Obesity, or corpulence, is a common and serious health condition. Generally, obesity occurs when someone exceeds the daily recommended amount of calories for their age, sex, and height or exceeds the recommended amount of unhealthy fats and sugar.1 It may also result from an inadequate involvement in physical activity. Consuming surplus amounts of calories can turn into excessive fats, which accumulate in the body and can later contribute to several chronic complications such as diabetes, cardiovascular diseases, musculoskeletal disorders, cancers, and inflammatory bowel disease (IBD).2
With the recognition of other contributing clinical and environmental factors to weight gain other than dietary patterns, epidemic obesity and the prevalence of inflammatory bowel disease is rising in the global adult population, where people assigned female at birth (AFAB) present a higher prevalence than people assigned male at birth (AMAB).3 Since weight gain is mostly associated with intestinal specific inflammation, a review study analysed 15-40% of IBD patients as obese; also, patients with premorbid obesity might be associated with developing risks of Crohn’s disease.4
What is Crohn’s Disease?
Crohn’s disease (CD) is a chronic intestinal inflammatory condition, which is also a type of Inflammatory bowel disease (IBD). Unlike its relative Ulcerative Colitis (an auto-immune condition), Crohn’s disease can cause inflammation anywhere in the digestive tract from the mouth to the anal opening.5,6 It mostly can affect parts of small or large intestines but is not limited to these specific regions. A study showed Crohn’s disease affects people AFAB in their peak reproductive years: most of them were under 35 years of age.7
Depending on the affected section of the gastrointestinal tract, Crohn’s disease can be differentiated into several types, which include:
Ileocolitis (most common type) is the inflammation of the small intestine, particularly the ileum and colon, which is a portion of the large intestines.
When swelling and inflammations start to develop in the ileum of the small intestine is known as Ileitis.
Gastroduodenal is the inflammation of the stomach and upper region of the small intestine called the duodenum.
This occurs when the upper half of the small intestine called the jejunum is inflamed and spotted as patchy areas. Jejunoileitis is typically uncommon and mostly appears in children rather than in adults.
Biologically, the gastrointestinal system is very unique. It has a special lining of remarkable defence that stretches a barrier consisting of epithelial lining between the lumen space and blood supply. However, in Crohn’s disease, there is a decrease in immune response, and defensive lineups are disrupted in the digestive tract causing inflammation in the affected region.
Signs and Symptoms
Individuals with Crohn's disease may experience several signs and symptoms ranging from mild to severe. These symptoms usually develop gradually, but sometimes they can appear without a warning sign. This sudden reactivation is known as a flare-up which causes more pronounced symptoms followed by no to mild periods of remission.8 Remissions can extend to many weeks or even years. But most of the flare-ups are difficult to predict since there’s no guarantee when they will reappear.
Following are the common sign and symptoms which occur when the disease is active:
- Chronic Diarrhoea.
- Abdominal pain.
- Rectal Bleeding.
- Mouth sores.
- Abnormal skin tags (usually on your buttocks).
- Anal fissures.
- Anal fistulas.
- Reduced Appetite.
Undernourishment or weight loss in patients is often featured with Crohn’s Disease (CD). However, some CD patients are surprisingly overweight. These patients may have severe symptoms which may require earlier medical interventions. Nearly 40% of Crohn’s disease patient's Body mass index (BMI) ranges between the overweight and obese scale.9,10
One case study reported that 32% of Crohn’s disease patients with mild or inactive CD were found overweight, out of which 8% were obese.11 According to emerging reviews anticipated weight gain is linked with nutritional issues, and obese people tend to have more visceral fat than non-IBD individuals, causing elevated risks of Crohn’s disease among the overweight population.11,12 Although limited data on the issue and its clinical relevance to obesity among adult CD patients still remain debatable.11
The underlying putative effects of obesity are connected with the adipose tissues and mesenteric adipose tissue (MAT) with pro-inflammatory response in Crohn’s disease.
Physiologically, adipose tissues are considered very dynamic in nature. They are able to secrete a diverse range of biological substances such as adipocytokines, and hormone-like proteins, such as leptin, and adiponectin. Exhibiting both endocrine and paracrine functions to maintain normal homeostasis. However, when abnormal adipose tissues start to expand in an unusual manner, they can influence obesity, in turn manifesting inflammation.
One of the major signs of Crohn’s disease is the development of mesenteric adipose tissues, which induces alterations in the gut wall. This is commonly termed the creeping fat, which is characterized by the patchy distribution of mesenteric tissues wrapping around the intestinal lining, causing severe inflammation and obstruction.13,14 Another study reported elevated levels of C-reactive protein (produced by the liver in response to inflammation) as a pro-inflammatory marker in obese subjects, which is an important source of mesenteric fat in Crohn’s disease. This elevation can trigger local inflammation and bacterial translocation.15,16
Moreover, people AFAB who tend to gain weight after the age of 18 years have been associated with an increased risk of Crohn’s disease, but not ulcerative colitis.17
Weight loss is the most common symptom of Crohn's disease and ulcerative colitis. Weight loss is generally indicated by malnutrition due to less intake of necessary calories than what the body needs. There are various factors for weight loss, including:
- Poor/ loss of appetite.
- Increase calorie burns in the body to fight the condition.
- Nutrient loss due to diarrhoea or intestinal bleeding.
Weight loss is a significant issue for many IBD patients, especially at a younger age with Crohn’s disease. According to a study, nearly 57% of individuals with Crohn’s disease experience significant weight loss.18
Weight loss in CD patients could be associated with a number of different aspects. Firstly, Crohn’s disease is an inflammatory condition that results in a generalised destructive breakdown of molecules. Furthermore, increased amounts of acute flare-ups in CD and pro-inflammatory responses can exert an anorexic effect in patients. The inflammatory alterations in the gut lining affect levels of a number of metabolic hormones such as leptin, adiponectin, and ghrelin might suppress the sense of hunger.
On the other hand, Crohn’s disease is particularly associated with malabsorption of both macronutrients and micronutrients, causing decreased absorption of water and nutrients in the intestines, thus causing severe diarrhoea.
When people think of Crohn’s disease, the first impression relates to gastrointestinal (GI) symptoms, such as abdominal pain, cramping, and more. But Crohn’s disease can trigger a number of gynaecological manifestations in people AFAB as well.
In particular, Crohn’s disease can cause specific complications in people AFAB’s genitourinary tracts (parts of the genital and urinary tract). Because these issues can hugely impact people AFAB's reproductive and psychological health and require the special attention of gynaecologists and gastroenterologists in these specified cases.
One of the most typical manifestations of CD in the genitourinary tract is defined as non-caseating granulomatous inflammation of the skin. More than half of the lesions are presented in the vulvar region which may cause ulcerations, knife-like pain and sometimes oedema to the affected region.
Approximately 25% of vulvar lesions are observed before GI symptoms appear. It is important to emphasise the significance of these findings because differential diagnoses of vulvovaginal lesions can exhibit critical elements for early recognition and intervention in non-recognized CD patients.17
Other major clinical problems that people AFAB with Crohn’s disease can experience:
- Irregular periods: With Crohn's disease, people AFAB may experience changes in their menstrual cycle. However, the established link between the menstrual cycle and irritable bowel syndrome is not fully assessed. Recent studies have shown that people AFAB with Crohn’s disease are more likely to experience diarrhoea during their menstrual phase along with changes in the cyclic patterns. This means people AFAB may observe an alteration in period flow varying from light to heavy menstrual bleeding.20
- Dysmenorrhea: people AFAB with CD may also experience painful periods (dysmenorrhea) with an irregular period cycle.21 A study from the journal Inflammatory Bowel Diseases 2013, found that around 40 per cent of people AFAB with Crohn’s disease experienced painful periods.
- Rectovaginal fistula: Rectovaginal fistula appears when an abnormal contact develops between the rectum and vaginal region. This can cause stool or faecal matter to be rerouted through the vagina, which can be scary. Almost one-third of the people with Crohn’s disease develop some type of fistula: an abnormal growth link between two body sections.23
- Endometriosis: Endometriosis is a painful condition that occurs when the uterine lining grows outside the uterus. Many researchers assume the connection and prevalence of Crohn’s disease with endometriosis.24
- Manifestations during Pregnancy: people AFAB with inactive Crohn’s disease usually have normal pregnancies. However, if conception happens during active CD flare-ups, this can have a high risk of relapse or induce an inflammatory reaction. It is recommended to plan conception after confirming at least 3 months of remission to limit the risk of miscarriage and premature labour.7
Individuals with Crohn's disease may also experience other symptoms which may go beyond digestive complications:
- Eye infections (Iritis)
- Skin conditions such as psoriasis
- Inflammation in joints (Spondolydis)
- Kidney stones
- Iron deficiency (anaemia)
- Vitamin D deficiency
- Venous/Arterial Thrombosis
Causes and Risk Factors
There is no known cause for Crohn’s disease. But certain important factors may contribute to the development of Crohn’s Disease:
- Immune system: It's probable that a virus or bacteria may trigger Crohn's disease development. However, researchers have yet to identify such a trigger. A few possibilities are expected that might induce the complication, such as a decrease in immune autophagy (natural cell degradation process), a drop in the defensive key effector that inhibits bacterial growth called defensins, and major secreted product known as mucins which help to lubricate the digestive tract and extravagant influx in cytokines release. Also, defects in the immune surveillance are another factor that represents a decline in the regulatory function of a NOD2 gene (Nucleotide-binding oligomerization domain-containing protein 2). This may alter immune responses due to gene mutation of NOD2 contributing to Crohn’s development. Such abnormal responses cause the immune system to attack the cells in the GI tract and promote bacterial translocation (dysbiosis).
- Heredity: Crohn's disease is more common in people who have a family history, especially with first-degree relatives (parents, siblings, or a child). Genes may play a critical role in people becoming more susceptible to the disease.
- Age: Crohn's disease can occur at any age, but it is more likely to develop the condition in the younger population. Crohn's disease is mostly diagnosed in people 30 years of age or less.4
- Smoking: Smoking is an extremely important controllable risk factor for developing Crohn's disease in patients. Smoking also increases the chance of developing severe Crohn’s disease and heightens the need for surgery.
- Nonsteroidal anti-inflammatory medication (NSAIDS): Some NSAIDs such as ibuprofen (Advil, Motrin IB, others), naproxen sodium, and diclofenac sodium can induce bowel inflammation that may lead to worsening the complications related to Crohn’s disease. Other medications such as Antibiotics might have a pro-inflammatory response. However, the studies in this domain are still unclear.
Generally, many healthcare providers order the following tests to evaluate and diagnose Crohn’s symptoms:
- Blood test: Several blood tests are recommended to check the levels of different substances present in the blood, such as:25
- Complete Blood Count (CBC) to identify high numbers of white blood cells that may indicate inflammation or infection, red blood cells, and platelets, whereas a comprehensive metabolic panel (CMP test) looks for blood proteins, creatinine, and electrolytes to measure metabolism. Low levels of these substances indicate Crohn’s disease.26
- Increased levels of Erythrocyte Sedimentation Rate (ESR) and C-reactive protein measures are associated with acute inflammations in the blood.27,28
- Sometimes antibodies blood test is also suggested to identify the type of IBD in an individual.
- ASCA antibody positivity indicates Crohn’s disease while pANCA indicates the presence of Ulcerative Colitis.29
- Stool test: Stool test analysis is required to check the presence of bacteria or parasites in the blood sample. Most analyses look for elevated levels of faecal calprotectin and faecal lactoferrin (biomarkers released in intestinal inflammation), which signal Crohn’s disease.15,30
- Colonoscopy: During a colonoscopy, the doctor uses an endoscope to examine skipping lesions in the ileocolonic region for major insight into Crohn’s disease.
- Computed tomography (CT) scan: A CT scan particularly takes images to look for mesenteric fat layer in bowel wall lining known as creeping fat sign, which is another important insight for CD diagnosis.
- Upper gastrointestinal (GI) exams are also recommended to observe upper GI complications using imaging techniques. Some endoscopic tests followed by biopsy may search for ulcerations referred to as cobblestones in the bowel tract.
Treating Crohn’s disease is mainly focused on maintaining remission and suppressing flare-ups. However, treatment may vary greatly from person to person, depending upon the severity of the disease.
- Antibiotics: Antibiotics (Augmentin) are prescribed to prevent abscesses in the GI tract.
- Antidiarrheal medication: Medications like loperamide (Imodium) can help to control diarrhoea.
- Biologics: These medications help to suppress the immune response and control tissue damage.
- Corticosteroids: Prednisone, Budesonide, and other corticosteroids ease inflammation in CD patients.
- Some other medications such as TNF inhibitors (infliximab) and NSAIDs (sulfasalazine) are given to ease symptoms.
- Surgery: Surgical therapy won’t cure Crohn’s disease, but it can ease complications. This may include surgery to correct intestinal perforations (holes), and dilation of strictures.
Causes of Weight Gain
There are several factors involved that cause excessive weight gain retention in people AFAB. This includes, environmental, genetic factors, anxiety, stress, menstrual cycle, hormonal changes during pregnancy, eating habits, menopause and lack of sleep.
Overeating or unhealthy dietary habits is a prominent cause of gaining weight. An unhealthy diet pattern influenced the consumption of refined sugar, omega-6 polyunsaturated fats, and fast food, combined with a lack of intake of fruits, vegetables, and fibres. This shift in diet pattern might be linked to pro-inflammatory responses in IBD. Some CD patients gain weight due to overeating during their remission period.31
Inactivity gives a driving surge to weight gain. Lack of exercise with high-calorie intake can affect the body’s metabolic mechanism and risk various complications. Also, exercise can be challenging for CD patients, especially during flare-ups. CD, people AFAB patients experiencing anxiety, depression, and mood swings during premenstrual syndrome may contribute to an unwillingness to perform physical activity, leading to obesity.32
Crohn’s medications can also promote weight gain. Medications like prednisone and Lyrica for treating pain can add to weight gain.
Managing Crohn’s Disease
There is no known cure for Crohn’s disease; however, managing proper treatment plans according to individuals’ symptoms can have a positive impact on lifestyle. It is recommended to discuss plans with health professionals to extend timelines for better remissions.
Tips and Tricks
e.g. bowel rest, avoiding triggers
The following tips can help patients to counter their symptoms. Avoiding certain food that might trigger Crohn’s features may assist to ease symptoms. Taking notes of triggering food ingredients and eliminating them from the diet can also prevent flare-ups.
Furthermore, stress is another culprit for Crohn’s flares. Mind diversion, physical exercise, and exposure to nature may help to reduce stress-related flare-ups.
Bowel rest is a method that aims to give rest to the gut, by providing necessary nutrients to the patient’s body via only fluid intake. Some patients may have prolonged bowel rest, depending on the person's symptoms. Since this liquid diet does not put any exertion on the intestines, it gives them an opportunity to take a break and heal.
Following a low residue, diet is considered the best option for Crohn’s patients, which can also relieve diarrhoea and abdominal pain. For strictures, it is better to avoid nuts, seeds, and caffeinated beverages.
A few excellent sources of vegetal proteins like skinned pulses have probiotic action and promote protective gut mucosal lining. Many studies demonstrated that fruits, extractive juices, and some vegetable consumption can have a protective immune-modulating effect in CD patients.31
Crohn’s disease is a tricky chronic inflammatory disease with a rising prevalence rate on a global level. Features high incidence margins in the young people AFAB population, especially those who are at obesity risk.17 Since there is no cure for Crohn’s disease, identifying risk factors with early clinical interventions and changes in controllable characteristics such as healthy dietary habits, avoiding cigarettes, physical activity, and managing stress can contribute greatly to helping CD flares and promoting remissions. Regular IBD surveillance and preconception counselling should be promoted among fertile people AFAB in collaboration with obstetricians and gastroenterologists to reduce adverse pregnancy outcomes and gynaecological symptoms among people AFAB.
- Obesity [Internet]. [cited 2022 Jul 27]. Available from: https://www.who.int/health-topics/obesity
- What is inflammatory bowel disease (Ibd)? | IBD [Internet]. 2022 [cited 2022 Jul 27]. Available from: https://www.cdc.gov/ibd/what-is-IBD.htm
- Global differences between women and men in the prevalence of obesity: is there an association with gender inequality? European Journal of Clinical Nutrition [Internet]. 2014 Oct 1;68(10):1101–6. Available from: https://www.researchgate.net/publication/263056142_Global_differences_between_women_and_men_in_the_prevalence_of_obesity_Is_there_an_association_with_gender_inequality
- Singh S, Dulai PS. Obesity in IBD: epidemiology, pathogenesis, disease course and treatment outcomes. Nature Reviews Gastroenterology & hepatology [Internet]. 2017 Feb 1 [cited 2021 Dec 15];14(2):110–21. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5550405/
- Team E. What is ulcerative colitis? | ulcerativecolitis [Internet]. InflammatoryBowelDisease.net. [cited 2022 Jul 27]. Available from: https://inflammatoryboweldisease.net/types-of-ibd/ulcerative-colitis
- Crohn’s disease - Symptoms and causes [Internet]. Mayo Clinic. [cited 2022 Jul 27]. Available from: https://www.mayoclinic.org/diseases-conditions/crohns-disease/symptoms-causes/syc-20353304
- Crohn’s disease in women. International Journal of Women’s Health [Internet]. 2013 Oct 18;5:681–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3804567/
- What causes crohn's disease flares? [Internet]. Crohn's and Colitis. [cited 2022 Jul 27]. Available from: https://www.crohnsandcolitis.com/living-with-crohns-uc/crohns/flare-ups
- Back IR, Marcon SS. BODY COMPOSITION IN PATIENTS WITH CROHN’S DISEASE AND ULCERATIVE COLITIS. [Internet]. 2017 Apr 1 [cited 2022 Mar 5];54(2):109–14. Available from: https://pubmed.ncbi.nlm.nih.gov/28198913/
- Bmi (Body mass index): what it is & how to calculate [Internet]. Cleveland Clinic. [cited 2022 Jul 27]. Available from: https://my.clevelandclinic.org/health/articles/9464-body-mass-index-bmi
- High prevalence of overweight and obesity in adults with Crohn's disease: Associations with disease and lifestyle factors [Internet]. academic.oup.com. Available from: https://academic.oup.com/ecco-jcc/article/7/7/e241/407634
- January 15 E on, June 10 2019 · Last reviewed on, 2022. Visceral fat is body fat thats stored within the abdominal cavity around a number of important internal organs such as the liver, pancreas and intestines. [Internet]. Diabetes. 2019 [cited 2022 Jul 27]. Available from: https://www.diabetes.co.uk/body/visceral-fat.html
- Mesenteric fat in crohn’s disease [Internet]. Crohn’s & Colitis Foundation. [cited 2022 Jul 27]. Available from: https://www.crohnscolitisfoundation.org/clinical-pearls/mesenteric-fat-crohns-disease
- https://www.intechopen.com/chapters/59154 [Internet]. www.intechopen.com. [cited 2022 Jul 15]. Available from: https://www.intechopen.com/chapters/59154
- Khalili H, et al. Measures of Obesity and Risk of Crohnʼs Disease and Ulcerative Colitis. Inflammatory Bowel Diseases [Internet]. 2015 Feb [cited 2020 Nov 14];21(2):361–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4308549/
- Peyrin-Biroulet, et al. Mesenteric fat as a source of C reactive protein and as a target for bacterial translocation in Crohn’s disease. Gut. 2011 Sep 21;61(1):78–85. Available from: https://gut.bmj.com/content/61/1/78
- Crohn’s disease in women. International Journal of Women’s Health [Internet]. 2013 Oct 18;5:681–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3804567/
- Determinants of Weight Loss prior to Diagnosis in Inflammatory Bowel Disease: A Retrospective Observational Study. Gastroenterology Research and Practice [Internet]. 2014;2014. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4259140/
- Normal menstruation (Monthly period): menstrual cycle & symptoms [Internet]. Cleveland Clinic. [cited 2022 Jul 27]. Available from: https://my.clevelandclinic.org/health/articles/10132-normal-menstruation
- Menstrual Cycle Changes in Women with Inflammatory Bowel Disease: A Study from the Ocean State Crohn’s and Colitis Area Registry. Inflammatory bowel diseases [Internet]. 2014 Mar 1 [cited 2020 Jul 31];20(3):534–40. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4347838/
- Dysmenorrhea [Internet]. 2019 [cited 2022 Jul 27]. Available from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/dysmenorrhea
- Dysmenorrhea in Women with Crohnʼs Disease. Inflammatory Bowel Diseases. 2013 Jun;19(7):1463–9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3813001/
- Scharl M, Rogler G, Biedermann L. Fistulizing Crohn’s Disease. Clinical and Translational Gastroenterology [Internet]. 2017 Jul 1;8(7):e106. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5539341/
- Jess T, Frisch M, Jørgensen KT, Pedersen BV, Nielsen NM. Increased risk of inflammatory bowel disease in women with endometriosis: a nationwide Danish cohort study. Gut [Internet]. 2012 Sep 1 [cited 2022 Jul 27];61(9):1279–83. Available from: https://gut.bmj.com/content/61/9/1279
- Team E. Blood tests for ibd [Internet]. InflammatoryBowelDisease.net. [cited 2022 Jul 27]. Available from: https://inflammatoryboweldisease.net/diagnostic-tests-and-procedures/blood-tests
- Comprehensive metabolic panel - health encyclopedia - university of rochester medical center [Internet]. [cited 2022 Jul 27]. Available from: https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=comprehensive_metabolic_panel
- Sed rate (Erythrocyte sedimentation rate) - mayo clinic [Internet]. [cited 2022 Jul 27]. Available from: https://www.mayoclinic.org/tests-procedures/sed-rate/about/pac-20384797
- Arnett DK, Blumenthal RS, Albert MA, Buroker AB, Goldberger ZD, Hahn EJ, et al. 2019 acc/aha guideline on the primary prevention of cardiovascular disease: a report of the american college of cardiology/american heart association task force on clinical practice guidelines. Circulation [Internet]. 2019 Sep 10 [cited 2022 Jul 27];140(11). Available from: https://www.ahajournals.org/doi/10.1161/CIR.0000000000000678
- Anti-saccharomyces cerevisiae antibodies(Asca) [Internet]. Testing.com. 2021 [cited 2022 Jul 27]. Available from: https://www.testing.com/tests/anti-saccharomyces-cerevisiae-antibodies-asca/
- Relief IBD. Faecal calprotectin | Testing & causes of high result [Internet]. IBDrelief. [cited 2022 Jul 27]. Available from: http://www.ibdrelief.com/learn/what-is-faecal-calprotectin-test-for-ibd
- The role of diet in the prevention and treatment of Inflammatory Bowel Diseases. Acta Bio Medica : Atenei Parmensis [Internet]. 2018;89(Suppl 9):60–75. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6502201/
- Premenstrual syndrome (Pms) - Symptoms and causes [Internet]. Mayo Clinic. [cited 2022 Jul 27]. Available from: https://www.mayoclinic.org/diseases-conditions/premenstrual-syndrome/symptoms-causes/syc-20376780