Association between inflammatory score, healthy lifestyle, and cardiovascular disease: a national cohort study

Abstract

Background: The inflammation score is currently regarded as a reliable composite index for comprehensive assessment of inflammatory status. However, the relationship between inflammation score and cardiovascular disease (CVD) is unclear. Thus, we aimed to explore the association of inflammatory score with CVD, as well as to evaluate whether adhering to a healthy lifestyle could alleviate this association.

Methods: We analyzed 6,164 participants aged ≥45 years who entered a prospective cohort study of the China Longitudinal Study of Health and Retirement (CHARLS) between 2011 and 2012 and were followed up for CVD incidence untill 2018. The inflammatory score was measured by summing of the Z-scores for C-reactive protein and white blood cell count at baseline. The healthy lifestyle score was calculated by four factors, smoking status, alcohol consumption, body mass index, and sleep duration. Cox proportional hazard models were utilized to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the incidence of CVD.

Results: During the 7-year follow-up period, there were 761 incident cases of CVD. Compared with the lowest tertiles, the highest inflammatory score was associated with an elevated risk of CVD (HR = 1.25, 95% CI = 1.04-1.49). Compared to the unhealthy lifestyle, participants adhered to a healthy lifestyle was inversely associated with CVD risk (HR = 0.74, 95% CI = 0.60-0.93). Of note, when participants adhered to a healthy lifestyle, the higher inflammatory score was no longer significantly correlated with CVD risk (HR = 1.00, 95% CI = 0.76-1.34). Additionally, a multiplicative interaction was detected between inflammatory score and healthy lifestyle score for CVD risk (p interaction <0.05).

Conclusion: The inflammation score was associated with higher risk of CVD incidence, but adherence to a healthy lifestyle may mitigate the adverse association of inflammation score and CVD among the middle-aged and older participants.

Keywords: China; cardiovascular disease; cohort study; healthy lifestyle; inflammatory score.

Figure 1

Flow chart of the study participant selection process.

Figure 2

The joint effect between inflammatory score and healthy lifestyle score on the risk of cardiovascular disease incidence. HRs and 95% CIs were calculated with the use of the Cox proportional hazards regression model with adjustment for age, gender, education level, marital status, residence, hypertension. CI, confidence interval. *p < 0.05. **p < 0.01.

Figure 3

Incidence risk for cardiovascular disease according to inflammatory score and overall lifestyle categories. HRs and 95% CIs were obtained from Cox proportional hazards models, and all models were adjusted for age, body mass index, gender, alcohol drinking, cigarette smoking, education level, marital status, residence, hypertension. CI, confidence interval; Ref, reference.

Figure 4

Subgroup analyses of inflammatory score and cardiovascular disease risk. The forest plot represents the hazard ratio of the comparison of the highest versus the lowest of inflammatory score. HRs and 95% CIs were adjusted for age, body mass index, gender, alcohol drinking, cigarette smoking, education level, marital status, residence, hypertension. *Indicates P for linear trend calculated from category median values. **Indicates P for interaction between strata and inflammatory score. p values are two-sided. CI, confidence interval; RERI, relative excess risk due to interaction.