Abstract 16588: Adiposity, Blood Pressure, and Incidence of Stroke Subtypes Among 0.5 Million Adult Chinese With 7 Years of Follow-Up
Introduction: Stroke is a major cause of mortality and disability worldwide, with particularly high rates in China that cannot be explained by known risk factors. Moreover, uncertainty remains about the associations of adiposity with different stroke subtypes.
Methods: China Kadoorie Biobank prospective study includes 512,891 people aged 30-79 years at recruitment in 2004-8 from 10 regions of China, with 20,000 resurveyed to assess regression dilution. During ~7 years of follow-up, ~30,000 first strokes were recorded among people without prior CVD (with ~75% confirmed by imaging). Cox regression related adiposity and usual systolic blood pressure (SBP) to stroke incidence, adjusting for age, sex, education, region, smoking, alcohol and other factors.
Results: Mean BMI was 24 kg/m2; 4% had BMI>30. Mean SBP/DBP was 131/78 mmHg. Adiposity was more strongly related to blood pressure than in Western populations, with 10 kg/m2 higher BMI yielding ~20 mmHg higher SBP. Each 20 mmHg higher usual SBP was associated with hazard ratios of 1.75 (95%CI 1.73-1.76) for ischaemic stroke (20,257 cases) and 2.49 (2.46-2.53) for haemorrhagic stroke (5,254 cases). Throughout its range, BMI was also strongly positively associated with ischaemic stroke (1.73 [1.69-1.77] per 10 kg/m2 higher BMI), approximately as expected from SBP relationships. The BMI (or other adiposity measures) association with haemorrhagic stroke (1.33 [1.25-1.42] per 10 kg/m2) was significantly weaker (heterogeneity P<0.0001), and was much weaker than expected from the relationships with SBP (Figure).
Conclusion: In Chinese adults, adiposity is positively associated with ischemic stroke, mainly through its effect on blood pressure. For haemorrhagic stroke, leanness, either per se or through some other factor(s), may increase risk, offsetting the protective effects of lower blood pressure. Planned multi-omic investigations will help investigate possible mechanisms.
Author Disclosures: Z. Chen: None. A. Iona: None. Y. Guo: None. M. Smith: None. R. Clarke: None. S. Lewington: None. Y. Chen: None. I. Millwood: None. Z. Bian: None. R. Walters: None. Y. Tang: None. S. Parish: None. R. Collins: None. J. Chen: None. R. Peto: None. L. Li: None.
- © 2014 by American Heart Association, Inc.