Abstract and Introduction
Background and Aims: Onset of inflammatory bowel disease (IBD) in men is most common during childbearing age, but little is known about the impact on fertility. Previous studies of fertility in men were small, which justifies this large nation-based registry study.
Methods: Fertility was assessed in a national cohort of men with IBD aged 15–44 years in 1964–2014, identified from the Swedish National Patient Register, and in a reference cohort matched for age and place of residence (ratio 1:5). Information about childbirths was found in the Swedish Multi-Generation Register. Patients with indeterminate colitis or inconsistent IBD coding were classified as IBD-unclassified (IBD-U).
Results: The cohorts included 29,104 men with IBD and 140,901 matched individuals. IBD patients had a lower fertility rate (number of births per 1000 person years) compared with the matched individuals; 1.28 (SD 1.27) versus 1.35 (SD 1.31; p < 0.001). Fertility was somewhat impaired in all IBD subtypes compared with the matched cohort; ulcerative colitis (UC) (hazard ratio [HR] 0.93, 95% CI 0.91–0.96), Crohn's disease (CD) (HR 0.95, 95% CI 0.92–0.98) and IBD-U 0.92, 95% CI 0.89–0.95. The cumulated total parity and the parity progression were also decreased for all IBD subtypes. Within the IBD cohort disease severity, intensity of medical treatment (CD) and bowel surgery (IBD-U) were further associated with impaired fertility.
Conclusions: This nationwide cohort study shows only slightly impaired fertility in men with IBD.
Inflammatory bowel disease (IBD) often presents during adolescence or early adulthood and reproductive issues are for this reason of great importance to these patients. Fertility (i.e. the number of children actually born) is decreased in women with IBD, while fertility in men has been less studied. Results from previous research suggest a reduced fertility in men with Crohn's disease (CD)[4–6] but normal fertility in men with ulcerative colitis (UC).[5,6]
The cause of the reduced fertility in men with IBD is not clear, both reduced fecundity (i.e., the biological reproductive capacity) and psychosocial factors may be the contributing factors. Active inflammation, poor nutrition, alcohol habits, smoking, sexual dysfunction, medication, surgery, depression and voluntary childlessness are proposed contributing factors.[7,8]
The impact of IBD on male fertility is however largely unknownprevious population-based studies are outdated, were of limited size and had methodological weaknesses. The objective of this study was to examine fertility in a large cohort of unselected men with IBD.
Aliment Pharmacol Ther. 2022;56(2):292-300. © 2022 Blackwell Publishing