Background: Sudden cardiac death (SCD) is often the first manifestation of coronary heart disease (CHD) among women. Data regarding BMI and risk of SCD are limited and conflicting.
Objectives: We examined the association of BMI repeatedly measured over 32 years and BMI during early and mid-adulthood with risk of SCD in the Nurses' Health Study.
Methods: We prospectively followed 72,484 women free of chronic disease from 1980-2012. We ascertained adult height, current weight, and weight at age 18 at baseline and updated weight biennially. The primary endpoint was SCD (n=445).
Results: When updated biennially, higher BMI was associated with greater SCD risk after adjusting for confounders (p, linear trend: <0.001). Compared to a BMI of 21.0-22.9, the multivariate RR (95%CI) of SCD was 1.46 (1.05, 2.04) for BMI 25.0-29.9, 1.46 (1.00, 2.13) for BMI 30.0-34.9 and 2.18 (1.44, 3.28) for BMI ≥35.0. Among women with a BMI ≥35.0, SCD remained elevated even after adjustment for interim development of CHD and other mediators (RR: 1.72; 95%CI: 1.13, 2.60). In contrast, the association between BMI and fatal CHD risk was completely attenuated after adjustment for mediators. The magnitude of the association between BMI and SCD was greater when BMI was assessed at baseline or at age 18, at which time SCD risk remained significantly elevated at BMI≥30 after adjustment for mediators.
Conclusions: Higher BMI was associated with greater risk of SCD, particularly when assessed earlier in adulthood. Strategies to maintain a healthy weight throughout adulthood may minimize SCD incidence.
Keywords: obesity; primary prevention; sudden cardiac death; women.