CARDIOVASCULAR JOURNAL OF AFRICA • Volume 35, No 1, January – April 2024 AFRICA 9 The results of this study indicated that PWV and Aix increased with increasing age. The values for PWV and Aix for the four groups by age are shown in Figs 1 and 2. To identify the variables that were independently correlated with PWV and Aix, a multivariable linear regression analysis including all studied participants (n = 110) was performed (Table 2). PWV was directly correlated with age, aortic SBP, HbA1c level and heart rate. Aix was directly correlated with age, aortic SBP and heart rate, and inversely correlated with radial SBP and radial DBP (Table 2). The results of this study indicate that age and the presence of concomitant disease was associated with significant differences between PWV and Aix. Interestingly, obese patients without concomitant disease did not show a significant increase in PWV or Aix. Discussion Obesity is a recognised independent predictor of CVD and/or mortality.17,18 Body fat distribution may have an effect on arterial compliance, and increased peripheral artery stiffness is associated with larger abdominal body fat mass.19 Lentferink et al. links obesity with higher arterial pressure and suggests that this might be as a result of an increased preload and afterload due to increased metabolic demand.20 The authors also suggest that in obese populations it can be anticipated that PWV will be higher if the arterial pressure surpasses the physiological adaptations.20 The results of this study indicated that arterial stiffness was increased in these obese patients, however concomitant disease such as hypertension and type 2 diabetes played a major role in arterial stiffness, increasing PWV by 19.7% in the obese patients and by 11.4% in non-obese patients (Table 1). A 1-m/s increase in aortic PWV has been shown to equate to a 39% increase in risk of cardiovascular events.9,10 In this study, the risk of CVD in the obese patient without additional disease was increased by 50.7%, and in obese patients with additional diseases, the risk increased by a further 35.1%. The results of this study show that PWV was directly correlated with HbA1c levels and this is similar to that found Table 1. Characteristic of the study participants (n = 110) Variables HV (n = 29) Nd (n = 23) OB (n = 29) OBd (n = 29) Age, years 37.21 ± 10.19 58.79 ± 8.43* 44.17 ± 14.63* 53.14 ± 9.99*# BMI, kg/m2 24.8 ± 1.9 24.7 ± 2.35 35.41 ± 4.20* 35.41 ± 4.87* Diabetes mellitus, % – 100 – 100 Current smoking, % 10.3 8.7 10.3 13.8 Hypertension, % – 65.2 – 75.9 Heart rate, bpm 68.62 ± 9.66 70.48 ± 14.16 68.86 ± 12.13 73.52 ± 10.63 Aortic PP, mmHg 32.93 ± 9.33 46.17 ± 18.81* 41.24 ± 16.58 45.62 ± 20.46* Radial PP, mmHg 41.241 ± 10.63 60.04 ± 18.50* 50.59 ± 15.11* 56.89 ± 21.23* MAP, mmHg 90.79 ± 11.30 101.13 ± 13.63* 96.89 ± 9.7* 104.83 ± 11.73*# Aortic SBP, mmHg 107.45 ± 16.05 129.00 ± 19.06* 118.28 ± 14.25 128.17 ± 21.28*# Aortic DBP, mmHg 76.48 ± 8.6 80.913 ± 10.32* 79.62 ± 6.68* 84.62 ± 9.52* Radial SBP, mmHg 117.28 ± 17.74 138.87 ± 19.15* 127.52 ± 14.51* 138.66 ± 22.84*# Radial DBP, mmHg 72.69 ± 10.59 79.35 ± 10.52* 78.41 ± 6.29* 83.28 ± 9.28*# HbA1c 5.06 ± 0.32 8.78 ± 2.12* 5.93 ± 1.45 11.25 ± 8.68*# TC 4.61 ± 1.35 5.00 ± 1.28 4.94 ± 1.06 4.56 ± 1.11 LDL-C 3.07 ± 1.41 3.20 ± 1.20 3.14 ± 0.95 2.82 ± 0.86 HDL-C 1.26 ± 0.25 1.28 ± 0.33 1.15 ± 0.18 1.24 ± 0.37 TG 1.07 ± 0.56 1.23 ± 0.64 1.50 ± 1.27 1.81 ± 1.37* Aix, % 24.241 ± 15.14 28.26 ± 10.26 23.48 ± 10.90 26.24 ± 8.52 PWV, m/s 6.59 ± 2.18 7.87 ± 3.61 7.93 ± 2.94 8.80 ± 3.30* BMI, body max index; PP, pulse pressure; SBP, systolic blood pressure; DBP, diastolic blood pressure; MAP, mean arterial pressure; HbA1c, glycated haemoglobin; TC, total cholesterol; LDL-C, low-density lipoprotein cholesterol; HDL, high-density lipoprotein cholesterol; TG, triglycerides; Aix, augmentation index; PWV, pulse-wave velocity; HV, healthy volunteers; Nd, non-obese with concomitant disease; OB, obese without concomitant disease; OBd, obese with concomitant disease. *p < 0.05 HV compared with Nd, OB and OBd, #p < 0.05 OB compared with OBd. Age categories (years) HV Nd OB OBd <30 30–39 40–49 50–59 60–70 Median values (m/s) 10 9 8 7 6 5 4 3 2 1 0 Fig. 1. PWV values for the study participants according to age categories and study groups. Age categories (years) HV Nd OB OBd <30 30–39 40–49 50–59 60–70 Median values (m/s) 40 35 30 25 20 15 10 5 0 Fig. 2. Aix values for the study participants according to age categories and study groups.
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