| Part One:Potential cardiovascular benefits of air pollution control in urban Chinese population aged 35～84 years over 2016～2030Background and ObjectiveAir pollution has become serve environmental and health problem in China. Ambient pariculate matter pollution ranks fourth among preventable risk factors responsiblefor China’s burden of disease. During 2008 Beijing Olympic Games, our government launched a series of measures to reduce pollutant emissions in the city, resulting in a dramatic decline in air pollution. Epidemiological studies have showed reduced air pollution is associated with reduction in cardiovascular deaths and all-cause deaths. We used a mathematical model to project cardiovascular health benefits achievable with sustained air quality improvement and further compared the benefits from traditional risk factors control in urban Chinese population aged 35～84 years old over 2016～2030.MethodsThe Cardiovascular Disease Policy Model-Chinais a computer-simulation, statetransition (Markov cohort) mathematical model of coronary heart disease (CHD) and stroke incidence, prevalence, mortality, and non-cardiovascular deaths in Chinese population aged 35～84 years old. Urban population trend was estimated based on projected totalpopulation and urbanization rate by United Nation Population Division. Future traditional cardiovascular risk factor trends for population aged 35～84 years were projected forward from 2016 to 2030 based on recent temporal trends from China Health and Nutrition Survey 1990 to 2009.Relative risks of CHD, stroke and all-cause mortality associated with long term PM2.5 exposure were incorporated into the model based on a meta-analysis of cohort studies. The model first simulatedfuture trends of air pollution (PM2.5) and traditional cardiovascular risk factor levels from 2016 to 2030assuming no policy interventions and projected future CHD, stroke, and all-cause deaths in adults aged 35～84 years. The modelthen projected cardiovascular deaths preventedand life years gained if any one of three air quality improvement goals were gradually achieved:1) the 2008 Beijing Olympic Games PM2.5 level of 55μg/m3,2) the China Class II air quality standard of 35μg/m3, and 3) the World Health Organization (WHO) standard of 10μg/m3. For comparison, we also simulated the magnitude of cardiovascular disease prevention achievable with partial control of two traditional cardiovascular disease risk factors (50% of currently uncontrolled systolic hypertension reduced＜140 mmHg or 50% lower both active and secondhand smoking prevalence).ResultsIn the status quo simulation holding the PM2.5 constant at 62μg/m3 and extending traditional risk factor trends forward, about 553,000 CHD deaths and 773,000 stroke deaths were projected annually in urban Chinese population aged 35～84 years old from 2016 to 2030. An average population-wide PM2.5 reduction to2008 Olympic levels would prevent 38,000 CHD deaths (6.8% reduction) and 20,000 stroke deaths (2.6% reduction)annually in urban China. Gradually lowering active and secondhand smoking to 50% of the 2016 prevalence would prevent 64,000 CHD deaths and 17,000 stroke deaths annually. A 50% control rate of systolic BP to 140mmHg among systolic hypertensive patients was projected to avert 75,000 CHD deaths and 130,000 stroke deaths and gain 1,047,000 life years, much larger health benefits than achieving the 2008 Beijing Olympics goal and close to the benefits from achieving China Class Ⅱ standard.ConclusionsAir pollution is a leading cardiovascular risk factor in urban China.Modest improvement in air quality could substantially reduce cardiovascular deaths. More aggressive air quality target could lead to larger cardiovascular benefits. Our government has realized economic development should not be at a sacrifice of environment. It is urgently needed to take our feasible and integrated measures to control air pollution to China Class Ⅱ air quality level.Part Two:Abdominal obesity and hypertension incidence among Chinese adults:a prospective studyBackground and ObjectiveHypertension is the leading risk factor for cardiovascular and all-cause mortality in China. The prevalence of hypertension among Chinese adults increased from 18% in 2002 to 25.2% in 2012. Meanwhile, the prevalence of abdominal obesity was also increasing in parallel with the increasing prevalence of hypertension. The prevalence of abdominal obesity in men (≥90cm) and in women (≥80cm) was dramatically increasing from 8.5% and 27.8% in 1993 to 27.8% and 45.9% in 2009, respectively. In order to provide scientific evidence for policy making, the study examined the relationship between abdominal obesity and hypertension incidence by using a cohort studyMethodsWe conducted a prospective cohort study of 27,020 Chinese adults aged 35～74 years old. Study participants were recruited from the China Multicenter Collaborative Study of Cardiovascular Epidemiology (ChinaMUCA) since 1998 and the International Collaborative Study of Cardiovascular Disease in Asia (InterAsia) during 2000～2001. Two Follow-up surveys were conducted during 2007-2008 and 2013～2015, respectively. A total of 15,289 participants were retained in the final analysis, including 6,952 men and 8,337 women. At baseline, information of participants on demographic, lifestyle and disease history was collected and waist circumference (WC), blood pressure was measured by trained staff.Abdominal obesity was defined as WC≥90cm in men and WC>85cm in women. During follow-up visits, participants’blood pressure was measured and information on antihypertensive treatment was also collected. Hypertension was defined as systolic blood pressure≥140mmHg and/or diastolic blood pressure≥90mmHg and/or anti-hypertensive treatment within two weeks. Cox proportional hazards model was used to estimate hazard ratios (HRs) and 95% confidence interval (95%CIs) of hypertension associated with WC and abdominal obesity. In addition, stratified analyses by selected risk factor groups and sensitivity analyses were conducted to test the robustness of our results.ResultsDuring a mean follow up duration of 11.2 years,6,126 participants were diagnosed of hypertension, including 2,857 cases in men and 3,269 cases in women. Among 949 men and 1,187 women with abdominal obesity,493 and 667 were diagnosed of hypertension during follow up periods, respectively. The cumulative incidence of hypertension for abdominal obesity was 51.9% for men and 56.2% for women, respectively. Compared with non-abdominal obesity, both men and women adults with abdominal obesity had increased risk of hypertension, with multivariate adjusted HR (95%CI) of 1.30(1.17-1.44) in men and 1.40(1.28-1.54) in women. With the group of WC<90cm as reference group, HR (95%CI) for hypertension in the group with WC of 90-94cm,95-99cm and≥100cm was 1.23 (1.08-1.40),1.36 (1.14-1.63) andl.53 (1.18-1.99) in men, respectively (P for trend 0.001); With the group of WC< 85cm as reference group, HR (95%CI) for hypertension in the group with WC of 85-89cm,90-94cm and≥95cmwas 1.41 (1.26-1.58),1.31 (1.11-1.54) and 1.55 (1.28-1.87)in women, respectively (P for trend 0.001). The results were generally consistent in stratified analyses and sensitivity analyses.ConclusionAbdominal obesity is an important risk factor for hypertension incidence among Chinese adults. Waist circumference is linearly associated with hypertension incidence. Hypertension is the leading risk factor for cardiovascular disease and the epidemic of abdominal obesity contributed to the increased prevalence of hypertension.Abdominal obesity should be targeted for hypertension prevention in programs and initiatives for obesity control. |
PDF Full Text Request