HDL-C, longitudinal change and risk of mortality in a Chinese cohort study.

BACKGROUND AND AIMS: High-density lipoprotein cholesterol (HDL-C) concentration and variability are both important factors of cardiovascular disease (CVD) and mortality. We aimed to explore the associations of HDL-C and longitudinal change in HDL-C with risk of mortality. METHODS AND RESULTS: We recruited a total of 69,163 participants aged ≥40 years and had medical examination records of HDL-C during 2010-2014 from the Yinzhou District, Ningbo, China. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression models. We observed a non-linear association of HDL-C with risks of non-accidental and CVD mortality. Compared with the moderate concentration group (1.4-1.6 mmol/L), HDL-C <1 mmol/L was associated with a higher risk of non-accidental mortality (HR: 1.13 (95% CI: 1.01-1.27)) and both HDL-C <1 mmol/L and ≥2 mmol/L were associated with a higher risk of CVD mortality (HRs: 1.23 (95% CI: 1.01-1.50) and 1.37 (95% CI: 1.03-1.82), respectively). Compared with the stable group ([-0.1, +0.1 mmol/L]), a large decrease ([-0.5, -0.3 mmol/L]) and very large decrease (<-0.5 mmol/L) in HDL-C were associated with a higher risk of non-accidental mortality (HRs: 1.40 (95% CI: 1.21-1.63) and 1.78 (95% CI: 1.44-2.20), respectively). Similar results were observed for CVD mortality and cancer mortality. CONCLUSION: Extremely low or high HDL-C and a large decrease or very large decrease in HDL-C were associated with a higher risk of cause-specific mortality. Monitoring of HDL-C may have utility in identifying individuals at higher risk of mortality.

Low LDL-C levels are associated with risk of mortality in a Chinese cohort study.

BACKGROUND AND AIMS: Although low-density lipoprotein cholesterol (LDL-C) has been considered as a risk factor of atherosclerotic cardiovascular disease, limited studies can be available to evaluate the association of LDL-C with risk of mortality in the general population. This study aimed to examine the association of LDL-C level with risk of mortality using a propensity-score weighting method in a Chinese population, based on the health examination data. METHODS: We performed a retrospective cohort study with 65,517 participants aged 40 years or older in Ningbo city, Zhejiang. LDL-C levels were categorized as five groups according to the Chinese dyslipidemia guidelines in adults. To minimize potential biases resulting from a complex array of covariates, we implemented a generalized boosted model to generate propensity-score weights on covariates. Then, we used Cox proportional hazard regression models with all-cause and cause-specific mortality as the dependent variables to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs). RESULTS: During the 439,186.5 person years of follow-up, 2403 deaths occurred. Compared with the median LDL-C group (100-130 mg/dL), subjects with extremely low LDL-C levels (group 1) had a higher risk of deaths from all-cause (HR = 2.53, 95% CI:1.80-3.53), CVD (HR = 1.84, 95% CI: 1.28-2.61), ischemic stroke (HR = 2.29, 95% CI:1.32-3.94), hemorrhagic stroke (HR = 3.49, 95% CI: 1.57-7.85), and cancer (HR = 2.12, 95% CI: 1.04-4.31) while the corresponding HRs in LDL-C group 2 were relatively lower than that in group 1. CONCLUSIONS: Low LDL-C levels were associated with an increased risk of all-cause, CVD, ischemic stroke, hemorrhagic stroke, and cancer mortality in the Chinese population.

Impact of Individual and Combined Lifestyle Factors on Mortality in China: A Cohort Study.

INTRODUCTION: Although numerous studies have suggested that lifestyle-related factors are associated with chronic diseases and preventable deaths, limited evidence is available for the Chinese population. METHODS: This study established a prospective cohort of >360,000 residents on the basis of the Yinzhou Health Information System in China during 2004-2017 and calculated the combined effects of lifestyle-related factors, including BMI, smoking, alcohol consumption, and physical activity, using a points system. A Cox regression model estimated the combined effects of lifestyle-related factors on total mortality, and a competing risk model estimated the combined effects on cancer and cardiovascular disease mortality. All data analyses were conducted in 2018‒2019. RESULTS: During 3,755,879 person-years of follow-up, 11,791 deaths were identified, including 4,983 from cancer and 3,143 from cardiovascular disease. Having a standard BMI, never smoking, never drinking, and engaging in physical activity more than 4 times per week had protective effects on total mortality. Overall, the risk of total and cause-specific mortality increased with the increment of risk score. Compared with subjects in the lowest quartile, the risk of total and cause-specific mortality peaked among individuals in the fourth quartile (total mortality: hazard ratio=1.87, 95% CI=1.77, 1.98; cancer mortality: hazard ratio=2.05, 95% CI=1.87, 2.25; cardiovascular disease mortality: hazard ratio=1.51, 95% CI=1.35, 1.68). Sensitivity analyses excluding individuals with follow-up <3 years did not materially change the results. CONCLUSIONS: The combined effects of lifestyle-related factors, including BMI, smoking, alcohol drinking, and physical activity, are associated with total, cancer, and cardiovascular disease mortality among the Chinese population.

Intra-individual variability of total cholesterol is associated with cardiovascular disease mortality: A cohort study.

BACKGROUND AND AIMS: The relationship between serum total cholesterol (TC) and mortality remains inconsistent. Additionally, intra-individual variability of cholesterol has been of increasing interest as a new indicator for health outcomes. We aimed to examine the association between TC and its variability and risk of mortality. METHODS AND RESULTS: We performed a retrospective cohort study with 122,645 individuals aged over 40 years in Ningbo, China. The intra-individual variability was calculated using four metrics including standard deviation, coefficient variation, variation independent of mean and average successive variability. Hazard ratios and 95% confidence intervals were estimated for the associations of baseline and variability in TC with risk of mortality by Cox proportional hazards regression models. During 591,585.3 person-years of follow-up, 4563 deaths (including 1365 from cardiovascular disease, 788 from stroke and 1514 from cancer) occurred. A U-shaped association was observed for baseline TC level and risk of total, cardiovascular and cancer mortality, with lowest mortality at 5.46 mmol/L, 5.04 mmol/L and 5.51 mmol/L, respectively. As compared with subjects with TC variability in the lowest quartile, individuals in the highest quartile had 21% higher risk of all-cause mortality (HR = 1.21, 95% CI: 1.05 to 1.40), and 41% higher risk of CVD mortality (HR = 1.41, 95%CI: 1.10 to 1.81). CONCLUSION: Both too low and too high baseline TC level were associated with higher risk of total, cardiovascular disease and cancer mortality. Variability of TC could be a risk factor of total and CVD mortality, independent of mean TC level. Future studies are needed to confirm these findings.