Adult malnutrition is much more widespread than is commonly recognized. Described in this article is the use of body mass index (BMI = weight in kg/(height in metres)2) as a measure of adult nutritional status, both of individuals and of communities. Concurrent assessment of the nutritional status of children and adults permits conclusions to be drawn about whether there is generalized undernutrition in a community or whether other factors (e.g., childhood infections or feeding practices) are more important in childhood malnutrition. Included is a tabular presentation that permits rapid assessment of both thinness or underweight (BMI values < 16, 17 and 18.5) and overweight (BMI > 25, 30 and 40). Examples of the use of BMI in both clinical and public health practice are also given.
PIP: Data on the body mass index (BMI) of a well-nourished population (range 18-25) were used to determine the prevalence of adults having a BMI less than 18.5 or greater than 30 in different regions of the world. Established market economies and former socialist economies had the highest prevalence of adults with a BMI greater than 30 (7-15%) and the lowest for adults with a BMI less than 18.5 (0-5%). The prevalence of underweight children younger than 5 in these same countries was 2-5%. China had one of the lowest prevalences of underweight children (1%) and the lowest prevalence of BMI greater than 30 (1%). 1% of adults in India had a BMI more than 30. India had the highest proportion of adults with a BMI less than 18.5 (30-70%), followed by sub-Saharan Africa (10-60%) and other Asian countries and islands (5-50%). Clinicians can use the cut-off points to identify individuals at risk due to thinness or overweight status and in women early in pregnancy, to select or exclude individuals for an intervention (e.g., food supplementation), and to monitor progress for a patient being treated for severe thinness or obesity. Public health and socioeconomic development programs can also use them similarly. For example, they can use them as a tool to determine the degree of undernutrition and overnutrition in adult populations worldwide as a proxy indicator of undernutrition and risks of diet-related noncommunicable diseases. They can also use them to monitor trends in community nutrition. This article provides an annex on sample sizes for BMI surveys, including a table providing BMIs and heights to guide clinicians and public health specialists in assessing thinness and overweight status.