Emmanuel Stamatakis

The ABC of Physical Activity for Health: A consensus statement from the British Association of Sport and Exercise Sciences

Absract Our understanding of the relationship between physical activity and health is constantly evolving. Therefore, the British Association of Sport and Exercise Sciences convened a panel of experts to review the literature and produce guidelines that health professionals might use. In the ABC of Physical Activity for Health, A is for All healthy adults, B is for Beginners, and C is for Conditioned individuals. All healthy adults aged 18–65 years should aim to take part in at least 150 min of moderate-intensity aerobic activity each week, or at least 75 min of vigorous-intensity aerobic activity per week, or equivalent combinations of moderate- and vigorous-intensity activities. Moderate-intensity activities are those in which heart rate and breathing are raised, but it is possible to speak comfortably. Vigorous-intensity activities are those in which heart rate is higher, breathing is heavier, and conversation is harder. Aerobic activities should be undertaken in bouts of at least 10 min and, ideally, should be performed on five or more days a week. All healthy adults should also perform muscle-strengthening activities on two or more days a week. Weight training, circuit classes, yoga, and other muscle-strengthening activities offer additional health benefits and may help older adults to maintain physical independence. Beginners should work steadily towards meeting the physical activity levels recommended for all healthy adults. Even small increases in activity will bring some health benefits in the early stages and it is important to set achievable goals that provide success, build confidence, and increase motivation. For example, a beginner might be asked to walk an extra 10 min every other day for several weeks to slowly reach the recommended levels of activity for all healthy adults. It is also critical that beginners find activities they enjoy and gain support in becoming more active from family and friends. Conditioned individuals who have met the physical activity levels recommended for all healthy adults for at least 6 months may obtain additional health benefits by engaging in 300 min or more of moderate-intensity aerobic activity per week, or 150 min or more of vigorous-intensity aerobic activity each week, or equivalent combinations of moderate- and vigorous-intensity aerobic activities. Adults who find it difficult to maintain a normal weight and adults with increased risk of cardiovascular disease or type 2 diabetes may in particular benefit from going beyond the levels of activity recommended for all healthy adults and gradually progressing towards meeting the recommendations for conditioned individuals. Physical activity is beneficial to health with or without weight loss, but adults who find it difficult to maintain a normal weight should probably be encouraged to reduce energy intake and minimize time spent in sedentary behaviours to prevent further weight gain. Children and young people aged 5–16 years should accumulate at least 60 min of moderate-to-vigorous-intensity aerobic activity per day, including vigorous-intensity aerobic activities that improve bone density and muscle strength.

Childhood obesity and overweight prevalence trends in England: evidence for growing socioeconomic disparities

Objective:Previous data indicate a rapidly increasing prevalence of obesity and overweight among English children and an emerging socioeconomic gradient in prevalence. The main aim of this study was to update the prevalence trends among school-age children and assess the changing socioeconomic gradient.Design:A series of nationally representative household-based health surveys conducted between 1997 and 2007 in England.Subjects:15 271 white children (7880 boys) aged 5 to 10 years with measured height and weight.Measurements:Height and weight were directly measured by trained fieldworkers. Overweight (including obesity) and obesity prevalence were calculated using the international body mass index cut-offs. Socioeconomic position (SEP) score was a composite score based on income and social class. Multiple linear regression assessed the prevalence odds with time point (1997/8, 2000/1, 2002/3, 2004/5, 2006/7) as the main exposure. Linear interaction terms of time by SEP were also tested for.Results:There are signs that the overweight and obesity trend has levelled off from 2002/3 to 2006/7. The odds ratio (OR) for overweight in 2006/7 compared with 2002/3 was 0.99 (95% CI 0.88–1.11) and for obesity OR=1.06 (0.86–1.29). The socioeconomic gradient has increased in recent years, particularly in 2006/7. Compared to 1997/8, the 2006/7 age and sex-adjusted OR for overweight was 1.88 (1.52 to 2.33) in low-SEP, 1.25 (1.04 to 1.50) in middle-SEP, and 1.13 (0.86 to 1.48) in high-SEP children.Conclusion:Childhood obesity and overweight prevalence among school-age children in England has stabilized in recent years, but children from lower socio-economic strata have not benefited from this trend. There is an urgent need to reduce socio-economic disparities in childhood overweight and obesity.

Metabolically Healthy Obesity and Risk of All-Cause and Cardiovascular Disease Mortality

CONTEXT Previous studies have identified an obese phenotype without the burden of adiposity-associated cardiometabolic risk factors, although the health effects remain unclear. OBJECTIVE We examined the association between metabolically healthy obesity and risk of cardiovascular disease (CVD) and all-cause mortality. DESIGN AND SETTING This was an observational study with prospective linkage to mortality records in community-dwelling adults from the general population in Scotland and England. PARTICIPANTS A total of 22,203 men and women [aged 54.1 (SD 12.7 yr), 45.2% men] without known history of CVD at baseline. INTERVENTIONS Based on blood pressure, high-density lipoprotein-cholesterol, diabetes diagnosis, waist circumference, and low-grade inflammation (C-reactive protein ≥ 3 mg/liter), participants were classified as metabolically healthy (0 or 1 metabolic abnormality) or unhealthy (two or more metabolic abnormalities). Obesity was defined as a body mass index of 30 kg/m(2) or greater. MAIN OUTCOME MEASURE Study members were followed up, on average, more than 7.0 ± 3.0 yr for cause-specific mortality. Cox proportional hazards models were used to examine the association of metabolic health/obesity categories with mortality. RESULTS There were 604 CVD and 1868 all-cause deaths, respectively. Compared with the metabolically healthy nonobese participants, their obese counterparts were not at elevated risk of CVD [hazard ratio (HR) 1.26, 95% confidence interval (CI) 0.74-2.13], although both nonobese (HR 1.59, 95% CI 1.30-1.94) and obese (HR 1.64, 95% CI 1.17-2.30) participants with two or more metabolic abnormalities were at elevated risk. Metabolically unhealthy obese participants were at elevated risk of all-cause mortality compared with their metabolically healthy obese counterparts (HR 1.72, 95% CI 1.23-2.41). CONCLUSION Metabolically healthy obese participants were not at increased risk of CVD and all-cause mortality over 7 yr.

Daily Sitting Time and All-Cause Mortality: A Meta-Analysis

Objective To quantify the association between daily total sitting and all-cause mortality risk and to examine dose-response relationships with and without adjustment for moderate-to-vigorous physical activity. Methods Studies published from 1989 to January 2013 were identified via searches of multiple databases, reference lists of systematic reviews on sitting and health, and from authors’ personal literature databases. We included prospective cohort studies that had total daily sitting time as a quantitative exposure variable, all-cause mortality as the outcome and reported estimates of relative risk, or odds ratios or hazard ratios with 95% confidence intervals. Two authors independently extracted the data and summary estimates of associations were computed using random effects models. Results Six studies were included, involving data from 595,086 adults and 29,162 deaths over 3,565,569 person-years of follow-up. Study participants were mainly female, middle-aged or older adults from high-income countries; mean study quality score was 12/15 points. Associations between daily total sitting time and all-cause mortality were not linear. With physical activity adjustment, the spline model of best fit had dose-response HRs of 1.00 (95% CI: 0.98-1.03), 1.02 (95% CI: 0.99-1.05) and 1.05 (95% CI: 1.02-1.08) for every 1-hour increase in sitting time in intervals between 0-3, >3-7 and >7 h/day total sitting, respectively. This model estimated a 34% higher mortality risk for adults sitting 10 h/day, after taking physical activity into account. The overall weighted population attributable fraction for all-cause mortality for total daily sitting time was 5.9%, after adjusting for physical activity. Conclusions Higher amounts of daily total sitting time are associated with greater risk of all-cause mortality and moderate-to-vigorous physical activity appears to attenuate the hazardous association. These findings provide a starting point for identifying a threshold on which to base clinical and public health recommendations for overall sitting time, in addition to physical activity guidelines.

Association between psychological distress and mortality: individual participant pooled analysis of 10 prospective cohort studies

Objective To quantify the link between lower, subclinically symptomatic, levels of psychological distress and cause-specific mortality in a large scale, population based study. Design Individual participant meta-analysis of 10 large prospective cohort studies from the Health Survey for England. Baseline psychological distress measured by the 12 item General Health Questionnaire score, and mortality from death certification. Participants 68 222 people from general population samples of adults aged 35 years and over, free of cardiovascular disease and cancer, and living in private households in England at study baseline. Main outcome measures Death from all causes (n=8365), cardiovascular disease including cerebrovascular disease (n=3382), all cancers (n=2552), and deaths from external causes (n=386). Mean follow-up was 8.2 years (standard deviation 3.5). Results We found a dose-response association between psychological distress across the full range of severity and an increased risk of mortality (age and sex adjusted hazard ratio for General Health Questionnaire scores of 1-3 v score 0: 1.20, 95% confidence interval 1.13 to 1.27; scores 4-6: 1.43, 1.31 to 1.56; and scores 7-12: 1.94, 1.66 to 2.26; P<0.001 for trend). This association remained after adjustment for somatic comorbidity plus behavioural and socioeconomic factors. A similar association was found for cardiovascular disease deaths and deaths from external causes. Cancer death was only associated with psychological distress at higher levels. Conclusions Psychological distress is associated with increased risk of mortality from several major causes in a dose-response pattern. Risk of mortality was raised even at lower levels of distress.

Overweight and obesity trends from 1974 to 2003 in English children: what is the role of socioeconomic factors?

Aims: To examine the childhood overweight and obesity prevalence trends between 1974 and 2003 and to assess whether these trends relate to parental social class and household income. Methods: A school based and a general population health survey: the National Study of Health and Growth in 1974, 1984, and 1994, and the Health Survey for England, yearly from 1996 to 2003. Participants were 14 587 white boys and 14 014 white girls aged 5–10 years. Overweight and obesity prevalence were calculated using UK specific as well as international body mass index (kg/m2) cut-offs. Socioeconomic status was measured using the Registrar General’s social class; household income (1997 onwards only) was adjusted for household size. Results: The prevalence of obesity (UK specific definition) in boys increased from 1.2% in 1984 to 3.4% in 1996–97 and 6.0% in 2002–03. In girls, obesity increased from 1.8% in 1984 to 4.5% in 1996–97 and 6.6% in 2002–03. Obesity prevalence has been increasing at accelerating rates in the more recent years. Children from manual social classes had marginally higher odds (OR 1.14, 95% CI 0.98 to 1.33) and children from higher income households had lower odds (OR 0.74, 95% CI 0.61 to 0.89) to be obese than their peers from non-manual class, and lower income households, respectively. Conclusion: Childhood obesity is increasing rapidly into the 2000s in England and these increases are more marked among children from lower socioeconomic strata. There is an urgent need for action to prevent further increase in obesity among children.

Overweight and obesity in infants and pre-school children in the European Union: a review of existing data

The objective of this study was to synthesize available information on prevalence and time trends of overweight and obesity in pre‐school children in the European Union. Retrieval and analysis or re‐analysis of existing data were carried out. Data sources include WHO databases, Medline and Google, contact with authors of published and unpublished documents. Data were analysed using the International Obesity Task Force reference and cut‐offs, and the WHO standard. Data were available from 18/27 countries. Comparisons were problematic because of different definitions and methods of data collection and analysis. The reported prevalence of overweight plus obesity at 4 years ranges from 11.8% in Romania (2004) to 32.3% in Spain (1998–2000). Countries in the Mediterranean region and the British islands report higher rates than those in middle, northern and eastern Europe. Rates are generally higher in girls than in boys. With the possible exception of England, there was no obvious trend towards increasing prevalence in the past 20–30 years in the five countries with data. The use of the WHO standard with cut‐offs at 1, 2 and 3 standard deviations yields lower rates and removes gender differences. Data on overweight and obesity in pre‐school children are scarce; their interpretation is difficult. Standard methods of surveillance, and research and policies on prevention and treatment, are urgently needed.

Psychological Distress as a Risk Factor for Cardiovascular Events: Pathophysiological and Behavioral Mechanisms

OBJECTIVES This study sought to estimate the extent to which behavioral and pathophysiological risk factors account for the association between psychological distress and incident cardiovascular events. BACKGROUND The intermediate processes through which psychological distress increases the risk of cardiovascular disease (CVD) are incompletely understood. An understanding of these processes is important for treating psychological distress in an attempt to reduce CVD risk. METHODS In a prospective study of 6,576 healthy men and women (ages 50.9 +/- 13.1 years), we measured psychological distress (using the 12-item version of the General Health Questionnaire >or=4) and behavioral (smoking, alcohol, physical activity) and pathophysiological (C-reactive protein, fibrinogen, total and high-density lipoprotein cholesterol, obesity, hypertension) risk factors at baseline. The main outcome was CVD events (hospitalization for nonfatal myocardial infarction, coronary artery bypass, angioplasty, stroke, heart failure, and CVD-related mortality). RESULTS Cigarette smoking, physical activity, alcohol intake, C-reactive protein, and hypertension were independently associated with psychological distress. There were 223 incident CVD events (63 fatal) over an average follow-up of 7.2 years. The risk of CVD increased in relation to presence of psychological distress in age- and sex-adjusted models (hazard ratio: 1.54, 95% confidence interval: 1.09 to 2.18, p = 0.013). In models that were adjusted for potential mediators, behavioral factors explained the largest proportion of variance ( approximately 65%), whereas pathophysiological factors accounted for a modest amount (C-reactive protein approximately 5.5%, hypertension, approximately 13%). CONCLUSIONS The association between psychological distress and CVD risk is largely explained by behavioral processes. Therefore, treatment of psychological distress that aims to reduce CVD risk should primarily focus on health behavior change.

Physically active lessons as physical activity and educational interventions: A systematic review of methods and results

OBJECTIVE Physically active lessons aim to increase childrens physical activity whilst maintaining academic time. This systematic review aimed to investigate the methods used in such interventions and their effects on physical activity and educational outcomes. METHODS In March 2014; PubMed, Web of Science, PsycINFO and ERIC electronic databases were searched. Inclusion criteria were: 1. Classroom lessons containing both PA and educational elements; 2. intervention studies featuring a control group or within-subjects baseline measurement period; 3. any age-group; and 4. English language. Studies assessing physically active lessons within complex interventions were excluded. Data were extracted onto a standardised form. Risk of bias was assessed using the Effective Public Health Practice Project (EPHPP) tool. RESULTS Eleven studies were identified: five examined physical activity outcomes only, three examined educational outcomes only and three examined both physical activity and educational outcomes. All studies found improved physical activity following physically active lessons: either in the whole intervention group or in specific demographics. Educational outcomes either significantly improved or were no different compared to inactive teaching. Studies ranged from low to high risk of bias. CONCLUSIONS Encouraging evidence of improved physical activity and educational outcomes following physically active lessons is provided. However, too few studies exist to draw firm conclusions. Future high-quality studies with longer intervention periods are warranted.

Trends in obesity among adults in England from 1993 to 2004 by age and social class and projections of prevalence to 2012

Background: This study aims to project the prevalence of adult obesity to 2012 by age groups and social class, by extrapolating the prevalence trends from 1993 to 2004. Repeated cross-sectional surveys were carried out of representative samples of the general population living in households in England conducted annually (1993 to 2004). Methods: Participants were classified as obese if their body mass index was over 30 kg/m2. Projections of obesity prevalence by 2012 were based on three scenarios: extrapolation of linear trend in prevalence from 1993 to 2004; acceleration (or slowing down) in rate of change based on the best fitting curve (power or exponential); and extrapolation of linear trend based on the six most recent years (1999 to 2004). Results: The prevalence of obesity increased significantly from 1993 to 2004 from 13.6% to 24.0% among men and from 16.9% to 24.4% among women. If obesity prevalence continues to increase at the same rate, it is projected that the prevalence of obesity in 2012 will be 32.1% (95% CI 30.4 to 34.8) in men and 31.0% (95% CI 29.0 to 33.1) in women. The projected 2012 prevalence for adults in manual social classes is higher (43%) than for adults in non-manual social classes (35%). Conclusion: If recent trends in adult obesity continue, about a third of all adults (almost 13 million individuals) would be obese by 2012. Of these, around 43% are from manual social classes, thereby adding to the public health burden of obesity-related illnesses. This highlights the need for public health action to halt or reverse current trends and narrow social class inequalities in health.