In a recent study published in BMC Public Health, a group of researchers quantified the impact of individual and combined cardiometabolic risk factors on cardiovascular disease (CVD) incidence and overall mortality and assessed the resultant loss of CVD-free years and overall life expectancy.
Study: Cardiovascular disease and all-cause mortality associated with individual and combined cardiometabolic risk factors. Image Credit: H_Ko/Shutterstock.com
Background
In 2020, CVD caused approximately 4.58 million deaths in China alone. With the nation's rapid development and aging populace, CVD-related conditions like hypertension, diabetes, and dyslipidemia have surged.
Around 66% of those with diabetes also face dyslipidemia and hypertension. Past research has separately explored these conditions' links to CVD, but comprehensive studies on their combined effects, especially within the Chinese demographic, remain sparse.
Delving into these cardiometabolic factors' individual and cumulative impacts on CVD risks and lifespan is essential to shape effective public health policies.
About the study
The China Hypertension Survey (CHS) conducted between 2012 and 2015 enrolled approximately half a million participants across 31 provinces. The present study focused on specific cities and counties, tracking over 30,000 individuals with initial health data during 2018-2019.
After filtering out those with pre-existing CVD and incomplete records, 22,596 participants remained for primary analysis.
Cardiovascular risk factors, such as hypertension, were classified using specific blood pressure criteria. Diabetes was determined per the 2017 Chinese Diabetes Society guidelines, and high Low-density lipoprotein cholesterol (LDL-C) levels were considered above 4.12 mmol/L.
Baseline data collected included demographics, lifestyle risks, medical histories, physical measurements, and blood tests.
Outcomes comprised fatal and nonfatal CVD incidents, documented and verified using medical records. The data was analyzed using advanced statistical methods, grouping participants based on their cardiometabolic disorders.
After adjusting for various factors, the study assessed the impact of individual and combined cardiometabolic issues on CVD risk. It calculated the Population attributable fraction (PAF) of hypertension, diabetes, and high LDL-C on overall health impact.
Results
The CHS was initiated with 22,596 participants in the present study, averaging 56.2 years of age. Of these, 37.33% reported a single cardiometabolic risk factor: hypertension, diabetes, or high LDL-C. A smaller 8.28% had two factors, and 6.06% manifested all three.
Predominantly, individuals with multiple risk factors were older, often lived in urban eastern regions, and had familial CVD history. Notably, as cardiometabolic health deteriorated, Body mass index (BMI), Fasting plasma glucose (FPG), and lipid levels surged, with those having all three factors recording a concerning average systolic blood pressure (SBP) of 152.7 mmHg.
During the study, 991 faced fatal or nonfatal CVD events. The incidence rates for CVD and all-cause mortality were 9.48 and 10.83 per 1,000 person-years, respectively. It was evident that possessing one to three risk factors considerably augmented CVD risks.
However, while those with the trio of factors doubled their CVD risk, the study could not correlate isolated diabetes or high LDL-C with increased CVD risks. Individuals with only diabetes had an amplified all-cause mortality risk, which intensified when combined with hypertension or when high LDL-C coexisted with hypertension.
When considering non-cardiovascular deaths as competing risks, the outcomes remained unchanged. Interestingly, using the American Heart Association/American College of Cardiology (AHA/ACC) criteria for hypertension, a magnified stroke risk emerged for those with one or two cardiometabolic conditions.
The reference group showcased adjusted mortality and CVD incidence rates of 9.74 and 7.31 per 1,000 person-years. In contrast, those with complete risk factors presented rates of 22.93 and 31.48 per 1000 person-years.
Concerning overall impact, diabetes and hypertension accounted for 2.65% and 19.35% of total CVD, respectively. High LDL-C, however, did not show a significant CVD risk association.
The aggregate mortality due to diabetes and hypertension was 5.08% and 10.85%, respectively. Additionally, the joint influence of hypertension and diabetes resulted in 21.48% of CVD cases and 15.38% of all-cause deaths.
In age-based predictions, 40 to 60-year-olds with the trio of cardiometabolic issues anticipated CVD about 3.1 years sooner than their healthier counterparts. The gap in CVD-free years diminished for those post-60 with these disorders.
Most alarmingly, for those over 75, these factors barely affected CVD-free years. Moreover, by age 40, the lifespan of individuals with all three disorders is reduced by a notable 4.3 years.
Conclusions
The present study highlighted that individuals with cardiometabolic disorders like diabetes, hypertension, or high LDL-C are at a heightened risk of CVD and all-cause mortality. The combined impact of diabetes and hypertension accounted for 21.48% of CVD cases.
For those aged 40 to 60, these risk factors significantly reduced CVD-free years and overall life expectancy. Despite the known risks, many in China struggle with managing these conditions concurrently.
The study underscores the need for integrated health management in China and stresses the value of primary prevention, promoting a healthier lifestyle to reduce CVD risks for those under 65.
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