Medical Research Council Epidemiology Unit

Cambridge, United Kingdom

Medical Research Council Epidemiology Unit

Cambridge, United Kingdom
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Hallal P.C.,Federal University of Pelotas | Andersen L.B.,University of Southern Denmark | Andersen L.B.,Norwegian School of Sport Sciences | Bull F.C.,University of Western Australia | And 3 more authors.
The Lancet | Year: 2012

To implement effective non-communicable disease prevention programmes, policy makers need data for physical activity levels and trends. In this report, we describe physical activity levels worldwide with data for adults (15 years or older) from 122 countries and for adolescents (13-15-years-old) from 105 countries. Worldwide, 31.1% (95% CI 30.9-31.2) of adults are physically inactive, with proportions ranging from 17.0% (16.8-17.2) in southeast Asia to about 43% in the Americas and the eastern Mediterranean. Inactivity rises with age, is higher in women than in men, and is increased in high-income countries. The proportion of 13-15-year-olds doing fewer than 60 min of physical activity of moderate to vigorous intensity per day is 80.3% (80.1-80.5); boys are more active than are girls. Continued improvement in monitoring of physical activity would help to guide development of policies and programmes to increase activity levels and to reduce the burden of non-communicable diseases.

Tsimikas S.,University of California at San Diego | Mallat Z.,University of Paris Descartes | Talmud P.J.,University College London | Kastelein J.J.P.,University of Amsterdam | And 8 more authors.
Journal of the American College of Cardiology | Year: 2010

Objectives This study sought to assess whether oxidation-specific biomarkers are associated with an increased risk of coronary artery disease (CAD) events. Background The relationship of a panel of oxidative biomarkers and lipoprotein(a) [Lp(a)] to CAD risk is not fully determined. Methods A prospective case-control study nested in the EPIC (European Prospective Investigation of Cancer)-Norfolk cohort of 45- to 79-year-old apparently healthy men and women followed for ∼6 years was designed. Cases consisted of participants in whom fatal or nonfatal CAD developed, matched by sex, age, and enrollment time with controls without CAD. Baseline levels of oxidized phospholipids on apolipoprotein B-100 particles and Lp(a) were measured in 763 cases and 1,397 controls. Their relationship to secretory phospholipase A 2 type IIA mass and activity, myeloperoxidase mass, and lipoprotein-associated phospholipase A2 activity and association with CAD events were determined. Results After adjusting for age, smoking, diabetes, low- and high-density lipoprotein cholesterol, and systolic blood pressure, the highest tertiles of oxidized phospholipids on apolipoprotein B-100 particles and Lp(a) were associated with a significantly higher risk of CAD events (odds ratios: 1.67 and 1.64, respectively; p < 0.001) compared with the lowest tertiles. The odds ratio of CAD events associated with the highest tertiles of oxidized phospholipids on apolipoprotein B-100 particles or Lp(a) was significantly potentiated (approximately doubled) by the highest tertiles of secretory phospholipase A2 activity and mass but less so for myeloperoxidase and lipoprotein-associated phospholipase A2 activity. The odds ratios for fatal CAD were higher than for the combined end point. After taking into account the Framingham Risk Score, c-index values progressively increased when oxidative biomarkers were added to the model. Conclusions This EPIC-Norfolk study links pathophysiologically related oxidation-specific biomarkers and Lp(a) with CAD events. Oxidation-specific biomarkers provide cumulative predictive value when added to traditional cardiovascular risk factors. © 2010 American College of Cardiology Foundation.

Wilks D.C.,Medical Research Council Human Nutrition Research | Besson H.,Medical Research Council Epidemiology Unit | Lindroos A.K.,Medical Research Council Human Nutrition Research | Ekelund U.,Medical Research Council Epidemiology Unit
Obesity Reviews | Year: 2011

This study aimed at synthesizing the prospective associations between measured physical activity (PA) and change in adiposity in children, adolescents and adults following from two previous reviews. Search terms were adapted and a systematic literature search was conducted (January 2000-September 2008) and later updated (up to October 2009), considering observational and intervention studies of weight gain that measured both PA and body composition. Sixteen observational studies (six comprising adults) and five trials (one comprising adults) were eligible. For consistency, whenever possible either baseline PA energy expenditure or accelerometer output (counts min-1) and change in per cent body fat were the extracted exposure and outcome measures. Results of observational studies suggest that PA is not strongly prospectively related with adiposity: five studies on children and three on adults reported no association between baseline PA and change in adiposity, one study found a weak positive association and the other studies observed a weak negative association. Negative associations were more frequently observed in studies that analysed the association between change in the exposure and outcome. Intervention studies show generally no effect on either PA or adiposity. In conclusion, despite the well-established health benefits of PA, it may not be a key determinant of excessive gain in adiposity. © 2010 The Authors. obesity reviews © 2010 International Association for the Study of Obesity.

Panter J.R.,University of East Anglia | Jones A.P.,University of East Anglia | Van Sluijs E.M.F.,Medical Research Council Epidemiology Unit | Griffin S.J.,Medical Research Council Epidemiology Unit
American Journal of Preventive Medicine | Year: 2010

Background: Walking and cycling to school represent an opportunity for children to achieve regular physical activity. These behaviors may be influenced by characteristics of the environment around homes and schools, yet few studies have quantified the potential associations between these two sets of factors. Purpose: This study aims to assess whether objectively measured characteristics of the neighborhood, route, and school environments are associated with active commuting to school among children, and it explores whether distance acts as a moderator in this association. Methods: A cross-sectional study was conducted of 2012 children (899 boys and 1113 girls) aged 9-10 years attending 92 schools in the county of Norfolk, United Kingdom. Questionnaires were completed by children and parents during Summer 2007. Attributes around the home and children's route to school were assessed using a GIS. School environments were assessed using a newly developed school audit and via questionnaires completed by head teachers. Data were analyzed in 2008. Results: Almost half of the children usually walked or cycled to school. Children who lived in a more deprived area and whose route to school was direct were less likely to walk or cycle to school, whereas those who had a higher density of roads in their neighborhood were more likely to walk. Further, children whose routes had a high density of streetlights were less likely to cycle to school. Distance did not moderate the observed associations. Conclusions: Objectively measured neighborhood and route factors are associated with walking and cycling to school. However, distance did not moderate the associations found here. Creating safe environments by improving urban design may influence children's commuting behavior. Intervention studies are needed to confirm the findings from this observational cross-sectional study. © 2010 American Journal of Preventive Medicine.

Panter J.R.,University of East Anglia | Jones A.P.,University of East Anglia | Van Sluijs E.M.F.,Medical Research Council Epidemiology Unit | Griffin S.J.,Medical Research Council Epidemiology Unit
Journal of Epidemiology and Community Health | Year: 2010

Background: Environmental perceptions appear to play a role in determining behaviour in children, although their influence on active commuting remains unclear. This study examines whether attitudes, social support and environmental perceptions are associated with active commuting behaviour in school children and whether these associations are moderated by the distance to school. Methods: Data were collected as part of the SPEEDY study (Sport, Physical activity and Eating behaviour: Environmental Determinants in Young people), a cross-sectional study of 2064 children from schools in Norfolk, UK. Data regarding the usual mode of travel to school, attitudes towards and social support for active commuting, perceptions of the neighbourhood and route to school were assessed using questionnaires completed by 2012 children and their parents. Distance to school was estimated using a Geographic Information System and this was used to compare associations between personal and environmental factors and active travel, across different distance categories. Results: Forty per cent of children reported usually walking to school, with 9% cycling and the remainder using motorised travel. Parental attitudes and safety concerns, the presence of social support from parents and friends and parent-reported neighbourhood walkability were all found to be predictors of active commuting, with children receiving peer and family support and living in supportive environments being more likely to walk or cycle. There was some evidence of a moderating effect of distance whereby attitudes were more important for short distances and safety concerns long. Conclusion: Both attitudinal and environmental perceptions are associated with children's active commuting behaviours. Given the difficulty in modifying attitudes directly, the effect on them of interventions to provide more supportive environments should be evaluated.

Lynch K.E.,University of Massachusetts Amherst | Landsbaugh J.R.,Medical Research Council Epidemiology Unit | Whitcomb B.W.,University of Massachusetts Amherst | Pekow P.,University of Massachusetts Amherst | And 2 more authors.
American Journal of Preventive Medicine | Year: 2012

Background: A growing body of evidence suggests that physical activity during pregnancy can reduce risk of pregnancy complications. However, factors influencing activity in pregnant Hispanic women, who have high rates of sedentary activity as compared to non-Hispanic whites, are not well characterized. Purpose: To assess patterns and correlates of physical activity among 1355 participants in Proyecto Buena Salud, a prospective cohort of pregnant Hispanic women in Massachusetts from 2006 to 2011. Methods: Analyses were conducted in 2012. Pre-, early-, mid-, and late-pregnancy physical activity were assessed using the Pregnancy Physical Activity Questionnaire. Women reported the frequency and duration of household/caregiving, occupational, sports/exercise, and transportation activities and were classified according to compliance with American College of Obstetricians and Gynecologists guidelines for physical activity. Results: Household/caregiving activity was the primary mode of pregnancy activity ranging from 56% to 60% of total activity while sports/exercise contributed the least (<10%). Compared to nulliparous women, women with two or more children were 85% less likely to become inactive at any time during pregnancy (OR=0.15, 95% CI=0.04, 0.56, p-trend <0.01). Women with one or more children increased their total physical activity on average 9.73±2.04 MET-hours/week and 12.04±2.39 MET-hours/week, respectively, with the onset of pregnancy (p<0.01). Those with the highest levels of total physical activity prior to pregnancy were 87% less likely to become inactive with the onset of pregnancy than those who were inactive prior to pregnancy (OR=0.13, 95% CI= 0.05, 0.29). Conclusions: Findings can inform culturally appropriate interventions designed to reduce pregnancy complications through the promotion of physical activity during pregnancy. © 2012 American Journal of Preventive Medicine.

Myint P.K.,University of East Anglia | Myint P.K.,Norwich University | Myint P.K.,University of Cambridge | Luben R.N.,University of Cambridge | And 2 more authors.
Hypertension | Year: 2011

The effect of fruit and vegetable consumption and blood pressure is unclear. A population-based cross-sectional study was conducted in 20 926 men and women aged 40 to 79 years participating in the European Prospective Investigation Into Cancer-Norfolk who completed a health questionnaire and attended a clinic from 1993 to 1997. The relationship between plasma vitamin C concentrations, as an indicator of fruit and vegetable intake, and systolic BP was examined. The magnitude of their association was assessed using dichotomized values of high (≥140 mm Hg) and low (<140 mm Hg) systolic blood pressure. A total of 20 926 participants (46% men; mean [SD] 58.5 years [9.2 years]) were included after excluding participants with any missing data for variables of interest. People with high vitamin C concentrations had lower clinic blood pressure. The likelihood of having high blood pressure was 22% lower (odds ratio: 0.78 [95% CI: 0.71 to 0.86]) for those who were in the top quartiles of plasma vitamin C levels compared with the bottom quartiles after adjusting for age, sex, body mass index, cholesterol, prevalent medical conditions, smoking, physical activity, alcohol consumption, social class, education, use of vitamin C-containing supplement, and antihypertensive medication. Sex-specific analysis, as well as repeated analysis after exclusion of people who used vitamin C-containing supplements or who were taking antihypertensive medication, did not alter the results. There appears to be a strong association between vitamin C concentrations, an indicator of fruit and vegetable consumption, and a lower level of blood pressure. This may provide further evidence for health benefits of dietary patterns with higher fruit and vegetable consumption. © 2011 American Heart Association, Inc.

Ogilvie D.,Medical Research Council Epidemiology Unit | Bull F.,Loughborough University | Powell J.,University of the West of England | Cooper A.R.,University of Bristol | And 4 more authors.
American Journal of Public Health | Year: 2011

Improving infrastructure for walking and cycling is increasingly recommended as a means to promote physical activity, prevent obesity, and reduce traffic congestion and carbon emissions. However, limited evidence from intervention studies exists to support this approach. Drawing on classic epidemiological methods, psychological and ecological models of behavior change, and the principles of realistic evaluation, we have developed an applied ecological framework by which current theories about the behavioral effects of environmental change may be tested in heterogeneous and complex intervention settings. Our framework guides study design and analysis by specifying the most important data to be collected and relations to be tested to confirm or refute specific hypotheses and thereby refine the underlying theories.

Helmerhorst H.J.F.,Medical Research Council Epidemiology Unit | Helmerhorst H.J.F.,University of Amsterdam | Brage S.,Medical Research Council Epidemiology Unit | Warren J.,Medical Research Council Human Nutrition Resource Center | And 4 more authors.
International Journal of Behavioral Nutrition and Physical Activity | Year: 2012

Physical inactivity is one of the four leading risk factors for global mortality. Accurate measurement of physical activity (PA) and in particular by physical activity questionnaires (PAQs) remains a challenge. The aim of this paper is to provide an updated systematic review of the reliability and validity characteristics of existing and more recently developed PAQs and to quantitatively compare the performance between existing and newly developed PAQs.A literature search of electronic databases was performed for studies assessing reliability and validity data of PAQs using an objective criterion measurement of PA between January 1997 and December 2011. Articles meeting the inclusion criteria were screened and data were extracted to provide a systematic overview of measurement properties. Due to differences in reported outcomes and criterion methods a quantitative meta-analysis was not possible.In total, 31 studies testing 34 newly developed PAQs, and 65 studies examining 96 existing PAQs were included. Very few PAQs showed good results on both reliability and validity. Median reliability correlation coefficients were 0.62-0.71 for existing, and 0.74-0.76 for new PAQs. Median validity coefficients ranged from 0.30-0.39 for existing, and from 0.25-0.41 for new PAQs.Although the majority of PAQs appear to have acceptable reliability, the validity is moderate at best. Newly developed PAQs do not appear to perform substantially better than existing PAQs in terms of reliability and validity. Future PAQ studies should include measures of absolute validity and the error structure of the instrument. © 2012 Helmerhorst et al.; licensee BioMed Central Ltd.

Steele R.M.,Medical Research Council Epidemiology Unit | van Sluijs E.M.F.,Medical Research Council Epidemiology Unit | Sharp S.J.,Medical Research Council Epidemiology Unit | Landsbaugh J.R.,Medical Research Council Epidemiology Unit | And 2 more authors.
International Journal of Behavioral Nutrition and Physical Activity | Year: 2010

Background: Participation in higher intensity activity (i.e. vigorous physical activity [VPA]) appears more consistently associated with lower adiposity, unfortunately little is known about the nature and patterns of VPA participation in children.Objective: To examine the volume and patterns of vigorous and sedentary activity during different segments of the week (weekend, school-based and out-of-school). We also investigated differences by sex, socioeconomic status (SES) and weight status.Design: A cross-sectional study including 1568 UK children aged 9-10 years.Outcome measures: Sedentary activity (mins), total activity (counts/min) and VPA (mins) were measured by accelerometry. Using a series of 2 level mixed effects linear regression models we tested differences across the segmented week (school time [0900-1500] vs. out-of-school time [0700-0900 & 1500-2100]; and weekday vs. weekend); all models were adjusted for sex, weight status (gender- and age-specific body mass index [BMI] cut points), SES, age and accelerometer registered wear time.Results: Boys and girls accumulated higher VPA out-of-school compared to during school (boys mean ± SD 16.9 ± 9.6 vs 12.6 ± 5.8; girls, 13.1 ± 7.7 vs 8.2 ± 4.0, both p < 0.001); but there were no differences for weekday v weekend VPA (p > 0.05). Less time was spent sedentary on weekdays compared to weekends (p < 0.001). Although boys were more physically active and girls accumulated more sedentary time, the overall pattern in which their physical activity intensity varied across the various day segments was similar when stratified by weight status and SES; and large volumes of sedentary time were observed each hour across the day.Conclusions: The promotion of VPA during the weekend may hold the greatest promise for increasing VPA. Interventions aimed at increasing physical activity in 9-10 year old children should aim to target all children independent of sex, SES or weight status. © 2010 Steele et al; licensee BioMed Central Ltd.

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