Author information

1 Division of Gastroenterology, Mount Sinai Hospital, New York, New York, USA; Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA. Electronic address: shailja.c.shah@vanderbilt.edu.

2 Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.

3 Public Health Unit, Epimad Registre, Lille University Hospital, France; Inserm LIRIC, UMR 995, Lille University, France.

4 Department of Medicine, Karolinska Institutet, Stockholm, Sweden.

5 CHEO Inflammatory Bowel Disease Centre, Division of Gastroenterology, Hepatology and Nutrition, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada; Department of Pediatrics and School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada.

6 Division of Gastroenterology, University of Copenhagen, Copenhagen, Denmark.

7 Division of Gastroenterology, National Hospital, Tórshavn, Faroe Islands.

8 Department of Medicine, McGill University, Montreal, Quebec, Canada.

9 Department of Gastroenterology, McGill University Health Center, Montreal, Quebec, Canada.

10 Division of Gastroenterology, University of Manitoba, Winnipeg, Manitoba, Canada.

11 Division of Gastroenterology, Dalhousie University, Halifax, Nova Scotia, Canada.

12 Division of Gastroenterology, National University Hospital of Iceland, Reykjavík, Iceland.

13 Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, United States.

14 Department of Gastroenterology, Oslo University Hospital and University of Oslo, Oslo, Norway.

15 Department of Medicine and Therapeutics, Institute of Digestive Disease, LKS Institute of Health Science, State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong.

16 Division of Gastroenterology, University of Otago, Christchurch, New Zealand.

17 Division of Gastroenterology, University of Rijeka, Rijeka, Croatia.

18 Division of Gastroenterology, St. Vincent's Hospital, Melbourne, Australia.

19 Division of Gastroenterology, Mount Sinai Hospital, New York, New York, USA.

20 Division of Gastroenterology, Semmelweis University, Budapest, Hungary.

21 Division of Gastroenterology, University of Regensburg, Regensburg, Germany.

22 Department of Medicine and Community Health Sciences, University of Calgary, Calgary, Alberta, Canada.

23 Department of Gastroenterology, North Zealand University Hospital, Frederikssund, Denmark.

Abstract

BACKGROUND & AIMS: Although the incidence of inflammatory bowel diseases (IBD) varies with age, few studies have examined variations between the sexes. We hypothesize that sex hormones are implicated in IBD pathogenesis. We therefore used population data from established cohorts to analyze sex differences in IBD incidence according to age of diagnosis.

METHODS: We identified population-based cohorts of patients with IBD for which incidence and age data were available (17 distinct cohorts from 16 regions of Europe, North America, Australia, and New Zealand). We collected data through December 2016 on 95,605 incident cases of CD (42,831 male and 52,774 female) and 112,004 incident cases of UC (61,672 male and 50,332 female). We pooled incidence rate ratios of Crohn's disease (CD) and ulcerative colitis (UC) for the combined cohort and compared differences according to sex using random-effects meta-analysis.

RESULTS: Female patients had a lower risk of CD during childhood, until the age range of 10-14 years (incidence rate ratio, 0.70; 95% CI, 0.53-0.93), but they had a higher risk of CD thereafter, which was statistically significant for the age groups of 25-29 years and older than 35 years. The incidence of UC did not differ significantly for female vs male patients (except for the age group of 5-9 years) until age 45 years; thereafter, men had a significantly higher incidence of UC than women.

CONCLUSIONS: In a pooled analysis of population-based studies, we found age of IBD onset to vary with sex. Sex hormones might affect pathogenesis of IBD in patients with epigenetic and genetic risk factors. Further studies are needed to investigate mechanisms of sex differences in IBD incidence.