Introducing an efficient sampling method for national surveys with limited sample sizes: application to a national study to determine quality and cost of healthcare.

BACKGROUND: Sampling a small number of participants from an entire country is not straightforward. In this case, researchers reluctantly sample from a single setting or few settings, which limits the generalizability of findings. Therefore, there is a need to design efficient sampling method for small sample size surveys that can produce generalizable results at the country level. METHODS: Data comprised of twenty proxy variables to measure health services demands, structures, and outcomes of 413 districts of Iran. We used two data mining methods (hierarchical clustering method (HCM) and model-based clustering method (MCM)) to create homogenous groups of districts, i.e., strata based on these variables. We compared the internal and stability validity of the methods by statistical indices. An expert group checked the face validity of the methods, particularly regarding the total number of strata and the combination of districts in each stratum. The efficiency of selected method, which is measured by the inverse of variance, was compared with a simple random sampling (SRS) through simulation. The sampling design was tested in a national study in Iran, which aimed to evaluate the quality and costs of medical care for eight selected diseases by only recruiting 300 participants per disease at the country level. RESULTS: MCM and HCM divided the districts into eight and two clusters, respectively. The measures of internal and stability validity showed that clusters created by MCM were more separated, compact, and stable, thus forming our optimum strata. The probability of death from stroke, chronic obstructive pulmonary disease, and in-hospital mortality rate were the most important indicators that distinguished the eight strata. Based on the simulation results, MCM increased the efficiency of the sampling design up to 1.7 times compared to SRS. CONCLUSIONS: The use of data mining improved the efficiency of sampling up to 1.7 times greater than SRS and markedly reduced the number of strata to eight in the entire country. The proposed sampling design also identified key variables that could be used to classify districts in Iran for sampling from these target populations in the future studies.

Global sodium consumption and death from cardiovascular causes.

BACKGROUND: High sodium intake increases blood pressure, a risk factor for cardiovascular disease, but the effects of sodium intake on global cardiovascular mortality are uncertain. METHODS: We collected data from surveys on sodium intake as determined by urinary excretion and diet in persons from 66 countries (accounting for 74.1% of adults throughout the world), and we used these data to quantify the global consumption of sodium according to age, sex, and country. The effects of sodium on blood pressure, according to age, race, and the presence or absence of hypertension, were calculated from data in a new meta-analysis of 107 randomized interventions, and the effects of blood pressure on cardiovascular mortality, according to age, were calculated from a meta-analysis of cohorts. Cause-specific mortality was derived from the Global Burden of Disease Study 2010. Using comparative risk assessment, we estimated the cardiovascular effects of current sodium intake, as compared with a reference intake of 2.0 g of sodium per day, according to age, sex, and country. RESULTS: In 2010, the estimated mean level of global sodium consumption was 3.95 g per day, and regional mean levels ranged from 2.18 to 5.51 g per day. Globally, 1.65 million annual deaths from cardiovascular causes (95% uncertainty interval [confidence interval], 1.10 million to 2.22 million) were attributed to sodium intake above the reference level; 61.9% of these deaths occurred in men and 38.1% occurred in women. These deaths accounted for nearly 1 of every 10 deaths from cardiovascular causes (9.5%). Four of every 5 deaths (84.3%) occurred in low- and middle-income countries, and 2 of every 5 deaths (40.4%) were premature (before 70 years of age). The rate of death from cardiovascular causes associated with sodium intake above the reference level was highest in the country of Georgia and lowest in Kenya. CONCLUSIONS: In this modeling study, 1.65 million deaths from cardiovascular causes that occurred in 2010 were attributed to sodium consumption above a reference level of 2.0 g per day. (Funded by the Bill and Melinda Gates Foundation.).

Estimated Global, Regional, and National Disease Burdens Related to Sugar-Sweetened Beverage Consumption in 2010.

BACKGROUND: Sugar-sweetened beverages (SSBs) are consumed globally and contribute to adiposity. However, the worldwide impact of SSBs on burdens of adiposity-related cardiovascular diseases (CVDs), cancers, and diabetes mellitus has not been assessed by nation, age, and sex. METHODS AND RESULTS: We modeled global, regional, and national burdens of disease associated with SSB consumption by age/sex in 2010. Data on SSB consumption levels were pooled from national dietary surveys worldwide. The effects of SSB intake on body mass index and diabetes mellitus, and of elevated body mass index on CVD, diabetes mellitus, and cancers were derived from large prospective cohort pooling studies. Disease-specific mortality/morbidity data were obtained from Global Burden of Diseases, Injuries, and Risk Factors 2010 Study. We computed cause-specific population-attributable fractions for SSB consumption, which were multiplied by cause-specific mortality/morbidity to compute estimates of SSB-attributable death/disability. Analyses were done by country/age/sex; uncertainties of all input data were propagated into final estimates. Worldwide, the model estimated 184 000 (95% uncertainty interval, 161 000-208 000) deaths/y attributable to SSB consumption: 133 000 (126 000-139 000) from diabetes mellitus, 45 000 (26 000-61 000) from CVD, and 6450 (4300-8600) from cancers. Five percent of SSB-related deaths occurred in low-income, 70.9% in middle-income, and 24.1% in high-income countries. Proportional mortality attributable to SSBs ranged from <1% in Japanese >65 years if age to 30% in Mexicans <45 years of age. Among the 20 most populous countries, Mexico had largest absolute (405 deaths/million adults) and proportional (12.1%) deaths from SSBs. A total of 8.5 (2.8, 19.2) million disability-adjusted life years were related to SSB intake (4.5% of diabetes mellitus-related disability-adjusted life years). CONCLUSIONS: SSBs are a single, modifiable component of diet that can impact preventable death/disability in adults in high-, middle-, and low-income countries, indicating an urgent need for strong global prevention programs.

Impact of Dietary and Metabolic Risk Factors on Cardiovascular and Diabetes Mortality in South Asia: Analysis From the 2010 Global Burden of Disease Study.

OBJECTIVES: To quantify cardiovascular disease and diabetes deaths attributable to dietary and metabolic risks by country, age, sex, and time in South Asian countries. METHODS: We used the 2010 Global Burden of Disease national surveys to characterize risk factor levels by age and sex. We derived etiological effects of risk factors-disease endpoints, by age, from meta-analyses. We defined optimal levels. We combined these inputs with cause-specific mortality rates to compute population-attributable fractions as a percentage of total cardiometabolic deaths. RESULTS: Suboptimal diet was the leading cause of cardiometabolic mortality in 4 of 5 countries, with population-attributable fractions from 40.7% (95% uncertainty interval = 37.4, 44.1) in Bangladesh to 56.9% (95% uncertainty interval = 52.4, 61.5) in Pakistan. High systolic blood pressure was the second leading cause, except in Bangladesh, where it superseded suboptimal diet. This was followed in all nations by high fasting plasma glucose, low fruit intake, and low whole grain intake. Other prominent burdens were more variable, such as low intake of vegetables, low omega-3 fats, and high sodium intake in India, Nepal, and Pakistan. CONCLUSIONS: Important similarities and differences are evident in cardiometabolic mortality burdens of modifiable dietary and metabolic risks across these countries, informing health policy and program priorities.

The state of US health, 1990-2010: burden of diseases, injuries, and risk factors.

IMPORTANCE: Understanding the major health problems in the United States and how they are changing over time is critical for informing national health policy. OBJECTIVES: To measure the burden of diseases, injuries, and leading risk factors in the United States from 1990 to 2010 and to compare these measurements with those of the 34 countries in the Organisation for Economic Co-operation and Development (OECD) countries. DESIGN: We used the systematic analysis of descriptive epidemiology of 291 diseases and injuries, 1160 sequelae of these diseases and injuries, and 67 risk factors or clusters of risk factors from 1990 to 2010 for 187 countries developed for the Global Burden of Disease 2010 Study to describe the health status of the United States and to compare US health outcomes with those of 34 OECD countries. Years of life lost due to premature mortality (YLLs) were computed by multiplying the number of deaths at each age by a reference life expectancy at that age. Years lived with disability (YLDs) were calculated by multiplying prevalence (based on systematic reviews) by the disability weight (based on population-based surveys) for each sequela; disability in this study refers to any short- or long-term loss of health. Disability-adjusted life-years (DALYs) were estimated as the sum of YLDs and YLLs. Deaths and DALYs related to risk factors were based on systematic reviews and meta-analyses of exposure data and relative risks for risk-outcome pairs. Healthy life expectancy (HALE) was used to summarize overall population health, accounting for both length of life and levels of ill health experienced at different ages. RESULTS: US life expectancy for both sexes combined increased from 75.2 years in 1990 to 78.2 years in 2010; during the same period, HALE increased from 65.8 years to 68.1 years. The diseases and injuries with the largest number of YLLs in 2010 were ischemic heart disease, lung cancer, stroke, chronic obstructive pulmonary disease, and road injury. Age-standardized YLL rates increased for Alzheimer disease, drug use disorders, chronic kidney disease, kidney cancer, and falls. The diseases with the largest number of YLDs in 2010 were low back pain, major depressive disorder, other musculoskeletal disorders, neck pain, and anxiety disorders. As the US population has aged, YLDs have comprised a larger share of DALYs than have YLLs. The leading risk factors related to DALYs were dietary risks, tobacco smoking, high body mass index, high blood pressure, high fasting plasma glucose, physical inactivity, and alcohol use. Among 34 OECD countries between 1990 and 2010, the US rank for the age-standardized death rate changed from 18th to 27th, for the age-standardized YLL rate from 23rd to 28th, for the age-standardized YLD rate from 5th to 6th, for life expectancy at birth from 20th to 27th, and for HALE from 14th to 26th. CONCLUSIONS AND RELEVANCE: From 1990 to 2010, the United States made substantial progress in improving health. Life expectancy at birth and HALE increased, all-cause death rates at all ages decreased, and age-specific rates of years lived with disability remained stable. However, morbidity and chronic disability now account for nearly half of the US health burden, and improvements in population health in the United States have not kept pace with advances in population health in other wealthy nations.

Patient experience with chronic obstructive pulmonary disease: a nationally representative demonstration study on quality and cost of healthcare services.

Introduction: Due to insufficient data on patient experience with healthcare system among patients with chronic obstructive pulmonary disease (COPD), particularly in developing countries, this study attempted to investigate the journey of patients with COPD in the healthcare system using nationally representative data in Iran. Methods: This nationally representative demonstration study was conducted from 2016 to 2018 using a novel machine-learning based sampling method based on different districts' healthcare structures and outcome data. Pulmonologists confirmed eligible participants and nurses recruited and followed them up for 3 months/in 4 visits. Utilization of various healthcare services, direct and indirect costs (including non-health, absenteeism, loss of productivity, and time waste), and quality of healthcare services (using quality indicators) were assessed. Results: This study constituted of a final sample of 235 patients with COPD, among whom 154 (65.5%) were male. Pharmacy and outpatient services were mostly utilized healthcare services, however, participants utilized outpatient services less than four times a year. The annual average direct cost of a patient with COPD was 1,605.5 USDs. Some 855, 359, 2,680, and 933 USDs were imposed annually on patients with COPD due to non-medical costs, absenteeism, loss of productivity, and time waste, respectively. Based on the quality indicators assessed during the study, the focus of healthcare providers has been the management of the acute phases of COPD as the blood oxygen levels of more than 80% of participants were documented by pulse oximetry devices. However, chronic phase management was mainly missed as less than a third of participants were referred to smoking and tobacco quit centers and got vaccinated. In addition, less than 10% of participants were considered for rehabilitation services, and only 2% completed four-session rehabilitation services. Conclusion: COPD services have focused on inpatient care, where patients experience exacerbation of the condition. Upon discharge, patients do not receive appropriate follow-up services targeting on preventive care for optimal controlling of pulmonary function and preventing exacerbation.

Quality and cost of healthcare services in patients with diabetes in Iran: Results of a nationwide short-term longitudinal survey.

Aims: To investigate the journey of patients with diabetes in the healthcare system using nationally-representative patient-reported data. Methods: Participants were recruited using a machine-learning-based sampling method based on healthcare structures and medical outcome data and were followed up for three months. We assessed the resource utilization, direct/indirect costs, and quality of healthcare services. Results: One hundred fifty-eight patients with diabetes participated. The most utilized services were medication purchases (276 times monthly) and outpatient visits (231 times monthly). During the previous year, 90% of respondents had a laboratory fasting blood glucose assessment; however, less than 70% reported a quarterly follow-up physician visit. Only 43% had been asked about any hypoglycemia episodes by their physician. Less than 45% of respondents had been trained for hypoglycemia self-management. The annual average health-related direct cost of a patient with diabetes was 769 USD. The average out-of-pocket share of direct costs was 601 USD (78.15%). Medication purchases, inpatient services, and outpatient services summed up 79.77% of direct costs with a mean of 613 USD. Conclusion: Healthcare services focused solely on glycemic control and the continuity of services for diabetes control was insufficient. Medication purchases, and inpatient and outpatient services imposed the most out-of-pocket costs.

Iran Quality of Care in Medicine Program (IQCAMP): Design and Outcomes.

BACKGROUND: Assessment of quality and cost of medical care has become a core health policy concern. We conducted a nationwide survey to assess these measures in Iran as a developing country. To present the protocol for the Iran Quality of Care in Medicine Program (IQCAMP) study, which estimates the quality, cost, and utilization of health services for seven diseases in Iran. METHODS: We selected eight provinces for this nationally representative short longitudinal survey. Interviewers from each province were trained comprehensively. The standard definition of seven high-burden conditions (acute myocardial infarction [MI], heart failure [HF], diabetes mellitus [DM], stroke, chronic obstructive pulmonary (COPD) disease, major depression, and end-stage renal disease [ESRD]) helped customize a protocol for disease identification. With a 3-month follow-up window, the participants answered pre-specified questions four times. The expert panels developed a questionnaire in four modules (demographics, health status, utilization, cost, and quality). The expert panel chose an inclusive set of quality indicators from the current literature for each condition. The design team specified the necessary elements in the survey to calculate the cost of care for each condition. The utilization assessment included various services, including hospital admissions, outpatient visits, and medication. RESULTS: Totally, 156 specialists and 78 trained nurses assisted with patient identification, recruitment, and interviewing. A total of 1666 patients participated in the study, and 1291 patients completed all four visits. CONCLUSION: The IQCAMP study was the first healthcare utilization, cost, and quality survey in Iran with a longitudinal data collection to represent the pattern, quantity, and quality of medical care provided for high-burden conditions.

Prevalence of Diabetes and Prediabetes, and Achievements in Diabetes Control in Iran; The Results of the STEPS of 2016.

BACKGROUND: Using the WHO STEPwise approach to NCD risk factor surveillance (STEPS), first round of Iran's STEPS completed in 2005. It has been repeated six times afterward. Here we report the results of 2016 round on the population characteristics and prevalence of diabetes and prediabetes, along with an assessment of the country-level performance on diabetes care in Iran. METHODS: Using a proportional-to-size cluster random sampling method, the STEPS 2016 included 18947 subjects aged≥25 years who matched the criteria (non-missing information on diabetes self-report, and biomarkers). For the analyses, survey design methods with weighted samples were employed. Different definitions of diabetes (biomarker-based, self-report, anti-diabetes medication use, or a combination) and prediabetes (different cutpoints of the biomarker) were calculated and presented. RESULTS: An estimated 5171035 persons aged≥25 years or 10.6% (95% CI: 10.0%-11.1%) had diabetes according to the serologic diagnosis of diabetes (FPG≥126 mg/dL) or the use of at least one anti-diabetes medication (1896 out of 18947). Employing the serologic diagnosis of diabetes among those who responded no to the self-reported question, 2.7% (2.5%-3.0%) of the population were not aware of their diabetes compared to 11.5% (10.9%-12.0%) who were diabetics according to the just self-reported question. Defining prediabetes as 100≤FPG<126 mg/dL or 5.7≤HbA1c<6.5%, an estimated 15244299 persons had prediabetes (5885 out of 18947). Overall, 52.1% (49.4%-54.7%) of patients with self-reported diabetes were under strict glycemic control (HbA1c<7%). Poor diabetes control (HbA1c>9%) was found in 18.4% (16.3%-20.6%) of the patients with self-reported diabetes. CONCLUSION: Since 2005, the prevalence of diabetes in Iran has been on a gradual increase in both genders with an increasing gap between females and males.

Major Depressive Disorder in Iran: Epidemiology, Health Care Provision, Utilization, and Challenges.

One in eight adults in Iran is estimated to have major depressive disorder (MDD) - a leading cause of disability in the country. Many remain undiagnosed, and some receive only partial treatment. An estimated 60% of those with MDD were reported to have received no treatment during the past year. In this paper, we have critically reviewed the current health-care structure in the country along with prevailing patterns of health-care service utilization. We have addressed the role of psychiatrists, general practitioners (GPs), psychologists, and other health-care personnel in the treatment and care of patients with MDD, with an emphasis on the quality of service provision. In addition, the strengths and weaknesses of primary healthcare (PHC), the health insurance system, and inpatient care have been discussed. We have paid attention to the contextual issues such as mental health literacy, stigma, and healthcare inequity where relevant. Finally, practical recommendations have been provided to improve the quality of care for patients with MDD in Iran.

National and sub-national trends of salt intake in Iranians from 2000 to 2016: a systematic analysis.

BACKGROUND: One fifth of the global burden of cardiovascular diseases (CVDs) in 2017 was attributable to excessive salt intake. As a member of the World Health Organization (WHO), Iran has committed itself to a 30% reduction in salt intake by 2025. Evidence on the amount and trend of salt intake among the Iranian population at national and sub-national levels is scarce. This study aimed to estimate the Iranian population's salt intake during 2000-2016 at the national and sub-national levels, by sex and age groups. METHODS: Data on national and sub-national mean salt intake was obtained through systematically searching the literature and contacting the research studies' principal investigators. Data collected through various methods were harmonized using the cross-walk method. Bayesian hierarchical and spatio-temporal-age regression models and simulation analysis were used to estimate the mean salt intake and its uncertainty interval across sex, age, year, and province. RESULTS: National age-sex standardized mean salt intake decreased from 10·53 g/day (95% uncertainty interval [UI]: 10·2 to 10·9) in 2000 to 9·41 (9·2 to 10·6) in 2016 (percent change: - 9·8% [- 21·1-3·1]). The age-standardized mean salt intake in women had decreased from 9·8 g/day (95% UI: 9·0-10·6) in 2000 to 9·1 g/day (8·6-9·7) in 2016 (percent change: - 6·6% [- 19·0-7·9]). The same measure in men was 11·1 g/day in 2000 (95% UI: 10·3-11·8) and 9·7 g/day (9·1-10·2) in 2016 (percent change: - 12·7% [- 23·0 - -0·9]). Age-sex standardized mean salt intake at the sub-national level in 2016 varied from 8·0 (95% UI: 7·0-9·0) to 10·5 (10·0-11·1). The difference between the provinces with the highest and the lowest levels of salt intake in 2016 was 31·3%. CONCLUSION: Salt intake decreased in Iran from 2000 to 2016, while persistently exceeding the recommended values. This declining trend was more pronounced between 2010 and 2016, which might be attributed to Iran's compliance to WHO's Action Plan for reducing NCDs.

A survey of the current status of web-based databases indexing Iranian journals.

BACKGROUND: The scientific output of Iran is increasing rapidly during the recent years. Unfortunately, most papers are published in journals which are not indexed by popular indexing systems and many of them are in Persian without English translation. This makes the results of Iranian scientific research unavailable to other researchers, including Iranians. The aim of this study was to evaluate the quality of current web-based databases indexing scientific articles published in Iran. METHODS: We identified web-based databases which indexed scientific journals published in Iran using popular search engines. The sites were then subjected to a series of tests to evaluate their coverage, search capabilities, stability, accuracy of information, consistency, accessibility, ease of use, and other features. Results were compared with each other to identify strengths and shortcomings of each site. RESULTS: Five web sites were indentified. None had a complete coverage on scientific Iranian journals. The search capabilities were less than optimal in most sites. English translations of research titles, author names, keywords, and abstracts of Persian-language articles did not follow standards. Some sites did not cover abstracts. Numerous typing errors make searches ineffective and citation indexing unreliable. CONCLUSION: None of the currently available indexing sites are capable of presenting Iranian research to the international scientific community. The government should intervene by enforcing policies designed to facilitate indexing through a systematic approach. The policies should address Iranian journals, authors, and indexing sites. Iranian journals should be required to provide their indexing data, including references, electronically; authors should provide correct indexing information to journals; and indexing sites should improve their software to meet standards set by the government.

Correction: Global, Regional, and National Consumption of Sugar-Sweetened Beverages, Fruit Juices, and Milk: A Systematic Assessment of Beverage Intake in 187 Countries.

[This corrects the article DOI: 10.1371/journal.pone.0124845.].

National and Subnational Cardiovascular Diseases Mortality Attributable to Salt Consumption in Iran by Sex and Age From 1990 to 2016.

BACKGROUND: Dietary salt consumption is an important factor for mortality from cardiovascular diseases (CVDs). Therefore, the aim of this study is to measure the levels of salt consumption and then estimate the effects of current levels of salt consumption on mortality from CVDs at national and subnational levels from 1990 to 2016 in Iran. METHODS: In this study, we will use national and subnational studies with data on salt consumption, including self-report or lab tests for sodium measurement and all available published data about salt and sodium (with conduct a systematic review) to estimate salt exposure levels. We will also use data from death registration system (DRS) to estimate CVDs mortality attributable to salt consumption. We will use mixed-effects model to explore the effects of some covariates on salt consumption and then spatial-temporal model will be used to take into account how the values of salt consumption in each point vary further across time, space, and age. We will compute the proportional reduction in CVD deaths that will occur if salt consumption reduces to an alternative level (5 g/d), using comparative risk assessment (CRA). The simulation analysis will be used to estimate the uncertainty of the number of deaths attributable to salt consumption. All analyses will be performed separately by sex and age groups, province and year in STATA and R software packages. CONCLUSION: The findings of this study seem to be helpful for providing good information about the salt consumption and CVDs mortality attributable to it for policymakers in directing future policy decisions and planning cost-effective strategies in Iran.

Cost effectiveness of a government supported policy strategy to decrease sodium intake: global analysis across 183 nations.

OBJECTIVE:  To quantify the cost effectiveness of a government policy combining targeted industry agreements and public education to reduce sodium intake in 183 countries worldwide. DESIGN:  Global modeling study. SETTING:  183 countries. POPULATION:  Full adult population in each country. INTERVENTION:  A "soft regulation" national policy that combines targeted industry agreements, government monitoring, and public education to reduce population sodium intake, modeled on the recent successful UK program. To account for heterogeneity in efficacy across countries, a range of scenarios were evaluated, including 10%, 30%, 0.5 g/day, and 1.5 g/day sodium reductions achieved over 10 years. We characterized global sodium intakes, blood pressure levels, effects of sodium on blood pressure and of blood pressure on cardiovascular disease, and cardiovascular disease rates in 2010, each by age and sex, in 183 countries. Country specific costs of a sodium reduction policy were estimated using the World Health Organization Noncommunicable Disease Costing Tool. Country specific impacts on mortality and disability adjusted life years (DALYs) were modeled using comparative risk assessment. We only evaluated program costs, without incorporating potential healthcare savings from prevented events, to provide conservative estimates of cost effectiveness MAIN OUTCOME MEASURE:  Cost effectiveness ratio, evaluated as purchasing power parity adjusted international dollars (equivalent to the country specific purchasing power of US$) per DALY saved over 10 years. RESULTS:  Worldwide, a 10% reduction in sodium consumption over 10 years within each country was projected to avert approximately 5.8 million DALYs/year related to cardiovascular diseases, at a population weighted mean cost of I$1.13 per capita over the 10 year intervention. The population weighted mean cost effectiveness ratio was approximately I$204/DALY. Across nine world regions, estimated cost effectiveness of sodium reduction was best in South Asia (I$116/DALY); across the world's 30 most populous countries, best in Uzbekistan (I$26.08/DALY) and Myanmar (I$33.30/DALY). Cost effectiveness was lowest in Australia/New Zealand (I$880/DALY, or 0.02×gross domestic product (GDP) per capita), although still substantially better than standard thresholds for cost effective (<3.0×GDP per capita) or highly cost effective (<1.0×GDP per capita) interventions. Most (96.0%) of the world's adult population lived in countries in which this intervention had a cost effectiveness ratio <0.1×GDP per capita, and 99.6% in countries with a cost effectiveness ratio <1.0×GDP per capita. CONCLUSION:  A government "soft regulation" strategy combining targeted industry agreements and public education to reduce dietary sodium is projected to be highly cost effective worldwide, even without accounting for potential healthcare savings.

Etiologic effects and optimal intakes of foods and nutrients for risk of cardiovascular diseases and diabetes: Systematic reviews and meta-analyses from the Nutrition and Chronic Diseases Expert Group (NutriCoDE).

BACKGROUND: Dietary habits are major contributors to coronary heart disease, stroke, and diabetes. However, comprehensive evaluation of etiologic effects of dietary factors on cardiometabolic outcomes, their quantitative effects, and corresponding optimal intakes are not well-established. OBJECTIVE: To systematically review the evidence for effects of dietary factors on cardiometabolic diseases, including comprehensively assess evidence for causality; estimate magnitudes of etiologic effects; evaluate heterogeneity and potential for bias in these etiologic effects; and determine optimal population intake levels. METHODS: We utilized Bradford-Hill criteria to assess probable or convincing evidence for causal effects of multiple diet-cardiometabolic disease relationships. Etiologic effects were quantified from published or de novo meta-analyses of prospective studies or randomized clinical trials, incorporating standardized units, dose-response estimates, and heterogeneity by age and other characteristics. Potential for bias was assessed in validity analyses. Optimal intakes were determined by levels associated with lowest disease risk. RESULTS: We identified 10 foods and 7 nutrients with evidence for causal cardiometabolic effects, including protective effects of fruits, vegetables, beans/legumes, nuts/seeds, whole grains, fish, yogurt, fiber, seafood omega-3s, polyunsaturated fats, and potassium; and harms of unprocessed red meats, processed meats, sugar-sweetened beverages, glycemic load, trans-fats, and sodium. Proportional etiologic effects declined with age, but did not generally vary by sex. Established optimal population intakes were generally consistent with observed national intakes and major dietary guidelines. In validity analyses, the identified effects of individual dietary components were similar to quantified effects of dietary patterns on cardiovascular risk factors and hard endpoints. CONCLUSIONS: These novel findings provide a comprehensive summary of causal evidence, quantitative etiologic effects, heterogeneity, and optimal intakes of major dietary factors for cardiometabolic diseases, informing disease impact estimation and policy planning and priorities.

Impact of Nonoptimal Intakes of Saturated, Polyunsaturated, and Trans Fat on Global Burdens of Coronary Heart Disease.

BACKGROUND: Saturated fat (SFA), ω-6 (n-6) polyunsaturated fat (PUFA), and trans fat (TFA) influence risk of coronary heart disease (CHD), but attributable CHD mortalities by country, age, sex, and time are unclear. METHODS AND RESULTS: National intakes of SFA, n-6 PUFA, and TFA were estimated using a Bayesian hierarchical model based on country-specific dietary surveys; food availability data; and, for TFA, industry reports on fats/oils and packaged foods. Etiologic effects of dietary fats on CHD mortality were derived from meta-analyses of prospective cohorts and CHD mortality rates from the 2010 Global Burden of Diseases study. Absolute and proportional attributable CHD mortality were computed using a comparative risk assessment framework. In 2010, nonoptimal intakes of n-6 PUFA, SFA, and TFA were estimated to result in 711 800 (95% uncertainty interval [UI] 680 700-745 000), 250 900 (95% UI 236 900-265 800), and 537 200 (95% UI 517 600-557 000) CHD deaths per year worldwide, accounting for 10.3% (95% UI 9.9%-10.6%), 3.6%, (95% UI 3.5%-3.6%) and 7.7% (95% UI 7.6%-7.9%) of global CHD mortality. Tropical oil-consuming countries were estimated to have the highest proportional n-6 PUFA- and SFA-attributable CHD mortality, whereas Egypt, Pakistan, and Canada were estimated to have the highest proportional TFA-attributable CHD mortality. From 1990 to 2010 globally, the estimated proportional CHD mortality decreased by 9% for insufficient n-6 PUFA and by 21% for higher SFA, whereas it increased by 4% for higher TFA, with the latter driven by increases in low- and middle-income countries. CONCLUSIONS: Nonoptimal intakes of n-6 PUFA, TFA, and SFA each contribute to significant estimated CHD mortality, with important heterogeneity across countries that informs nation-specific clinical, public health, and policy priorities.

The Impact of Dietary and Metabolic Risk Factors on Cardiovascular Diseases and Type 2 Diabetes Mortality in Brazil.

BACKGROUND: Trends in food availability and metabolic risk factors in Brazil suggest a shift toward unhealthy dietary patterns and increased cardiometabolic disease risk, yet little is known about the impact of dietary and metabolic risk factors on cardiometabolic mortality in Brazil. METHODS: Based on data from Global Burden of Disease (GBD) Study, we used comparative risk assessment to estimate the burden of 11 dietary and 4 metabolic risk factors on mortality due to cardiovascular diseases and diabetes in Brazil in 2010. Information on national diets and metabolic risks were obtained from the Brazilian Household Budget Survey, the Food and Agriculture Organization database, and large observational studies including Brazilian adults. Relative risks for each risk factor were obtained from meta-analyses of randomized trials or prospective cohort studies; and disease-specific mortality from the GBD 2010 database. We quantified uncertainty using probabilistic simulation analyses, incorporating uncertainty in dietary and metabolic data and relative risks by age and sex. Robustness of findings was evaluated by sensitivity to varying feasible optimal levels of each risk factor. RESULTS: In 2010, high systolic blood pressure (SBP) and suboptimal diet were the largest contributors to cardiometabolic deaths in Brazil, responsible for 214,263 deaths (95% uncertainty interval [UI]: 195,073 to 233,936) and 202,949 deaths (95% UI: 194,322 to 211,747), respectively. Among individual dietary factors, low intakes of fruits and whole grains and high intakes of sodium were the largest contributors to cardiometabolic deaths. For premature cardiometabolic deaths (before age 70 years, representing 40% of cardiometabolic deaths), the leading risk factors were suboptimal diet (104,169 deaths; 95% UI: 99,964 to 108,002), high SBP (98,923 deaths; 95%UI: 92,912 to 104,609) and high body-mass index (BMI) (42,643 deaths; 95%UI: 40,161 to 45,111). CONCLUSION: suboptimal diet, high SBP, and high BMI are major causes of cardiometabolic death in Brazil, informing priorities for policy initiatives.