Percentage of population with<unk>  reported in various studies in different countries (see sources in the table) The prevalence of<unk>  varies by country and by age range examined. The bar graph at right shows the percentage of the population reporting symptoms of<unk>  in studies from various geographic regions (see table below for references). The following table contains a list of studies performed in different countries that measured the prevalence of<unk>  and<unk> -like symptoms: Percentage of population reporting symptoms of<unk>  in various studies from various geographic areas Location Prevalence Author/year Notes Canada 6% Boivin, 2001 Japan 10% Quigley, 2006 Study measured prevalence of GI abdominal pain/cramping United Kingdom 8.2% 10.5% Ehlin, 2003 Wilson, 2004 Prevalence increased substantially 1970–2004 United States 14.1% Hungin, 2005 Most undiagnosed United States 15% Boivin, 2001 Estimate Pakistan 14% Jafri, 2007 Much more common in 16–30 age range. 56% male, 44% female Pakistan 34% Jafri, 2005 College students Mexico City 35% Schmulson, 2006 n=324. Also measured functional diarrhea and functional vomiting. High rates attributed to "stress of living in a populated city." Brazil 43% Quigley, 2006 Study measured prevalence of GI abdominal pain/cramping Mexico 46% Quigley, 2006 Study measured prevalence of GI abdominal pain/cramping Gender Women are around two to three times more likely to be diagnosed with<unk>  and four to five times more likely to seek specialty care for it than men. These differences likely reflect a combination of both biological (sex) and social (gender) factors. People diagnosed with<unk>  are usually younger than 45 years old. Studies of females with<unk>  show symptom severity often fluctuates with the menstrual cycle, suggesting hormonal differences may play a role. Endorsement of gender-related traits has been associated with quality of life and psychological adjustment in<unk> . Gender differences in healthcare-seeking may also play a role. Gender differences in trait anxiety may contribute to lower pain thresholds in women, putting them at greater risk for a number of chronic pain disorders. Finally, sexual trauma is a major risk factor for<unk> , as are other forms of abuse. Because women are at higher risk of sexual abuse than men, sex-related risk of abuse may contribute to the higher rate of<unk>  in women.
Irritable bowel syndrome
Bile acid malabsorption
Crohn's disease
Colorectal cancer
Ulcerative colitis
Non-celiac gluten sensitivity
IBS
Inflammatory bowel disease