Impact traditional CVD risk factors reduces as patients get older
Impact of Aging on the Strength of Cardiovascular Risk Factors: A Longitudinal Study Over 40 Years
Traditional CV risk factors have mainly been studied in middle-aged individuals, followed for 10 years. Thus, the usefulness of these risk factors in the elderly is not clear, and data suggest that their impact is declining with age [1-4]. In this study, the impact of aging on the strengths of traditional CV risk factors was evaluated in a longitudinal fashion, in regards to incident cases of MI, ischemic stroke, and HF.
For this purpose, 2322 men aged 50 years at a baseline examination were followed for 40 years. The CV risk factors BMI, LDL-c HDL-c TG, SBP, DBP, fasting glucose and smoking were identified at baseline and re-evaluated at ages 60, 70, 77, and 82 years. Patients with a history of MI, stroke, or HF at baseline were excluded from this study. The endpoints were derived from the Swedish Cause of Death Registry and the Swedish Hospital discharge register . Poisson models were used to measure the interaction between risk factors and age to account for the possible time-varying effects of risk factors.
A significant interaction was noted between age and the set of all traditional risk factors regarding incident MI (P=0.0033), incident ischemic stroke (P=0.025), and incident HF (P=0.0007).
When the interactions between the individual risk factors and age were calculated, BMI and smoking showed P<0.05 (P=0.020 and P=0.026, respectively) regarding incident MI, SBP showed P<0.05 (P=0.0067) regarding stroke, and SBP and HDL-c showed P<0.05 (P=0.0045 and P=0.016, respectively) regarding HF.
The impact of all traditional CV risk factors declined with increasing age, with declining risk ratios (RR) at the respective time points. In older patients, some risks were no longer significantly elevated, for instance BMI was only related to incident MI at ages 50 and 60, and SBP and smoking only showed significant relations up to 77 years.
Some RRs were still statistically significant at old age, or even higher than at middle-age, including LDL-c for MI, and BMI and fasting glucose for HF:
- RR for LDL-c regarding MI at age 82 years: 1.67; 95%CI: 1.33-2.11; P<0.001 (vs. RR: 1.27, 95%CI: 1.01-1.61, P=0.044 at age 50 years).
- RR for BMI regarding HF at age of 82 years: 1.30; 95%CI: 1.07-1.57; P=0.008 (vs. RR: 1.58, 95%CI: 1.07-2.35, P=0.23 at age 50 years).
- RR for fasting glucose regarding HF at age 82 years: 1.11; 95%CI: 1.03-1.19; P=0.008 (vs. RR: 1.09, 95%CI: 0.94-1.26, P=0.259 at age 50 years).
In general, the impact of traditional CV risk factors on CVD declines with age, and some risk factors no longer show a significant relation with CVD. Some risk factor do show significant associations with CVD at 82 years of age, including LDL-c for MI, and fasting glucose for HF.