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Isao Saito, Koutatsu Maruyama, Tadahiro Kato, Yasunori Takata, Kiyohide Tomooka, Ryoichi Kawamura, Yuichi Uesugi, Yoshihiko Naito, Haruhiko Osawa and Takeshi Tanigawa

(HOMA-IR) was calculated as fasting insulin [μU/mL] × fasting glucose [mg/dL]/405). Lifestyle A self-administrated questionnaire was used to assess medical history, smoking habits, and regular alcohol consumption. Current smokers were defined as individuals who had smoked 100 cigarettes in their

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Anita T. Cote, Angela M. Devlin and Constadina Panagiotopoulos

Second-generation antipsychotic (SGA) medications, used to treat youth for a wide-range of mental health conditions, are associated with excessive weight gain and other comorbidities, placing these individuals at high risk for cardiovascular disease. Little is known about the effect of physical activity (PA) on cardiovascular risk in these children. Anthropometrics, fasting blood sample and self-report PA were obtained in 386 children diagnosed with mental health conditions (6–18 y). PA was classified as below (<60 min/day) or meets (>60 min/day) current recommended guidelines for daily PA in children. SGA-treated (n = 166) and SGA-naive (n = 220) were compared in the analysis. The SGA-treated children had higher (p < .05) BMI z-score, waist-to-height ratio, fasting glucose, and LDL-cholesterol than SGA-nai’ve children. Waist circumference, waist-to-height ratio, HDL cholesterol, fasting insulin, and HOMA-IR were significantly different by PA status. After adjusting for SGA-treatment duration, sex, age, and ethnicity, higher PA was associated with lower insulin resistance (HOMA-IR) in SGA-treated (mean, 95% CI; below vs. meets: 2.10 [1.84, 2.37] vs. 1.59 [1.37, 1.81], p = .046) but not in SGA-naive (1.70 [1.47, 1.94] vs 1.55 [1.35, 1.75], p = .707) children. Upon initial screening, SGA-treated children that reported meeting the minimal recommendations for daily PA displayed lower measures of adiposity and improved insulin resistance.

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Andrea Di Blasio, Pascal Izzicupo, Emanuele D’Angelo, Sandra Melanzi, Ines Bucci, Sabina Gallina, Angela Di Baldassarre and Giorgio Napolitano

Purpose:

High-intensity aerobic interval training (AIT) has been reported to be more effective than continuous aerobic training (CoAT) to improve metabolic health. The aim of our study was to investigate whether moderate-intensity AIT is more effective than CoAT on metabolic health when applied to a walking training program.

Design/Methods:

Thirty-two postmenopausal women (55.37 ± 3.46 years) were investigated for body composition, plasma glucose, insulin, lipids, adiponectin, HOMA-IR, HOMA-AD, aerobic fitness, dietary habits, and spontaneous physical activity, and randomly assigned to one of two different walking training programs: CoAT or AIT.

Results:

CoAT and AIT elicited the same physiological benefits, including: reduction of plasma glucose, insulin, HOMA-IR and HOMA-AD, and increase of plasma HDL-C, adiponectin, and aerobic fitness.

Conclusions:

An AIT scheme as part of an outdoor walking training program elicits the same physiological adaptations as a CoAT scheme, probably because walking does not promote exercise intensities that elicit greater effects.

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Sheri J. Hartman, Catherine R. Marinac, Lisa Cadmus-Bertram, Jacqueline Kerr, Loki Natarajan, Suneeta Godbole, Ruth E. Patterson, Brittany Morey and Dorothy D. Sears

homeostatic model assessment of insulin resistance (HOMA-IR)], which are both implicated in promoting the development and progression of breast cancer. 17 , 18 Cross-sectional data indicate that healthy women who spend more time sitting have higher levels of CRP and higher HOMA-IR scores compared with

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Marc S. Mitchell, Catherine A. Gaul, Patti-Jean Naylor and Constadina Panagiotopoulos

The aim of this study was to explore the relationship between insulin resistance (IR) and objectively measured habitual moderate-to-vigorous physical activity (MVPA) in First Nations youth. A cross-sectional study was conducted in 2 rural villages in northern British Columbia, Canada. Thirty-nine healthy youth (16 males and 23 females; age = 11.8yrs ± 2.2; range = 8.8–18.5yrs) participated. PA was measured with ActiGraph GT1M accelerometers. The homeostasis model assessment estimate of IR (HOMA-IR) was used to define IR. Duration of MVPA was inversely related to HOMA-IR (r=−.44, p < .01). From the regression model, 30 min of habitual MVPA corresponded to HOMA-IR levels that were 15% lower. In conclusion, these findings suggest that active First Nations youth have lower HOMA-IR values.

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Bumsoo Ahn, Robert McMurray and Joanne Harrell

The relationship between insulin resistance (HOMA-IR), percent body fat, and aerobic fitness (VO2max per unit fat free mass; mL/kgFFM/min) was examined in 1,710 children. Percent body fat was estimated from sum of skinfolds, and VO2max was estimated from submaximal cycle ergometer tests. Overnight fasting blood samples were obtained. VO2max (mL/kgFFM/min) and percent body fat were correlated with HOMA-IR (r=-0.076, p < .002; r=.420, p < .001, respectively); as was VO2max in units of mL/kg/min (r=-0.264, p < .001). When VO2max in mL/kg/min was used, a progressive increase in HOMA-IR was found with decreasing fitness (p < .05). However, when mL/kgFFM/min was used, HOMA-IR scores remained similar between moderate-fit and low-fit group. The stronger association between aerobic fitness (mL/kg/min) and HOMA-IR is partially due to the significant association of fat mass to HOMA-IR. Therefore, our recommendation is to express aerobic fitness in units of mL/kgFFM/min to eliminate the confounding factor of adiposity and better understand the influence of muscle on insulin resistance.

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Erik Hemmingsson, Ulf Ekelund and Joanna Udden

Background:

The impact of walking and bicycling on insulin resistance (IR) in women with abdominal obesity is unclear.

Methods:

Pooled analysis of data from a randomized trial on physically active commuting (bicycling + walking vs walking only) in women with abdominal obesity [n = 98; age:47.3 ± 7.6 yrs; waist circumference (WC):103.1 ± 7.8 cm]. Bicycling and walking data were collected during 7 consecutive days by trip meters (Trelock FC-410) and pedometers (Yamax digiwalker SW-200) at baseline, 2, 4, and 6 months. Owing to a skew distribution we analyzed bicycling as a binary dummy variable with a 10 km/week cut-off. Fasting serum insulin and homeostatic model assessment – insulin resistance (HOMA-IR) were assessed at baseline and 6 months, as were body mass index (BMI), WC, and dual x-ray absorptiometry (DXA)-assessed % whole-body fat.

Results:

Increased bicycling by 10 km/wk was associated with reductions in fasting serum insulin at follow-up independent of age, treatment allocation, baseline phenotype, Δ walking, and Δ % body fat (β = −10.9, P = .042), but not HOMA-IR (β = −2.0, P = .13). Increased walking was not associated with fasting serum insulin (P = .33) or HOMA-IR (P = .44) at follow-up, after adjustment for the same covariates and Δ bicycling.

Conclusion:

Increased bicycling but not walking was associated with reduced insulin levels at follow-up. Bicycling may be more effective than walking for reducing insulin levels in abdominally obese women.

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Elin Ekblom-Bak, Örjan Ekblom, Kate A. Bolam, Björn Ekblom, Göran Bergström and Mats Börjesson

Background:

Although moderate-to-vigorous physical activity (MVPA) is mainly recommended for glucose control, light physical activity (LIPA) may also have the potential to induce favorable changes. We investigated sedentary time (SED) substitution with equal time in LIPA and MVPA, and the association with markers of glucose regulation and insulin sensitivity after stratification by waist circumference, fitness and fasting glucose levels.

Methods:

A total of 654 men and women, 50 to 64 years, from the SCAPIS pilot study were included. Daily SED, LIPA and MVPA were assessed using hip-worn accelerometers. Fasting plasma glucose, insulin and HOMA-IR were determined.

Results:

Substituting 30 min of SED with LIPA was significantly associated with 3.0% lower fasting insulin values and 3.1% lower HOMA-IR values, with even lower levels when substituting SED with MVPA. Participants with lower fitness and participants with high fasting glucose levels benefited significantly more from substituting 30 min of SED with LIPA compared with participants with normal to high fitness levels and participants with normal glucose levels, respectively.

Conclusions:

LIPA, and not only MVPA, may have beneficial associations with glucose regulation. This is of great clinical and public health importance, not least because it may confer a higher compliance rate to regular PA.

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Hye-Ryun Hong, Jin-Kyung Cho, Ji-Young Lee, Jin-Koo Park and Hyun-Sik Kang

The present study investigated the relationships among metabolic risk factors, major lifestyle factors, and serum cytokines in a sample of Korean children. In a cross-sectional design, we studied a total of 275 children (130 boys and 145 girls) aged 12–13 years. Measured variables included anthropometrics, blood pressures (BP), VO2max, physical activity (PA), dietary intakes, lipids, glucose, and insulin. We explored the extent to which dietary intakes, VO2max, PA, and serum cytokines explained variance in a clustered risk score, which is a sum of Z scores for waist circumference, BP, TG, HDLC, and HOMA-IR, using a stepwise linear regression by blocks. VO2max, vigorous PA (VPA), and leptin were independent predictors for the clustered risk score while adjusting for age and Tanner stage. Our findings suggest that the clustered risk score is associated not only with low levels of VO2max and VPA, but also with elevated serum leptin in Korean children.

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Russell Jago, Karsten Froberg, Ashley R. Cooper, Stig Eiberg and Lars Bo Andersen

Background:

It is not clear the extent to which change in adiposity and cardiovascular fitness (CRF) during early childhood are associated with change in cardiovascular risk factors or if associations are independent or interactive.

Methods:

383 Danish children were examined at ages 6 and 9. CRF, sum of skinfolds (SSF), and blood pressure were assessed. Fasting blood samples were used to calculate total cholesterol (TC), high and low density lipoprotein cholesterol (HDL-C & LDL-C), triglycerides, insulin, glucose, and HOMA-IR. Regression models examined whether CRF change or SSF change were independently or interactively associated with risk variables.

Results:

Change in SSF was independently associated with change in TC (z =4.83, P < .0o1), LDL-C (z =4.38, P < .001), systolic (z = 3.45, P < .001), and diastolic (z = 2.45, P = .014) blood pressure. CRF change was independently associated with change in TC (z =-3.86, P < .001), HDL-C (z =3.85, P < .001), and systolic blood pressure (z = 2.06, P = .040).

Conclusions:

Change in fitness and adiposity were independently associated with the development of cardiovascular risk factors among young children suggesting a need to increase CRF and prevent weight gain early during development to improve cardiovascular health.