estimate obtained. Simple definitions, commonly used in research, performed poorly compared with the Rome III criteria. Studies estimating population prevalence of constipation should use definitions based on the Rome criteria where possible.

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Constipation is a common community health problem. There are many factors that are widely thought to be associated with constipation but real-world evidence of these associations is difficult to locate. These potential risk factors may be categorised as demographic, lifestyle and health-related factors. This review presents the available evidence for each factor by an assessment of quantitative data from cross-sectional studies of community-dwelling adults published over the last 30 years. It appears that there is evidence of an association between constipation and female gender, residential location, physical activity and some health-related factors such as self-rated health, some surgery, certain medical conditions and certain medications. The available evidence for most other factors is either conflicting or insufficient. Therefore, further research is necessary to determine if each factor is truly associated with constipation and whether it can be regarded as a potential risk factor. It is recommended that studies investigating a broad range of factors are conducted in populations in community settings. Multivariate analyses should be performed to account for all possible confounding factors. In this way, valuable evidence can be accumulated for a better understanding of potential risk factors for constipation in the community.

Laxatives are widely available without prescription and, as a consequence, they are commonly used for self-management of constipation by community-dwelling adults. However, it is not clear to what extent laxatives are used. Nor is it clear how laxatives are chosen, how they are used and whether consumers are satisfied with their performance. This review of published literature in the last 30 years shows the prevalence of laxative use in community-dwelling adults varied widely from 1% to 18%. The prevalence of laxative use in adults with any constipation (including both chronic and sporadic constipation) also varied widely from 3% to 59%. Apart from any geographical differences and differences in research methodologies, this wide range of estimated prevalence may be largely attributed to different definitions used for laxatives. This review also shows that laxative choice varies, and healthcare professionals are infrequently involved in selection. Consequently, satisfaction levels with laxatives are reported to be low and this may be because the laxatives chosen may not always be appropriate for the intended use. To improve constipation management in community and primary healthcare settings, further research is required to determine the true prevalence of laxative use and to fully understand laxative utilisation.

This review of over 80 articles published in the last 30 years shows that estimates of the prevalence of chronic constipation in community-dwelling adults varied widely from 2.4% to 39.6% in general adult populations and from 4% to 25.8% in older adult populations. Estimates of the prevalence of any constipation (including both chronic and sporadic constipation) also varied widely from 2.6% to 31.0% in general adult populations and from 4.4% to 44.5% in older adult populations. Apart from any country or regional differences, this wide range of estimated prevalence may be attributed to different definitions used for both chronic and any constipation as well as different data collection methods and sampling differences. Sampling issues include sample size, representativeness and age range of populations sampled. Further research is required to examine the impact of different definitions on prevalence estimates to help determine the best definitions for use in future epidemiological studies. If standard definitions can be universally agreed and used, along with appropriate sampling and data collection methods, more precise estimates of constipation prevalence should be attained. This would allow more meaningful comparisons between countries and may also provide the ability to pool results.