Associations of 24 h time-use compositions of sitting, standing, physical activity and sleeping with optimal cardiometabolic risk and glycaemic control: The Maastricht Study.

AIMS/HYPOTHESIS: The associations of sitting, standing, physical activity and sleep with cardiometabolic health and glycaemic control markers are interrelated. We aimed to identify 24 h time-use compositions associated with optimal metabolic and glycaemic control and determine whether these varied by diabetes status. METHODS: Thigh-worn activPAL data from 2388 participants aged 40-75 years (48.7% female; mean age 60.1 [SD = 8.1] years; n=684 with type 2 diabetes) in The Maastricht Study were examined. Compositional isometric log ratios were generated from mean 24 h time use (sitting, standing, light-intensity physical activity [LPA], moderate-to-vigorous physical activity [MVPA] and sleeping) and regressed with outcomes of waist circumference, fasting plasma glucose (FPG), 2 h plasma glucose, HbA1c, the Matsuda index expressed as z scores, and with a clustered cardiometabolic risk score. Overall analyses were adjusted for demographics, smoking, dietary intake and diabetes status, and interaction by diabetes status was examined separately. The estimated difference when substituting 30 min of one behaviour with another was determined with isotemporal substitution. To identify optimal time use, all combinations of 24 h compositions possible within the study footprint (1st-99th percentile of each behaviour) were investigated to determine those cross-sectionally associated with the most-optimal outcome (top 5%) for each outcome measure. RESULTS: Compositions lower in sitting time and with greater standing time, physical activity and sleeping had the most beneficial associations with outcomes. Associations were stronger in participants with type 2 diabetes (p<0.05 for interactions), with larger estimated benefits for waist circumference, FPG and HbA1c when sitting was replaced by LPA or MVPA in those with type 2 diabetes vs the overall sample. The mean (range) optimal compositions of 24 h time use, considering all outcomes, were 6 h (range 5 h 40 min-7 h 10 min) for sitting, 5 h 10 min (4 h 10 min-6 h 10 min) for standing, 2 h 10 min (2 h-2 h 20 min) for LPA, 2 h 10 min (1 h 40 min-2 h 20 min) for MVPA and 8 h 20 min (7 h 30 min-9 h) for sleeping. CONCLUSIONS/INTERPRETATION: Shorter sitting time and more time spent standing, undergoing physical activity and sleeping are associated with preferable cardiometabolic health. The substitutions of behavioural time use were significantly stronger in their associations with glycaemic control in those with type 2 diabetes compared with those with normoglycaemic metabolism, especially when sitting time was balanced with greater physical activity.

Effects of breaking up sitting with light-intensity physical activity on cognition and mood in university students.

BACKGROUND: University students often exhibit high levels of sedentary behavior that is negatively associated with cognition and mood. On the other hand, light-intensity physical activity (LIPA) may improve cognitive performance and mood. Therefore, this study investigated the acute effect of LIPA breaks during prolonged sitting on attention, executive functioning, and mood. METHODS: A randomized crossover design was used in this study. In total, 21 healthy adults (15 women, age = 24 ± 3 years, BMI = 23 ± 2 kg/m2 ) completed three prolonged sitting conditions: (1) without a demanding cognitive task (SIT), (2) with a demanding cognitive task (COGN), and (3) with every 25 min sitting interrupted by a 5-minute walk (INTERRUPT). Attention, executive function (response inhibition, task shifting, and working memory updating), and mood were assessed before and after each condition. RESULTS: Linear mixed models analyses showed that prolonged sitting frequently interrupted by LIPA (INTERRUPT) or with cognitively demanding activities (COGN) significantly improved task shifting compared to SIT. However, INTERRUPT did not significantly improve task shifting compared with COGN. No significant acute effects on attention, response inhibition, working memory updating, or mood were found. CONCLUSIONS: Frequent LIPA breaks or cognitively demanding activities have a selective, acute positive impact on one aspect of cognitive performance compared to idle sitting. No evidence was found that LIPA breaks have an acute improvement in attention, executive function, and mood compared to sitting with cognitive loading. To further investigate the effect of PA on cognitive performance, it is necessary to consider cognitive loading and control for the cognitive activity during sitting in the experimental design.

Sedentary behaviour and physical activity are associated with biomarkers of endothelial dysfunction and low-grade inflammation-relevance for (pre)diabetes: The Maastricht Study.

AIMS/HYPOTHESIS: Biomarkers of endothelial dysfunction and low-grade inflammation are important in the pathogenesis of CVD and can potentially be modified by physical activity and sedentary behaviour. Effects of physical activity on biomarkers of endothelial dysfunction may be especially prominent in type 2 diabetes. METHODS: In the population-based Maastricht Study (n = 2363, 51.5% male, 28.3% type 2 diabetes, 15.1% prediabetes [defined as impaired glucose tolerance and impaired fasting glucose]), we determined biomarkers of endothelial dysfunction and low-grade inflammation, and combined z scores were calculated. Physical activity and sedentary behaviour were measured by activPAL. Linear regression analyses were used with adjustment for demographic, lifestyle and cardiovascular risk factors. RESULTS: The association between total, light, moderate-to-vigorous and vigorous intensity physical activity and sedentary time on the one hand and biomarkers of endothelial dysfunction on the other were generally significant and were consistently stronger in prediabetes and type 2 diabetes as compared with normal glucose metabolism status (p for interaction <0.05). Associations between physical activity and sedentary behaviour on the one hand and low-grade inflammation on the other were also significant and were similar in individuals with and without (pre)diabetes (p for interaction >0.05). CONCLUSIONS/INTERPRETATION: Physical activity and sedentary behaviour are associated with biomarkers of endothelial dysfunction and low-grade inflammation. For biomarkers of endothelial dysfunction, associations between physical activity and sedentary behaviour were consistently stronger in (pre)diabetes than in normal glucose metabolism. Whether increasing physical activity or decreasing sedentary time can positively influence biomarkers of endothelial dysfunction in individuals with prediabetes and type 2 diabetes requires further study.

Daily patterns of physical activity, sedentary behavior, and prevalent and incident depression-The Maastricht Study.

This study aims to compare the accelerometer-measured daily patterns of PA and sedentary behavior among participants with and without prevalent/incident depressive symptoms. We used data from 5582 individuals in The Maastricht Study (59.9 ± 8.6 years, 50.3% women). Daily patterns of sedentary time, light-intensity physical activity (LiPA), moderate-to-vigorous physical activity (MVPA), and sit-to-stand transitions were objectively measured at baseline with the activPAL3 activity monitor. Depressive symptoms were assessed using the 9-item Patient Health Questionnaire, both at baseline and annually (median follow-up: 5.1 years). General linear models were used to compare patterns of physical activity and sedentary behavior between those with and without prevalent/incident depressive symptoms. Participants with prevalent depressive symptoms had significantly more sedentary time (18.6 min/day) and lower LiPA (26.8 min/day) and MVPA (4.8 min/day) than participants without depressive symptoms. Considering the daily patterns, participants with prevalent depressive symptoms had significantly more sedentary time early in the afternoon (12:00-18:00), early evening (18:00-21:00), and during the night (00:00-03:00), less time in LiPA in all periods between 09:00-21.00 and less MVPA in the morning (09:00:12:00), early afternoon (12:00-15:00), and evening (18:00-21:00), than those without. Similar differences in activity and sedentary behavior patterns between those and without incident depressive symptoms were observed albeit the differences were smaller. Overall, we did not find specific time slots particularly associated with both prevalent and incident depressive symptoms. These findings may indicate that less sedentary time and more intense PA can be important targets for the prevention of depression irrespective of the timing of the day.

Carotid stiffness is associated with retinal microvascular dysfunction-The Maastricht study.

OBJECTIVE: This study investigated whether arterial stiffening is a determinant of subtle retinal microvascular changes that precede diabetic retinopathy. RESEARCH DESIGN AND METHODS: This study used cross-sectional data from the Maastricht Study, a type 2 diabetes-enriched population-based cohort study. We used multivariable linear regression analysis to investigate, in individuals without and with type 2 diabetes, the associations of carotid distensibility coefficient and carotid-femoral pulse wave velocity with retinal microvascular diameters and flicker light-induced dilation and adjusted for cardiovascular and lifestyle risk factors. RESULTS: The retinal microvascular diameter study population consisted of N = 2434 participants (51.4% men, mean ± SD age 59.8 ± 8.1 years, and 28.1% type 2 diabetes). No measures of arterial stiffness were significantly associated with microvascular diameters. Greater carotid distensibility coefficient (i.e., lower carotid stiffness) was significantly associated with greater retinal arteriolar flicker light-induced dilation (per standard deviation, standardized beta [95% CI] 0.06 [0.00; 0.12]) and non-significantly, but directionally similarly, associated with greater retinal venular flicker light-induced dilation (0.04 [-0.02; 0.10]). Carotid-femoral pulse wave velocity (i.e., aortic stiffness) was not associated with retinal microvascular flicker light-induced dilation. The associations between carotid distensibility coefficient and retinal arteriolar and venular flicker light-induced dilation were two- to threefold stronger in individuals with type 2 diabetes than in those without. CONCLUSION: In this population-based study greater carotid, but not aortic, stiffness was associated with worse retinal flicker light-induced dilation and this association was stronger in individuals with type 2 diabetes. Hence, carotid stiffness may be a determinant of retinal microvascular dysfunction.

Lifestyle interventions to reduce sedentary behaviour in clinical populations: A systematic review and meta-analysis of different strategies and effects on cardiometabolic health.

Cardiometabolic comorbidities are highly prevalent in clinical populations, and have been associated (partly) with their sedentary lifestyle. Although lifestyle interventions targeting sedentary behaviour (SB) have been studied extensively in the general population, the effect of such strategies in clinical populations is not yet clear. Therefore, this systematic review and meta-analysis evaluated the effect of different lifestyle interventions on SB and cardiometabolic health in clinical populations. Randomised controlled trials were collected from five bibliographic databases (PubMed, Embase, Web of Science, The Cochrane Central Register of Controlled Trials, and Scopus). Studies were eligible for inclusion if they evaluated a lifestyle intervention to reduce objectively measured SB, in comparison with a control intervention among persons with a clinical condition. Data were pooled using a random-effects meta-analysis. In total, 7094 studies were identified. Eighteen studies met the inclusion criteria and were categorised in five population groups: overweight/obesity, type 2 diabetes mellitus, cardiovascular, neurological/cognitive and musculoskeletal diseases. Participants reduced their SB by 64 min/day (95%CI: [-91, -38] min/day; p < 0.001), with larger within-group differences of multicomponent behavioural interventions including motivational counselling, self-monitoring, social facilitation and technologies (-89 min/day; 95%CI: [-132, -46] min/day; p < 0.001). Blood glycated haemoglobin concentration (-0.17%; 95% CI: [-0.30, -0.04]%; p = 0.01), fat percentage (-0.66%; 95% CI: [-1.26, -0.06]%, p = 0.03) and waist circumference (-1.52 cm; 95%CI: [-2.84, -0.21] cm; p = 0.02) were significantly reduced in the intervention groups compared to control groups. Behavioural lifestyle interventions reduce SB among clinical populations and improve cardiometabolic risk markers such as waist circumference, fat percentage, and glycaemic control. Sedentary behaviour, Cardiometabolic health, Clinical populations.

Cardiometabolic risk factors as determinants of peripheral nerve function: the Maastricht Study.

AIMS/HYPOTHESIS: We aimed to examine associations of cardiometabolic risk factors, and (pre)diabetes, with (sensorimotor) peripheral nerve function. METHODS: In 2401 adults (aged 40-75 years) we previously determined fasting glucose, HbA1c, triacylglycerol, HDL- and LDL-cholesterol, inflammation, waist circumference, blood pressure, smoking, glucose metabolism status (by OGTT) and medication use. Using nerve conduction tests, we measured compound muscle action potential, sensory nerve action potential amplitudes and nerve conduction velocities (NCVs) of the peroneal, tibial and sural nerves. In addition, we measured vibration perception threshold (VPT) of the hallux and assessed neuropathic pain using the DN4 interview. We assessed cross-sectional associations of risk factors with nerve function (using linear regression) and neuropathic pain (using logistic regression). Associations were adjusted for potential confounders and for each other risk factor. Associations from linear regression were presented as standardised regression coefficients (ß) and 95% CIs in order to compare the magnitudes of observed associations between all risk factors and outcomes. RESULTS: Hyperglycaemia (fasting glucose or HbA1c) was associated with worse sensorimotor nerve function for all six outcome measures, with associations of strongest magnitude for motor peroneal and tibial NCV, ßfasting glucose = -0.17 SD (-0.21, -0.13) and ßfasting glucose = -0.18 SD (-0.23, -0.14), respectively. Hyperglycaemia was also associated with higher VPT and neuropathic pain. Larger waist circumference was associated with worse sural nerve function and higher VPT. Triacylglycerol, HDL- and LDL-cholesterol, and blood pressure were not associated with worse nerve function; however, antihypertensive medication usage (suggestive of history of exposure to hypertension) was associated with worse peroneal compound muscle action potential amplitude and NCV. Smoking was associated with worse nerve function, higher VPT and higher risk for neuropathic pain. Inflammation was associated with worse nerve function and higher VPT, but only in those with type 2 diabetes. Type 2 diabetes and, to a lesser extent, prediabetes (impaired fasting glucose and/or impaired glucose tolerance) were associated with worse nerve function, higher VPT and neuropathic pain (p for trend <0.01 for all outcomes). CONCLUSIONS/INTERPRETATION: Hyperglycaemia (including the non-diabetic range) was most consistently associated with early-stage nerve damage. Nonetheless, larger waist circumference, inflammation, history of hypertension and smoking may also independently contribute to worse nerve function.

Accelerometer-derived sedentary time and physical activity and the incidence of depressive symptoms - The Maastricht Study.

BACKGROUND: This study examined the associations between accelerometer-derived sedentary time (ST), lower intensity physical activity (LPA), higher intensity physical activity (HPA) and the incidence of depressive symptoms over 4 years of follow-up. METHODS: We included 2082 participants from The Maastricht Study (mean ± s.d. age 60.1 ± 8.0 years; 51.2% men) without depressive symptoms at baseline. ST, LPA and HPA were measured with the ActivPAL3 activity monitor. Depressive symptoms were measured annually over 4 years of follow-up with the 9-item Patient Health Questionnaire (PHQ-9). Cox regression analysis was performed to examine the associations between ST, LPA, HPA and incident depressive symptoms (PHQ-9 ⩾ 10). Analyses were adjusted for total waking time per day, age, sex, education level, type 2 diabetes mellitus, body mass index, total energy intake, smoking status and alcohol use. RESULTS: During 7812.81 person-years of follow-up, 203 (9.8%) participants developed incident depressive symptoms. No significant associations [Hazard Ratio (95% confidence interval)] were found between sex-specific tertiles of ST (lowest v. highest tertile) [1.13 (0.76-1.66], or HPA (highest v. lowest tertile) [1.14 (0.78-1.69)] and incident depressive symptoms. LPA (highest v. lowest tertile) was statistically significantly associated with incident depressive symptoms in women [1.98 (1.19-3.29)], but not in men (p-interaction <0.01). CONCLUSIONS: We did not observe an association between ST or HPA and incident depressive symptoms. Lower levels of daily LPA were associated with an increased risk of incident depressive symptoms in women. Future research is needed to investigate accelerometer-derived measured physical activity and ST with incident depressive symptoms, preferably stratified by sex.

Which is more important for cardiometabolic health: sedentary time, higher intensity physical activity or cardiorespiratory fitness? The Maastricht Study.

AIMS/HYPOTHESES: Our aim was to examine the independent and combined (cross-sectional) associations of sedentary time (ST), higher intensity physical activity (HPA) and cardiorespiratory fitness (CRF) with metabolic syndrome and diabetes status. METHODS: In 1933 adults (aged 40-75 years) ST and HPA (surrogate measure for moderate to vigorous physical activity) were measured with the activPAL3. CRF was assessed by submaximal cycle-ergometer testing. Metabolic syndrome was defined according to the Adult Treatment Panel (ATP) III guidelines. Diabetes status (normal, prediabetes [i.e. impaired glucose tolerance and/or impaired fasting glucose] or type 2 diabetes) was determined from OGTT. (Multinomial) logistic regression analyses were used to calculate likelihood for the metabolic syndrome, prediabetes and type 2 diabetes according to ST, HPA and CRF separately and combinations of ST-CRF and HPA-CRF. RESULTS: Higher ST, lower HPA and lower CRF were associated with greater odds for the metabolic syndrome and type 2 diabetes independently of each other. Compared with individuals with high CRF and high HPA (CRFhigh-HPAhigh), odds for the metabolic syndrome and type 2 diabetes were higher in groups with a lower CRF regardless of HPA. Individuals with low CRF and low HPA (CRFlow-HPAlow) had a particularly high odds for the metabolic syndrome (OR 5.73 [95% CI 3.84, 8.56]) and type 2 diabetes (OR 6.42 [95% CI 3.95, 10.45]). Similarly, compared with those with high CRF and low ST (CRFhigh-STlow), those with medium or low CRF had higher odds for the metabolic syndrome, prediabetes and type 2 diabetes, irrespective of ST. In those with high CRF, high ST was associated with significantly high odds for the metabolic syndrome (OR 2.93 [95% CI 1.72, 4.99]) and type 2 diabetes (OR 2.21 [95% CI 1.17, 4.17]). The highest odds for the metabolic syndrome and type 2 diabetes were observed in individuals with low CRF and high ST (CRFlow-SThigh) (OR [95% CI]: the metabolic syndrome, 9.22 [5.74, 14.80]; type 2 diabetes, 8.38 [4.83, 14.55]). CONCLUSIONS/INTERPRETATION: These data suggest that ST, HPA and CRF should all be targeted in order to optimally reduce the risk for the metabolic syndrome and type 2 diabetes.

Reliability of HR-pQCT Derived Cortical Bone Structural Parameters When Using Uncorrected Instead of Corrected Automatically Generated Endocortical Contours in a Cross-Sectional Study: The Maastricht Study.

Most HR-pQCT studies examining cortical bone use an automatically generated endocortical contour (AUTO), which is manually corrected if it visually deviates from the apparent endocortical margin (semi-automatic method, S-AUTO). This technique may be prone to operator-related variability and is time consuming. We examined whether the AUTO instead of the S-AUTO method can be used for cortical bone analysis. Fifty scans of the distal radius and tibia from participants of The Maastricht Study were evaluated with AUTO, and subsequently with S-AUTO by three independent operators. AUTO cortical bone parameters were compared to the average parameters obtained by the three operators (S-AUTOmean). All differences in mean cortical bone parameters between AUTO and S-AUTOmean were < 5%, except for lower AUTO cortical porosity of the radius (- 16%) and tibia (- 6%), and cortical pore volume (Ct.Po.V) of the radius (- 7%). The ICC of S-AUTOmean and AUTO was > 0.90 for all parameters, except for cortical pore diameter of the radius (0.79) and tibia (0.74) and Ct.Po.V of the tibia (0.89), without systematic errors on the Bland-Altman plots. The precision errors (RMS-CV%) of the radius parameters between S-AUTOmean and AUTO were comparable to those between the individual operators, whereas the tibia RMS-CV% between S-AUTOmean and AUTO were higher than those of the individual operators. Comparison of the three operators revealed clear inter-operator variability. This study suggests that the AUTO method can be used for cortical bone analysis in a cross-sectional study, but that the absolute values-particularly of the porosity-related parameters-will be lower.

Breaking sitting with light activities vs structured exercise: a randomised crossover study demonstrating benefits for glycaemic control and insulin sensitivity in type 2 diabetes.

AIMS/HYPOTHESIS: We aimed to examine the effects of breaking sitting with standing and light-intensity walking vs an energy-matched bout of structured exercise on 24 h glucose levels and insulin resistance in patients with type 2 diabetes. METHODS: In a randomised crossover study, 19 patients with type 2 diabetes (13 men/6 women, 63 ± 9 years old) who were not using insulin each followed three regimens under free-living conditions, each lasting 4 days: (1) Sitting: 4415 steps/day with 14 h sitting/day; (2) Exercise: 4823 steps/day with 1.1 h/day of sitting replaced by moderate- to vigorous-intensity cycling (at an intensity of 5.9 metabolic equivalents [METs]); and (3) Sit Less: 17,502 steps/day with 4.7 h/day of sitting replaced by standing and light-intensity walking (an additional 2.5 h and 2.2 h, respectively, compared with the hours spent doing these activities in the Sitting regimen). Blocked randomisation was performed using a block size of six regimen orders using sealed, non-translucent envelopes. Individuals who assessed the outcomes were blinded to group assignment. Meals were standardised during each intervention. Physical activity and glucose levels were assessed for 24 h/day by accelerometry (activPAL) and a glucose monitor (iPro2), respectively. The incremental AUC (iAUC) for 24 h glucose (primary outcome) and insulin resistance (HOMA2-IR) were assessed on days 4 and 5, respectively. RESULTS: The iAUC for 24 h glucose (mean ± SEM) was significantly lower during the Sit Less intervention than in Sitting (1263 ± 189 min × mmol/l vs 1974 ± 324 min × mmol/l; p = 0.002), and was similar between Sit Less and Exercise (Exercise: 1383 ± 194 min × mmol/l; p = 0.499). Exercise failed to improve HOMA2-IR compared with Sitting (2.06 ± 0.28 vs 2.16 ± 0.26; p = 0.177). In contrast, Sit Less (1.89 ± 0.26) significantly reduced HOMA2-IR compared with Exercise (p = 0.015) as well as Sitting (p = 0.001). CONCLUSIONS/INTERPRETATION: Breaking sitting with standing and light-intensity walking effectively improved 24 h glucose levels and improved insulin sensitivity in individuals with type 2 diabetes to a greater extent than structured exercise. Thus, our results suggest that breaking sitting with standing and light-intensity walking may be an alternative to structured exercise to promote glycaemic control in patients type 2 diabetes. TRIAL REGISTRATION: Clinicaltrials.gov NCT02371239 FUNDING: : The study was supported by a Kootstra grant from Maastricht University Medical Centre+, and the Dutch Heart Foundation. Financial support was also provided by Novo Nordisk BV, and Medtronic and Roche made the equipment available for continuous glucose monitoring.

Associations Between Bipedal Stance Stability and Locomotor Stability Following a Trip in Unilateral Vestibulopathy.

Posturography is used to assess balance in clinical settings, but its relationship to gait stability is unclear. We assessed if dynamic gait stability is associated with standing balance in 12 patients with unilateral vestibulopathy. Participants were unexpectedly tripped during treadmill walking and the change in the margin of stability (MoSchange) and base of support (BoSchange) relative to nonperturbed walking was calculated for the perturbed and first recovery steps. The center of pressure (COP) path during 30-s stance with eyes open and closed, and the distance between the most anterior point of the COP and the anterior BoS boundary during forward leaning (ADist), were assessed using a force plate. Pearson correlations were conducted between the static and dynamic variables. The perturbation caused a large decrease in the BoS, leading to a decrease in MoS. One of 12 correlations was significant (MoSchange at the perturbed step and ADist; r = -.595, P = .041; nonsignificant correlations: .068 ≤ P ≤ .995). The results suggest that different control mechanisms may be involved in stance and gait stability, as a consistent relationship was not found. Therefore, posturography may be of limited use in predicting stability in dynamic situations.

Associations of total amount and patterns of sedentary behaviour with type 2 diabetes and the metabolic syndrome: The Maastricht Study.

AIMS/HYPOTHESIS: The study investigated cross-sectional associations of total amount and patterns of sedentary behaviour with glucose metabolism status and the metabolic syndrome. METHODS: We included 2,497 participants (mean age 60.0 ± 8.1 years, 52% men) from The Maastricht Study who were asked to wear an activPAL accelerometer 24 h/day for 8 consecutive days. We calculated the daily amount of sedentary time, daily number of sedentary breaks and prolonged sedentary bouts (≥30 min), and the average duration of the sedentary bouts. To determine glucose metabolism status, participants underwent an oral glucose tolerance test. Associations of sedentary behaviour variables with glucose metabolism status and the metabolic syndrome were examined using multinomial logistic regression analyses. RESULTS: Overall, 1,395 (55.9%) participants had normal glucose metabolism, 388 (15.5%) had impaired glucose metabolism and 714 (28.6%) had type 2 diabetes. The odds ratio per additional hour of sedentary time was 1.22 (95% CI 1.13, 1.32) for type 2 diabetes and 1.39 (1.27, 1.53) for the metabolic syndrome. No significant or only weak associations were seen for the number of sedentary breaks, number of prolonged sedentary bouts or average bout duration with either glucose metabolism status or the metabolic syndrome. CONCLUSIONS/INTERPRETATION: An extra hour of sedentary time was associated with a 22% increased odds for type 2 diabetes and a 39% increased odds for the metabolic syndrome. The pattern in which sedentary time was accumulated was weakly associated with the presence of the metabolic syndrome. These results suggest that sedentary behaviour may play a significant role in the development and prevention of type 2 diabetes, although longitudinal studies are needed to confirm our findings.

The effect of training during treatment with chemotherapy on muscle strength and endurance capacity: A systematic review.

Background Treatment of cancer with chemotherapy decreases endurance capacity and muscle strength. Training during chemotherapy might prevent this. There are no clear guidelines concerning which type of training and which training dose are effective. This review aims to gain insight into the different training modalities during chemotherapy and the effects of such training to improve endurance capacity and muscle strength in order to obtain the knowledge to compose a future training program which trains cancer patients in the most effective way. Material and methods A systematic search of PubMed was carried out. In total, 809 studies of randomized controlled trials studying the effects of training during chemotherapy on endurance capacity and muscle strength were considered. Only 14 studies met all the inclusion criteria. The studies were assessed on methodological quality by using Cochrane criteria for randomized controlled trials. Results The quality of the studies was generally poor and the study populations varied considerably as the training programs were very heterogeneous. Variables of endurance capacity reported beneficial effects in 10 groups (59%). Increases due to training ranged from 8% to 31%. Endurance capacity decreased in nine of 13 control groups (69%), which ranged from 1% to 32%. Muscle strength improved significantly in 17 of 18 intervention groups (94%), ranging from 2% to 38%. Muscle strength also improved in 11 of 14 control groups (79%), but this increase was only minimal, ranging from 1.3% to 6.5%. Conclusions This review indicates that training during chemotherapy may help in preventing the decrease in muscle strength and endurance capacity. It is important to know which training intensity and duration is the most effective in training cancer patients, to provide a training program suitable for every cancer patient. Training should be based on good research and should be implemented into international guidelines and daily practice. More research is needed.

Evaluation of a combined lifestyle intervention for overweight and obese patients in primary health care: a quasi-experimental design.

BACKGROUND: Combined lifestyle interventions (CLIs) are designed to reduce risk factors for lifestyle-related diseases through increasing physical activity and improvement of dietary behaviour. OBJECTIVE: To evaluate the effects of a CLI for overweight and obese patients on lifestyle-related risk factors and health care consumption, in comparison to usual care. METHODS: Data on anthropometric and metabolic measurements, morbidity, drugs prescriptions and general practitioner (GP) consultations were extracted from electronic health records (timeframe: July 2009-August 2013). Using a quasi-experimental design, health outcomes of 127 patients who participated in a 1-year CLI were compared to a group of 254 matched patients that received usual care. Baseline to post-intervention changes in health outcomes between intervention and comparison group were evaluated using mixed model analyses. RESULTS: Compared to baseline, both groups showed reductions in body mass index (BMI), blood pressure, total cholesterol and low density lipoprotein cholesterol in year post-intervention. For these outcome measures, no significant differences in changes were observed between intervention and comparison group. A significant improvement of 0.08 mmol/l in high density lipoprotein (HDL) cholesterol was observed for the intervention group above the comparison group (P < 0.01). No significant intergroup differences were shown in drugs prescriptions and number of GP consultations. CONCLUSION: A CLI for overweight and obese patients in primary health care resulted in similar effects on health outcomes compared to usual care. Only an improvement on HDL cholesterol was shown. This study indicates that implementation and evaluation of a lifestyle intervention in primary health care is challenging due to political and financial barriers.

Decline in physical activity during adolescence is not associated with changes in mental health.

BACKGROUND: The majority of studies investigating associations between physical activity and mental health in adolescents have been cross-sectional in design. Potential associations between physical activity and mental health may be better examined longitudinally as physical activity levels tend to decrease in adolescence. Few studies have investigated these associations longitudinally in adolescents and none by measuring physical activity objectively. METHODS: A total of 158 Dutch adolescents (mean age 13.6 years, 38.6% boys, grades 7 and 9 at baseline) participated in this longitudinal study. Physical activity, depressive symptoms and self-esteem were measured at baseline and at the 1-year follow-up. Physical activity was objectively measured with an ActivPAL3™ accelerometer during one full week. Depressive symptoms were measured with the Center for Epidemiologic Studies Depression Scale (CES-D) and self-esteem was assessed with the Rosenberg Self-Esteem Scale (RSE). Results were analysed using structural equation modelling. RESULTS: Physical activity levels decreased 15.3% over a 1-year period (p < .001), with significantly (p = .001) greater decreases during grade 7 (-20.7%) than during grade 9 (-5.0%). Overall, depressive symptoms decreased (-12.1%, p < .001) over a 1-year period, while self-esteem did not change significantly (+2.9%, p = .066). Higher levels of depressive symptoms at baseline predicted a greater decline in depressive symptoms (ß = -.51, p < .001) and higher levels of self-esteem at baseline predicted a smaller increase in self-esteem (ß = -.48, p < .001). The decline in physical activity did not appear to predict any change in depressive symptoms and self-esteem. CONCLUSION: The decline in physical activity over a 1-year period during adolescence is not associated with a change in mental health. Further studies in adolescents aiming to investigate whether a change in physical activity is associated with a change in mental health should control for baseline levels of mental health and academic year differences.

Identifying waking time in 24-h accelerometry data in adults using an automated algorithm.

As accelerometers are commonly used for 24-h measurements of daily activity, methods for separating waking from sleeping time are necessary for correct estimations of total daily activity levels accumulated during the waking period. Therefore, an algorithm to determine wake and bed times in 24-h accelerometry data was developed and the agreement of this algorithm with self-report was examined. One hundred seventy-seven participants (aged 40-75 years) of The Maastricht Study who completed a diary and who wore the activPAL3™ 24 h/day, on average 6 consecutive days were included. Intraclass correlation coefficient (ICC) was calculated and the Bland-Altman method was used to examine associations between the self-reported and algorithm-calculated waking hours. Mean self-reported waking hours was 15.8 h/day, which was significantly correlated with the algorithm-calculated waking hours (15.8 h/day, ICC = 0.79, P = < 0.001). The Bland-Altman plot indicated good agreement in waking hours as the mean difference was 0.02 h (95% limits of agreement (LoA) = -1.1 to 1.2 h). The median of the absolute difference was 15.6 min (Q1-Q3 = 7.6-33.2 min), and 71% of absolute differences was less than 30 min. The newly developed automated algorithm to determine wake and bed times was highly associated with self-reported times, and can therefore be used to identify waking time in 24-h accelerometry data in large-scale epidemiological studies.

The implementation and sustainability of a combined lifestyle intervention in primary care: mixed method process evaluation.

BACKGROUND: The impact of physical inactivity and unhealthy diet on health is increasingly profound. Lifestyle interventions targeting both behaviors simultaneously might decrease the prevalence of overweight and comorbidities. The Dutch 'BeweegKuur' is a combined lifestyle intervention (CLI) in primary care, to improve physical activity and dietary behavior in overweight people. In a cluster randomized controlled trial, the (cost-) effectiveness of an intensively guided program has been compared to a less intensively guided program. This process evaluation aimed to assess protocol adherence and potential differences between clusters. In addition, sustainability (i.e. continuation of the CLI in practice after study termination) was evaluated. METHODS: Existing frameworks were combined to design the process evaluation for our intervention and setting specifically. We assessed reach, fidelity, dose delivered and received, context and implementation strategy. Both qualitative and quantitative data were used for a comprehensive evaluation. Data were collected in semi-structured interviews with health care providers (HCPs, n = 25), drop-out registration by HCPs, regular questionnaires among participants (n = 411) and logbooks kept by researchers during the trial. RESULTS: Protocol adherence by professionals and participants varied between the programs and clusters. In both programs the number of meetings with all HCPs was lower than planned in the protocol. Participants of the supervised program attended, compared to participants of the start-up program, more meetings with physiotherapists, but fewer with lifestyle advisors and dieticians. The 'BeweegKuur' was not sustained, but intervention aspects, networks and experiences were still utilized after finalization of the project. Whether clusters continued to offer a CLI seemed dependent on funding opportunities and collaborations. CONCLUSIONS: Protocol adherence in a CLI was problematic in both HCPs and participants. Mainly the amount of dietary guidance was lower than planned, and decreased with increasing guidance by PT. Thus, feasibility of changing physical activity and dietary habits simultaneously by one intervention in one year was not as high as expected. Also the sustainability of CLI was poor. When a CLI program is started, re-invention should be allowed and maximum effort should be taken to guarantee long term continuation, by planning both implementation and sustainability carefully. TRIAL REGISTRATION: Current Controlled Trials ISRCTN46574304 . Registered 23 December 2010.

Which activity monitor to use? Validity, reproducibility and user friendliness of three activity monitors.

BACKGROUND: Health is associated with amount of daily physical activity. Recently, the identification of sedentary time as an independent factor, has gained interest. A valid and easy to use activity monitor is needed to objectively investigate the relationship between physical activity, sedentary time and health. We compared validity and reproducibility of physical activity measurement and posture identification of three activity monitors, as well as user friendliness. METHODS: Healthy volunteers wore three activity monitors simultaneously: ActivPAL3, ActiGraphGT3X and CAM. Data were acquired under both controlled (n = 5) and free-living conditions (n = 9). The controlled laboratory measurement, that included standardized walking intensity and posture allocation, was performed twice. User friendliness was evaluated with a questionnaire. Posture classification was compared with direct observation (controlled measurement) and with diaries (free living). Accelerometer intensity accuracy was tested by correlations with walking speed. User friendliness was compared between activity monitors. RESULTS: Reproducibility was at least substantial in all monitors. The difference between the two CAM measurements increased with walking intensity. Amount of correct posture classification by ActivPAL3 was 100.0% (kappa 0.98), 33.9% by ActiGraphGT3X (kappa 0.29) and 100.0% by CAM (kappa 0.99). Correlations between accelerometer intensity and walking speed were 0.98 for ActivPAL3, 1.00 for ActiGraphGT3X and 0.98 for CAM. ICCs between activity monitors and diary were 0.98 in ActivPAL3, 0.59 and 0.96 in ActiGraphGT3X and 0.98 in CAM. ActivPAL3 and ActiGraphGT3X had higher user friendliness scores than the CAM. CONCLUSIONS: The ActivPAL3 is valid, reproducible and user friendly. The posture classification by the ActiGraphGT3X is not valid, but reflection of walking intensity and user friendliness are good. The CAM is valid; however, reproducibility at higher walking intensity and user friendliness might cause problems. Further validity studies in free living are recommended.

Active commuting to school, cognitive performance, and academic achievement: an observational study in Dutch adolescents using accelerometers.

BACKGROUND: The current study examined the associations between active commuting to school, cognitive performance, and academic achievement in Dutch adolescents. In addition, it was explored whether these associations were moderated by sex and mediated by depressive symptoms. METHODS: Students in grades 7 and 9 (N = 270; mean age 13.4 years; 53% boys) were included. Active commuting to school was measured objectively by an ActivPAL3™ accelerometer. Cognitive performance was measured by the d2 Test of attention (key components of executive functioning) and the Symbol Digit Modalities Test (information-processing speed). Academic achievement was determined by the mean of the school grades obtained in Dutch, mathematics and English. Depressive symptoms were self-reported. RESULTS: Active commuting to school constituted 28% of the total amount of time spent moving per week. Active commuting to school was not significantly associated with cognitive performance and academic achievement, overall. However, active commuting to school was positively associated with performance on the d2 Test of attention in girls (ß = .17, p = .037), but not in boys (ß = -.03, p = .660). The associations were not mediated by depressive symptoms. CONCLUSIONS: The associations between active commuting to school and cognitive performance and academic achievement are weak and might be moderated by sex, while the greatest benefits on cognition due to active commuting to school might be with regard to executive functioning. Future studies might make use of experimental designs, because causal relations between active commuting to school and cognitive performance or academic achievement would provide important implications for both education and public health.