Inverse Relationship Between Physical Activity, Adiposity, and Arterial Stiffness in Healthy Middle-Aged Subjects.

BACKGROUND: Several obesity related factors are reported to exacerbate premature arterial stiffening, including inactivity and metabolic disarray. The aim of the current study was to investigate the relationship between physical activity, arterial stiffness and adiposity using objective methods. To further explore the role of adiposity in this complex process, obesity associated anthropometric and humoral biomarkers were measured. METHODS: Seventy-nine healthy, lifelong nonsmoking subjects were recruited. Habitual physical activity was measured using accelerometry. Arterial stiffness [augmentation index (AIx) and pulse wave velocity (PWV)] was measured using tonometry. Body composition was estimated using bioimpedence. Adipose associated biomarkers, leptin and adiponectin, were also measured. RESULTS: Sedentary time was significantly associated with AIx (r = 0.38, P < .001), PWV (r = 0.33, P < .01), body fat composition (r = 0.40, P < .001) and age (r = 0.30, P < .01). Moderate-to-vigorous physical activity (MVPA) was inversely correlated with AIx (r = -0.28, P < .05), body fat composition (r = -0.30, P < .01), postprandial insulin (r = -0.35, P < .01), and leptin/adiponectin ratio (r = -0.28, P < .05). MVPA, body fat composition, and postprandial insulin remained independent predictors of AIx but not PWV. CONCLUSION: The more time healthy individuals spend being sedentary, the greater their body fat and arterial stiffness. Conversely higher activity levels are associated with reduced body fat and less arterial stiffness.

Comparison of semi-automated and manual measurements of carotid intima-media thickening.

Carotid intima-media thickening (CIMT) is a marker of both arteriosclerotic and atherosclerotic risks. Technological advances have semiautomated CIMT image acquisition and quantification. Studies comparing manual and automated methods have yielded conflicting results possibly due to plaque inclusion in measurements. Low atherosclerotic risk subjects (n = 126) were recruited to minimise the effect of focal atherosclerotic lesions on CIMT variability. CIMT was assessed by high-resolution B-mode ultrasound (Philips HDX7E, Phillips, UK) images of the common carotid artery using both manual and semiautomated methods (QLAB, Phillips, UK). Intraclass correlation coefficient (ICC) and the mean differences of paired measurements (Bland-Altman method) were used to compare both methodologies. The ICC of manual (0.547 ± 0.095 mm) and automated (0.524 ± 0.068 mm) methods was R = 0.74 and an absolute mean bias ± SD of 0.023 ± 0.052 mm was observed. Interobserver and intraobserver ICC were greater for automated (R = 0.94 and 0.99) compared to manual (R = 0.72 and 0.88) methods. Although not considered to be clinically significant, manual measurements yielded higher values compared to automated measurements. Automated measurements were more reproducible and showed lower interobserver variation compared to manual measurements. These results offer important considerations for large epidemiological studies.

Dietary quality in a sample of adults with type 2 diabetes mellitus in Ireland; a cross-sectional case control study.

BACKGROUND: A number of dietary quality indices (DQIs) have been developed to assess the quality of dietary intake. Analysis of the intake of individual nutrients does not reflect the complexity of dietary behaviours and their association with health and disease. The aim of this study was to determine the dietary quality of individuals with type 2 diabetes mellitus (T2DM) using a variety of validated DQIs. METHODS: In this cross-sectional analysis of 111 Caucasian adults, 65 cases with T2DM were recruited from the Diabetes Day Care Services of St. Columcille's and St. Vincent's Hospitals, Dublin, Ireland. Forty-six controls did not have T2DM and were recruited from the general population. Data from 3-day estimated diet diaries were used to calculate 4 DQIs. RESULTS: Participants with T2DM had a significantly lower score for consumption of a Mediterranean dietary pattern compared to the control group, measured using the Mediterranean Diet Score (Range 0-9) and the Alternate Mediterranean Diet Score (Range 0-9) (mean ± SD) (3.4 ± 1.3 vs 4.8 ± 1.8, P < 0.001 and 3.3 ± 1.5 vs 4.2 ± 1.8, P = 0.02 respectively). Participants with T2DM also had lower dietary quality than the control population as assessed by the Healthy Diet Indicator (Range 0-9) (T2DM; 2.6 ± 2.3, control; 3.3 ± 1.1, P = 0.001). No differences between the two groups were found when dietary quality was assessed using the Alternate Healthy Eating Index. Micronutrient intake was assessed using the Micronutrient Adequacy Score (Range 0-8) and participants with T2DM had a significantly lower score than the control group (T2DM; 1.6 ± 1.4, control; 2.3 ± 1.4, P = 0.009). When individual nutrient intakes were assessed, no significant differences were observed in macronutrient intake. CONCLUSION: Overall, these findings demonstrate that T2DM was associated with a lower score when dietary quality was assessed using a number of validated indices.

Cardiac output is not related to the slowed O2 uptake kinetics in type 2 diabetes.

PURPOSE: This study aimed to investigate whether cardiac output (CO) responses were related to VO2 kinetics during cycling in type 2 diabetes. METHODS: A total of 9 middle-aged women with uncomplicated type 2 diabetes, 9 nondiabetic overweight women, and 11 nondiabetic lean women were recruited. Initially, the ventilatory threshold (VT) and peak VO2 were determined during a maximal graded test. Then, on two separate days, subjects completed three 7-min bouts of constant-load cycling at each of three intensities: 50% VT, 80% VT, and midpoint between VT and peak VO2 (50% Δ). CO (inert gas rebreathing) was recorded at 30 and 240 s of an additional bout at each intensity. VO2 kinetic parameters were determined by fitting a biexponential (50% VT and 80% VT) or triexponential (50% Δ) function to the VO2 data. RESULTS: Peak VO2 was significantly lower in type 2 diabetes compared with the two nondiabetic groups (P < 0.05). The time constant of phase 2 was significantly greater (P < 0.05) in type 2 diabetes compared with the nondiabetic heavy and lean groups at 50% VT (34.2 ± 15.7 vs 15.4 ± 7.3 and 20.2 ± 9.7 s) and 80% VT (39.1 ± 9.0 vs 24.8 ± 8.8 and 36.8 ± 7.9 s), but none of the VO2 kinetic parameters were different at 50% Δ. CO responses during exercise were not different among the three groups, and at 80% VT, the change in CO from 30 to 240 s was significantly larger in type 2 diabetes compared with the two nondiabetic groups. CONCLUSIONS: The results confirm that type 2 diabetes slows the dynamic response of VO2 during light and moderate relative intensity exercise in females but that this occurs in the absence of any slowing of the CO response during the initial period of exercise.