Systemic hemodynamics in relation to glucose tolerance: the Health 2000 Survey

Influence of early life risk factors and lifestyle on systemic vascular resistance in later adulthood: the cardiovascular risk in young Finns study

PURPOSE

There are limited data available concerning the effects of lifetime risk factors and lifestyle on systemic hemodynamics, especially on systemic vascular resistance. The purpose of the study was to evaluate how lifetime cardiovascular risk factors (body mass index (BMI), high-density lipoprotein, low-density lipoprotein, triglycerides, systolic blood pressure, blood glucose) and lifestyle factors (vegetable consumption, fruit consumption, smoking and physical activity) predict systemic vascular resistance index (SVRI) and cardiac index (CI) assessed in adulthood.

MATERIALS AND METHODS

Our study cohort comprised 1635 subjects of the Cardiovascular Risk in Young Finns Study followed up for 27 years since baseline (1980; aged 3-18 years, females 54.3%) who had risk factor and lifestyle data available since childhood. Systemic hemodynamics were measured in 2007 (aged 30-45 years) by whole-body impedance cardiography.

RESULTS

In the multivariable regression analysis, independent predictors of the adulthood SVRI were childhood BMI, blood glucose, vegetable consumption, smoking, and physical activity (p ≤ .046 for all). Vegetable consumption, smoking, and physical activity remained significant when adjusted for corresponding adult data (p ≤ .036 for all). For the CI, independent predictors in childhood were BMI, systolic blood pressure, vegetable consumption, and physical activity (p ≤ .044 for all), and the findings remained significant after adjusting for corresponding adult data (p ≤ .046 for all). The number of childhood and adulthood risk factors and unfavourable lifestyle factors was directly associated with the SVRI (p < .001) in adulthood. A reduction in the number of risk factors and unfavourable lifestyle factors or a favourable change in BMI status from childhood to adulthood was associated with a lower SVRI in adulthood (p < .001).

CONCLUSION

Childhood BMI, blood glucose, vegetable consumption, smoking and physical activity independently predict systemic vascular resistance in adulthood. A favourable change in the number of risk factors or BMI from childhood to adulthood was associated with lower vascular resistance in adulthood.

Measurement of aortofemoral volume wave velocity during the routine 12-channel ECG: relation to age, physiological hemoglobin A 1C, triglycerides and SBP in healthy individuals

OBJECTIVE

Measurements of pulse wave velocity are generally thought to be too impractical for clinical routine. This study aimed to develop a method that can be performed during routine 12-channel ECG.

METHODS

A 12-channel ECG simultaneously supplies arterial impedance plethysmographic signals from the extremities beside segmental multifrequency impedance measurements for obtaining body composition. The origin of the plethysmographic signal (volume wave) at the arms and legs was determined at the level of the elbows and the knees. The volume wave velocity (VWV) at the aorta and femoral arteries was calculated from the time difference of the plethysmographic signals between arms and legs.

RESULTS

Automated measurement of VWV was highly reproducible (r = 0.96). In 107 participants in perfect health, VWV in different models was positively related to age, physiological hemoglobin A 1C, triglycerides, normal standardized unattended blood pressure, but not to physiological low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol. Aortofemoral VWV was significantly higher in patients with established coronary artery disease than in healthy controls of the same age group (18.1 ± 5.8 vs. 11.9 ± 1.7 m/s, P < 0.001). VWV in study participants was higher than tonometrically determined pulse wave velocity as muscular arteries are included (13.2 ± 5.81 vs. 8.8 ± 2.98 m/s, n = 115, P < 0.001).

CONCLUSION

These background arterial impedance plethysmographic measurements for the measurement of VWV made simultaneously during 12-channel ECG show promise for large-scale, routine clinical assessment of large artery function.

Relationship between Central Arterial Stiffness and Insulin Resistance in Chinese Community-Dwelling Population without Diabetes Mellitus

OBJECTIVE

Insulin resistance (IR) is a pathological condition present not only in patients with type 2 diabetes mellitus (DM), but also in community-dwelling population without DM. Both central arterial stiffness and IR are closely correlated with cardiovascular morbidity and mortality. The relationship between central arterial stiffness and IR has not been described in Chinese community-dwelling population without DM. The current analysis was designed to investigate the relationship between central arterial stiffness and IR in Chinese community-dwelling population without DM.

METHODS

There were 1150 participants fully assessed for not only homeostasis model assessment of insulin resistance (HOMA-IR) but also carotid-femoral pulse wave velocity (cfPWV).

RESULTS

Median age was 39 (18-80) years, and 69.7% were men. Bivariate correlation analysis showed that cfPWV was significantly related to HOMA-IR (P < 0.05). Logistic regression analysis indicated that cfPWV was independently associated with HOMA-IR (P < 0.05).

CONCLUSIONS

This community-based analysis testified that the relationship between central arterial stiffness and IR was evident as early as during nondiabetic stage. Early interventions in Chinese community-dwelling population without DM to improve the IR are also important in the prevention of cardiovascular diseases.

The Independent and Joint Association of Blood Pressure, Serum Total Homocysteine, and Fasting Serum Glucose Levels With Brachial-Ankle Pulse Wave Velocity in Chinese Hypertensive Adults

This study aimed to investigate the independent and joint association of blood pressure (BP), homocysteine (Hcy), and fasting blood glucose (FBG) levels with brachial-ankle pulse wave velocity (baPWV, a measure of arterial stiffness) in Chinese hypertensive adults.The analyses included 3967 participants whose BP, Hcy, FBG, and baPWV were measured along with other covariates. Systolic BP (SBP) was analyzed as 3 categories (SBP < 160 mmHg; 160 to 179 mmHg; ≥ 180 mmHg); Hcy as 3 categories (< 10 μmol/L; 10 to 14.9 μmol/L; ≥ 15.0 μmol/L) and FBG: normal (FBG < 5.6 mmol/L), impaired (5.6 mmol/L ≤ FBG < 7.0 mmol/L), and diabetes mellitus (FBG ≥ 7.0 mmol/L). We performed linear regression analyses to evaluate their associations with baPWV with adjustment for covariables.When analyzed individually, BP, Hcy, and FBG were each associated with baPWV. When BP and FBG were analyzed jointly, the highest baPWV value (mean ± SD: 2227 ± 466 cm/s) was observed in participants with FBG ≥ 7.0 mmol/L and SBP ≥ 180 mmHg (β = 432.5, P < 0.001), and the lowest baPWV value (mean ± SD: 1692 ± 289 cm/s) was seen in participants with NFG and SBP < 160 mmHg. When Hcy and FBG were analyzed jointly, the highest baPWV value (2072 ± 480 cm/s) was observed in participants with FBG ≥ 7.0 mmol/L and Hcy ≥ 15.0 μmol/L (β = 167.6, P < 0.001), while the lowest baPWV value (mean ± SD: 1773 ± 334 cm/s) was observed in participants with NFG and Hcy < 10 μmol/L.In Chinese hypertensive adults, SBP, Hcy, and FBG are individually and jointly associated with baPWV.Our findings underscore the importance of identifying individuals with multiple risk factors of baPWV including high SBP, FBG, and Hcy.

Micronucleus evaluation in mitogen-stimulated lymphocytes of patients with acromegaly

Acromegaly is a syndrome characterized by a sustained elevation of circulating growth hormone and insulin-like growth factor-1 (IGF-1). Insulin-like growth factor-1 is a potent mitogen and has a role in the transformation of normal cells to malignant cells. This study aims to evaluate the spontaneous micronucleus (MN) frequency by using the cytokinesis-block MN assay to determine genetic damage in the lymphocytes of patients with acromegaly. The study was carried out in 20 patients who had active acromegaly and in 20 age- and sex-matched healthy controls. The MN values were measured in binucleated cells obtained from mitogen-stimulated lymphocytes of patients and control subjects. The distribution of binucleated cells with 1, 2, 3, or more MNs was also measured. We found significantly higher MN frequency values in the lymphocytes of acromegalic patients than in those of the control subjects (2.23 ± 0.68 vs 1.03 ± 0.54, P = .001). The MN frequency increased with increasing IGF-1 levels of acromegalic patients (P = .036, R = 0.47). We observed that the number of binucleated cells with 2 MNs was higher for the majority of patients with acromegaly than for control subjects. Furthermore, the receiver operating characteristic curve (area under the curve = 0.914, P < .0001) was calculated to assess the discriminative power of the MN frequency. Our results indicate that increased MN frequency in the lymphocytes of patients with acromegaly may reflect genomic instability and this increased MN frequency may be associated with elevated levels of circulating growth hormone and IGF-1.

Arterial pulse wave velocity in relation to carotid intima-media thickness, brachial flow-mediated dilation and carotid artery distensibility: the Cardiovascular Risk in Young Finns Study and the Health 2000 Survey

OBJECTIVE

Increased arterial pulse wave velocity (PWV) is a strong predictor of cardiovascular events and mortality. The data regarding the relationships between PWV and other indices of vascular damage is limited and partly controversial. We conducted the present study to examine PWV in relation to non-invasive measures of early atherosclerosis (brachial flow-mediated dilation [FMD], carotid intima-media thickness [IMT]) and local arterial stiffness (carotid artery distensibility [Cdist]).

METHODS

The study population consisted of 1754 young adults (aged 30-45 years, 45.5% males) participating in the Cardiovascular Risk in Young Finns Study (YFS), and of 336 older adults (aged 46-76 years, 43.2% males) participating in the Health 2000 Survey. FMD was measured only in the YFS cohort. FMD, IMT and Cdist were assessed by ultrasound, and PWV was measured using the whole-body impedance cardiography device.

RESULTS

In young adults, FMD and IMT were not associated with PWV independently of cardiovascular risk factors. Moreover, FMD status was not found to modulate the association between cardiovascular risk factors and PWV. In older adults, PWV and IMT were directly and independently associated (β=1.233, p=0.019). In both cohorts, PWV was inversely related with Cdist, and this relation remained significant (p<0.04) in models adjusted for cardiovascular risk factors.

CONCLUSIONS

The current findings suggest that PWV reflects a different aspect of vascular damage than FMD or IMT in young adults, whereas in older adults the information provided by PWV and IMT may be, to some extent, similar as regards subclinical vascular damage. The present observations also suggest that PWV and Cdist represent, at least in part, a similar adverse vascular wall process.

Arterial tension time reflects subclinical atherosclerosis, arterial stiffness and stroke volume

OBJECTIVE

To introduce and evaluate a new haemodynamic parameter known as arterial tension time (ATT) and study whether ATT is associated with traditional cardiovascular risk factors as well as with indices of arterial stiffness, cardiac pump function and subclinical atherosclerosis.

METHODS

  Arterial tension time was measured from the whole-body impedance cardiography (ICG) signal and defined as the time difference between the onset of arterial distension induced by stroke volume (SV) and maximal integrated arterial distension. As measures of subclinical atherosclerosis and arterial stiffness, carotid artery intima-media thickness (IMT), Young's elastic modulus (YEM), arterial stiffness index (ASI) and carotid artery compliance (CAC) were assessed with ultrasound in 336 Finnish adults (aged 46-76 years, 43·2% men) participating in the Health 2000 Survey. In addition, pulse wave velocity (PWV) and stroke volume index (SI), as indices of arterial stiffness and cardiac pump function, were assessed with ICG.

RESULTS

  Arterial tension time was associated inversely with PWV, IMT, YEM and ASI (P<0·002 for all) and directly with SI and CAC (P<0·001 for both). Age, systolic blood pressure, diastolic blood pressure and fasting glucose were independent determinants of decreased ATT (P<0·04 for all). Moreover, accumulation of cardiovascular risk factors was associated with the decrease in ATT (P for trend <0·001).

CONCLUSION

Decreased ATT was associated with increased arterial stiffness, increased subclinical atherosclerosis and decreased SV. Current results suggest that ATT provides simultaneous information on several aspects of cardiovascular structure and function and could possibly serve as a new integrated parameter for cardiovascular risk stratification.