Using the theory of reasoned action to determine physicians' intention to measure body mass index in children and adolescents.

Background: Over the past few decades, childhood obesity has become a major public health issue in the United States. Numerous public and professional organizations recommend that physicians periodically screen for obesity in children and adolescents using the body mass index (BMI). However, studies have shown that physicians infrequently measure BMI in children and adolescents.

Objectives: The purpose of this study was to use the theory of reasoned action (TRA) to explain physicians' intentions to measure BMI in children and adolescents. The study objectives were to (1) determine if attitude and subjective norm predict physicians' intention to measure BMI in children and adolescents; (2) determine if family physicians and pediatricians differ in terms of theoretical factors; and (3) assess differences in behavioral beliefs, outcome evaluations, normative beliefs, and motivation to comply among physicians based on their level of intention to measure BMI.

Methods: A cross-sectional mailed survey of 2590 physicians (family physicians and pediatricians) practicing in 4 states was conducted. A self-administered questionnaire was designed that included items related to the TRA constructs. The association between the theoretical constructs was examined using correlation and regression analyses. Student's t test was used to determine differences between family physicians and pediatricians on theoretical constructs and to compare the underlying beliefs of nonintenders with intenders.

Results: The usable response rate was 22.8%. Less than half (44%) of the physicians strongly intended to measure BMI in children and adolescents. Together, the TRA constructs attitude and subjective norm explained up to 49.9% of the variance in intention. Pediatricians had a significantly (P<.01) higher intention to measure BMI as compared to family physicians. There were significant (P<.01) behavioral and normative belief differences between physicians who intend and those who do not intend to measure BMI.

Conclusion: The TRA is a useful model in identifying the factors that are associated with physicians' intentions to measure BMI.