Impact of blood pressure, cholesterol and glucose in the association between adiposity measures and coronary heart disease and stroke among Iranian population

Sex differences in risk factors for coronary heart disease events: a prospective cohort study in Iran

We investigated sex-specific associations and their differences between major cardiovascular risk factors and the risk of incident coronary heart disease (CHD) and hard CHD (defined as nonfatal myocardial infarction and CHD death). A total of 7518 (3377 men) participants from the Tehran Lipid and Glucose Study were included. Cox models were used to estimate the hazard ratios (HRs) and women-to-men ratios of HRs for CHD events associated with each risk factor. During 20 years of follow-up (1999-2018), 1068 (631 men) and 345 (238 men) new cases of CHD and hard CHD, respectively, were documented. In total population, the incidence rates per 1000 person-years were 9.5 (9.0-10.1) and 2.9 (2.6-3.2) for CHD and hard CHD, respectively. Hypertension, diabetes, pre-diabetes, and a high waist-to-hip ratio (WHR) were associated with a greater HR of hard CHD in women than men; the women-to-men HRs were 2.85 [1.36-5.98], 1.92 [1.11-3.31], 2.04 [1.09-3.80] and 1.42 [1.10-1.82], respectively. Diabetes was associated with a higher HR of CHD in women than men (ratio of HRs 1.49 (1.10-2.01). In conclusion, we found that hypertension, diabetes, pre-diabetes, and high WHR conferred a greater excess risk of CHD events in women than in men, suggesting that Iranian women may require greater attention for the prevention of CHD events.

Risk factors for incident cardiovascular events among adults in low- and middle-income countries: A systematic review and meta-analysis of prospective cohort studies

The relative contributions of risk factors for cardiovascular events at a population level has received little attention in low- and middle-income countries (LMICs). We estimated the population attributable fraction (PAF) of risk factors associated with incident cardiovascular events in LMICs. We searched six databases for relevant articles, supplemented with a manual search of reference lists. Articles included in the meta-analyses were those based on prospective community-based cohorts and incorporating adjusted hazard ratios (HR) or relative risks with 95% confidence intervals (95% CI) for associations between risk factors and a composite cardiovascular and/or stroke endpoint. Pooled HRs and 95% CI were calculated using the random effects model. We assessed heterogeneity using the I² test and study quality using the Newcastle-Ottawa Scale. We calculated the PAF of each associated risk factor. The protocol was registered in PROSPERO (CRD42019122741). We identified 18 cohorts from LMICs with 1,125,846 participants, 77,045 composite cardiovascular events and 42,216 strokes. Substantial proportions of incident cardiovascular events were attributable to hypertension (HR [95% CI], 2.23 [2.01-2.48], PAF = 28%); current smoking (1.44 [1.31-1.58], PAF = 10%); and diabetes mellitus (1.93 [1.67-2.23], PAF = 8%). Other risk factors identified included number of children, depression, bone mineral density, and air pollution. A substantial proportion of incident cardiovascular events were linked to traditional metabolic and behavioural modifiable risk factors. However, other novel risk factors also appear to contribute. Targeting of these established and novel risk factors has the potential to reduce the burden of CVD in LMICs.

Very Low-Density Lipoprotein Cholesterol May Mediate a Substantial Component of the Effect of Obesity on Myocardial Infarction Risk: The Copenhagen General Population Study

BACKGROUND

Individuals with obesity have higher concentrations of very low-density lipoprotein (VLDL) cholesterol and increased risk of myocardial infarction. We hypothesized that VLDL cholesterol explains a fraction of the excess myocardial infarction risk in individuals with obesity.

METHODS

We included 29 010 individuals free of myocardial infarction at baseline, nested within 109 751 individuals from the Copenhagen General Population Study. During 10 years of follow-up, 2306 individuals developed myocardial infarction. Cholesterol content in large and small VLDLs, in intermediate-density lipoprotein (IDL), and in LDL was measured directly with nuclear magnetic resonance spectroscopy.

RESULTS

Median concentrations of cholesterol in large and small VLDLs were 0.12 mmol/L (interquartile range [IQR], 0.07-0.20 mmol/L; 4.5 mg/dL [IQR, 2.6-6.9 mg/dL]) and 0.6 mmol/L (IQR, 0.5-0.8 mmol/L; 25 mg/dL [IQR, 20-30 mg/dL]) in individuals with obesity vs 0.06 mmol/L (IQR, 0.03-0.1 mmol/L; 2.2 mg/dL [IQR, 1.1-3.8 mg/dL]), and 0.5 mmol/L (IQR, 0.4-0.6 mmol/L; 20 mg/dL (IQR, 16-25 mg/dL]) in individuals with normal weight; in contrast, concentrations of IDL and LDL cholesterol were similar across body mass index (BMI) categories. Cholesterol in large and small VLDLs combined explained 40% (95% CI, 27%-53%) of the excess risk of myocardial infarction associated with higher BMI. In contrast, IDL and LDL cholesterol did not explain excess risk of myocardial infarction, whereas systolic blood pressure explained 17% (11%-23%) and diabetes mellitus explained 8.6% (3.2%-14%).

CONCLUSIONS

VLDL cholesterol explains a large fraction of excess myocardial infarction risk in individuals with obesity. These novel findings support a focus on cholesterol in VLDL for prevention of myocardial infarction and atherosclerotic cardiovascular disease in individuals with obesity.

Associations of Skeletal Muscle Mass and Fat Mass With Incident Cardiovascular Disease and All-Cause Mortality: A Prospective Cohort Study of UK Biobank Participants

Background There is debate whether body mass index is a good predictor of health outcomes because different tissues, namely skeletal muscle mass (SMM) and fat mass (FM), may be differentially associated with risk. We investigated the association of appendicular SMM (aSMM) and FM with fatal and nonfatal cardiovascular disease (CVD) and all-cause mortality. We compared their prognostic value to that of body mass index. Methods and Results We studied 356 590 UK Biobank participants aged 40 to 69 years with bioimpedance analysis data for whole-body FM and predicted limb muscle mass (to calculate aSMM). Associations between aSMM and FM with CVD and all-cause mortality were examined using multivariable Cox proportional hazards models. Over 3 749 501 person-years of follow-up, there were 27 784 CVD events and 15 844 all-cause deaths. In men, aSMM was positively associated with CVD incidence (hazard ratio [HR] per 1 SD 1.07; 95% CI, 1.06-1.09) and there was a curvilinear association in women. There were stronger positive associations between FM and CVD with HRs per SD of 1.20 (95% CI, 1.19-1.22) and 1.25 (95% CI, 1.23-1.27) in men and women respectively. Within FM tertiles, the associations between aSMM and CVD risk largely persisted. There were J-shaped associations between aSMM and FM with all-cause mortality in both sexes. Body mass index was modestly better at discriminating CVD risk. Conclusions FM showed a strong positive association with CVD risk. The relationship of aSMM with CVD risk differed between sexes, and potential mechanisms need further investigation. Body fat and SMM bioimpedance measurements were not superior to body mass index in predicting population-level CVD incidence or all-cause mortality.

Analysis of risk factors for carotid intima-media thickness in patients with type 2 diabetes mellitus in Western China assessed by logistic regression combined with a decision tree model

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in patients with type 2 diabetes (T2DM). Carotid intima-media thickness (CIMT) is considered a preclinical stage of atherosclerosis. Therefore, it is necessary to identify the related risk factors for CIMT to facilitate the early prevention of CVD. Previous studies have shown that visceral fat area (VFA) is a risk factor for T2DM and CVD. However, few studies have focused on the effects of VFA on CIMT associated with T2DM. Moreover, considering that the body fat distribution shows regional and racial heterogeneity, the purpose of this study was to investigate the predictive value of VFA and other risk factors for CIMT associated with T2DM in Western China.

METHODS

In a cross-sectional study, a total of 1372 patients with T2DM were divided into the CIMT (-) group (n = 965) and the CIMT (+) group (n = 407) based on CIMT values. In addition to the univariate analyses, logistic regression analysis and a decision tree model were simultaneously performed to establish a correlation factor model for CIMT.

RESULTS

Univariate analyses showed that sex, smoking status, age, heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), height, weight, body mass index (BMI), waist circumference, hip circumference, waist-hip ratio, VFA, subcutaneous fat area, and the levels of 2-h C-peptide, serum creatinine, urea nitrogen and uric acid were significantly different between the two groups (all p < 0.05). Smoking, increased VFA, female sex and increased BMI were risk factors in the logistic regression analyses (OR = 5.759, OR = 1.364, OR = 2.239, OR = 1.186, respectively). In the decision tree model, smoking was the root node, followed by sex, waist circumference, VFA and chronic kidney disease (CKD) in order of importance.

CONCLUSIONS

In addition to smoking, sex and BMI, VFA has a significant effect on CIMT associated with T2DM in the Chinese Han population in Western China. In addition, the decision tree model could help clinicians make more effective decisions, with its simplicity and intuitiveness, making it worth promoting in future medical research.Trial registration ChiCTR, ChiCTR1900027739. Registered 24 November 2019-Retrospectively registered, http://www.chictr.org.cn/index.aspx.

Contribution of serum lipids as effect modifiers to a relationship between mean arterial pressure and coronary heart disease in Chinese rural population: the Henan Rural Cohort Study

OBJECTIVES

The aim of this study was to evaluate the relationship between mean arterial pressure (MAP) and coronary heart disease (CHD) in Chinese rural population. In addition, we hypothesised that this relationship might be mediated by some degree of serum lipids.

DESIGN

This is a cross-sectional study.

SETTING

The participants were from the Henan Rural Cohort Study, initiated in five rural areas (Tongxu county of Kaifeng city, Yima county of Sanmenxia city, Suiping county of Zhumadian city, Xinxiang county of Xinxiang city and Yuzhou county of Xuchang city) in Henan Province, China, during July 2015 and September 2017.

PARTICIPANTS

The study included 39 020 subjects aged 18-79 years as current research population.

OUTCOME MEASURES

Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using an electronic sphygmomanometer. MAP was calculated by one-third SBP plus two-thirds DBP. The study used restricted cubic splines and logistic regression models to evaluate the ORs and 95% CIs. Mediation analysis using bootstrap was performed to examine the contribution of serum lipids to MAP-related CHD.

RESULTS

The adjusted OR (95% CI) for the highest MAP quartile with the risk of CHD was 1.45 (1.24 to 1.69) compared with the lowest quartile. Simultaneously, each 1-SD increment in MAP was significantly associated with a 12% increased risk of CHD. A linear dose-response relationship between MAP and CHD was found (p value for non-linear=0.1169) in the fully adjusted model. We further reported that 36.07% of proportion explained risk of CHD was mediated through serum lipids.

CONCLUSIONS

Increased MAP was a significant marker of CHD in Chinese rural population. Meanwhile, the relationship was mediated by some degree of serum lipids, and triglyceride was the strongest mediator.

TRIAL REGISTRATION NUMBER

Henan Rural Cohort study has been registered at Chinese Clinical Trial Register (ChiCTR-OOC-15006699) and the stage it relates to is Post-results.

Influence of blood glucose fluctuation, C-peptide level and conventional risk factors on carotid artery intima-media thickness in Chinese Han patients with type 2 diabetes mellitus

BACKGROUND

Some studies have suggested that blood glucose fluctuation and C-peptide level were considered as predictive factors for carotid artery intima-media thickness (CIMT). However, the relationships of these variables are unclear. This research was aimed to identify the potential effects of blood glucose fluctuation, C-peptide level and conventional risk factors on CIMT.

METHODS

A total of 280 type 2 diabetes mellitus (T2DM) patients were enrolled into this study. Population characteristics were obtained through medical history and clinical parameters. The patients were divided into two groups according to the critical value of CIMT (0.9). Research data were analyzed to identify risk factors of CIMT between the two groups.

RESULTS

The comparison results of basic information showed that differences in age and illness years between the two groups were statistically significant (p = 0.0002 and p = 0.0063). Logistic regression analysis results indicated that smoking, uric acid (UA) levels, 2 h C-peptide and standard deviation of blood glucose (SDBG) were the influence factors for CIMT thickening (p = 0.032, p = 0.047, p = 0.049 and p = 0.042, respectively). Blood glucose fluctuation could affect the risk of some complications. In largest amplitude of glycemic excursions (LAGE) > 4.4 group, the CIMT abnormal rate was 27.10%, which was significantly higher than 12.12% in the LAGE ≤ 4.4 group (p = 0.012). The CIMT abnormal rate of SDBG > 2.0 group was 27.81%, which was significantly higher than that of the SDBG ≤ 2.0 group (p = 0.018).

CONCLUSIONS

Blood glucose fluctuation is an independent risk factor associated with CIMT in T2DM patients, in addition to conventional risk factors, such as smoking, high UA level and 2 h C-peptide. Therefore, more attention should be given to the change of CIMT and the complications.

Different Weight Histories and Risk of Incident Coronary Heart Disease and Stroke: Tehran Lipid and Glucose Study

Background

This study aimed to determine the association between different weight histories, including cumulative excess weight, cumulative excess waist circumference (WC), duration of general and central adiposity, current and maximum body mass index, and current and maximum WC, and incident coronary heart disease (CHD) and stroke.

Methods and Results

The study population consisted of 4398 adults aged ≥40 years without CHD or stroke at baseline. Associations between different weight histories and CHD and stroke were determined by multivariable time‐varying Cox regression models after adjustment for age, sex, and time‐varying confounders. Further adjustment was also done for mediators (eg, diabetes mellitus, hypercholesterolemia, and hypertension). During median follow‐up of 13.9 years, 718 incident CHD and 158 stroke events were documented. Multivariable adjusted hazard ratios (HRs) were calculated in the sex and confounder adjusted model for CHD per 1‐SD increase in cumulative excess weight (HR: 1.02; 95% confidence interval [CI], 0.96–1.07), cumulative excess WC (HR: 1.14; 95% CI, 1.04–1.24), duration of general adiposity (HR: 1.00; 95% CI, 0.92–1.08), duration of central adiposity (HR: 1.01; 95% CI, 0.93–1.09), current body mass index (HR: 1.03; 95% CI, 0.99–1.07), current WC (HR: 1.21; 95% CI, 1.11–1.32), maximum body mass index (HR: 1.01; 95% CI, 0.95–1.07), and maximum WC (HR: 1.17; 95% CI, 1.07–1.28). After further adjustment for mediators, current and maximum WC still showed a significant risk (HR: 1.13 [95% CI, 1.03–1.23] and 1.09 [95% CI, 1.00–1.20], respectively). Moreover, in the sex and confounder adjusted model, cumulative excess WC and maximum WC were associated with higher risk of stroke (hazard ratio: 1.21 [95% CI, 0.99–1.48] and 1.25 [95% CI, 1.02–1.55], respectively).

Conclusions

Exposure to cumulative excess weight and cumulative excess WC confers little additional risk beyond their current and maximum values. Even current and maximum WC were associated with incident CHD in the presence of obesity mediators, and the latter was a significant predictor of stroke in the presence of confounders.