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1.  Active travel to non-school destinations but not to school is associated with higher physical activity levels in an ethnically diverse sample of inner-city schoolchildren 
BMC Public Health  2017;17:13.
This study investigated the association of travel mode to school and non-school destinations with objectively assessed health markers and physical activity in an ethnically diverse sample of inner-city UK schoolchildren.
We used data from the Camden Active Spaces project (n = 450 children aged 9.1 yrs) to examine associations of school travel mode and frequency of active travel to non-school destinations with daily and out-of-school physical activity, sedentary time and health markers; whilst controlling for appropriate covariates including objectively measured route length.
High frequency of active travel to non-school destinations was associated with more time in moderate-to-vigorous physical activity during out-of-school periods (3.8, 0.8–6.9 min/d) and greater out-of-school (738, 197.4–1278.6 steps/d) and daily step counts (588.1, 51.6–1124.6 steps/d). No associations were observed between school travel mode, health outcomes and activity levels.
High frequency of active travel to non-school destinations is associated with higher levels of physical activity. These findings highlight the contribution of travel to non-school destinations to overall physical activity levels in schoolchildren.
Electronic supplementary material
The online version of this article (doi:10.1186/s12889-016-3920-1) contains supplementary material, which is available to authorized users.
PMCID: PMC5216598  PMID: 28056909
Active transport; Accelerometry; Sedentary behaviour
2.  The interaction between systemic inflammation and psychosocial stress in the association with cardiac troponin elevation: A new approach to risk assessment and disease prevention 
Preventive Medicine  2016;93:46-52.
We have previously shown that there is a complex and dynamic biological interaction between acute mental stress and acute release of inflammatory factors into the blood stream in relation to heart disease. We now hypothesize that the presence of chronic psychosocial stress may modify the weight of single test results for inflammation as a predictor of heart disease. Using a cross-sectional design, 500 participants free from heart disease drawn from the Whitehall II study in UK in 2006–2008 were tested for plasma fibrinogen as an inflammatory factor, financial strain as a marker of chronic psychosocial stress, coronary calcification measured using computed tomography, and for plasma high-sensitivity cardiac troponin T (HS-CTnT) as a marker of cardiac risk. Fibrinogen concentration levels above the average were associated with a 5-fold increase in the odds of HS-CTnT positivity only among individuals with financial strain (N = 208, OR = 4.73, 95%CI = 1.67 to 13.40, P = 0.003). Fibrinogen was in fact not associated with HS-CTnT positivity in people without financial strain despite the larger size of that subsample (n = 292, OR = 0.84, 95%CI = 0.42 to 1.67, P = 0.622). A test for interaction on the full sample (N = 500) showed a P value of 0.010 after adjusting for a range of demographics, health behaviours, traditional cardiovascular risk factors, psychosocial stressors, inflammatory cytokines, and coronary calcification. In conclusion, elevated fibrinogen seems to be cardio-toxic only when is combined with financial strain. Chronic psychosocial stress may modify the meaning that we should give to single test results for inflammation. Further research is needed to confirm our results.
•Chronic psychosocial stress modifies the association between inflammation and CVD.•A single test result of elevated fibrinogen can be the result of a healthy acute response to stress.•Therefore a finding of elevated fibrinogen cannot always be interpreted as a sign of poor health.•Elevated fibrinogen is associated with CVD only in individuals with chronic stress.
PMCID: PMC5126095  PMID: 27663429
Allostasis; Atherosclerosis; Cardiovascular diseases; Fibrinogen; Neuroendocrinology; Psychological stress; Socioeconomic factors; Troponin T
3.  Blood Pressure and Fibrinogen Responses to Mental Stress as Predictors of Incident Hypertension over an 8-Year Period 
Annals of Behavioral Medicine  2016;50(6):898-906.
Heightened blood pressure (BP) responses to mental stress predict raised BP levels over subsequent years, but evidence for associations with incident hypertension is limited, and the significance of inflammatory responses is uncertain.
We investigated the relationship between BP and plasma fibrinogen responses to stress and incident hypertension over an average 8-year follow-up.
Participants were 636 men and women (mean age 59.1 years) from the Whitehall II epidemiological cohort with no history of cardiovascular disease and hypertension. They performed standardized behavioral tasks (color/word conflict and mirror tracing), and hypertension was defined by clinic measures and medication status.
Of participants in the highest systolic BP reactivity tertile, 29.3 % became hypertensive over the follow-up period compared with 16.5 % of those in the lowest tertile, with an odds ratio of 2.02 (95 % CI 1.17–3.88, p = 0.012) after adjustment for age, sex, grade of employment, body mass index, smoking, alcohol consumption, physical activity, follow-up time, subjective stress response, perceived task difficulty, perceived task engagement, and baseline BP. Similar associations were observed for diastolic BP reactivity (odds ratio 2.05, 95 % CI 1.23–3.40, p = 0.006) and for impaired systolic BP post-stress recovery (odds ratio 2.06, 95 % CI 1.19–3.57, p = 0.010). Fibrinogen reactions to tasks also predicted future hypertension in women (odds ratio 2.64, 95 % CI 1.11–6.30, p = 0.029) but not men.
These data suggest that heightened cardiovascular and inflammatory reactivity to mental stress is associated with hypertension risk, and may be a mechanism through which psychosocial factors impact on the development of hypertension.
PMCID: PMC5126198  PMID: 27401000
Stress reactivity; Stress recovery; Allostatic load; Inflammation
4.  Aggio et al. Respond to “Lessons for Research on Cognitive Aging” 
American Journal of Epidemiology  2016;183(12):1086-1087.
PMCID: PMC4908212  PMID: 27226248
5.  Context-Specific Associations of Physical Activity and Sedentary Behavior With Cognition in Children 
American Journal of Epidemiology  2016;183(12):1075-1082.
In the present study, we investigated how overall and specific domains of physical activity and sedentary behavior at the age of 7 years were associated with cognition at the age of 11 years in 8,462 children from the Millennium Cohort Study. Data were collected from 2001 to 2013. Participation in domains of physical activity and sedentary behavior at 7 years of age were reported. Activity levels were also measured objectively. Cognition was assessed using the British Ability Scales. General linear models were used to assess longitudinal associations of physical activity and sedentary behavior, measured both objectively and via self-report, with cognition. Analyses were adjusted for prespecified covariates. Sports/physical activity club attendance (B = 0.6, 95% confidence interval (CI): 0.2, 1.1), doing homework (B = 0.5, 95% CI: 0.0, 0.9), and objectively measured sedentary time (B = 0.8, 95% CI: 0.1, 1.4) at age 7 years were positively associated with cognition at age 11 years in final the models. Television viewing was negatively associated with cognition (B = −1.7, 95% CI: −2.4, −1.0), although the association was attenuated to the null after adjustments for baseline cognition. Objectively measured light physical activity was inversely associated with cognition (B = −0.7, 95% CI: −1.3, −0.1). Moderate-to-vigorous physical activity was also inversely associated with cognition in girls only (B = −1.1, 95% CI: −2.0, −0.3). Associations of physical activity and sedentary behavior with cognition appear to be context-specific in young people.
PMCID: PMC4908213  PMID: 27226249
cognition; cognitive function; physical activity; sedentary behavior
6.  Decreased reaction time variability is associated with greater cardiovascular responses to acute stress 
Psychophysiology  2016;53(5):739-748.
Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75‐min recovery. RT measures were generated from an ex‐Gaussian distribution that yielded three predictors: mu‐RT, sigma‐RT, and tau‐RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = −.009, SE = .005, p = .09) and diastolic (B = −.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = −.007, SE = .003, p = .03) and impaired vagal tone (B = −.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses.
PMCID: PMC4855624  PMID: 26894967
Reaction times; Cardiovascular; Acute stress; Reactivity and recovery
7.  Sedentary behaviour among elite professional footballers: health and performance implications 
Elite athletes should have little concern about meeting recommended guidelines on physical activity. However, sedentary behaviour is considered a health risk independent of physical activity, and is recognised in public health guidelines advising against prolonged sedentary time. There has been very little research on athletes’ physical activity behaviour outside elite sport.
Given health and performance links, we investigated in-season post-training activity levels in 28 elite professional footballers during the English Premiership season. Players volunteered to wear a triaxial wrist accelerometer for 1 week, removing it only for training and matches. In total, 25 players met the inclusion criteria for analysis. Players recorded on average 632.6 min wear time p/day during the post-training period (SD±52.9) for a mean of 3.8 days (SD±1.5).
On average, players recorded 76.2 min p/day (SD±28.8) of moderate or vigorous activity post-training. The majority (79%) of post-training time was spent in sedentary activities (500.6 min per day±59.0).
Professional footballers are alarmingly sedentary in their leisure time, and comparatively more so than non-athletic groups of a similar age and older. This raises questions over optimum recovery and performance, as well as long-term health and cardiovascular risk. Worryingly, retirement from elite sport is likely to further imbalance activity and sedentary behaviour. Promoting regular periodic light to moderate leisure time activity could be beneficial. Further research and provision of education and support for players is required in this area.
PMCID: PMC4838833  PMID: 27110383
8.  Post-menopausal Women Exhibit Greater Interleukin-6 Responses to Mental Stress Than Older Men 
Annals of Behavioral Medicine  2016;50:564-571.
Acute stress triggers innate immune responses and elevation in circulating cytokines including interleukin-6 (IL-6). The effect of sex on IL-6 responses remains unclear due to important limitations of previous studies.
The purpose of this study was to examine sex differences in IL-6 responses to mental stress in a healthy, older (post-menopausal) sample accounting for several moderating factors.
Five hundred six participants (62.9 ± 5.60 years, 55 % male) underwent 10 min of mental stress consisting of mirror tracing and Stroop task. Blood was sampled at baseline, after stress, and 45 and 75 min post-stress, and assayed using a high sensitivity kit. IL-6 reactivity was computed as the mean difference between baseline and 45 min and between baseline and 75 min post-stress. Main effects and interactions were examined using ANCOVA models.
There was a main effect of time for the IL-6 response (F3,1512 = 201.57, p = <.0001) and a sex by time interaction (F3,1512 = 17.07, p = <.001). In multivariate adjusted analyses, IL-6 reactivity was significantly greater in females at 45 min (M = 0.37 ± 0.04 vs. 0.20 ± 0.03 pg/mL, p = .01) and at 75 min (M = 0.57 ± 0.05 vs. 0.31 ± 0.05 pg/mL, p = .004) post-stress compared to males. Results were independent of age, adiposity, socioeconomic position, depression, smoking and alcohol consumption, physical activity, statin use, testing time, task appraisals, hormone replacement, and baseline IL-6. Other significant predictors of IL-6 reactivity were lower household wealth, afternoon testing, and baseline IL-6.
Healthy, post-menopausal females exhibit substantially greater IL-6 responses to acute stress. Inflammatory responses if sustained over time may have clinical implications for the development and maintenance of inflammatory-related conditions prevalent in older women.
PMCID: PMC4933724  PMID: 26943141
Sex; Mental stress; Pro-inflammatory reactivity; Interleukin-6
9.  The effect of experimentally induced sedentariness on mood and psychobiological responses to mental stress 
The British Journal of Psychiatry  2016;208(3):245-251.
Evidence suggests a link between sedentary behaviours and depressive symptoms. Mechanisms underlying this relationship are not understood, but inflammatory processes may be involved. Autonomic and inflammatory responses to stress may be heightened in sedentary individuals contributing to risk, but no study has experimentally investigated this.
To examine the effect of sedentary time on mood and stress responses using an experimental design.
Forty-three individuals were assigned to a free-living sedentary condition and to a control condition (usual activity) in a cross-over, randomised fashion and were tested in a psychophysiology laboratory after spending 2 weeks in each condition. Participants completed mood questionnaires (General Health Questionnaire and Profile of Mood States) and wore a motion sensor for 4 weeks.
Sedentary time increased by an average of 32 min/day (P = 0.01) during the experimental condition compared with control. Being sedentary resulted in increases in negative mood independent of changes in moderate to vigorous physical activity (ΔGHQ = 6.23, ΔPOMS = 2.80). Mood disturbances were associated with greater stress-induced inflammatory interleukin-6 (IL-6) responses (β = 0.37).
Two weeks of exposure to greater free-living sedentary time resulted in mood disturbances independent of reduction in physical activity. Stress-induced IL-6 responses were associated with changes in mood.
PMCID: PMC4771942  PMID: 26294364
10.  How to reduce sitting time? A review of behaviour change strategies used in sedentary behaviour reduction interventions among adults 
Health Psychology Review  2015;10(1):89-112.
Sedentary behaviour – i.e., low energy-expending waking behaviour while seated or lying down – is a health risk factor, even when controlling for physical activity. This review sought to describe the behaviour change strategies used within interventions that have sought to reduce sedentary behaviour in adults. Studies were identified through existing literature reviews, a systematic database search, and hand-searches of eligible papers. Interventions were categorised as ‘very promising’, ‘quite promising’, or ‘non-promising’ according to observed behaviour changes. Intervention functions and behaviour change techniques were compared across promising and non-promising interventions. Twenty-six eligible studies reported thirty-eight interventions, of which twenty (53%) were worksite-based. Fifteen interventions (39%) were very promising, eight quite promising (21%), and fifteen non-promising (39%). Very or quite promising interventions tended to have targeted sedentary behaviour instead of physical activity. Interventions based on environmental restructuring, persuasion, or education were most promising. Self-monitoring, problem solving, and restructuring the social or physical environment were particularly promising behaviour change techniques. Future sedentary reduction interventions might most fruitfully incorporate environmental modification and self-regulatory skills training. The evidence base is, however, weakened by low-quality evaluation methods; more RCTs, employing no-treatment control groups, and collecting objective data are needed.
PMCID: PMC4743603  PMID: 26315814
sedentary behaviour; behaviour change; intervention
11.  Effect of short-term weight loss on mental stress-induced cardiovascular and pro-inflammatory responses in women 
Stress (Amsterdam, Netherlands)  2015;18(5):602-606.
Epidemiologic evidence links psychosocial stress with obesity but experimental studies examining the mechanisms that mediates the effect of stress on adiposity are scarce. The aim of this study was to investigate whether changes in adiposity following minimal weight loss affect heightened stress responses in women, and examine the role of the adipokine leptin in driving inflammatory responses. Twenty-three overweight or obese, but otherwise healthy, women (M age = 30.41 ± 8.0 years; BMI = 31.9 ± 4.1 kg/m2) completed standardized acute mental stress before and after a 9-week calorie restriction program designed to modify adiposity levels. Cardiovascular (blood pressure and heart rate) and inflammatory cytokines (leptin and interleukin-6; IL-6) responses to mental stress were assessed several times between baseline and a 45-min post-stress recovery period. There were modest changes in adiposity measures while the adipokine leptin was markedly reduced (−27%) after the intervention. Blood pressure reactivity was attenuated (−3.38 ± 1.39 mmHg) and heart rate recovery was improved (2.07 ± 0.96 Bpm) after weight loss. Blood pressure responses were inversely associated with changes in waist to hip ratio post intervention. Decreased levels of circulating leptin following weight loss were inversely associated with the IL-6 inflammatory response to stress (r = −0.47). We offered preliminary evidence suggesting that modest changes in adiposity following a brief caloric restriction program may yield beneficial effect on cardiovascular stress responses. In addition, reductions in basal leptin activity might be important in blunting pro-inflammatory responses. Large randomized trials of the effect of adiposity on autonomic responses are thus warranted.
PMCID: PMC4732430  PMID: 26181102
Adiposity; inflammation; interleukin-6; leptin; mental stress
12.  Long terms trends of multimorbidity and association with physical activity in older English population 
Multimorbidity has become one of the main challenges in the recent years for patients, health care providers and the health care systems globally. However, literature describing the burden of multimorbidity in the elderly population, especially longitudinal trends is very limited. Physical activity is recommended as one of the main lifestyle changes in the prevention and management of multiple chronic diseases worldwide; however, the evidence on its association with multimorbidity remains inconclusive. Therefore, we aimed to assess the longitudinal trends of multimorbidity and the association between multimorbidity and physical activity in a nationally representative cohort of the English population aged ≥50 years between 2002 and 2013.
We used data on 15,688 core participants from six waves of the English Longitudinal Study of Ageing, with complete information on physical activity. Self-reported physical activity was categorised as inactive, mild, moderate and vigorous levels of physical activity. We calculated the number of morbidities and the prevalence of multimorbidity (more than 2 chronic conditions) between 2002 and 2013 overall and by levels of self-reported physical activity. We estimated the odds ratio (OR) and 95 % confidence intervals (CI) for multimorbidity by each category of physical activity, adjusting for potential confounders.
There was a progressive decrease over time in the proportion of participants without any chronic conditions (33.9 % in 2002/2003 vs. 26.8 % in 2012/2013). In contrast, the prevalence of multimorbidity steadily increased over time (31.7 % in 2002/2003 vs. 43.1 % in 2012/2013). Compared to the physically inactive group, the OR for multimorbidity was 0.84 (95 % CI 0.78 to 0.91) in mild, 0.61 (95 % CI 0.56 to 0.66) in moderate and 0.45 (95 % CI 0.41 to 0.49) in the vigorous physical activity group.
This study demonstrated an inverse dose-response association between levels of physical activity and multimorbidity, however, given the increasing prevalence of multimorbidity over time, there is a need to explore causal associations between physical activity and multimorbidity and its impact as a primary prevention strategy to prevent the occurrence of chronic conditions later in life and reduce the burden of multimorbidity.
Electronic supplementary material
The online version of this article (doi:10.1186/s12966-016-0330-9) contains supplementary material, which is available to authorized users.
PMCID: PMC4717631  PMID: 26785753
Multimorbidity; Physical activity; Cohort; Longitudinal trend
13.  Examining techniques for measuring the effects of nutrients on mental performance and mood state 
European Journal of Nutrition  2016;55(6):1991-2000.
Intake of specific nutrients has been linked to mental states and various indices of cognitive performance although the effects are often subtle and difficult to interpret. Measurement of so-called objective variables (e.g. reaction times) is often considered to be the gold standard for assessing outcomes in this field of research. It can, however, be argued that data on subjective experience (e.g. mood) are also important and may enrich existing objective data. The aim of this review is to evaluate methods for measuring mental performance and mood, considering the definition of subjective mood and the validity of measures of subjective experience.
A multi-stakeholder expert group was invited by ILSI Europe to come to a consensus around the utility of objective and subjective measurement in this field, which forms the basis of the paper. Therefore, the present review reflects a succinct overview of the science but is not intended to be a systematic review.
The proposed approach extends the traditional methodology using standard ‘objective’ measurements to also include the consumers’ subjective experiences in relation to food. Specific recommendations include 1) using contemporary methods to capture transient mood states; 2) using sufficiently sensitive measures to capture effects of nutritional intervention; 3) considering the possibility that subjective and objective responses will occur over different time frames; and 4) recognition of the importance of expectancy and placebo effects for subjective measures.
The consensus reached was that the most informative approach should involve collection and consideration of both objective and subjective data.
PMCID: PMC5009169  PMID: 26744300
Mood; Cognition; Objective; Subjective; Food; Mental health; Affective assessment
14.  All-cause mortality effects of replacing sedentary time with physical activity and sleeping using an isotemporal substitution model: a prospective study of 201,129 mid-aged and older adults 
Sedentary behaviour, sleeping, and physical activity are thought to be independently associated with health outcomes but it is unclear whether these associations are due to the direct physiological effects of each behaviour or because, across a finite 24-hour day, engagement in one behavior requires displacement of another. The aim of this study was to examine the replacement effects of sedentary behaviour (total sitting, television/computer screen time combined), sleeping, standing, walking, and moderate-to-vigorous physical activity on all-cause mortality using isotemporal substitution modelling.
Longitudinal analysis (4.22 ± 0 · 9 years follow-up/849,369 person-years) of 201,129 participants of the 45 and Up study aged ≥45 years from New South Wales, Australia.
Seven thousand four hundred and sixty deaths occurred over follow-up. There were beneficial associations for replacing total sitting time with standing (per-hour HR: 95 % CI: 0.95, 0.94–0.96), walking (0.86, 0.81–0.90), moderate-to-vigorous physical activity (0.88, 0.85–0.90), and sleeping in those sleeping ≤ 7 h/day (0.94, 0.90–0.98). Similar associations were noted for replacing screen time. Replacing one hour of walking or moderate-to-vigorous physical activity with any other activity class was associated with an increased mortality risk by 7–18 %. Excluding deaths in the first 24 months of the follow up and restricting analyses to those who were healthy at baseline did not materially change the above observations.
Although replacing sedentary behaviour with walking and moderate-to-vigorous physical activity are associated with the lowest mortality risk, replacements with equal amounts of standing and sleeping (in low sleepers only) are also linked to substantial mortality risk reductions.
Electronic supplementary material
The online version of this article (doi:10.1186/s12966-015-0280-7) contains supplementary material, which is available to authorized users.
PMCID: PMC4589071  PMID: 26419654
Physical activity; Sedentary behaviour; Mortality; Longitudinal; Isotemporal substitution; Prevention; Sitting; Screen time; Mortality; Epidemiology; Sleeping; Public health; Population cohort
15.  The association between fibrinogen reactivity to mental stress and high-sensitivity cardiac troponin T in healthy adults 
Psychoneuroendocrinology  2015;59:37-48.
•We analyzed mental stress, fibrinogen, and CVD within an integrated framework.•Fibrinogen is not a positive mediator between mental stress and CVD.•The higher the fibrinogen response to mental stress is, the lower the risk of CVD, assessed by detectable HS-CTnT levels.
Plasma fibrinogen is considered as a positive mediator between mental stress and cardiovascular disease because it is an acute-phase protein released in response to mental stress and a coagulation factor. However those three factors have never been studied together within a single integrated framework, using cardiac troponin T as a marker of cardiovascular risk.
491 disease-free men and women aged 53–76 were tested for fibrinogen levels before, immediately after, and following recovery from standardized mental stress tasks. We measured plasma cardiac troponin T using a high-sensitivity assay (HS-CTnT) and coronary calcification using electron-beam dual-source computed tomography.
The average fibrinogen concentration increased by 5.1% (s.d. = 7.3) in response to stress and then tended to return to baseline values. People with higher baseline fibrinogen values had smaller increases (blunted responses) following the stress task (P = 0.001), and people with higher stress responses showed better recovery (P < 0.001). In unadjusted analyses, higher baseline fibrinogen was associated with higher chances of having detectable HS-CTnT (P = 0.072) but, conversely, higher fibrinogen response was associated with lower chances of having detectable HS-CTnT (P = 0.007). The adjustment for clinical, inflammatory, and haemostatic factors, as well as for coronary calcification eliminated the effect of baseline fibrinogen, whereas the negative association between fibrinogen response and HS-CTnT remained robust: the odds of detectable HS-CTnT halved for each 10% increase in fibrinogen concentration due to stress (OR = 0.49, P = 0.007, 95% CI = 0.30–0.82).
Greater fibrinogen responses to mental stress are associated with lower likelihood of detectable high-sensitivity troponin T plasma concentration. A more dynamic fibrinogen response appears to be advantageous for cardiovascular health.
PMCID: PMC4512259  PMID: 26010862
Stress; Psychological; Fibrinogen; Troponin T; Atherosclerosis; Allostasis
17.  ‘On Your Feet to Earn Your Seat’: update to randomised controlled trial protocol 
Trials  2015;16:330.
This update describes changes to procedures for our randomised controlled trial of ‘On Your Feet to Earn Your Seat’, a habit-based intervention to reduce sedentary behaviour in older adults. Some of the amendments have arisen from the addition of new sites, each offering different possibilities and constraints for study procedures. Others have been made in response to problems encountered in administering intended recruitment procedures at the London sites described in our original protocol. All changes have received ethics and governance clearance, and were made before or during data collection and prior to analyses.
Five non-London UK NHS-based sites (three general practices, one hospital, one NHS Foundation Trust) have been added to the study, each employing locally-tailored variations of recruitment and data collection procedures followed at the London sites. In contrast to the London sites, accelerometry data are not being collected nor are shopping vouchers being given to participants at the new sites. Data collection was delayed at the London sites because of technical difficulties in contacting participants. Subsequently, a below-target sample size was achieved at the London sites (n = 23), and recruitment rates cannot be estimated. Additionally, the physical inactivity inclusion criterion (i.e., <30 consecutive minutes of leisure time activity) has been removed from all sites, because we found that participants at the London sites meeting this criterion at consent subsequently reported activity above this threshold at the baseline assessment.
This is primarily a feasibility trial. The addition of new sites, each employing different study procedures, offers the opportunity to assess the feasibility of alternative recruitment and data collection methods, so enriching the informational value of our analyses of primary outcomes. Recruitment has finished, and the coincidence of a small sample at the London sites with addition of new sites has ensured a final sample size similar to our original target.
Trial registration
Current Controlled Trials ISRCTN47901994 (registration date: 16th January 2014)
PMCID: PMC4525743  PMID: 26242218
Sedentary behaviour; Physical activity; Behaviour change; Habit; Older adults
18.  Job Strain as a Risk Factor for Type 2 Diabetes: A Pooled Analysis of 124,808 Men and Women 
Diabetes Care  2014;37(8):2268-2275.
The status of psychosocial stress at work as a risk factor for type 2 diabetes is unclear because existing evidence is based on small studies and is subject to confounding by lifestyle factors, such as obesity and physical inactivity. This collaborative study examined whether stress at work, defined as “job strain,” is associated with incident type 2 diabetes independent of lifestyle factors.
We extracted individual-level data for 124,808 diabetes-free adults from 13 European cohort studies participating in the IPD-Work Consortium. We measured job strain with baseline questionnaires. Incident type 2 diabetes at follow-up was ascertained using national health registers, clinical screening, and self-reports. We analyzed data for each study using Cox regression and pooled the study-specific estimates in fixed-effect meta-analyses.
There were 3,703 cases of incident diabetes during a mean follow-up of 10.3 years. After adjustment for age, sex, and socioeconomic status (SES), the hazard ratio (HR) for job strain compared with no job strain was 1.15 (95% CI 1.06–1.25) with no difference between men and women (1.19 [1.06–1.34] and 1.13 [1.00–1.28], respectively). In stratified analyses, job strain was associated with an increased risk of diabetes among those with healthy and unhealthy lifestyle habits. In a multivariable model adjusted for age, sex, SES, and lifestyle habits, the HR was 1.11 (1.00–1.23).
Findings from a large pan-European dataset suggest that job strain is a risk factor for type 2 diabetes in men and women independent of lifestyle factors.
PMCID: PMC4113178  PMID: 25061139
19.  The mediation of coronary calcification in the association between risk scores and cardiac troponin T elevation in healthy adults: Is atherosclerosis a good prognostic precursor of coronary disease? 
Preventive Medicine  2015;77:150-154.
Conventional cardiac risk scores may not be completely accurate in predicting acute events because they only include factors associated with atherosclerosis, considered as the fundamental precursor of cardiovascular disease. In UK in 2006–2008 (Whitehall II study) we tested the ability of several risk scores to identify individuals with cardiac cell damage and assessed to what extent their estimates were mediated by the presence of atherosclerosis.
430 disease-free, low-risk participants were tested for high-sensitivity cardiac troponin-T (HS-CTnT) and for coronary calcification using electron-beam, dual-source, computed tomography (CAC). We analysed the data cross-sectionally using ROC curves and mediation tests.
When the risk scores were ranked according to the magnitude of ROC areas for HS-CTnT prediction, a score based only on age and gender came first (ROC area = 0.79), followed by Q-Risk2 (0.76), Framingham (0.70), Joint-British-Societies (0.69) and Assign (0.68). However, when the scores were ranked according to the extent of mediation by CAC (proportion of association mediated), their order was essentially reversed (age&gender = 6.8%, Q-Risk2 = 9.7%, Framingham = 16.9%, JBS = 17.8%, Assign = 17.7%). Therefore, the more accurate a score is in predicting detectable HS-CTnT, the less it is mediated by CAC; i.e. the more able a score is in capturing atherosclerosis the less it is able to predict cardiac damage. The P for trend was 0.009.
The dynamics through which cardiac cell damage is caused cannot be explained by ‘classic’ heart disease risk factors alone. Further research is needed to identify precursors of heart disease other than atherosclerosis.
•The classic cardiac risk scores are based on factors associated with atherosclerosis.•We test atherosclerosis as a mediator between risk scores and cardiac damage.•The more accurate a score is, the less it is mediated by atherosclerosis.•The association with atherosclerosis limits the accuracy of cardiac risk scores.•Atherosclerosis is not a good prognostic precursor of cardiac events.
PMCID: PMC4518041  PMID: 26051205
Acute coronary syndrome; Troponin T; Coronary artery disease; Risk factors; Risk assessment; Tomography; X-ray computed; Routine Diagnostic tests; Physiopathology; Aetiology
20.  Sedentary behaviour among elite professional footballers: health and performance implications 
Elite athletes should have little concern about meeting recommended guidelines on physical activity. However, sedentary behaviour is considered a health risk independent of physical activity, and is recognised in public health guidelines advising against prolonged sedentary time. There has been very little research on athletes’ physical activity behaviour outside elite sport.
Given health and performance links, we investigated in-season post-training activity levels in 28 elite professional footballers during the English Premiership season. Players volunteered to wear a triaxial wrist accelerometer for 1 week, removing it only for training and matches. In total, 25 players met the inclusion criteria for analysis. Players recorded on average 632.6 min wear time p/day during the post-training period (SD±52.9) for a mean of 3.8 days (SD±1.5).
On average, players recorded 76.2 min p/day (SD±28.8) of moderate or vigorous activity post-training. The majority (79%) of post-training time was spent in sedentary activities (500.6 min per day±59.0).
Professional footballers are alarmingly sedentary in their leisure time, and comparatively more so than non-athletic groups of a similar age and older. This raises questions over optimum recovery and performance, as well as long-term health and cardiovascular risk. Worryingly, retirement from elite sport is likely to further imbalance activity and sedentary behaviour. Promoting regular periodic light to moderate leisure time activity could be beneficial. Further research and provision of education and support for players is required in this area.
PMCID: PMC4838833  PMID: 27110383
21.  Healthy obesity and objective physical activity123 
Background: Disease risk is lower in metabolically healthy obese adults than in their unhealthy obese counterparts. Studies considering physical activity as a modifiable determinant of healthy obesity have relied on self-reported measures, which are prone to inaccuracies and do not capture all movements that contribute to health.
Objective: We aimed to examine differences in total and moderate-to-vigorous physical activity between healthy and unhealthy obese groups by using both self-report and wrist-worn accelerometer assessments.
Design: Cross-sectional analyses were based on 3457 adults aged 60–82 y (77% male) participating in the British Whitehall II cohort study in 2012–2013. Normal-weight, overweight, and obese adults were considered “healthy” if they had <2 of the following risk factors: low HDL cholesterol, hypertension, high blood glucose, high triacylglycerol, and insulin resistance. Differences across groups in total physical activity, based on questionnaire and wrist-worn triaxial accelerometer assessments (GENEActiv), were examined by using linear regression. The likelihood of meeting 2010 World Health Organization recommendations for moderate-to-vigorous activity (≥2.5 h/wk) was compared by using prevalence ratios.
Results: Of 3457 adults, 616 were obese [body mass index (in kg/m2) ≥30]; 161 (26%) of those were healthy obese. Obese adults were less physically active than were normal-weight adults, regardless of metabolic health status or method of physical activity assessment. Healthy obese adults had higher total physical activity than did unhealthy obese adults only when assessed by accelerometer (P = 0.002). Healthy obese adults were less likely to meet recommendations for moderate-to-vigorous physical activity than were healthy normal-weight adults based on accelerometer assessment (prevalence ratio: 0.59; 95% CI: 0.43, 0.79) but were not more likely to meet these recommendations than were unhealthy obese adults (prevalence ratio: 1.26; 95% CI: 0.89, 1.80).
Conclusions: Higher total physical activity in healthy than in unhealthy obese adults is evident only when measured objectively, which suggests that physical activity has a greater role in promoting health among obese populations than previously thought.
PMCID: PMC4515867  PMID: 26156738
obesity; metabolic risk factor clustering; metabolic health; physical activity; epidemiology
22.  Acceptability of a theory-based sedentary behaviour reduction intervention for older adults (‘On Your Feet to Earn Your Seat’) 
BMC Public Health  2015;15:606.
Adults aged 60 years and over spend most time sedentary and are the least physically active of all age groups. This early-phase study explored acceptability of a theory-based intervention to reduce sitting time and increase activity in older adults, as part of the intervention development process.
An 8-week uncontrolled trial was run among two independent samples of UK adults aged 60–75 years. Sample 1, recruited from sheltered housing on the assumption that they were sedentary and insufficiently active, participated between December 2013 and March 2014. Sample 2, recruited through community and faith centres and a newsletter, on the basis of self-reported inactivity (<150 weekly minutes of moderate-to-vigorous activity) and sedentary behaviour (≥6 h mean daily sitting), participated between March and August 2014. Participants received a booklet offering 16 tips for displacing sitting with light-intensity activity and forming activity habits, and self-monitoring ‘tick-sheets’. At baseline, 4-week, and 8-week follow-ups, quantitative measures were taken of physical activity, sedentary behaviour, and habit. At 8 weeks, tick-sheets were collected and a semi-structured interview conducted. Acceptability was assessed for each sample separately, through attrition and adherence to tips, ANOVAs for behaviour and habit changes, and, for both samples combined, thematic analysis of interviews.
In Sample 1, 12 of 16 intervention recipients completed the study (25 % attrition), mean adherence was 40 % (per-tip range: 15–61 %), and there were no clear patterns of changes in sedentary or physical activity behaviour or habit. In Sample 2, 23 of 27 intervention recipients completed (15 % attrition), and mean adherence was 58 % (per-tip range: 39–82 %). Sample 2 decreased mean sitting time and sitting habit, and increased walking, moderate activity, and activity habit. Qualitative data indicated that both samples viewed the intervention positively, found the tips easy to follow, and reported health and wellbeing gains.
Low attrition, moderate adherence, and favourability in both samples, and positive changes in Sample 2, indicate the intervention was acceptable. Higher attrition, lower adherence, and no apparent behavioural impact among Sample 1 could perhaps be attributable to seasonal influences. The intervention has been refined to address emergent acceptability problems. An exploratory controlled trial is underway.
Electronic supplementary material
The online version of this article (doi:10.1186/s12889-015-1921-0) contains supplementary material, which is available to authorized users.
PMCID: PMC4489366  PMID: 26135402
Older adults; Sedentary behaviour; Sitting; Physical activity; Intervention; Habit; Behaviour change
23.  Effects of reallocating time in different activity intensities on health and fitness: a cross sectional study 
The effects of replacing time in specific activity categories for other categories (e.g. replacing sedentary time with light activity) on health and fitness are not well known. This study used isotemporal substitution to investigate the effects of substituting activity categories in an equal time exchange fashion on health and fitness in young people.
Participants were drawn from schools in Camden, London (n = 353, mean age 9.3 ± 2.3 years). Time sedentary, in light and in moderate-to-vigorous activity (MVPA) was measured via accelerometry. The effects of substituting time in activity categories (sedentary, light and MVPA) with equivalent time in another category on health and fitness were examined using isotemporal substitution.
In single and partition models, MVPA was favourably associated with body fat %, horizontal jump distance and flexibility. Time sedentary and in light activity were not associated with health and fitness outcomes in these models. In substitution models, replacing one hour of sedentary time with MVPA was favourably associated with body fat % (B = −4.187; 95 % confidence interval (CI), −7.233, −1.142), horizontal jump distance (B = 16.093; 95 % CI, 7.476, 24.710) and flexibility (B = 4.783; 95 % CI, 1.910, 7.656). Replacing time in light activity with MVPA induced similar benefits but there were null effects for replacing sedentary with light intensity.
Substituting time sedentary and in light activity with MVPA was associated with favourable health and fitness. Time in sedentary behaviour may only be detrimental to health and fitness when it replaces time in MVPA in young people.
Electronic supplementary material
The online version of this article (doi:10.1186/s12966-015-0249-6) contains supplementary material, which is available to authorized users.
PMCID: PMC4482052  PMID: 26104041
Sedentary behaviour; Physical activity; Accelerometry; Isotemporal substitution; Fitness
24.  Prospective association between objective measures of childhood motor coordination and sedentary behaviour in adolescence and adulthood 
Higher levels of gross motor coordination are positively associated with physical activity in childhood, but little is known about how they relate to sedentary behaviour. The aim of this study was to investigate the longitudinal association between gross motor coordination at childhood and sedentary behaviour in adolescence and adulthood.
Data were from the 1970 British Cohort Study (the age 10, 16, and 42-year surveys). At age 10 the participant’s mother provided information on how often participants watched TV and played sports and a health visitor administered several tests to assess gross motor coordination. At aged 16 and 42-years participants reported their daily screen and TV time, respectively, and physical activity status. We examined associations between gross motor coordination at age 10 with sedentary behaviour and physical activity at age 16 and 42, using logistic regression.
In multivariable models, higher levels of gross motor coordination were associated with lower odds of high screen time (n = 3073; OR 0.79, 95 % CI 0.64, 0.98) at 16-years although no associations with physical activity were observed (OR 1.16, 95 % CI 0.93, 1.44). Similar associations were observed with TV time in adulthood when participants were aged 42, and in addition high gross motor coordination was also associated with physical activity participation (n = 4879; OR 1.18, 95 % CI 1.02, 1.36).
Intervention efforts to increase physical activity participation and reduce sedentary behaviour over the life course may be best targeted towards children with low gross motor coordination.
Electronic supplementary material
The online version of this article (doi:10.1186/s12966-015-0236-y) contains supplementary material, which is available to authorized users.
PMCID: PMC4464137  PMID: 26054403
Motor coordination; Physical activity; Sedentary; Birth cohort
25.  Hostility and Physiological Responses to Acute Stress in People With Type 2 Diabetes 
Psychosomatic Medicine  2015;77(4):458-466.
Hostility is associated with cardiovascular mortality and morbidity, and one of the mechanisms may involve heightened reactivity to mental stress. However, little research has been conducted in populations at high risk for cardiovascular disease. The aim of the present study was to assess the relationship between hostility and acute stress responsivity in individuals with Type 2 diabetes.
A total of 140 individuals (median age [standard deviation] 63.71 [7.00] years) with Type 2 diabetes took part in laboratory-based experimental stress testing. Systolic blood pressure, diastolic blood pressure, heart rate, plasma interleukin-6 (IL-6), and salivary cortisol were assessed at baseline, during two stress tasks, and 45 and 75 minutes later. Cynical hostility was assessed using the Cook Medley Cynical Hostility Scale.
Participants with greater hostility scores had heightened increases in IL-6 induced by the acute stress tasks (B = 0.082, p = .002), independent of age, sex, body mass index, smoking, household income, time of testing, medication, and baseline IL-6. Hostility was inversely associated with cortisol output poststress (B = −0.017, p = .002), independent of covariates. No associations between hostility and blood pressure or heart rate responses were observed.
Hostile individuals with Type 2 diabetes may be susceptible to stress-induced increases in inflammation. Further research is needed to understand if such changes increase the risk of cardiovascular disease in this population.
PMCID: PMC4431675  PMID: 25886832
Type 2 diabetes mellitus; hostility; interleukin-6; salivary cortisol; psychological stress; AUC = area under the curve; BMI = body mass index; CAD = coronary artery disease; CI = confidence intervals; CVD = cardiovascular disease; DBP = diastolic blood pressure; HbA1c = glycated hemoglobin; HR = heart rate; IL-6 = interleukin-6; SBP = systolic blood pressure; T2DM = Type 2 diabetes mellitus

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