Angular stomatitis and riboflavin status

Summary of published paper¹

Severe angular stomatitis

Between 1990 and 1993, fear of persecution led 83,000 ethnic Nepalese to flee from Bhutan to refugee camps in Nepal. Between December 1998 and March 1999, reported cases of angular stomatitis (thinning or fissuring at the mouth angles) increased six-fold, from 5.5 to 35.6 cases per 1000 per month. The highest rates were found in children and adolescents. This increase followed the removal of a fortified cereal from food rations, withdrawn in January 1999 due to programme constraints. Consequently, the riboflavin content of the daily ration fell from less than 0.6 mg/day to 0.4 mg/day, well below the WHO recommended amounts of 1.35-1.8 mg/day for adolescents.

Mild/moderate angular stomatitis

Angular stomatitis (AS) has classically been linked with deficiencies of riboflavin, other B group vitamins and iron. Potential functional consequences of riboflavin deficiency in humans include decreases in motor skills and attention span, and reduced absorption or utilisation of iron.

In October 1999, 463 adolescent refugees were randomly surveyed to assess the prevalence of AS and the prevalence of low concentrations of riboflavin, folate, vitamin B-12 and iron. Interviews and physical examinations were made and blood samples taken. Biochemical measures were used to determine whether riboflavin status was associated with AS and to assess the potential of using AS as a screening measure for low riboflavin concentrations. Riboflavin status was assessed using the erythrocyte glutathione reductase (EGR) activity coefficient (EGR is a riboflavin dependent enzyme).

The main findings of the survey were that AS was common (26.8%), the prevalence of low riboflavin concentration was high (85.8%) and riboflavin status was associated with AS. Adolescents with AS had significantly lower riboflavin concentrations than did adolescents without AS.

Scarred angular stomatitis

The authors of the survey concluded that AS was a good screening measure for low riboflavin concentration. It had a high specificity and positive predictive value (PPV) but a low sensitivity in detecting low riboflavin concentration. Because PPV increases with the prevalence of the condition, the PPV would be expected to be lower where prevalence of AS is lower. The high PPV in this survey (89%) shows that AS can be used in conjunction with other relevant nutrient data, e.g. data on the nutrient composition of the food basket, as a surveillance tool to indicate marginal riboflavin concentrations in refugee or displaced populations. The low sensitivity of AS, however, limits its utility as an individual screening measure for low riboflavin concentrations.

¹Blank H et al (2002). Angular stomatitis and riboflavin status among adolescent Bhutanese refugees living in south-eastern Nepal. American Journal of Clinical Nutrition, vol 76, pp 430-435