Selection of measures in epidemiologic studies of the consequences of obesity

Abstract

The most popular measure for conducting analyses in studies of adiposity is body mass index (BMI); however, BMI does not discriminate between muscle and adipose tissue and does not directly assess regional adiposity. In this article, we address the question of whether alternatives to BMI should be used in epidemiologic analyses of the consequences of obesity. In general, measures of fat distribution such as waist circumference and sagittal abdominal diameter are more highly correlated with cardiovascular disease risk factors and diabetes than BMI; however, differences are usually small. Precise measures of adiposity from methods such as dual-energy x-ray absorptiometry may provide more specific and larger associations with disease, but published studies show that this is not always true. Further, practical considerations such as cost and feasibility must influence the choice of measure in many studies of large populations. Measures of adiposity are highly correlated with each other, and the additional cost of a more precise measure may not be justified in many circumstances. Validated prediction equations that include multiple anthropometric measures, along with demographic variables, may offer a practical means of obtaining assessments of total adiposity in large populations, whereas waist circumference can provide a feasible assessment of abdominal adiposity. Finally, public health messages to the public must be simple to be effective. Therefore, investigators may need to consider the ease of translation of results to the public when choosing a measure.

Obesity and risk of monoclonal gammopathy of undetermined significance and progression to multiple myeloma: a population-based study

“…BMI is a limited measure as it does not give information on fat distribution and does not distinguish between lean and fat mass; however, studies have shown that BMI is highly correlated with other more precise measures of body composition and fat distribution and has been shown to be at least approximately equivalent in the ability to predict diseases. 45 We found in our data that the obesity measures were highly correlated (r 5 0.37-0.95), but the lack of an acceptable gold standard for measuring body fatness makes it difficult to use only 1 measure. Using multiple markers for late-life body fatness deals with the limitations that pertain to each measure and strengthens our findings.…”

Longitudinal associations of energy balance-related behaviours and cross-sectional associations of clusters and body mass index in Norwegian adolescents

“…Furthermore, the questions assessing SS consumption do not measure portion size. Since BMI is used as an indicator for a healthy or unhealthy weight, it could also be that adolescents in the healthy cluster have a higher muscle mass (28) . There are several other limitations of the present study that have to be mentioned.…”

The metabolic syndrome: useful concept or clinical tool? Report of a WHO Expert Consultation

“…However, measurement of BMI and waist circumference often provide comparable estimates of the relationship between degree of adiposity and CVD risk [28], and each may make independent contributions in this regard [29]. Consequently, either measurement can provide a simple approach to identifying individuals at risk for developing the component parts of the metabolic syndrome that contribute to CVD risk.…”