Smoking is the only factor that has been demonstrated to have a direct influence on the development of inflammatory intestinal diseases, such as Crohn's disease. In addition, it has a negative influence on numerous aspects of their evolution, such as the response to medical treatment and surgery or the onset of complications.
This is one of the conclusions presented at the recent scientific seminar organised by the Biomedical Research Institute (IBI) within the framework of the BIOCAPS programme. Intestinal inflammation and its consequences brought together specialists such as Juan Clofent, from the Hospital de Sagunto (Valencia), who identified smoking as the main trigger for this type of disorder during his presentation concerning environmental factors, at the Hospital Álvaro Cunqueiro, in Vigo.
Clofent also mentioned the use of non-steroidal anti-inflammatories or oral contraceptives, which may alter the defence mechanisms of the intestinal mucosa and have therefore been linked to an increased risk for, and poor evolution of. inflammatory intestinal diseases. “In addition, these conditions tend to develop more often in countries with a high socioeconomic level. The western diet, with its low fibre and omega 3 fatty acid content and high content of trans fats, is a trigger. Moreover, new studies have confirmed the influence of a low level of vitamin D,” he explained.
Along with diet, Vicent Hernández, a specialist from the Hospital Álvaro Cunqueiro, highlighted the negative effects of various lifestyles in developed countries on the composition of the intestinal microbiota. “It has been observed that disease incidence is related to the degree of development, as measured in terms of gross domestic product,” he explained.
The increased consumption of refined sugars, fatty acids, fast food, cereals and bread, together with the lower consumption of fruit, vegetables and fibre are the factors in the western diet which, according to Hernández, are mainly responsible for the increased incidence of this type of disease. “A higher intake of fats, polyunsaturated fatty acids, omega-6 fatty acids and meat is associated with a higher risk of onset of Crohn's disease and ulcerative colitis, whereas fruit and fibre consumption is related to a lower risk of Crohn's disease and vegetable consumption with a lower risk of ulcerative colitis,” he added.
In addition to these dietary factors, it has been reported that the incidence of these conditions is higher in communities with better sanitary conditions. “This could be explained by the hygiene theory, according to which an improvement in sanitary conditions decreases exposure to infectious agents, which has the benefit of reducing the incidence of infectious diseases, but also has the paradoxical effect of a poorly regulated immune system, which is the basis for allergic and autoimmune diseases,” explained Hernández.
However, it must be remembered that a westernised lifestyle also brings with it a better ability to diagnose these diseases (due to a greater understanding of them and better diagnostic methods), and this may also be contributing to their increased incidence in developing countries.
Progress in early diagnosis
Intestinal inflammation affects between 2.5 and 3 million people in Europe, with a direct cost to the healthcare system of up to 5.6 billion euros per year and an increasing incidence. These figures make progress in the early diagnosis of this disease, a field in which Dr. Cristina Saro from the Hospital de Cabueñes (Asturias) works, of particular importance.
“Although the origin of this group of diseases remains unknown, important progress has been made in our understanding of their pathophysiology, in other words how they work and which mechanisms perpetuate the inflammation, in the past 20 years,” explained Dr. Saro. This progress has resulted in the availability of more effective treatments as well as better diagnostic and follow-up methods for these diseases.
Improvements in, and the wider availability of, technology, together with better medical training in the fields of endoscopy and radiology, have all combined to improve and increase the number of diagnoses. In addition to these factors, the specialist from the Hospital de Cabueñes includes “the increased awareness of the general population as regards health aspects in general, and specifically these diseases, thus meaning that patients tend to attend health centres much more rapidly when they notice the first warning signs and symptoms” as a factor that aids early diagnosis.