A Healthy Lifestyle Index Predicts All-Cause Mortality in Older Adults Independent of Psychological Distress, Chronic Conditions, and Functional Limitations: NHIS 1997 To 2018

Peter D. Hart^{1, 2,}

¹Health Promotion Research, Havre, Montana, USA

²Kinesmetrics Lab, Tallahassee, Florida, USA

Cite this paper:
Peter D. Hart. A Healthy Lifestyle Index Predicts All-Cause Mortality in Older Adults Independent of Psychological Distress, Chronic Conditions, and Functional Limitations: NHIS 1997 To 2018. American Journal of Applied Psychology. 2025; 13(1):17-22. doi: 10.12691/ajap-13-1-3

Abstract

Background: Chronic disease, emotional health, and functional ability are known predictors of mortality in elderly populations. However, the extent to which healthy lifestyle characteristics such as alcohol use, smoking, physical activity (PA), and healthy weight collectively and independently influence mortality in these populations is unclear. Purpose: The aim of this study was to examine the association between a healthy lifestyle index (HLI) and risk of all-cause mortality while controlling for health status commonly seen in older adults (i.e., psychological distress, chronic conditions, and functional limitations). Methods: A total of 22 consecutive years (1997 to 2018) of National Health Interview Survey (NHIS) data were combined (N=671,696) and linked to National Center for Health Statistics (NCHS) 2019 mortality files. A baseline sample of 113,547 adults met inclusion criteria of 65+ years of age, linkageeligible, and complete data. The HLI was created using four health metrics (alcohol use, smoking, PA, and BMI), each on a 3-point intensity scale. The HLI was created by summing the metric variableswith total score between 0 and 8. Psychological distress was assessed using the Kessler 6-item scale. Functional limitations wereassessed using the FL12 scale of functional limitation severity. Finally, a chronic conditions score was created as the number suffered out of 9 conditions. Multiple linear regression was used with least squares means to examine the sex-specific relationship between the HLI and age. Cox proportional hazards modeling was employed to estimate hazard ratio (HR) statistics and 95% confidence intervals (CIs). Fully adjusted HR statistics were adjusted for the above variables as well as age, sex, race, and income. Results: A total of 51,607 deaths by all causes were observed during a median follow-up of 10.4 (SE=0.05) years. The HLI increased linearly (p<0.0001) across the three different age groups (65-74 yr, 75-84 yr, and 85+ yr) in both males (means: 3.31, 3.57, and 3.89) and females (means: 3.82, 4.10, and 4.41), respectively. In the fully adjusted hazards model, risk of all-cause mortality decreased linearly (p<0.0001) for participants having an HLI of 0 (HR=2.10, 1.83-2.40), 1 (HR=1.44, 1.32-1.57), 2 (HR=1.39, 1.29-1.49), 3 (HR=1.27, 1.19-1.36), 4 (HR=1.20, 1.12-1.28), 5 (HR=1.12, 1.04-1.20), 6 (HR=1.15, 1.07-1.24), and 7+ (HR=1.00, reference). Conclusion: The HLI used in this study predicted all-cause mortality riskina dose-response manner, independent of psychological distress, chronic conditions, functional limitations, and demographic covariates. Adopting a healthy lifestyle may contribute to survival irrespective of health status and age.

Keywords:
Gerontology Functional ability Behavioral health Mortality Population health

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