Inflammatory bowel diseases: epidemiology and risk factors (review)

The global spread of IBD is likely due to the westernization of the diet and the environment, which leads to changes in the gut microbiome and increases the risk of disease in people with a genetic predisposition. In light of the increasing incidence of IBD worldwide, it is important to evaluate risk factors in order to develop prognostic risk models for IBD and various variants of the course of UC and CD and methods to combat these diseases. This review article examines key aspects related to the negative and beneficial effects of various factors on the development and course of IBD. The data shows that smoking (OR = 1.76; 95% CI: 1.40–2.22), obesity class II or III (OR = 1.86; 95% CI: 1.30–2.68 for CD and OR = 2.97; 95% CI: 1.75–5.17), taking antibiotics one year before the diagnosis (OR = 1.61;95% CI: 1.26–2.05 for UC and OR = 1.20; 95% CI: 1.09–1.31 for CD), nonsteroidal anti-inflammatory drugs (Relative Risk (RR) = 1.53; 95% CI: 1.08–2.16 for UC), combined oral contraceptives (UC by 3.3%; 95% ДИ: 2.1–4.4 and CD by 6.4%; 95% ДИ: 5.1–7.7), can not only increase the risks of exacerbations of IBD, but also contribute to the development of these conditions. These factors can aggravate the course of an existing disease: for example, the frequency of hospitalizations (OR = 2.35; 95% CI: 1.56–3.52) and the probability of resistance to genetically engineered biological drugs (GEBD) (OR = 1.6; 95% CI: 1.39–1.83). Dietary factors such as ultra-processed foods (RR = 1.82; 95% CI: 1.22–2.72), confectionery (≥ 100 g/day) (RR = 2.58; 95% CI: 1.44–4.62) and trans fats (RR = 1.34; 95% CI: 0.94–1.92) can have a negative impact, increasing the risk of developing IBD. Physical activity is considered as factors that have a protective effect on the course of IBD, reducing the frequency of exacerbations (RR = 0.78; 95% CI: 0.54–1.13 for UC and RR = 0.72; 95% CI: 0.55–0.94 for CD). Dietary fiber (24 g/day) reduces the risk of developing CD (RR = 0.59; 95% CI:0.39–0.90), and a large number of fruits in the diet reduces the risk of developing both UC (OR = 0.69; 95% CI: 0.49–0.96) and CD (OR = 0.57; 95% CI: 0.44–0.74).