Page 72 - IJPS-11-1

International Journal of
Population Studies Health-related quality of life and mortality

Figure 4. Survival analysis of the Health Care Survey of the Municipality of Campinas, São Paulo, Brazil Cohort elders (60 years and older) with better
and worse Health-Related Quality of Life based on the 36-item Short Form Health Survey physical and mental components (2008 – 2018). Note: *p < 0.05,
**p < 0.01
Abbreviations: MC: Mental component; PC: Physical component.

5.15 TLS), and mental health (5.64 THS vs. 5.04 TLS). In an inverse dose-response relationship between HRQoL
PC, 50% of deaths in THS occurred at 5.81 years, while in and all-cause mortality over a 10-year follow-up period.
TLS, this occurred at 5.04 years. In MC, the corresponding Specifically, lower PC scores were associated with a higher
times were 5.59 years for THS and 5.11 years for TLS. risk of premature death among the older adult population.
Table 2 illustrates the crude analysis, indicating that the Within the SF-36 domains, physical functioning emerged as
risk of death in individuals with lower physical functioning a robust predictor of mortality, remaining significant even
was over twice as high (HR = 2.35; 95% CI 1.79 – 3.09) after adjustments. We also observed significant associations
compared to those with higher scores. Similarly, individuals with role-physical, self-rated general health status, role-
with greater impairment in role-physical exhibited nearly emotional, social functioning, and mental health. These
double the risk (HR = 1.92; 95% CI 1.50 – 2.45). Notably, findings corroborate the theoretical perspectives posited
bodily pain did not demonstrate a significant association by Idler & Benyamini (1997), emphasizing the predictive
with mortality. After adjustments, the risk of all-cause power of self-reported physical, emotional, and social
mortality was found to be 74% higher in older adults dimensions of health for future health events.
with lower scores in physical functioning and 42% higher Our results align with a recent systematic review and
in those with lower scores in role-physical, relative to meta-analysis (Phyo et al., 2020) that analyzed 47 studies,
the reference category of THS. In addition, impairments of which 43 (91.5%) reported that better QoL was linked
in role-emotional, along with lower scores in mental to a lower risk of mortality in at least one of the evaluated
health and general health domains increased the risk of domains. In addition, the strong association between PC
mortality by approximately 36% when compared to THS. and all-cause mortality in our study corroborates findings
The highest risk of death (HR = 1.28) was observed in the from this systematic review and other research conducted
group exhibiting greater impairment in social functioning in developed countries (Haring et al., 2011; Phyo et al.,
compared to the reference category. Importantly, a low 2021; Ul-Haq et al., 2014). However, the relationship
score in PC significantly predicted all-cause mortality over between MC and mortality exhibited variability across
10 years, increasing the probability of death by 47% relative
to THS group. In contrast, MC did not show a significant studies (Haring et al., 2011; Otero-Rodríguez et al., 2010;
association with mortality risk. Tsai et al., 2007).
Stratified analyses by sex revealed similar associations In the systematic review and meta-analysis by Phyo
between HRQoL and mortality among both men and et al. (2020), of the 33 studies that evaluated the physical
women. Evaluation of Schoenfeld residuals and the dimension of HRQoL, 30 confirmed the association
overall proportionality analysis showed satisfactory results between improved HRQoL and decreased risk of
(Supplementary File 1 - Figures S1-S7). premature mortality. On the other hand, among the
23 studies assessing the mental dimension, only 13 found a
4. Discussion significant association with reduced mortality risk.
This study utilized a cohort of older adults drawn from a Moreover, studies in high- and upper-middle-income
representative sample of Campinas, a city in the state of São countries reinforce the conclusions drawn by Phyo et al.
Paulo with over 1 million inhabitants. Our findings reveal (2020) (Hart, 2019; Nevarez-Flores et al., 2023). Research

Volume 11 Issue 1 (2025) 66 https://doi.org/10.36922/ijps.1928