Correlation of telomere length with the Charlson Comorbidity Index via the zero- inflated negative binomial regression model: NHANES 1999–2002

Background: Telomere shortening is correlated with aging and cellular death. The Charlson Comorbidity Index (CCI) is the most widely used tool to quantify comorbidities and assess 10-year mortality. This study aimed to explore the relationship between telomere length and the CCI. Methods: This study sample was drawn from the National Health and Nutrition Examination Survey (NHANES) over two consecutive cycles, 1999--2000 and 2001--2002, and included 3,410 eligible participants. The zero-inflated negative binomial (ZINB) model was used to examine the effect of telomere length on the CCI. Results: In the count part (CCI≥0), with the other variables held constant, the expected change in the CCI for a one-unit decrease in telomere length was 0.882 (RR=0.882, p=0.527). In the logit part (CCI = 0), the log odds of having a CCI equal to zero increased by 1.025 for telomere length (OR = 1.025, p=0.945). Within the outcomes of the ZINB model for subgroups aged 20--59 years, the expected change in the CCI for a one-unit decrease in telomere length was 0.851 (RR=0.851, p=0.531). For telomere length, the log odds of the CCI being zero increased by 2.051 (OR=2.051, p=0.025) in the logit part (CCI = 0). Conclusions: This study suggested that the shorter the telomere length, the higher the CCI index. Shortening of telomeres may be associated with poorer prognosis and survival. In addition, there was a positive correlation between increasing age, smoking status, BMI, and the CCI. These findings may help patients improve their behavior and lifestyle habits.