Article Text
Abstract
Background Elevated blood pressure and excess weight are established major risk factors for cardiovascular disease (CVD). Previous studies have suggested that hypertension is a greater cardiovascular hazard among obese compared with lean individuals, but the epidemiological evidence is conflicting.
Methods and Results The interaction between systolic blood pressure (SBP) and BMI on fatal or non-fatal coronary heart disease (CHD), ischaemic stroke and hemorrhagic stroke was examined using pooled data from the Asia Pacific Cohort Studies Collaboration. Participants of the study were 419 448 men and women aged >30 years at baseline. BMI was categorised into five groups (12.0–18.4, 18.5–22.9, 23.0–24.9, 25.0–29.9 and 30.0–60.0 kg/m2). Cox proportional hazard models, stratified by sex and study, were used to estimate HRs adjusting for age and smoking status, and the interaction between SBP and BMI was assessed by likelihood ratio test. During 2 619 241 person-years of follow-up, there were 10 877 CVD events (59% in Asia, 34% women, 71% fatal). For all forms of CVD except haemorrhagic stroke, there was evidence of an antagonistic interaction between SBP and BMI such that the risks of subsequent CHD (p=0.01), ischaemic stroke (p=0.03) and CVD (p=0.001) associated with increases in SBP were higher in normal-weight individuals compared with obese individuals.
Conclusion Increased SBP is an important determinant of subsequent cardiovascular risk irrespective of body size and, in relative terms, lean individuals were shown to have a poorer prognosis for CHD and ischaemic stroke.