The Association of Lipids and Lipoproteins with Hip Fracture Risk: The Cardiovascular Health Study

Confounding association between plasma HDL-C levels and increased fracture risk: A correspondence

Background

This article explores the association between fractures, particularly in the elderly, and elevated plasma high-density lipoprotein cholesterol (HDL-C) levels. The study challenges the conventional idea of HDL-C as "good cholesterol" by revealing its potential role as a risk factor for fractures. Factors contributing to fractures in the elderly, such as diminishing bone strength due to aging-related tissue breakdown, are discussed. Sedentary lifestyles, low bone mineral density (BMD), and habits like smoking and alcohol consumption compound fracture susceptibility.

Materials and Methods

The study delves into mechanisms linking elevated HDL-C to fractures, using data from the ASPREE-Fracturesub-study of the ASPREE trial involving Australian and American participants aged 65 and above.

Results

The study showed that over a 4-year period, elevated HDL-C levels in healthy older people were linked to a 14% higher fracture risk. This revelation expands the understanding of fracture risk factors beyond the established norms.

Conclusion

The article emphasizes the need to reconsider HDL-C's traditional role as an indicator of cardiovascular health, particularly in light of medications like Statins and Anacetrapib that raise HDL-C levels. It calls for further exploration into the relationship between HDL-C, fractures at varying sites, and different age groups. Practical implications involve incorporating fracture risk associated with high HDL-C into clinical considerations, alongside advocating lifestyle changes for optimal HDL-C levels. In summary, this study prompts a reevaluation of HDL-C's implications in clinical practice, demanding further investigation into the intricacies of this relationship.

Sex-Specific Relationships between HDL-Cholesterol Levels and 10-Year Mortality in Individuals with Atherosclerotic Cardiovascular Disease: A Nationwide Cohort Study of South Koreans

Large epidemiological studies show U-shaped relationships between high-density lipoprotein cholesterol (HDL-C) levels and all-cause mortality in individuals without atherosclerotic cardiovascular diseases (ASCVD). Association in those with ASCVD by sex is unclear. We examined the association between HDL-C levels and 10-year all-cause mortality in subjects (≥40 years of age) with ASCVD using the 2010 National Health Insurance Service and the National Death Registry of Korea. We categorized HDL-C levels into three groups (low: <40 mg/dL for males, <50 mg/dL for females; high: 40-90 mg/dL for males, 50-90 mg/dL for females; extremely high: >90 mg/dL) and 10 mg/dL intervals. We conducted a sex-stratified and adjusted Cox proportional hazards analysis. Out of 1,711,548 individuals (54% female, mean age 61.4 years), 10-year mortality was observed in 218,252 (12.8%). Males had a higher mortality rate than females (16.2% vs. 9.8%; p < 0.001). When adjusting for age, body mass index, LDL-cholesterol, triglycerides, hypertension, diabetes, smoking, and alcohol consumption, the low and extremely high HDL-C groups had significantly higher hazard ratios for 10-year mortality compared to the high HDL-C group in males [1.183 (1.166-1.199), 1.359 (1.288-1.434)] and in females [1.153 (1.138-1.169), 1.095 (1.029-1.167)]. The frequency distribution bars for the 10-year mortality rate showed sex-specific nadirs of 50-59 mg/dL in males and 70-79 mg/dL in females. In this ASCVD cohort, the extremely high HDL-C (>90 mg/dL) group had 35.9% and 9.5% higher 10-year mortality risks than the high HDL-C group for males and females, respectively. There was a slightly U-shaped relationship between baseline HDL-C levels and a 10-year mortality rate, with earlier inflection in males than in females.

The Paradoxical Association of Lipids with Survival and Walking Ability of Hip Fractures in Geriatric Patients After Surgery: A 1-Year Follow-Up Study

Background

We aimed to explore the association between lipids and the survival and walking ability of hip fractures in geriatric patients after surgery.

Methods

Restricted cubic spline (RCS) was established to explore the nonlinear relationship between lipids and 1-year mortality of hip fractures, and the cut-off points were also determined by RCS. Then, the patients were divided into three groups: low, middle, and high levels of LDL-c. Then, the survival and walking ability of patients from different groups were compared, and the Cox regression and Logistics regression were used to identify the relationships between lipids and the survival and walking ability of hip fractures.

Results

The patients with middle levels of LDL-c had a significantly high survival probability than those with low or high levels of LDL-c (p < 0.001). The patients with low levels of LDL-c and with high levels of LDL-c may have a poor prognosis compared with patients with middle levels of LDL-c in 6-month mortality, 6-month free walking ability, 1-year mortality, and 1-year free walking ability (All p < 0.05).

Conclusion

Low and high levels of LDL-c may both relate to the poor survival and walking ability of hip fractures.

The interplay between circulating high-density lipoprotein, age and fracture risk: a new cohort study and systematic meta-analysis

Previous findings on the association between high-density lipoprotein cholesterol (HDL-C) and fracture have yielded inconsistent results and it is unclear if the association varies with age and sex. We sought to evaluate the prospective association between HDL-C levels and fracture risk and assess if the association is modified by age and sex. Circulating HDL-C levels were measured at baseline in a population-based sample of 2,448 men aged 42-61 years. Cox regression was used to estimate hazard ratios (HRs) and 95% CIs. Incident fractures (n = 134) occurred during a median follow-up of 25.7 years. In analysis adjusted for several risk factors, the HR (95% CI) for fractures was 1.00 (0.85-1.20) per 1 standard deviation (SD) increase in HDL-C levels. Comparing the extreme tertiles of HDL-C levels, the corresponding adjusted HR (95% CI) was 0.94 (0.62-1.45). In a meta-analysis of eight cohort studies (including the current study) comprising 74,378 participants and 4,621 fracture cases, the fully-adjusted risk estimate (95% CI) for fracture was 1.03 (0.96-1.10) per 1SD increase in HDL-C levels and 1.05 (0.92-1.20) comparing extreme tertiles of HDL-C. The pooled risk estimate (95% CIs) for fracture per 1SD increase were 1.09 (1.01-1.17) and 0.98 (0.93-1.04) for age groups ≥ 60 and < 60 years, respectively, and the corresponding risks comparing the extreme tertiles of HDL-C levels were 1.21 (1.09-1.33) and 0.95 (0.85-1.07) (p-value for interaction < 0.05). Age may modify the association between HDL-C levels and fracture risk - an increased fracture risk associated with increased HDL-C levels is only evident in older age (≥ 60 years).

Evaluation of the Association between Low-Density Lipoprotein (LDL) and All-Cause Mortality in Geriatric Patients with Hip Fractures: A Prospective Cohort Study of 339 Patients

BACKGROUND

Many factors affect the prognosis of hip fractures in the elderly. Some studies have suggested a direct or indirect association among serum lipid levels, osteoporosis, and hip fracture risk. LDL levels were found to have a statistically significant nonlinear U-shaped relationship with hip fracture risk. However, the relationship between serum LDL levels and the prognosis of patients with hip fractures remains unclear. Therefore, in this study, we assessed the influence of serum LDL levels on patient mortality over a long-term follow-up period.

METHODS

Elderly patients with hip fractures were screened between January 2015 and September 2019, and their demographic and clinical characteristics were collected. Linear and nonlinear multivariate Cox regression models were used to identify the association between LDL levels and mortality. Analyses were performed using Empower Stats and R software.

RESULTS

Overall, 339 patients with a mean follow-up period of 34.17 months were included in this study. Ninety-nine patients (29.20%) died due to all-cause mortality. Linear multivariate Cox regression models showed that LDL levels were associated with mortality (HR = 0.69, 95%CI: 0.53, 0.91, p = 0.0085) after adjusting for confounding factors. However, the linear association was unstable, and nonlinearity was identified. An LDL concentration of 2.31 mmol/L was defined as the inflection point for prediction. A LDL level < 2.31 mmol/L was associated with mortality (HR = 0.42, 95%CI: 0.25, 0.69, p = 0.0006), whereas LDL > 2.31 mmol/L was not a risk factor for mortality (HR = 1.06, 95%CI: 0.70, 1.63, p = 0.7722).

CONCLUSIONS

The preoperative LDL level was nonlinearly associated with mortality in elderly patients with hip fractures, and the LDL level was a risk indicator of mortality. Furthermore, 2.31 mmol/L could be considered a predictor cut-off for risk.

Association of Plasma High-Density Lipoprotein Cholesterol Level With Risk of Fractures in Healthy Older Adults

Importance

Increased levels of high-density lipoprotein cholesterol (HDL-C) have been associated with osteoporosis. Preclinical studies have reported that HDL-C reduces bone mineral density by reducing osteoblast number and function. However, the clinical significance of these findings is unclear.

Objective

To determine whether higher HDL-C levels are predictive of an increased fracture risk in healthy older adults.

Design, Setting, and Participants

This cohort study is a post hoc analysis of data from the Aspirin in Reducing Events in the Elderly (ASPREE) clinical trial and the ASPREE-Fracture substudy. ASPREE was a double-blind, randomized, placebo-controlled primary prevention trial of aspirin that recruited participants between 2010 and 2014. These comprised community-based older adults (16 703 Australians aged ≥70 years, 2411 US participants ≥65 years) without evident cardiovascular disease, dementia, physical disability, and life-limiting chronic illness. The ASPREE-Fracture substudy collected data on fractures reported postrandomization from Australian participants. Cox regression was used to calculate hazard ratio (HR) and 95% CI. Data analysis for this study was performed from April to August 2022.

Exposure

Plasma HDL-C.

Main Outcomes and Measures

Fractures included were confirmed by medical imaging and included both traumatic and minimal trauma fractures. Fractures were adjudicated by an expert review panel.

Results

Of the 16 262 participants who had a plasma HDL-C measurement at baseline (8945 female participants [55%] and 7319 male [45%]), 1659 experienced at least 1 fracture over a median (IQR) of 4.0 years (0.02-7.0 years). In a fully adjusted model, each 1-SD increment in HDL-C level was associated with a 14% higher risk of fractures (HR, 1.14; 95% CI, 1.08-1.20). The results remained similar when these analyses were stratified by sex. Sensitivity and stratified analyses demonstrated that these associations persisted when the analyses were repeated to include only (1) minimal trauma fractures, (2) participants not taking osteoporosis medications, (3) participants who were never smokers and reported that they did not drink alcohol, and (4) participants who walked outside for less than 30 minutes per day and reported no participation in moderate/vigorous physical activity and to examine only (5) statin use. No association was observed between non-HDL-C levels and fractures.

Conclusions and Relevance

This study suggests that higher levels of HDL-C are associated with an increased fracture risk. This association was independent of common risk factors for fractures.