A Study Of The Distribution Characteristics And Influencing Factors Of Pulse Wave Velocity In The Elderly

Objective:Brachial-ankle pulse wave velocity(ba PWV)has emerged as a well-accepted method of measuring arterial stiffness.The level of ba PWV gradually increases with age.Arterial stiffness can be defined as ba PWV greater than or equal to 1400 cm/s according to the Chinese Application Guideline of the Vascular Health Evaluation System.In addition,arterial stiffness is an important phenotype of vascular aging.ba PWV has been used to evaluate the degree of vascular aging and diagnose supernormal vascular aging(SUPERNOVA)and early vascular aging(EVA).According to the literature,SUPERNOVA can be diagnosed as a standardized ba PWV of the same age less than the10th percentile,and EVA as greater than the 90th percentile.Atherosclerosis refers to the change of vascular structure,that is,the formation of focal fibrous atherosclerotic plaque.Arterial stiffness reflects the decline of vascular elastic function,which is mainly related to the degradation of elastic fibers and the deposition of collagen fibers in the media of the artery.They form the foundations of the classic cardiovascular continuum and cardiovascular aging continuum respectively and jointly promote the occurrence of cardiovascular disease(CVD).(1)The elderly included in previous studies usually had a variety of chronic diseases and the sample size was usually small.The distribution of ba PWV in the healthy elderly population is not clear,and there is no recognized cut-off of ba PWV for the diagnosis of SUPERNOVA and EVA.Therefore,it is necessary to explore the distribution characteristics of ba PWV in healthy elderly and develop the cut-off of ba PWV for diagnosing SUPERNOVA and EVA.(2)China’s population has been aging rapidly.The cardiovascular aging continuum based on arterial stiffness plays an important role in the occurrence of CVD in the elderly.Arterial stiffness is considered to be an early and reversible stage of CVD.In previous studies,only age and blood pressure were consistently independently associated with ba PWV,while the relationship between other cardiovascular risk factors and ba PWV was often inconsistent.Therefore,it is also necessary to explore the relationship between modifiable cardiovascular risk factors and ba PWV,arterial stiffness,and vascular aging in the elderly,so as to provide a theoretical basis for the prevention of CVD.(3)Obesity is defined as abnormal or excessive fat accumulation that presents a risk to CVD.Body mass index(BMI)is the most commonly used index to evaluate obesity.However,many epidemiological investigations have found the risk of death decreases with the increase of BMI within a certain range,which is known as the"obesity paradox".One reason may be that BMI includes many body components such as fat and muscle,which play different roles in diseases.Unlike younger individuals,lower BMI in the elderly is more likely to represent a loss of muscle mass.Therefore,this study intended to further explore the relationship between fat and muscle components and ba PWV,arterial stiffness,and vascular aging in the elderly.Methods:This study was conducted in the department of geriatrics of Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology and was approved by the hospital’s medical ethics committee.(1)ba PWV was measured in 752 healthy elderly individuals aged at least 60 years from 2010 to 2022.SUPERNOVA and EVA were diagnosed based on the 10th and 90th percentiles of ba PWV at different ages.Other measures mainly included BMI,mean arterial pressure(MAP),heart rate(HR),triglycerides(TG),low-density lipoprotein cholesterol(LDL-C),and glycosylated hemoglobin A1c(Hb A1c).Linear regression,binary logistic regression,and ordered multiple logistic regression models were fitted to analyze the effects of the above modifiable cardiovascular risk factors on ba PWV,arterial stiffness,and vascular aging in the elderly.(2)ba PWV was measured at least twice in 951 elderly individuals from 2010 to 2022,and the annual change(?)was calculated.Linear regression and binary logistic regression models were fitted to analyze the effects of the annual change of the above modifiable cardiovascular risk factors on?ba PWV and increased ba PWV at follow-up in the elderly and new-onset arterial stiffness and EVA in elderly men.(3)ba PWV and body composition(including the overall,trunk,and limb fat and muscle mass)were measured in 322 elderly individuals from 2020 to 2022.Body fat ratio,body skeletal muscle ratio,fat mass index(FMI),trunk fat mass index(TFMI),appendicular fat mass index(AFMI),skeletal muscle mass index(SMI),trunk skeletal muscle mass index(TSMI),and appendicular skeletal muscle mass index(ASMI)were calculated.The effects of body composition on ba PWV and EVA in elderly men were analyzed by fitting linear regression,restricted cubic spline regression,and binary logistic regression model in the cross-sectional study.In addition,ba PWV and body composition were measured at least twice in 64 elderly individuals,and the change(?)was calculated.The effect of the change of body composition on?ba PWV was analyzed by fitting linear regression in the longitudinal study.Results:(1)The mean age was 66±7 years,and 491(65.3%)were men.The average ba PWV was 1570±271 cm/s,and there was no significant difference between gender.ba PWV increased with age,and the median and 10th and 90th percentiles were 1443(1234～1713),1540(1307～1886),1644(1394～1966),and 1895(1491～2310)cm/s at the age of 60～64,65～69,70～74,and≥75 years,respectively.ba PWV was correlated independently and positively with MAP,HR,and TG,and negatively with BMI in elderly men.MAP,HR,TG,and BMI were also independently associated with arterial stiffness,and only MAP and HR were independently associated with vascular aging in elderly men.ba PWV was correlated independently and positively with MAP and HR,and negatively with BMI in elderly women.Only MAP and HR were independently associated with arterial stiffness in elderly women.MAP,HR,TG,and BMI were independently correlated with vascular aging in elderly women.(2)The mean age was 67±8 years,and 717(75.4%)were men.The median follow-up was 3.1 years.During the follow-up period,the average ba PWV increased from 1700±355cm/s to 1810±384 cm/s(P<0.001),and the average?ba PWV was 29±114 cm/s.?MAP,?HR,and?Hb A1c were independently and positively correlated with?ba PWV in elderly men.?MAP and?HR were also positively correlated with the risk of increased ba PWV at follow-up in elderly men,while?BMI was negatively correlated with the risk.In addition,only?MAP was independently associated with new-onset arterial stiffness and EVA in elderly men.?MAP,?HR,and?TG were independently and positively correlated with?ba PWV in elderly women,while?BMI was negatively correlated with?ba PWV.?MAP and?HR were also independently associated with the risk of increased ba PWV at follow-up in elderly women.(3)The mean age was 69±8 years,the average ba PWV was 1840±451 cm/s,the average body fat ratio was 25.2±4.3%,the average body skeletal muscle ratio was69.0±4.2%,the average BMI was 24.2±2.7 kg/m~2,the average FMI was 6.2±1.6 kg/m~2,and the average SMI was16.7±1.2 kg/m~2.In the cross-sectional analysis,ba PWV was positively correlated with body fat ratio and negatively correlated with body skeletal muscle ratio in elderly men,but there was no significance after adjusting for confounding factors.Only BMI,SMI,and ASMI were negatively correlated with ba PWV after adjusting for confounding factors,while the overall and segmental FMI were not independently correlated with ba PWV.The median follow-up time was 12 months.ba PWV and body composition measures had no significant changes during the follow-up period.Change of body composition measures had no significant correlation with?ba PWV.Conclusions:(1)The distribution of ba PWV was described in the healthy elderly from our research center.It can be used to evaluate the distribution position of ba PWV of the elderly compared with the healthy ones at the same age.We provided a basis for further multicenter research.(2)The cut-off points of ba PWV were developed for the diagnosis of SUPERNOVA and EVA in the elderly based on its 10th and 90th percentiles at different ages.(3)High MAP,HR,TG,and Hb A1c,and low SMI may be the modifiable risk factors for ba PWV,arterial stiffness,and vascular aging in the elderly.Further research is needed to establish its causal relationship.