What is the clinical evidence from this study?

Study design: Cohort. Population: Community-dwelling older adults (n=3239). Intervention: Lowest quintile of LDL-C (<2.61 mmol/L) vs. Highest quintile of LDL-C (≥4.10 mmol/L). Primary outcome: All-cause mortality (HR 1.67, 95% CI 1.26-2.21, p=<0.001).

March 8, 2022Open Access

Low and High-Density Lipoprotein Cholesterol and 10-Year Mortality in Community-Dwelling Older Adults: The Shanghai Aging Study

Q: What are the key findings of this study?

The lowest quintile of LDL-C (<2.61 mmol/L) was associated with a significantly higher risk of all-cause mortality (HR 1.67) compared to the highest quintile (≥4.10 mmol/L) in older adults.

Key Result

The lowest quintile of LDL-C (<2.61 mmol/L) was associated with a significantly higher risk of all-cause mortality (HR 1.67) compared to the highest quintile (≥4.10 mmol/L) in older adults.

Study Design

Type

Cohort (n=3,239)

Multicenter

Structured PICO

Does the level of LDL-C and HDL-C affect all-cause mortality in community-dwelling older adults?

Population

3,239 community-dwelling older Chinese adults free of lipid-lowering agents from the Shanghai Aging Study

Intervention

Low and high-density lipoprotein cholesterol (LDL-C and HDL-C) levels

Comparator

Highest quintile of LDL-C (≥4.10 mmol/L) and third quintile of HDL-C (1.21-1.39 mmol/L)

Outcome

All-cause mortality at median 10 years follow-uphard clinical

In older Chinese adults not on lipid-lowering therapy, low LDL-C and both low and high HDL-C levels were associated with increased long-term all-cause mortality.

Main Result

Effect estimate: HR 1.67 (95% CI 1.26-2.21)

Absolute Event Rate: 26.36% vs 11.71%

p-value: p=<0.001

Limitations

Relied on a single measurement of LDL-C and HDL-C at baseline
Potential reverse causality due to underlying chronic diseases
Possibility of residual confounding from unmeasured variables such as diets, occupation history, and air pollution
Focused only on all-cause mortality due to relatively small number of events limiting cause-specific mortality analysis
Post-hoc analysis where sample size was not calculated according to mortality rate
Findings may not be generalized to other populations in China with different demographic characteristics

Abstract

Background: The relationship between serum cholesterol and mortality remains disputed. This study aimed to examine the association of low and high-density lipoprotein cholesterol (LDL-C and HDL-C) with all-cause mortality among community-dwelling older adults in the Shanghai Aging Study. Methods: We followed 3,239 participants free of lipid-lowering agents for a median of 10 years. Levels of LDL-C and HDL-C were measured at baseline using fasting blood samples. Survival status was confirmed by the local mortality surveillance system. The associations between the levels of LDL-C, HDL-C, and all-cause mortality were assessed by Cox proportional hazards models. Results: for trend < 0.05). Using the highest quintile of LDL-C (≥4.10 mmol/L) as a reference, the lowest quintile of LDL-C (<2.61 mmol/L) was associated with the highest risk of mortality, after adjusting for confounders (HR 1.67; 95% CI 1.26-2.21), exclusion of death within the first 2 years of follow-up (HR 1.57; 95% CI 1.17-2.11), and exclusion of functionally impaired participants (HR 1.46; 95% CI 1.07-2.00). A U-shape relationship was found between HDL-C level and the mortality risk. Using the third quintile of HDL-C (1.21-1.39 mmol/L) as a reference, HR (95% CI) was 1.46 (1.09-1.95) for the lowest quintile (<1.09 mmol/L) and 1.45 (1.07-1.96) for the highest quintile (≥1.61 mmol/L) of HDL-C, after adjusting for confounders; and 1.57 (1.15-2.15) for the lowest quintile and 1.45 (1.04-2.01) for the highest quintile of HDL-C, after exclusion of death within the first 2 years of follow-up; and 1.55 (1.11-2.16) for the lowest quintile and 1.42 (1.00-2.02) for the highest quintile of HDL-C, after exclusion of functionally impaired participants. Conclusions: We found an inverse association of LDL-C and a U-shape relationship of HDL-C with long-term all-cause mortality in a cohort with community-dwelling older Chinese adults. Levels of LDL-C and HDL-C are suggested to be managed properly in late life.

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