A randomized controlled trial of orthodontist-based brief advice to prevent child obesity.

OBJECTIVE: We conducted a randomized controlled trial to test whether brief exercise and diet advice provided during child patient visits to their orthodontic office could improve diet, physical activity, and age-and-gender-adjusted BMI. METHODS: We enrolled orthodontic offices in Southern California and Tijuana, Mexico, and recruited their patients aged 8-16 to participate in a two-year study. At each office visit, staff provided the children with "prescriptions" for improving diet and exercise behaviors. Multilevel models, which adjusted for clustering, determined differential group effects on health outcomes, and moderation of effects. RESULTS: We found differential change in BMI favoring the intervention group, but only among male participants (p < 0.001; Cohen's d = 0.085). Of four dietary variables, only junk food consumption changed differentially, in favor of the intervention group (p = 0.020; d = 0.122); the effect was significant among overweight/obese (p = 0.001; d = 0.335) but not normal weight participants. Physical activity declined non-differentially in both groups and both genders. CONCLUSION: The intervention, based on the Geoffrey Rose strategy, had limited success in achieving its aims. IMPLICATIONS: Orthodontists can deliver non-dental prevention advice to complement other health-practitioner-delivered advice. Higher fidelity to trial design is needed to adequately test the efficacy of clinician-based brief advice on preventing child obesity and/or reversing obesity.