Triglycerides Paradox Among the Oldest Old: "The Lower the Better?"

Abstract

Objectives: Currently, most treatment guidelines suggest lowering hypertriglyceridemia of any severity, even in elderly individuals. However associations of serum triglycerides (TGs) with adverse health and mortality risk decrease with age, it remains unclear among the oldest old (aged 80 years and older). The study was to investigate the relationship of serum TG concentrations with cognitive function, activities of daily living (ADLs), frailty, and mortality among the oldest old in a prospective cohort study.

Design: Longitudinal prospective cohort study.

Setting: Community-based setting in longevity areas in China.

Participants: A total of 930 (mean age = 94.0 years) Chinese oldest old.

Measurements: The TG concentrations were measured at baseline survey in 2009. Cognitive function, ADLs, frailty, and mortality were determined over 5 years of follow-up. Cox proportional hazards models and competing risk models were performed to explore the association, adjusting for potential confounders.

Results: Each 1-mmol/L increase in TGs was associated with a nearly 20% lower risk of cognitive decline, ADL decline, and frailty aggravation during the 5 years of follow-up. Consistently, higher TGs (each 1 mmol/L) was associated with lower 5-year all-cause mortality after fully adjustment (hazard ratio [HR] = 0.79; 95% confidence interval [CI] = 0.69-0.89). Nonelevated TG concentrations (less than 2.26 mmol/L) were associated with higher mortality risk (HR = 1.72; 95% CI = 1.22-2.44), relative to TGs of 2.26 mmol/L or more. We observed similar results regarding TG concentrations and mortality in 1-year lag analysis and when excluding participants with identified chronic disease.

Conclusion: In the oldest old, a higher concentration of TGs was associated with a lower risk of cognitive decline, ADL decline, frailty aggravation, and mortality. This paradox suggests the clinical importance of revisiting the concept of "the lower the better" for the oldest old. J Am Geriatr Soc 67:741-748, 2019.

Keywords: activities of daily living; cognitive function; frailty; mortality; triglycerides.

Figure 1.. The association of TG (each 1 mmol/L) with cognitive decline, ADL decline, frailty aggravation and mortality during 5 years of follow-up.^a

Abbreviation: ADL= activities of daily living; RR=risk ratio; TG=triglycerides. ^aAdjusted for age, sex, educational level, marital status, self-reported quality of life, regular exercise, central obesity, BMI, cognitive impairment (was not adjusted in the analyses of cognitive decline), disability (was not adjusted in the analyses of ADL decline), frailty (was not adjusted in the analyses of frailty aggravation), CVD, TLC and CKD.

Figure 2.. The 5-year all-cause mortality risk for different TG concentrations.^a

*p<0.05; **p<0.01; Abbreviation: TG= triglycerides; HR=hazard ratio. ^a Adjusted for age, sex, educational level, marital status, self-reported quality of life, regular exercise, central obesity, BMI, cognitive impairment, disability, frailty, CVD, TLC and CKD.

Figure 3.. The association between TG and 5-year all-cause mortality risk in different subgroup.^a

Abbreviation: CKD= chronic kidney disease; CVD= cardiovascular and cerebrovascular disease; TG= triglycerides; HR=hazard ratio. ^a Adjusted for age, sex, educational level, marital status, self-reported quality of life, regular exercise, central obesity, BMI, cognitive impairment, disability, frailty, CVD, TLC and CKD.