Risk Factor Trends in Cardiometabolic Mortality Decline
Risk Factor Trends in Cardiometabolic Mortality Decline
Background Cardiovascular disease mortality has declined and diabetes mortality has increased in high-income countries. We estimated the potential role of trends in population body mass index, systolic blood pressure, serum total cholesterol and smoking in cardiometabolic mortality decline in 26 industrialized countries.
Methods Mortality data were from national vital statistics. Body mass index, systolic blood pressure and serum total cholesterol were from a systematic analysis of population-based data. We estimated the associations between change in cardiometabolic mortality and changes in risk factors, adjusted for change in per-capita gross domestic product. We calculated the potential contribution of risk factor trends to mortality decline.
Results Between 1980 and 2009, age-standardized cardiometabolic mortality declined in all 26 countries, with the annual decline between <1% in Mexico to ~5% in Australia. Across the 26 countries together, risk factor trends may have accounted for ~48% (men) and ~40% (women) of cardiometabolic mortality decline. Risk factor trends may have accounted for >60% of decline among men and women in Finland and Switzerland, men in New Zealand and France, and women in Italy; their benefits were smallest in Mexican, Portuguese, and Japanese men and Mexican women. Risk factor trends may have slowed down mortality decline in Chilean men and women and had virtually no effect in Argentinean women. The contributions of risk factors to mortality decline seemed substantially larger among men than among women in the USA, Canada and The Netherlands.
Conclusions Industrialized countries have varied widely in the extent of risk factor prevention, and its likely benefits for cardiometabolic mortality.
Cardiovascular disease (CVD) mortality has declined for decades in high-income countries. The effects of smoking, high blood pressure and cholesterol, and excess weight on the CVD risk of individuals have been established in randomized trials and/or prospective cohorts. This knowledge has led to clinical interventions and public health actions to reduce risk factors in individual patients as well as populations. The question however remains whether, and how much, changes in risk factors have contributed to the observed CVD decline at the population level in different countries.
The contributions of risk factor trends to long-term mortality decline have been assessed using repeated surveys in Finland. Some studies, including by the authors of the current work, have used modelling to quantify the mortality and disease burden attributable to risk factors or to assign a portion of the CVD mortality decline to risk factor trends in selected populations; these studies have assumed that the causal effects from individual-level epidemiological studies apply to whole populations. In the 1980s, the MONICA (Multinational MONItoring of trends and determinants in CArdiovascular disease) Project was established to empirically examine the relationship between risk factor changes in the population and CVD trends over a 10-year period using data from 38 centres in 21 countries. In the MONICA Project, changes in smoking, blood pressure, serum cholesterol and body mass index (BMI) partially explained the cross-population variation in CHD decline but there was substantial unexplained variation.
During the 15+ years since the MONICA Project, CVD mortality has further declined but diabetes prevalence and mortality has increased in high-income countries, with substantial differences in trends across countries and between men and women. Risk factor trends also had similarities as well as noticeable differences by sex and country. For example, BMI increased more among men and women in Australia and USA than in Western Europe, but American men and Australian women had the fourth and eighth largest decline in systolic blood pressure (SBP) among industrialized countries; in contrast, American women had the third smallest SBP decline. Serum total cholesterol (TC) declined more in Nordic countries and New Zealand than in Southern Europe, with Sweden and Finland now having lower TC than Italy.
There are no empirical cross-country assessments of the associations between trends in multiple risk factors and CVD mortality since the MONICA Project, especially at the national level; only modelling studies have been done in specific countries. Further, the role of risk factors in the rise in diabetes mortality has not been assessed. We used advances in data on mortality and risk factors to examine the effect of trends in risk factors on cardiometabolic (CVD and diabetes) mortality trends empirically in national populations of industrialized countries. Our aim was to answer the important question of how much changes in risk factors may have contributed to the observed mortality decline at the population level.
Abstract and Introduction
Abstract
Background Cardiovascular disease mortality has declined and diabetes mortality has increased in high-income countries. We estimated the potential role of trends in population body mass index, systolic blood pressure, serum total cholesterol and smoking in cardiometabolic mortality decline in 26 industrialized countries.
Methods Mortality data were from national vital statistics. Body mass index, systolic blood pressure and serum total cholesterol were from a systematic analysis of population-based data. We estimated the associations between change in cardiometabolic mortality and changes in risk factors, adjusted for change in per-capita gross domestic product. We calculated the potential contribution of risk factor trends to mortality decline.
Results Between 1980 and 2009, age-standardized cardiometabolic mortality declined in all 26 countries, with the annual decline between <1% in Mexico to ~5% in Australia. Across the 26 countries together, risk factor trends may have accounted for ~48% (men) and ~40% (women) of cardiometabolic mortality decline. Risk factor trends may have accounted for >60% of decline among men and women in Finland and Switzerland, men in New Zealand and France, and women in Italy; their benefits were smallest in Mexican, Portuguese, and Japanese men and Mexican women. Risk factor trends may have slowed down mortality decline in Chilean men and women and had virtually no effect in Argentinean women. The contributions of risk factors to mortality decline seemed substantially larger among men than among women in the USA, Canada and The Netherlands.
Conclusions Industrialized countries have varied widely in the extent of risk factor prevention, and its likely benefits for cardiometabolic mortality.
Introduction
Cardiovascular disease (CVD) mortality has declined for decades in high-income countries. The effects of smoking, high blood pressure and cholesterol, and excess weight on the CVD risk of individuals have been established in randomized trials and/or prospective cohorts. This knowledge has led to clinical interventions and public health actions to reduce risk factors in individual patients as well as populations. The question however remains whether, and how much, changes in risk factors have contributed to the observed CVD decline at the population level in different countries.
The contributions of risk factor trends to long-term mortality decline have been assessed using repeated surveys in Finland. Some studies, including by the authors of the current work, have used modelling to quantify the mortality and disease burden attributable to risk factors or to assign a portion of the CVD mortality decline to risk factor trends in selected populations; these studies have assumed that the causal effects from individual-level epidemiological studies apply to whole populations. In the 1980s, the MONICA (Multinational MONItoring of trends and determinants in CArdiovascular disease) Project was established to empirically examine the relationship between risk factor changes in the population and CVD trends over a 10-year period using data from 38 centres in 21 countries. In the MONICA Project, changes in smoking, blood pressure, serum cholesterol and body mass index (BMI) partially explained the cross-population variation in CHD decline but there was substantial unexplained variation.
During the 15+ years since the MONICA Project, CVD mortality has further declined but diabetes prevalence and mortality has increased in high-income countries, with substantial differences in trends across countries and between men and women. Risk factor trends also had similarities as well as noticeable differences by sex and country. For example, BMI increased more among men and women in Australia and USA than in Western Europe, but American men and Australian women had the fourth and eighth largest decline in systolic blood pressure (SBP) among industrialized countries; in contrast, American women had the third smallest SBP decline. Serum total cholesterol (TC) declined more in Nordic countries and New Zealand than in Southern Europe, with Sweden and Finland now having lower TC than Italy.
There are no empirical cross-country assessments of the associations between trends in multiple risk factors and CVD mortality since the MONICA Project, especially at the national level; only modelling studies have been done in specific countries. Further, the role of risk factors in the rise in diabetes mortality has not been assessed. We used advances in data on mortality and risk factors to examine the effect of trends in risk factors on cardiometabolic (CVD and diabetes) mortality trends empirically in national populations of industrialized countries. Our aim was to answer the important question of how much changes in risk factors may have contributed to the observed mortality decline at the population level.
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