Table 1.
Pooled prevalence of functional constipation according to the criteria used to define its occurrence, year of study, method of questionnaire administration, validation status of questionnaire, methods of sampling, and research based on disease types.
| Number of studies | Number of participants | Pooled prevalence (95% confidence interval) | I2 | p-value for χ2 | |
|---|---|---|---|---|---|
| CRITERIA USED TO DEFINE ITS PRESENCE | |||||
| Rome I | NA | NA | NA | - | - |
| Rome II | 20 | 77,140 | 10.6% (7.2–15.4) | 100% | 0 |
| Rome III | 18 | 41,315 | 6.5% (3.4–12.0) | 100% | 0 |
| Rome IV | 1 | 5,624 | 8.1% (5.6–11.8) | 97% | <0.01 |
| STUDY YEAR | |||||
| Between 1991 and 2000 | 4 | 8,677 | 5.5% (3.6–8.2) | 97% | <0.01 |
| Between 2001 and 2010 | 20 | 89,310 | 8.5% (5.7–12.4) | 100% | 0 |
| Between 2011 and 2020 | 12 | 23,130 | 10.9% (5.5–20.4) | 99% | 0 |
| METHOD OF QUESTIONNAIRE ADMINISTRATION | |||||
| Interview-administered questionnaire | 27 | 68,996 | 7.3% (4.6–11.3) | 99% | 0 |
| Self-administered questionnaire | 5 | 43,296 | 11.9% (6.3–21.5) | 100% | 0 |
| Unclear administered questionnaire | 8 | 11,787 | 11.0% (5.5–20.7) | 99% | <0.01 |
| VALIDATION STATUS OF QUESTIONNAIRE | |||||
| Validated | 3 | 24,984 | 8.6% (6.0–12.3) | 99% | <0.01 |
| Not validated | 36 | 99,095 | 8.4% (5.7–12.2) | 100% | 0 |
| SAMPLING METHODS | |||||
| Stratify and random sampling | 15 | 76,740 | 6.7% (4.8–9.2) | 99% | 0 |
| Random sampling only | 12 | 22,473 | 13.1% (7.2–22.5) | 99% | 0 |
| Convenience sampling | 12 | 24,866 | 7.2% (3.1–15.5) | 99% | 0 |
| DISEASE TYPES OF RESEARCH | |||||
| Constipation only | 27 | 75,452 | 12.1% (8.4–17.1) | 100% | 0 |
| Constipation and other gastrointestinal disorders | 12 | 48,627 | 3.9% (2.2–6.7) | 97% | <0.01 |
NA, not applicable.