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Volume 32, Number 6—June 2026

Research

Association of Frailty and Frailty Trajectory with Risk for Respiratory Infectious Diseases

Jin Yang1, Hao Yan1, Huan Chen, Dan Liu, Zhihao Li, and Chen MaoComments to Author 
Author affiliation: School of Public Health, Southern Medical University, Guangzhou, China; National Institute of Health Data Science of China, Southern Medical University, Guangzhou

Main Article

Table 3

Hazard ratios of incident RIDs in final assessment of association of frailty and frailty trajectory with risk for RIDs*

Category Events/no. participants Model 1
Model 2
HR (95% CI) p value HR (95% CI) p value
Grouped by physical frailty
Nonfrail 462/8,089 Referent Referent
Prefrail 655/8,350 1.28 (1.14–1.45) <0.001 1.17 (1.04–1.33) 0.011
Frail 72/409 3.04 (2.37–3.90) <0.001 2.27 (1.75–2.95) <0.001
Per 1-point increase

1.36 (1.27–1.46)
<0.001

1.25 (1.17–1.35)
<0.001
Grouped by frailty index
Nonfrail 573/10,424 Referent Referent
Prefrail 495/5,794 1.44 (1.27–1.62) <0.001 1.28 (1.13–1.45) <0.001
Frail 121/630 3.31 (2.72–4.03) <0.001 2.59 (2.10–3.19) <0.001
Per 0.1-point increase

1.66 (1.53–1.80)
<0.001

1.48 (1.36–1.62)
<0.001
RID subgroups
Influenza
Grouped by physical frailty
Nonfrail 9/8,089 Referent Referent
Prefrail 20/8,350 2.04 (0.92–4.50) 0.078 1.81 (0.81–4.05) 0.146
Frail 2/409 4.04 (0.87–18.81) 0.075 2.36 (0.45–12.47) 0.312
Per 1-point increase

1.38 (0.96–1.98)
0.079

1.20 (0.79–1.80)
0.382
Grouped by frailty index
Nonfrail 18/10,424 Referent Referent
Prefrail 9/5,794 0.85 (0.38–1.91) 0.696 0.73 (0.32–1.65) 0.443
Frail 4/630 3.35 (1.12–9.98) <0.05 2.09 (0.63–6.95) 0.228
Per 0.1-point increase 1.82 (1.15–2.90) <0.05 1.53 (0.94–2.50) 0.087
OALRTI
Grouped by physical frailty
Nonfrail 242/8,089 Referent Referent
Prefrail 301/8,350 1.12 (0.94–1.33) 0.194 1.03 (0.86–1.22) 0.760
Frail 28/409 2.13 (1.44–3.16) <0.001 1.64 (1.09–2.48) <0.05
Per 1-point increase 1.22 (1.10–1.36) <0.001 1.14 (1.02–1.27) 0.024
Grouped by frailty index
Nonfrail 278/10,424 Referent Referent
Prefrail 233/5,794 1.40 (1.18–1.67) <0.001 1.28 (1.07–1.53) 0.007
Frail 60/630 3.29 (2.49–4.36) <0.001 2.77 (2.06–3.73) <0.001
Per 0.1-point increase 1.63 (1.45–1.83) <0.001 1.51 (1.32–1.71) <0.001
Pneumonia
Grouped by physical frailty
Nonfrail 247/8,089 Referent Referent
Prefrail 408/8,350 1.47 (1.26–1.73) <0.001 1.34 (1.14–1.58) <0.001
Frail 53/409 4.12 (3.06–5.55) <0.001 2.96 (2.16–4.05) <0.001
Per 1-point increase 1.53 (1.40–1.67) <0.001 1.39 (1.27–1.52) <0.001
Grouped by frailty index
Nonfrail 320/10,424 Referent Referent
Prefrail 312/5,794 1.58 (1.35–1.84) <0.001 1.38 (1.17–1.62) <0.001
Frail 76/630 3.53 (2.75–4.55) <0.001 2.67 (2.04–3.50) <0.001
Per 0.1-point increase 1.73 (1.56–1.92) <0.001 1.52 (1.35–1.70) <0.001

*Data from UK Biobank (https://www.ukbiobank.ac.uk) collected during 2012–2013. Model 1 is adjusted for age and sex; model 2 is adjusted for all covariates. HRs and 95% CIs were estimated using Cox proportional hazards models. A 2-sided p<0.05 was considered statistically significant. FI, frailty index; HR, hazard ratio; OALRTI, other acute lower respiratory tract infection; PF, physical frailty; RID, respiratory infectious disease.

Main Article

1These first authors contributed equally to this article.

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