Predicting all-cause and cause-specific mortality by static and dynamic measurements of allostatic load: a 10-year population-based cohort study in Taiwan

Abstract

Objective: To evaluate the role of allostatic load (AL), either static or dynamic measurements, in predicting all-cause and cause-specific mortality of older people in Taiwan.

Design: A prospective cohort study.

Setting: Population-based community study.

Participants: One thousand twenty-three community-dwelling older people.

Measurements: Allostatic load (calculated by systolic blood pressure, diastolic blood pressure, total cholesterol, high-density lipoprotein cholesterol, triglyceride, glycosylated hemoglobin, fasting glucose, waist-to-hip ratio, body mass index, dehydroepiandrosterone sulfate, insulin-like growth factor-1, 12-hour urine cortisol, 12-hour urine epinephrine, 12-hour urine norepinephrine, 12-hour urine dopamine, white blood cell count, neutrophils, interleukin-6, albumin, creatinine) and all-cause and cause-specific mortality from national death registry.

Intervention: None.

Results: Adjusted for age and sex, each 1-point increase in AL score was associated with 20% incremental risk of mortality [hazard ratio 1.20, 95% confidence interval (CI) 1.09-1.31]. This association can be extended to cause-specific mortality in both sexes in general. In addition, the higher AL score quintile was significantly associated with higher risk of 10-year all-cause mortality (P < .0001). This association was consistent across different cause-specific mortality (ie, malignant neoplasm (P = .008), cardiometabolic diseases (P < .0001), infectious diseases (P < .0001), respiratory diseases (P < .0001), and others (P = .0002), respectively. Compared with AL score decliners, adjusted for age, sex, and baseline AL score in 2000, participants with fast increase had significantly higher mortality (HR 2.68, 95% CI 1.23-5.84, P = .01). The effect was stronger in men (HR 2.83, 95% CI 1.1-7.29, P = .03 in slow increase; HR 4.06, 95% CI 1.56-10.6, P = .001 in fast increase group), but it was insignificant in female participants.

Conclusions: Higher AL score or rapid increase of AL score significantly increased subsequent mortality risk in older adults, either measured statically or dynamically. AL is predictive of 10-year mortality regardless of cause of death, and rapid increase in AL score is associated with higher subsequent mortality.

Keywords: Allostatic load; elderly; geriatrics; homeostasis; mortality.