Epidemiologic survey on the prevalence and distribution of childhood functional constipation in the northern areas of China: a population-based study.

Objective Functional constipation (FC) is a common complaint in childhood but the prevalence still remains unclear, the aim of this study was to explore the prevalence of FC in childhood in the northern parts of China. Methods A screening program on FC in childhood was carried out in 5 northern cities (Beijing, Tianjin, Shenyang, Changchun, Harbin) of China according to symptoms under the Rome Ⅲ criteria. Random clustered sampling of the inhabitants was carried out under stratification of cities, geographic zones, schools or nurseries.Sample size of each area was in proportion to the population of the area. The range of age was 4-14. All subjects under study were requested to fill in a questionnaire distributed by the teachers. The screening program was carried out immediately after a section survey was completed. All together, 20 000 questionnaires were distributed with 19 638 retrievals. According to the result of the screening, a small number of patients who met the criteria were further selected to undergo a detailed clinical examination in the hospital including laboratory examination, colonic transit time, defecography or/and barium enema, electromyologram and anorectal manometry to exclude organic disease of the colon. Simultaneously, a detailed questionnaire was requested to fill under the assistance of trained doctors or medical students.Prevalence of FC of the population was adjusted by the rate of correct diagnosis from the detailed study. Results The adjusted point prevalence of FC in 5 northern cities of China according to Rome Ⅲ criteria was 4.73% with higher prevalence rate of FC seen in the Beijing area (5.02%) than in other cities (4.82%, 4.76%, 4.27%, 4.40%, with P＜0.001 ). Male to female ratio was 1.26:1 with majority of the FC fell in the 4-6 year olds (5.76%). Conclusion FC appeared a common disorder in childhood in the northern parts of China which called for greater attention. Higher prevalence was noted in the age groups of 4-6. Key words: Functional constipation; Epidemiology; Childhood