Joint effects of systolic blood pressure and serum cholesterol on cardiovascular disease in the Asia Pacific region

Abstract

Background: Although interest in multifactorial interventions for cardiovascular disease is increasing, data on the strength and shape of the joint effects of blood pressure and cholesterol levels on the risk of cardiovascular disease are scarce, confined primarily to coronary heart disease (CHD) mortality in early middle-aged Western populations.

Methods and results: This analysis included 29 cohorts from Asia (78% of the total 380,216 participants) and 7 from Australia and New Zealand, with a total of 2,547,447 person-years of observation. Stratified time-dependent Cox proportional-hazards analyses were used to regress time until first event against baseline systolic blood pressure (SBP) and total cholesterol levels. A total of 3079 CHD and 4247 stroke events occurred; stroke subtypes were confirmed by CT, MRI, or necropsy in 1471 (35%) stroke events. Usual values of SBP were strongly linearly associated with ischemic stroke, hemorrhagic stroke, and CHD. The slope of the association with SBP became steeper with decreasing levels of cholesterol for ischemic stroke (P=0.007) and CHD (P< or =0.0001). For example, for the cholesterol groups of <4.75, 4.75 to 5.49, 5.50 to 6.24, and > or =6.25 mmol/L, each 10-mm Hg-higher systolic pressure was associated with 34% (95% CI, 30% to 37%), 28% (95% CI, 21% to 35%), 25% (95% CI, 18% to 32%), and 21% (95% CI, 13% to 27%) higher CHD risk, respectively. Adjustments for other leading cardiovascular risk factors made no appreciable differences in these results.

Conclusions: In Asia-Pacific populations, there are hazards of increasing SBP at all cholesterol levels and hazards of increasing cholesterol at all levels of SBP, but the associations of SBP with CHD risk and ischemic stroke risk are slightly steeper among those with low cholesterol levels. The joint effects of SBP and total cholesterol on cardiovascular disease seem consistent across various Western and Asian populations.