Abstract 13195: Race, Body Mass Index, and the Risk of Atrial Fibrillation: The Multi-Ethnic Study of Atheroclerosis

Abstract

Introduction: Higher body mass index (BMI) is associated with an increased risk of incident atrial fibrillation (AF), but it is not known if this relationship varies based on race/ethnicity. Hypothesis: The relationship between BMI and incident AF will vary by race/ethnicity. Methods: Eligible MESA participants had no AF at baseline. The risk of incident AF as a function of baseline BMI was modelled using Cox proportional hazards. Formal tests of interaction by race/ethnicity were performed. Restricted cubic splines models were used to explore non-linear relationships. Results: Among 6,739 participants, 0.8% were underweight, 27.8% had normal BMI, 39.0% were overweight, 21.1% had grade I obesity, 7.6% had grade II obesity, and 3.7% had grade III obesity. Over 79,860 person-years of follow-up (median 13.8), 991 participants (14.7%) had new-onset AF. With BMI modeled as a categorical variable, only those with grade II and grade III obesity had an increased risk of AF (HR 1.48, 95% CI 1.13 - 1.94, p = 0.005 for grade II obesity and HR 2.21, 95% CI 1.11 - 4.40, p = 0.02 for grade III obesity ). The relationship between BMI and AF risk was non-linear, best characterized as J-shaped. However, the risk of AF as a function of BMI varied substantially by race/ethnicity (p-value for interaction = 0.02), with Chinese-American participants having a much higher risk of AF with higher BMI and African-American participants having minimal increased risk of AF with higher BMI (Figure 1). Conclusions: Obesity is associated with an increased risk of incident AF. The relationship between BMI and the risk of AF is J-shaped and this relationship differs by race/ethnicity, such that Chinese-Americans have a more pronounced increased risk of AF with higher BMI, while African-Americans have minimal increased risk. Further exploration of the differential effects of BMI by race/ethnicity on cardiovascular outcomes is needed.