Even if risk factors stay at year 2000 levels, cardiovascular disease events in China will likely increase by more than a half between 2010–2030 due to aging and population growth. We forecast that projected cardiovascular risk factor trends will increase cardiovascular events by approximately an additional 14% in Chinese adults from 2010–2030, above and beyond demographic effects. The recent rate of decline in smoking will not be sufficient to counteract approximately 26 million cardiovascular disease events and nine million cardiovascular deaths added by deleterious trends in SBP, TC, diabetes, and BMI. We projected that an aggressive tobacco control policy—lowering active smoking prevalence to 20% by 2020 and 10% by 2030—would produce a reduction in total mortality in Chinese men despite adverse trends in other risk factors. Only lowering SBP across the adult population would reduce cardiovascular and non-cardiovascular deaths in men and women.
We projected that unfavorable trends in SBP, TC, diabetes and BMI would substantially augment cardiovascular disease event rates, and especially so for ischemic stroke. Chinese surveys have documented consumption of more dietary fats,1
and less physical activity3
over time. Additionally, relatively few Chinese adults with dyslipidemia,37
high blood pressure38
are aware of these risk factors. Zhao et al. found a transition toward increased ischemic stroke and decreased hemorrhagic strokes in Beijing.39
In our model, less hemorrhagic stroke coupled with increased ischemic stroke occurred only if we simulated a modest SBP decline and large TC and diabetes increases. Because of the predominance of stroke in China and the strong association between blood pressure and stroke, optimistic blood pressure trend and intervention scenarios reduced cardiovascular and non-cardiovascular outcomes most dramatically. If BMI has cardiovascular effects not mediated by SBP, total cholesterol, HDL40–41
or effects mediated by factors not modeled here,42
BMI would be on par with SBP and TC as a driver of adverse cardiovascular disease trends.
The Chinese government taxes tobacco products, and has achieved a steady though slight decline in smoking. Only an extremely aggressive approach to tobacco control would prevent at least 4.5 million deaths from all causes in men from 2010 to 2030, and keep all-cause mortality from rising despite expected increased cardiovascular deaths. A stronger tobacco taxation policy could save millions of lives, and generate government revenues that would eclipse losses to industry and tobacco farmers.43
We assumed increasing TC will increase CHD. CHD incidence declined in Japan despite a 0.5 mmol/l (20 mg/dl) mean rise in TC in adults between 1980 and 2000, presumably in part because SBP and smoking decreased, elevated cholesterol requires a long ‘incubation period’, 44
or TC does not capture unique dietary influences or sub-fraction changes. Cardiovascular disease death rates usually decline with economic development, a trend slowed, but not reversed by unfavorable cholesterol trends.45
We simulated one driver of decline in deaths with economic development by immediately improving case-fatality—lower case-fatality would lead to 25% fewer cardiovascular deaths in the base case and blunt cardiovascular mortality increases from unfavorable risk factor trends.
Assuming the higher diabetes prevalence or stronger diabetes coefficients resulted in two-thirds to twice more the projected cardiovascular disease events compared with the main assumption fasting glucose-only diabetes definition of diabetes and CMCS diabetes coefficients. CMCS diabetes risk coefficients are weak compared with other studies,7, 46
perhaps due to under-diagnosis or inclusion of predominantly mild cases of diabetes
Prior Markov-style population models of cardiovascular disease in China used risk factor relative risks from Western and Asian cohort studies10, 47
or China-specific risk equations.48
The accuracy of re-calibrated Framingham prediction equations for Chinese populations remains controversial.6–8
Our simulations substituting Framingham coefficients for the CMCS coefficients yielded CHD and stroke projections that varied from the main projections by up to 16 percentage points. Stroke projections varied mostly because TC was not a significant predictor of total stroke in Framingham.49
Stroke predictions were more detailed and probably more accurate using China-specific stroke equations, but there was uncertainty regarding whether CMCS or Framingham CHD diabetes and cholesterol coefficients should be used.
Aging and growth of the Chinese population are certain, but the trends projected here were based on limited survey data gathered since China’s economic reforms after 1979 and remain uncertain. Much hinges on future rates of economic development and urbanization. HDL was not modeled (except as an indirect product of BMI), nor was widespread passive smoking exposure in Chinese women, both due to limited past survey data. Artificial ceilings limiting highest future risk factor levels may be overly conservative: on Nauru, diabetes prevalence already exceeds 30%,25
and total cholesterol was as high as 7.0 mmol/l in 1970’s Finland.50
On the other hand, generalizing the rapid rise in total cholesterol observed in the urban Beijing population19
to all of China may have led to overestimation. For this analysis, for the sake of simplicity, uncertainty about trend projections was tested using only one-way sensitivity analyses, which are limited compared with multi-way analyses.
In this computer modeling study, unfavorable trends in SBP, TC, and diabetes from 2010–2030 were projected to increase cardiovascular disease events by approximately 14% above and beyond the increase expected due to aging and population growth, even if active cigarette smoking continues the recent rate of decline. Population-wide risk reduction policies, screening for cardiovascular disease risk factors, and scaling up of successful local risk factor prevention and treatment programs should be included in China’s health system reform. Even if other adverse risk factor trends continue unabated, national policy targeted toward aggressive tobacco control policy or blood pressure lowering could save 2.9–5.7 million lives during the next 20 years.