The burden of cardiovascular disease attributable to high body mass index—an observational study (2024)

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Abstract

Introduction

In 1995, an expert group at the National Institutes of Health first proposed the Body Mass Index (BMI), which is calculated by dividing body weight (kg) by height square (m²). Due to its simplicity and practicality, it was chosen to evaluate the weight categories.¹ For individuals over 18, BMI categories are defined as underweight (BMI<18.5kg/m²), normal weight (BMI=18.5–24.9kg/m²), and high BMI (BMI ≥ 25kg/m²). High BMI (HBMI) includes overweight (BMI=25.0–29.9kg/m²), and obesity (BMI ≥ 30kg/m²). According to statistics, 39–49% of the world's population (2.8–3.5 billion people) suffer from HBMI.² The burden of HBMI health care costs continues to increase dramatically. In 2008, direct and indirect medical expenses due to HBMI exceeded $147 billion in the United States.³ By 2030, total health care costs due to HBMI are expected to double every decade to an alarming $860.7–956.9 billion, accounting for 16–18% of total health care costs in the United States.⁴ Epidemiological data showed, in 2017, that global numbers of disability-adjusted life years (DALYs) and deaths attributable to HBMI were 147.7 million and 2.4 million, respectively, and cardiovascular disease (CVD) emerged as the leading cause of DALYs and deaths.⁵ Further, long-term and large-scale studies have consistently shown that HBMI populations increased CVD morbidity and mortality risk.^6–8 Therefore, in order to avoid the social and economic burden of HBMI, especially CVD attributable to HBMI, relevant policies must be formulated and implemented in a timely and effective manner.

In order to develop effective control and prevention strategies, it is important to accurately evaluate the current burden and temporal trends of CVD attributable to HBMI worldwide. Currently, no studies have provided detailed information on estimating the global CVD burden attributable to HBMI. The Global Burden of Disease Study (GBD) systematically and scientifically assessed the epidemiological characteristics of 87 risk factors and 369 diseases and injuries in 204 countries and regions between 1990 and 2019.^9,10 Therefore, we systematically assessed the current burden and temporal trend of CVD attributable to HBMI by calendar year, age, sex, GBD region, nation, socioeconomic status, and specific CVD based on the most recent GBD 2019.

Methods

Data sources

The CVD-related DALYs and deaths attributable to HBMI by calendar year, age, sex, GBD region, nation, socioeconomic status, and specific CVD were obtained from the Global Health Data Exchange (GHDx) query tool (http://ghdx.healthdata.org/gb dresults-tool). Detailed application methods of GBD 2019 and the risk assessment specifically for HBMI were previously reported.^5,9,10 The Washington University Institutional Review Committee reviewed and approved the informed consent waiver since de-identification and aggregation data were used in GBD 2019.

Definitions

High BMI was defined as BMI ≥25kg/m² for adults aged≥20 years, and the cut-off value from the International Obesity Working Group standard was used for children aged<20 years.⁹ Cardiovascular disease mainly include stroke, ischemic heart disease, hypertensive heart disease, and atrial fibrillation/flutter in GBD 2019. Stroke can be divided into ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage.¹⁰

The DALYs, a composite measure to quantify the overall CVD burden attributable to HBMI, represents the sum of years of life lost (YLLs) due to premature death from HBMI-related CVD and years lived with disability (YLDs) due to HBMI-related CVD. Years of life lost due to HBMI-related CVD were calculated by multiplying the number of deaths in each age group by the standard life expectancy for that age group. Years lived with disability were calculated by multiplying the number of people with HBMI-related CVD by disability weight. Disability weight represents the magnitude of outcome-related health loss and ranges from 0 (full health) to 1 (death).

The Socio-demographic Index (SDI), a composite indicator, is used to quantify the development status of a geographical location. The SDI was calculated on the basis of mean educational attainment for people aged 15 or older, the total fertility rate for women under 25, and the per capita income distribution lag. The SDI ranges from 0 to 1, where 0 represents the lowest development levels and 1 represents the highest development levels. The cut-off value of the SDI quintile was identified using estimates from countries with populations over 1 million. The 204 countries and regions were divided into five groups according to the SDI quintile: high SDI (0.805–1), high-middle SDI (0.690∼<0.805), middle SDI (0.608∼<0.690), low-middle SDI (0.455∼<0.608), and low SDI regions (0∼<0.455). According to social economy and geography, countries and regions around the world are divided into 21 GBD regions.

Statistical analyses

We used absolute number, age-standardized rates (ASRs), estimated annual percentage change (EAPC), and % change in absolute numbers of DALYs and deaths to quantify the CVD burden attributable to HBMI and reported by calendar year, age, sex, GBD region, nation, socioeconomic status, and specific CVD. The ASR was calculated by standardizing the global age structure, which is considered necessary when comparing the sample population over time or the population at different locations¹¹ Uncertainty interval (UI) was calculated based on 1000 drawing level estimates for each parameter. A total of 95% UI was defined as values ranked 25th and 975th in all 1000 draws. Absolute number, ASR, and % change in absolute number are directly extracted and represented in 95% UI. The EAPC calculation method is described elsewhere.¹¹ If both the EAPC estimate and 95% CI upper bound are both<0, the ASR showed a downward trend. By contrast, if both the EAPC estimate and 95% CI lower bound are both>0, the ASR showed an upward trend. Otherwise, the ASR showed stability over time. All analysis and figure production was done using the R program (version 4.2.2, R Core Team).

Results

Overall burden of CVD attributable to HBMI

Globally, the numbers of CVD-related DALYs and deaths attributable to HBMI have more than doubled from 1990 to 2019. Conversely, the ASRs of CVD-related DALYs and deaths attributable to HBMI showed a minor decreasing trend, with EAPC of −0.18 and −0.43, respectively. The ASR of CVD-related DALYs attributable to HBMI decreased from 1050.8 per 100 000 people in 1990 to 1045.4 per 100 000 people in 2019, and ASR of CVD-related deaths attributable to HBMI decreased from 43.3 per 100 000 people in 1990 to 40.1 per 100 000 people in 2019 (Tables1 and 2). The global number of CVD-related DALYs attributable to HBMI have increased from 22165469 in 1990 to 48 236 091 in 2019 for males, and have increased from 21 074 533 in 1990 to 38 478 536 in 2019 for females. The global number of CVD-related deaths attributable to HBMI have increased from 759 219 in 1990 to 1662 477 in 2019 for males, and have increased from 850 458 in 1990 to 1564 490 in 2019 for females. Nevertheless, from 1990 and 2019, the ASRs of CVD-related DALYs and deaths attributable to HBMI remained relatively stable for females and males (Table1, Table2, and see Supplementary material online, Figure 1S).

With regard to age and sex, in 2019, age-specific rates of CVD-related DALYs and deaths attributable to HBMI were higher in males than in females before 80 years, but lower in males than in females after 80 years. The number of CVD-related DALYs attributable to HBMI was higher in males than in females before 70 years, whereas the number was higher in females than in males after 70 years. The number of CVD-related deaths attributable to HBMI was higher in males than in females before 75 years, whereas the number was higher in females than in males after 75 years. Additionally, the number of CVD-related DALYs attributable to HBMI peaked in the age group 60–64 years in males, while the peak in females was seen in the age group 65–69 years. The number of CVD-related deaths attributable to HBMI peaked in the age group 65–69 years in males, while the peak in females was seen in the age group 75–79 years (Figure 1).

Among the 21 GBD regions, in 2019, the lowest ASRs of CVD-related DALYs and deaths attributable to HBMI were seen in High-income Asia Pacific. Conversely, the highest ASRs of CVD-related DALYs and deaths attributable to HBMI were seen in Central Asia (Tables1 and2). From 1990 to 2019, the largest increase in ASRs of CVD-related DALYs and deaths attributable to HBMI were in Southeast Asia. Conversely, the largest decrease in ASRs of CVD-related DALYs and deaths attributable to HBMI were in Australasia and High-income Asia Pacific. Furthermore, South Asia was the region with the greatest increase in the numbers of DALYs and deaths, while Western Europe was the region with the greatest decrease in the numbers of DALYs and deaths. The variations in HBMI-related CVD burden metrics (DALYs and deaths) by GBD regions in 2019 and temporal trends from 1990 to 2019 can be found in Tables1 and2.

Among 204 countries and territories, in 2019, the country with the lowest ASRs of CVD-related DALYs and deaths attributable to HBMI was Japan, whereas the countries with the highest ASRs of CVD-related DALYs and deaths attributable to HBMI were Solomon Islands and Uzbekistan. Notably, the country with the larger number of CVD-related DALYs and deaths attributable to HBMI was China. From 1990 to 2019, the highest EAPCs of CVD-related DALYs and deaths attributable to HBMI were seen in the Philippines and Mozambique, whereas the lowest EAPCs of DALYs and deaths were seen in the Republic of Korea and Israel. The greatest decrease in CVD-related numbers of DALYs and deaths attributable to HBMI was seen in Denmark and Norway, whereas the greatest increase in numbers of CVD-related DALYs and deaths attributable to HBMI was seen in the Philippines and Djibouti (see Supplementary material online, Table 1S and 2S,Figures 2 and3).

Relationship between SDI and HBMI effects on CVD burden

The ASRs of CVD-related DALYs and deaths attributed to HBMI were lower in high SDI regions than in other regions in 2019. Specifically, middle and high-middle SDI regions, such as North Africa and Middle East, Central Asia, and Eastern Europe, had the highest ASRs of CVD-related DALYs and deaths attributed to HBMI, whereas high SDI regions, such as Western Europe, High-income Asia Pacific, and Australasia had lowest the ASRs of CVD-related DALYs and deaths attributed to HBMI (Table1, Table2, and Figure4). High SDI regions such as Western Europe, Australasia, High-income Asia Pacific, and High-income North America showed a decline in ASRs of CVD-related DALYs and deaths attributed to HBMI from 1990 to 2019. In contrast, lower SDI and middle SDI regions, such as South Asia, Oceania, and East Asia, showed an increase in ASRs of CVD-related DALYs and deaths attributed to HBMI, whereas ASRs of CVD-related DALYs and deaths attributed to HBMI in North Africa and the Middle East remained stable from 1990 to 2019 (Table1, Table2, and Figure4).

In 2019, the lowest ASRs of CVD-related DALYs and deaths attributed to HBMI were seen in the high SDI regions, whereas the highest ASRs of CVD-related DALYs and deaths attributed to HBMI were seen in the High-middle SDI regions (Table1, Table2, and Figure4). Across all countries, the ASRs of CVD-related DALYs and deaths attributed to HBMI increased with increasing SDI until SDI was ∼0.60, but subsequently decreased with increasing SDI. Based on SDI alone, the ASR of DALYs in Nauru and Solomon Islands is much higher than expected, and the ASR of deaths in Nauru and Uzbekistan is much higher than expected. Associations between ASRs of DALYs and death and SDI by country in 2019 are presented in Supplementary material online, Figure 2S.

Impact of HBMI on specific CVD

In 2019, for CVD levels, the leading cause of age-standardized DALYs and deaths rates globally were ischemic heart disease (499.4 DALYs per 100 000 people and 20.7 deaths per 100 000 people), followed by stroke (416.6 DALYs per 100 000 people and 13.2 deaths per 100 000 people), hypertensive heart disease (106.9 DALYs per 100 000 people and 5.3 deaths per 100 000 people) and atrial fibrillation/flutter (22.5 DALYs per 100 000 people and 0.89 deaths per 100 000 people). The main cause of the numbers of DALYs and deaths globally was also ischemic heart disease, followed by stroke, hypertensive heart disease, and atrial fibrillation/flutter (Figure 5). For stroke levels, global age‐standardized DALYs and deaths rates were highest for intracerebral hemorrhage (236.2 DALYs per 100 000 people and 7.4 deaths per 100 000 people), followed by ischemic stroke (132.1 DALYs per 100 000 people and 4.6 deaths per 100 000 people) and subarachnoid hemorrhage (48.4 DALYs per 100 000 people and 1.2 deaths per 100 000 people). The numbers of DALYs and deaths were highest for intracerebral hemorrhage, followed by ischemic stroke and subarachnoid hemorrhage (see Supplementary material online, Figure 3S).

From 1990 to 2019, the numbers of CVD-related DALYs and deaths attributed to HBMI showed an upward trend in all CVD and stroke. Similarly, we also observed that the ASRs of CVD-related DALYs and deaths attributed to HBMI showed an upward trend in hypertensive heart disease and atrial fibrillation/flutter.However, the ASRs of CVD-related DALYs and deaths attributed to HBMI showed a downward trend in ischemic heart disease and all stroke.

Discussion

This study systematically evaluated the current burden and temporal trend of CVD attributable to HBMI worldwide from 1990 to 2019, and demonstrated that CVD attributable to HBMI remains a challenging health concern. Our results highlight that CVD attributable to HBMI is becoming a major global and regional public health concern and call for necessary measures to curb the high and increasing CVD burden attributable to HBMI.

In this study, CVD attributable to HBMI increased significantly in the global numbers of DALYs and deaths, while ASRs for these two metrics decreased slightly from 1990 to 2019, which may be attributed to age standardization on basis of population and age structure. In many regions, the dramatic increase in the prevalence of obesity leads to an increased CVD burden worldwide.^12,13 Although researchers have put forward a series of interventions to curb HBMI over the past decade, the HBMI has not shown a downward trend, but an upward trend.^12,14,15 More effective and targeted strategies are urgently needed to implement cost-effective interventions to reduce the incidence of HBMI.

Our study found that the global numbers of CVD-related DALYs and deaths attributable to HBMI was higher in males than in females before 70 years, but lower in males than in females after 75 years. Age-specific rates of CVD-related DALYs and deaths attributable to HBMI were higher in males than in females before 80 years, but lower in males than in females after 80 years. A possible reason for this phenomenon is that older females have a significantly higher global prevalence of HBMI than older males.¹² Decision makers should pay more attention to gender differences in CVD attributable to HBMI and formulate relevant policies to reduce the incidence of CVD attributable to HBMI.

Previous evidence was consistent with our findings, indicating that the CVD burden attributable to HBMI has shown an upward trend in low-income and middle-income regions and countries in the past 30 years. In some low-income regions and countries, people with higher socioeconomic status may prefer larger body sizes.^16,17 In addition, rich people in some low-income countries are prone to HBMI, probably because they obtain excess/surplus food and engage in low-level manual labor-intensive occupations.¹⁸ In many middle-income regions and countries, such as South Asia and East Asia, with growing economies, the dramatic increase in consumption of dietary fats and animal products by residents and longer sitting lifestyles has led to a dramatic increase in the prevalence of HBMI.^19,20 Moreover, the traditional diet of vegetables, bean products, cereals, and fish, which is believed to reduce blood cholesterol and prevent CVD, is gradually being replaced by a high-fat and high-sugar fast food diet.^20,21 Our results also showed that there is currently serious HBMI-related CVD burden in many middle-income and a few high-income regions and countries. Unhealthy lifestyles and lack of exercise are the main reasons for HBMI in these regions.^22,23 The high and growing burden of HBMI in low-income and middle-income regions or countries is now increasingly observed, which has attracted the attention of a few countries. In October 2020, China announced a strategic plan for the prevention and control of HBMI among children and adolescents, which made it clear that the annual growth rate of HMBI among children and adolescents would be reduced by 70% in 2020–2030 compared with that in 2002–2017, and emphasized the importance of healthy diet and physical activities, as well as the responsibilities of parents, schools and medical care.²⁴ However, most high and increasing burden regions and countries^22,23,25,26 have not adopted clear policies to prevent and manage HBMI.

Our study observed that high SDI regions or countries have lower current burdens than other SDI regions and countries, and its temporal trend from 1990 to 2019 have also shown a downward trend. A series of strategies taken by high SDI regions or countries to prevent HBMI have led to a significant reduction in the HBMI-related CVD burden. The plight of the most affected overweight and obese populations, like those in high-income regions or countries has been well publicized.^25,27 European Association for the Study of Obesity (EASO) has developed the clinical practice guidelines for adult obesity management in Europe, the network of obesity management centers, interdisciplinary guidelines for metabolism and bariatric surgery, and a set of suggestions for primary health care providers for childhood obesity. High-income countries have adequate financial resources to launch programs and initiatives aimed at promoting healthy food.²⁸ Higher education levels and health awareness are also major reasons for the lower incidence of HBMI in high-income countries.²⁹ A pooled analysis from 200 countries observed the prevalence of HBMI is still low in the poorest regions of the world, especially in South Asia.³⁰ Surprisingly, we also found that some low-income regions, such as South Asia, have lower HBMI burden. The potential reason is that these poor people have low food intake due to food shortages in these regions. The poor, in addition, often engage in manual work that requires high energy consumption.

As stated in previous studies,^5,12 CVD was the leading cause of HBMI-related deaths and DALYs. Obesity contributes directly to CVD risk factors, including hypertension, type 2 diabetes, dyslipidemia, and sleep disorders. Obesity also contributes to the development of CVD and CVD mortality independently of other CVD risk factors.³¹ Similar to our results, some recent studies showed that CVD due to HBMI mainly includes ischemic heart disease and stroke, especially ischemic stroke.³² The excess risk of ischemic heart disease and stroke associated with HBMI is mediated by a combination of elevated blood pressure, serum total cholesterol, and fasting glucose levels.³³

In general, due to differences in SDI across regions or countries, high SDI regions or countries have lower CVD burden attributable to HBMI, while low SDI regions or countries have higher CVD burden attributable to HBMI. Policymakers in low-income regions and countries can learn from some valuable experiences of high-income regions and countries and take immediate action to prevent the HBMI epidemic, thus reducing the major economic losses of CVD due to HBMI. People in low-income and middle-income countries should maintain a healthy lifestyle, exercise appropriately, and raise awareness of the dangers of HBMI. The government should formulate relevant laws, regulations, and ethic-specific guidelines to prevent and control CVD burden due to HBMI according to the epidemic characteristics of CVD burden due to HBMI in the country.

Limitations

As far as we know, this is the first time to use the latest GBD 2019 study to comprehensively assess the CVD burden attributable to HBMI by calendar year, age, sex, GBD region, nation, socioeconomic status, and specific CVD from 1990 to 2019, which will aid public health policy-makers. There are, however, several potential limitations that we should not ignore. First, since only major CVD affected by HBMI are included in GBD 2019, other CVD such as heart failure and sudden cardiac death should also be paid attention to. Second, because HBMI is usually accompanied by other CVD risk factors, such as high blood lipids and high fasting blood glucose, and hyperlipidemia, it is difficult to distinguish the independent effects of HBMI on CVD. Third, data from some countries and regions may be based on information in the sample, which may not necessarily represent the whole country and region.

Conclusion

Overall, the CVD burden attributable to HBMI was higher globally and regionally, particularly in the middle and high-middle SDI regions, in 2019. The CVD burden attributable to HBMI has increased globally and regionally, particularly in low and low-middle SDI regions, over the past 30 years. The leading causes of CVD burden attributable to HBMI were ischemic heart disease, stroke, hypertensive heart disease, and atrial fibrillation/flutter. Our results can provide policymakers and implementors with effective and targeted scientific evidence to precisely prevent and control CVD burden attributable to HBMI.

Acknowledgements

The authors appreciate the works of the Global Burden of Disease Study 2019 collaborators.

Data availability

The data underlying this study were derived from public database: Institute for Health Metrics and Evaluation (IHME), at http://ghdx.healthdata.Org/gbd-results-tool.

Funding sources

None.

Author contributions

Study design: D.X.J., W.B.B., and H.F.F. Data collection: J.Y. and Z.X.Q. Data analyses: D.X.J. and W.B.B. Results interpretations: all authors. Manuscript writing: all authors. Manuscript proofing: all authors.

Conflict of Interest

The authors declare that they have no conflict of interests.

References

© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.

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