What is oral submucous fibrosis and which populations are most commonly affected?

Oral Submucous Fibrosis (OSMF): Definition and Affected Populations

Oral submucous fibrosis is a chronic, progressive, scarring disease affecting the oral cavity, oropharynx, and sometimes esophageal mucosa, characterized by progressive fibrosis of submucosal tissue leading to restricted mouth opening and increased oral cancer risk. 1

Clinical Definition and Pathophysiology

OSMF is defined by the following key features:

• Progressive accumulation of collagen fibers in the lamina propria and submucosa of oral mucosa, with cross-linking leading to hyalinization that makes collagen resistant to proteolysis 2, 1
• Presence of fibrous bands as the main characteristic feature, causing progressive constriction of the cheeks and mouth 3, 4
• Epithelial atrophy (though sometimes epithelial hyperplasia with or without dysplasia may occur) accompanied by extracellular matrix remodeling 2, 1
• Narrowing of blood vessels due to fibrosis, resulting in compromised blood supply and tissue hypoxia 1
• Clinical manifestations including severe pain, reduced mouth opening (trismus), and difficulty with eating and swallowing 4

Populations Most Commonly Affected

OSMF predominantly affects people of South Asia and Southeast Asia, where areca nut chewing is widespread. 1, 3

Geographic Distribution

• Highest prevalence in the Indian subcontinent and Southeast Asian countries 1, 5
• Increasingly found in other parts of the world due to migration patterns and global spread of areca nut products 5

Gender Distribution

• Males are affected more commonly than females, with approximately 67% male versus 33% female distribution 5

Primary Risk Factor

• Areca nut chewing and its commercial preparations represent the main etiological factor 1, 3, 4
• The areca nut has been classified as a "group one human carcinogen" by international cancer agencies 1

Malignant Transformation Risk

OSMF is classified as a potentially malignant disorder with significant cancer risk:

• Malignant transformation occurs in 7-12% of OSMF cases, making oral squamous cell carcinoma in the background of OSMF one of the most common malignancies in South and Southeast Asian countries 2, 1, 5
• Patients with multiple oral potentially malignant disorders (OPMDs) coexisting with OSMF have substantially elevated risk: those with two OPMDs have 3-4 times higher risk, while those with three or more OPMDs have 7-10 times higher risk of malignant transformation 5
• Common coexisting lesions include leukoplakia (86% of cases with multiple OPMDs), candidiasis (12%), and both conditions together (2%) 5

Clinical Significance

The widespread use of areca nut products, particularly in India, has contributed to rising OSMF incidence, making this a significant public health concern requiring early identification of high-risk populations for prevention and control measures 5.