Longitudinal changes in device-measured physical activity from childhood to young adulthood: the PANCS follow-up study.

BACKGROUND: There is a lack of longitudinal studies examining changes in device-measured physical activity and sedentary time from childhood to young adulthood. We aimed to assess changes in device-measured physical activity and sedentary time from childhood, through adolescence, into young adulthood in a Norwegian sample of ostensibly healthy men and women. METHODS: A longitudinal cohort of 731 Norwegian boys and girls (49% girls) participated at age 9 years (2005-2006) and 15 years (2011-2012), and 258 of these participated again at age 24 years (2019-2021; including the COVID-19 pandemic period). Physical activity and sedentary time were measured using ActiGraph accelerometers. Linear mixed models were used to analyse changes in physical activity and sedentary time and whether low levels of childhood physical activity track, i.e., persist into young adulthood (nchange=721; ntracking=640). RESULTS: The most prominent change occurred between the ages of 9 to 15 years, with an increase in sedentary time (150 min/day) and less time spent in light (125 min/day), moderate (16 min/day), and vigorous physical activity (8 min/day). Only smaller changes were observed between the ages of 15 and 24 years. Changes in moderate-to-vigorous physical activity from childhood to young adulthood differed between subgroups of sex, tertiles of body mass index at baseline and tertiles of peak oxygen uptake at baseline. While the tracking models indicated low absolute stability of physical activity from childhood to young adulthood, children in the lowest quartiles of moderate-to-vigorous (OR:1.88; 95%CI: 1.23, 2.86) and total physical activity (OR: 1.87; 95%CI: 1.21, 2.87) at age 9 years were almost 90% more likely to be in these quartiles at age 24 years compared to those belonging to the upper three quartiles at baseline. CONCLUSIONS: We found a substantial reduction in physical activity and increase in time spent sedentary between age 9 and 15 years. Contrary to previous studies, using mainly self-reported physical activity, little change was observed between adolescence and young adulthood. The least active children were more likely to remain the least active adults and could be targeted for early intervention.

Optimal measuring point for ST deviation in chest pain patients with possible acute coronary syndrome.

INTRODUCTION: In the ECG, significant ST elevation or depression according to specific amplitude criteria can be indicative of acute coronary syndrome (ACS). Guidelines state that the ST amplitude should be measured at the J point, but data to support that this is the optimal measuring point for ACS detection is lacking. We evaluated the impact of different measuring points for ST deviation on the diagnostic accuracy for ACS in unselected emergency department (ED) chest pain patients. MATERIAL AND METHODS: We included 14,148 adult patients with acute chest pain and an ECG recorded at a Swedish ED between 2010 and 2014. ST deviation was measured at the J point (STJ) and at 20, 40, 60 and 80 ms after the J point. A discharge diagnosis of ACS or not at the index visit was noted in all patients. RESULTS: In total, 1489 (10.5%) patients had ACS. ST amplitude criteria at STJ had a sensitivity of 28% and a specificity of 92% for ACS. With these criteria, the highest positive and negative predictive values for ACS were obtained near the J point, but the optimal point varied with ST deviation, age group and sex. The overall best measuring points were STJ and ST20. CONCLUSIONS: This study indicates that the diagnostic accuracy of the ECG criteria for ACS is very low in ED chest pain patients, and that the optimal measuring point for the ST amplitude in the detection of ACS differs between ST elevation and depression, and between patient subgroups.

Is vigorous-intensity physical activity required for improving bone mass in adolescence? Findings from a Brazilian birth cohort.

The association between moderate and vigorous physical activity throughout adolescence and areal bone density (aBMD) at 18 years of age was evaluated. Vigorous-intensity physical activity at 11, 15, and 18 years was associated with aBMD in early adulthood, especially in boys. Cross-sectional analyses showed a positive association between moderate physical activity and aBMD. INTRODUCTION: To evaluate independent associations of moderate and vigorous physical activity (MPA, VPA) across adolescence with areal bone mineral density (aBMD). METHODS: Physical activity (PA) was assessed at 11, 15, and 18 years of age by self-report and at 18 years by accelerometry in the 1993 Pelotas Birth Cohort Study. Time spent in MPA and VPA was determined using metabolic equivalents and specific cutoffs based on raw acceleration. Lumbar spine and femoral neck aBMD were measured by DXA at 18 years. Statistical analyses evaluated the association of MPA and VPA with aBMD, after adjusting for skin color, asset index, current height and age at menarche, and peak strain score (based on ground reaction forces of PA). RESULTS: Lumbar spine and femoral neck aBMD were available for 3947 (49.9% of boys) and 3960 (49.6% of boys) individuals, respectively. Time spent in MPA at 11 and 15 years was not associated with aBMD. VPA at all time points was positively related to both lumbar spine and femoral neck aBMD in boys. Results were consistent for objectively measured VPA. Girls who achieved 75+ minutes/week of VPA in at least two follow-ups showed higher aBMD at 18 years of age. Boys who reached 75+ minutes/week of VPA at all follow-ups had on average 0.117 g/cm2 (95% CI: 0.090; 0.144) higher femoral neck aBMD than those who never achieved this threshold. CONCLUSIONS: Self-reported VPA but not MPA throughout adolescence was associated with aBMD. Recommendation for PA in young people should consider the importance of VPA.

Why complicate an important task? An orderly display of the limb leads in the 12-lead electrocardiogram and its implications for recognition of acute coronary syndrome.

BACKGROUND: In the standard ECG display, limb leads are presented in a non-anatomical sequence: I, II, III, aVR, aVL, aVF. The Cabrera system is a display format which instead presents the limb leads in a cranial/left-to-caudal/right sequence, i.e. in an anatomically sequential order. Lead aVR is replaced in the Cabrera display by its inverted version, -aVR, which is presented in its logical place between lead I and lead II. MAIN TEXT: In this debate article possible implications of using the Cabrera display, instead of the standard, non-contiguous lead display, are presented, focusing on its use in patients with possible acute coronary syndrome. The importance of appreciating reciprocal limb-lead ECG changes and the diagnostic and prognostic value of including aVR or lead -aVR in ECG interpretation in acute coronary syndrome is covered. Illustrative cases and ECGs are presented with both the standard and contiguous limb lead display for each ECG. A contiguous lead display is useful when diagnosing acute coronary syndrome in at least 3 ways: 1) when contiguous leads are present adjacent to each other, identification of ST elevation in two contiguous leads is simple; 2) a contiguous lead display facilitates understanding of lead relationships as well as reciprocal changes; 3) it makes the common neglect of lead aVR unlikely. CONLUSIONS: It is logical to display the limb leads in their sequential anatomical order and it may have advantages both in diagnostics and ECG learning.

Age is associated with increased mortality in the RETTS-A triage scale.

BACKGROUND: Triage is widely used in the emergency department (ED) in order to identify the patient's level of urgency and often based on the patient's chief complaint and vital signs. Age has been shown to be independently associated with short term mortality following an ED visit. However, the most commonly used ED triage tools do not include age as an independent core variable. The aim of this study was to investigate the relationship between age and 7- and 30-day mortality across the triage priority level groups according to Rapid Emergency Triage and Treatment System - Adult (RETTS-A), the most widely used triage tool in Sweden. METHODS: In this cohort, we included all adult patients visiting the ED at the Karolinska University Hospital, Sweden, from 1/1/2010 to 1/1/2015, n = 639,387. All patients were triaged according to the RETTS-A and subsequently separated into three age strata: 18-59, 60-79 and ≥ 80 years. Descriptive analyses and logistic regression was used. The primary outcome measures were 7- and 30-day mortality. RESULTS: We observed that age was associated with both 7 and 30-day mortality in each triage priority level group. Mortality was higher in older patients across all triage priority levels but the association with age was stronger in the lowest triage group (p-value for interaction = < 0.001). Comparing patients ≥80 years with patients 18-59 years, older patients had a 16 and 7 fold higher risk for 7 day mortality in the lowest and highest triage priority groups, respectively. The corresponding numbers for 30-d mortality were a 21- and 8-foldincreased risk, respectively. CONCLUSION: Compared to younger patients, patients above 60 years have an increased short term mortality across the RETTS-A triage priority level groups and this was most pronounced in the lowest triage level. The reason for our findings are unclear and data suggest a validation of RETTS-A in aged patients.

Associations of multiple unhealthy lifestyle behaviors with overweight/obesity and abdominal obesity among Brazilian adolescents: A country-wide survey.

BACKGROUND AND AIMS: Physical inactivity, unhealthy diet, smoking and heavy drinking are four key unhealthy lifestyle behaviors (ULB) that may influence body weight and obesity development. More recently, sedentary time has been recognized as another potentially emerging ULB related to obesity. We therefore investigated the association of multiple ULB with overweight/obesity and abdominal obesity among Brazilian adolescents. METHODS AND RESULTS: This cross-sectional study involved 62,063 students (12-17 years). Physical inactivity, high screen time, low fiber intake, binge drinking and smoking were self-reported and combined to a ULB risk score, ranging from zero to five. Participants were classified as overweight/obese or with abdominal obesity using sex and age-specific cut-off points for BMI and waist circumference, respectively. Poisson regression models were used to examine the associations between ULB with overweight/obesity and abdominal obesity, adjusted for socio-demographic variables. Overall, 2.3%, 18.9%, 43.9%, 32.3% and 2.6% of participants reported zero, one, two, three and four/five ULB, respectively. Higher ULB risk score was associated with overweight/obesity and abdominal obesity in a dose-response gradient. Among 32 possible combinations of ULB, the three most prevalent combinations (physical inactivity + low fiber intake; high screen time + low fiber intake; physical inactivity + high screen time + low fiber intake) were positively associated with general and abdominal obesity. CONCLUSIONS: Our findings suggest a synergistic relationship between ULB and general and abdominal obesity. Preventive efforts targeting combined ULB should be sought to reduce the prevalence of general and abdominal obesity in Brazilian youth.

Secular and longitudinal physical activity changes in population-based samples of children and adolescents.

The aims of this study were to investigate whether physical activity (PA) and sedentary time (ST) in 9- and 15-year-olds differed between 2005-2006 and 2011-2012 (secular change), and to investigate changes in PA and ST from age 9 to 15 (longitudinal change). In 2005-2006, we invited nationally representative samples of Norwegian 9- (n=1470) and 15-year-olds (n=1348) to participate. In 2011-2012, we invited a new nationally representative sample of 9-year-olds (n=1945), whereas 15-year-olds (n=1759) were invited to participate either based on previous participation in 2005-2006 or from a random sample of schools. We assessed PA and ST objectively using accelerometers. In 2011-2012, both 9- and 15-year-olds spent more time sedentary (≥35.7 min/d, P<.001) and less time in light PA (≥35.2 min/d, P<.001) compared to their peers in 2005-2006. Nine-year-old girls also spent less time in moderate-to-vigorous PA (MVPA) (4.2 min/d, P=.041). In both age groups, the proportion accumulating an average of 60 min/d of MVPA did not differ between the two cohorts. From age 9 to 15, girls and boys decreased their time spent in LPA (≥106.7 min/d, P<.001) and in MVPA (≥20.8 min/d, P<.001). During the same period, ST increased by a mean of >2 h/d (P<.011). We observed an adverse secular change in PA from 2005-2006 to 2011-2012 among 9- and 15-year-olds, and a large decline in PA in the participants followed longitudinally from age 9 to 15 years.

Correlates of accelerometer-assessed physical activity in pregnancy-The 2015 Pelotas (Brazil) Birth Cohort Study.

Objective methods to measure physical activity (PA) have become available and widely used given the high degree of precision to evaluate PA. However, few studies have used accelerometers to measure PA during pregnancy, especially in low- and middle-income countries. We assessed overall PA, moderate, vigorous, and moderate-to-vigorous physical activity (MVPA) objectively measured among pregnant women and their correlates in a population-based study. PA was assessed for seven consecutive days using a raw triaxial wrist-worn accelerometer in women interviewed around 16 and 24 weeks of gestation in the 2015 Pelotas (Brazil) Birth Cohort Study. The average acceleration, which expresses overall PA, was presented in milli-g (1 mg = 0.001 g), and average time (min/day) spent in MVPA (>100 mg) was also analyzed in 5- and 10-min bouts. Analyses were performed using linear regression. In total, 2317 women were included in the analyses. Overall PA was 27.6 mg. Pregnant women spent on average 14 min/day in MVPA and 0.4 min in vigorous PA. Time spent in MVPA and total PA were inversely associated with years in school and income, and were lower among women receiving advice to not exercise. MVPA was also inversely associated with age, lower among women living with a partner, and higher among non-white women. The study indicated low levels of PA among pregnant women. The identified correlates may provide a framework to better understand factors influencing PA during pregnancy and thus inform future interventions.

Does body mass index modify the association between physical activity and screen time with cardiometabolic risk factors in adolescents? Findings from a country-wide survey.

BACKGROUND: Moderate and vigorous physical activity (MVPA) and screen time (ST) have been associated with cardiometabolic health in youth. However, previous studies are conflicting whether these associations are independent of each other and it is unknown if they are modified by adiposity. We aimed to examine the independent and joint associations between MVPA and ST with cardiometabolic risk across body mass index (BMI) categories. METHODS: A total of 36 956 Brazilian adolescents (12-17 years) from the Study of Cardiovascular Risks in Adolescents were included. Information on time spent in MVPA and ST were assessed by self-reports. Blood pressure, Homeostasis Model Assessment of Insulin Resistance, triglycerides, high-density lipoprotein-cholesterol and waist circumference were used to calculate a cardiometabolic risk score (sex-age-specific top-risk quintile for each biomarker). Ordered logistic regression was used to examine the associations. RESULTS: In final adjusted models, both higher MVPA (proportional odds ratio (POR)=0.80; 95% confidence interval (CI): 0.67-0.95) and ST (POR=1.23; 95% CI: 1.10-1.37) were independently associated with cardiometabolic risk. After stratification by normal weight vs overweight/obese, the inverse independent association for MVPA remained unchanged, whereas ST was positively associated with cardiometabolic risk only in overweight/obese adolescents (POR=1.62; 95% CI: 1.18-2.22). Participants who met the recommendations for both MVPA and ST had lower odds for cardiometabolic risk, especially if they were overweight/obese (POR=0.46; 95% CI: 0.31-0.68). CONCLUSIONS: MVPA and ST are independently associated with cardiometabolic risk; the association with ST, however, appears modified by BMI. Normal-weight adolescents should be encouraged to increase MVPA, whereas a combination of increasing MVPA and decreasing ST is recommended in those who are overweight or obese.

Does adiposity mediate the relationship between physical activity and biological risk factors in youth?: a cross-sectional study from the International Children's Accelerometry Database (ICAD).

BACKGROUND/OBJECTIVES: To model the association between accumulating 60 daily minutes of moderate-to-vigorous physical activity and a composite score of biological risk factors into a direct and an indirect effect, using abdominal obesity as the mediator. SUBJECTS/METHODS: Cross-sectional data from the International Children's Accelerometry Database (ICAD) including 6-18-year-old children and adolescents (N=3412) from 4 countries providing at least 3 days of accelerometry-assessed physical activity. A standardized composite risk score was calculated from systolic blood pressure and fasting blood samples of insulin, glucose, triacylglycerol and inverse HDL-cholesterol. Abdominal obesity was assessed by the waist-circumference:height ratio. Two-stage regression analysis, allowing for exposure-mediator interaction, was used for the effect decomposition. RESULTS: Participants achieving 60 daily minutes of moderate-to-vigorous physical activity had a 0.31 (95% CI: -0.39, -0.23) standard deviations lower composite risk score than those achieving less than 60 min. Modelling the associations suggested that 0.24 standard deviations (95% CI: -0.32, -0.16) was attributed to the direct effect and -0.07 (95% CI: -0.11, -0.02) to the indirect effect indicating that 22% of the total effect was mediated by central adiposity. Modelling 30 and 90 min of moderate-to-vigorous physical activity per day resulted in changes in the direct but not the indirect effect. CONCLUSIONS: One hour of daily moderate-to-vigorous physical activity was associated with clinically relevant differences in metabolic control compared to engagement in less than this minimally recommended amount. The majority of the difference was explained by the direct effect of physical activity.International Journal of Obesity advance online publication, 31 October 2017; doi:10.1038/ijo.2017.241.

Objectively measured sedentary time and physical activity and associations with body weight gain: does body weight determine a decline in moderate and vigorous intensity physical activity?

OBJECTIVES: High levels of physical activity (PA) may prevent the development of obesity. However, the magnitude and direction of the association between PA of various intensities, sedentary time and weight status remain unclear. Thus, we examined whether objectively measured sedentary time and PA independently predict gain in body weight, change in body weight and to examine the possibility of reverse causation. METHODS: We examined the prospective associations between sedentary time, PA and body weight (BW). Baseline measurements were conducted in 2008/2009 and follow-up measurements in 2014/2015 in a random sample of the adult Norwegian population (N=1710, 45.1% men). Moderate and vigorous intensity PA (MVPA) and sedentary time were measured by accelerometry and BW and height self-reported. We first modelled the associations between baseline sedentary time and PA with BW at follow-up. We then modelled the reverse associations (BW as the exposure) and sedentary time and PA (as outcomes) in separate models. All models were adjusted for age, sex, baseline value of the outcome, socio-economic status, alcohol consumption, smoking, monitor wear time and follow-up time. RESULTS: Body mass index (BMI) increased by 0.2 units (P=0.003) between baseline and follow-up, and 46.5% of participants were either overweight (36.4%) or obese (10.1%) at baseline increasing to 49.6% (11.7% obese) at follow-up. Baseline sedentary time, MVPA and vigorous PA were not associated with BW at follow-up after adjustment for covariates. In contrast, baseline BW was inversely associated with MVPA (ß=-0.11; 95% confidence interval (CI); -0.21, -0.009) and VPA (ß=-0.035; 95% CI; -0.059, -0.011) in adjusted models. These associations were unchanged when BW was substituted by BMI. CONCLUSIONS: Baseline BW seems to determine a decrease in MVPA in healthy adult Norwegian men and women, more so than the reverse.

Cross-sectional and prospective associations between moderate to vigorous physical activity and sedentary time with adiposity in children.

BACKGROUND: Physical activity (PA) and sedentary time (SED) have both been suggested as potential risk factors for adiposity in children. However, there is paucity of data examining the temporal associations between these variables. OBJECTIVE: This study aimed to analyze the cross-sectional and prospective associations between PA, SED and body composition in children. METHODS: A total of 510 children (age at baseline 10.1±0.8, age at follow-up 11.8±0.9) from six Portuguese schools from the Oeiras Municipality participated in this study. PA and SED were measured by accelerometry and trunk fat mass (TFM) and body fat mass (BFM) were measured by dual energy X-ray absorptiometry. Fat mass index (FMI) was calculated as BFM divided by height squared. Several regression models adjusted for age, sex, maturity status, follow-up duration, baseline levels of the outcome variable and SED or moderate to vigorous PA (MVPA) were performed. RESULTS: MVPA (min per day) was cross-sectionally inversely associated with adiposity indexes (FMI, TFM and BFM). Adiposity indexes were inversely associated with time in MVPA. In prospective analyses, MVPA was associated with a lower levels of FMI (ß=-0.37, 95% confidence interval (CI): -0.49 to -0.26, P<0.001), TFM (ß=-0.20, 95% CI: -0.29 to -0.10, P<0.001) and BFM (ß=-0.37, 95% CI: -0.49 to -0.26, P<0.001). When the model was adjusted for age, sex, maturity status and for baseline levels of the outcome variables MVPA remained a significant predictor of lower adiposity indexes (FMI: ß=-0.09, 95% CI: -0.16 to -0.01, P<0.05; TFM: ß=-0.08, 95% CI: -0.15 to -0.01, P<0.05; BFM: ß=-0.07, 95% CI: -0.15 to 0.00, P<0.05). Adiposity was not associated with MVPA when modeled as the exposure in prospective analyses. SED was not related with adiposity indexes, except for the relationship with FMI. CONCLUSIONS: In cross-sectional and prospective analyses, MVPA is associated with lower adiposity independent of covariates and SED. Results suggest that promoting MVPA is important for preventing gain in adiposity in healthy children.

Objectively measured sedentary time, physical activity and kidney function in people with recently diagnosed Type 2 diabetes: a prospective cohort analysis.

AIM: To assess the prospective association between objectively measured physical activity and kidney function over 4 years in people with Type 2 diabetes. METHODS: Individuals (120 women and 206 men) participating in the ADDITION-Plus trial underwent assessment of sedentary time (SED-time), time spent in moderate-to-vigorous-intensity physical activity (MVPA) and total physical activity energy expenditure (PAEE) using a combined heart rate and movement sensor, and kidney function [estimated glomerular filtration rate (eGFR), serum creatinine and urine albumin-to-creatinine ratio (ACR)] at baseline and after 4 years of follow-up. Multivariate regression was used to quantify the association between change in SED-time, MVPA and PAEE and kidney measures at four-year follow-up, adjusting for change in current smoking status, waist circumference, HbA1c , systolic blood pressure, triglycerides and medication usage. RESULTS: Over 4 years, there was a decline in eGFR values from 87.3 to 81.7 ml/min/1.73m(2) (P < 0.001); the prevalence of reduced eGFR (eGFR < 60 ml/min/1.73m(2) ) increased from 6.1 to 13.2% (P < 0.001). There were small increases in serum creatinine (median: 81-84 µmol/l, P < 0.001) and urine ACR (median: 0.9-1.0 mg/mmol, P = 0.005). Increases in SED-time were associated with increases in serum creatinine after adjustment for MVPA and cardiovascular risk factors (ß = 0.013, 95% CI: 0.001, 0.03). Conversely, increases in PAEE were associated with reductions in serum creatinine (ß = -0.001, 95% CI: -0.003, -0.0001). CONCLUSION: Reducing time spent sedentary and increasing overall physical activity may offer intervention opportunities to improve kidney function among individuals with diabetes. (Trial Registry no. ISRCTN 99175498).

Body fat measurement in adolescent girls with type 1 diabetes: a comparison of skinfold equations against dual-energy X-ray absorptiometry.

AIM: Skinfold measurement is an inexpensive and widely used technique for assessing the percentage of body fat (%BF). This study assessed the accuracy of prediction equations for %BF based on skinfold measurements compared to dual-energy X-ray absorptiometry (DXA) in girls with type 1 diabetes and healthy age-matched controls. METHODS: We included 49 healthy girls and 44 girls with diabetes aged 12-19 years old, comparing the predicted %BF based on skinfold measurements and the %BF values obtained by a Lunar DPX-L scanner. The agreement between the methods was assessed using an Bland-Altman plot. RESULTS: The skinfold measurements were significantly higher in girls with diabetes (p = 0.003) despite a nonsignificant difference in total %BF (p = 0.1). A significant association between bias and %BF was found for all tested equations in the Bland-Altman plots. Regression analysis showed that the association between skinfold measurements and %BF measured by DXA differed significantly (p = 0.039) between the girls with diabetes and the healthy controls. CONCLUSION: The accuracy of skinfold thickness equations for assessment of %BF in adolescent girls with diabetes is poor in comparison with DXA measurements as criterion. Our findings highlight the need for the development of new prediction equations for girls with type 1 diabetes.

Physical activity, sedentary time and gain in overall and central body fat: 7-year follow-up of the ProActive trial cohort.

OBJECTIVE: The objective of this study is to examine the independent associations of time spent in moderate-to-vigorous physical activity (MVPA) and sedentary (SED-time), with total and abdominal body fat (BF), and the bidirectionality of these associations in adults at high risk of type 2 diabetes. DESIGN AND SUBJECTS: We measured MVPA (min per day) and SED-time (h per day) by accelerometry, and indices of total (body weight, fat mass (FM), BF% and FM index) and abdominal BF (waist circumference (WC)) using standard procedures in 231 adults (41.3 ± 6.4 years) with parental history of type 2 diabetes (ProActive UK) at baseline, 1-year and 7-year follow-up. Mixed effects models were used to quantify the independent associations (expressed as standardised ß-coefficients (95% confidence interval (CI))) of MVPA and SED-time with fat indices, using data from all three time points. All models were adjusted for age, sex, intervention arm, monitor wear time, follow-up time, smoking status, socioeconomic status and MVPA/SED-time. RESULTS: MVPA was inversely and independently associated with all indices of total BF (for example, 1 s.d. higher MVPA was associated with a reduction in FM, ß = -0.09 (95% CI: -0.14, -0.04) s.d.) and abdominal BF (for example, WC: ß = -0.07 (-0.12, -0.02)). Similarly, higher fat indices were independently associated with a reduction in MVPA (for example, WC: ß = -0.25 (-0.36, -0.15); FM: ß = -0.27 (-0.36, -0.18)). SED-time was positively and independently associated with most fat indices (for example, WC: ß = 0.03 (-0.04, 0.09); FM: ß = 0.10 (0.03, 0.17)). Higher values of all fat indices independently predicted longer SED-time (for example, WC: ß = 0.10 (0.02, 0.18), FM: ß = 0.15 (0.07, 0.22)). CONCLUSIONS: The associations of MVPA and SED-time with total and abdominal BF are bidirectional and independent among individuals at high risk for type 2 diabetes. The association between BF and MVPA is stronger than the reciprocal association, highlighting the importance of considering BF as a determinant of decreasing activity and a potential consequence. Promoting more MVPA and less SED-time may reduce total and abdominal BF.

The link between family history and risk of type 2 diabetes is not explained by anthropometric, lifestyle or genetic risk factors: the EPIC-InterAct study.

AIMS/HYPOTHESIS: Although a family history of type 2 diabetes is a strong risk factor for the disease, the factors mediating this excess risk are poorly understood. In the InterAct case-cohort study, we investigated the association between a family history of diabetes among different family members and the incidence of type 2 diabetes, as well as the extent to which genetic, anthropometric and lifestyle risk factors mediated this association. METHODS: A total of 13,869 individuals (including 6,168 incident cases of type 2 diabetes) had family history data available, and 6,887 individuals had complete data on all mediators. Country-specific Prentice-weighted Cox models were fitted within country, and HRs were combined using random effects meta-analysis. Lifestyle and anthropometric measurements were performed at baseline, and a genetic risk score comprising 35 polymorphisms associated with type 2 diabetes was created. RESULTS: A family history of type 2 diabetes was associated with a higher incidence of the condition (HR 2.72, 95% CI 2.48, 2.99). Adjustment for established risk factors including BMI and waist circumference only modestly attenuated this association (HR 2.44, 95% CI 2.03, 2.95); the genetic score alone explained only 2% of the family history-associated risk of type 2 diabetes. The greatest risk of type 2 diabetes was observed in those with a biparental history of type 2 diabetes (HR 5.14, 95% CI 3.74, 7.07) and those whose parents had been diagnosed with diabetes at a younger age (<50 years; HR 4.69, 95% CI 3.35, 6.58), an effect largely confined to a maternal family history. CONCLUSIONS/INTERPRETATION: Prominent lifestyle, anthropometric and genetic risk factors explained only a marginal proportion of the excess risk associated with family history, highlighting the fact that family history remains a strong, independent and easily assessed risk factor for type 2 diabetes. Discovering factors that will explain the association of family history with type 2 diabetes risk will provide important insight into the aetiology of type 2 diabetes.

Rate of weight gain predicts change in physical activity levels: a longitudinal analysis of the EPIC-Norfolk cohort.

OBJECTIVE: To investigate the relationship of body weight and its changes over time with physical activity (PA). DESIGN: Population-based prospective cohort study (Norfolk cohort of the European Prospective Investigation into Cancer and Nutrition, EPIC-Norfolk, United Kingdom). SUBJECTS: A total of 25 639 men and women aged 39-79 years at baseline. PA was self-reported. Weight and height were measured by standard clinical procedures at baseline and self-reported at 18-month and 10-year follow-ups (calibrated against clinical measures). Main outcome measure was PA at the 10-year follow-up. RESULTS: Body weight and PA were inversely associated in cross-sectional analyses. In longitudinal analyses, an increase in weight was associated with higher risk of being inactive 10 years later, after adjusting for baseline activity, 18-month activity, sex, baseline age, prevalent diseases, socioeconomic status, education, smoking, total daily energy intake and alcohol intake. Compared with stable weight, a gain in weight of >2 kg per year in the short-, medium- and long-term was consistently and significantly associated with greater likelihood of physical inactivity after 10 years, with the most pronounced effect for long-term weight gain, OR=1.89 (95% CI: 1.30-2.70) in fully adjusted analysis. Weight gain of 0.5-2 kg per year over long-term was substantially associated with physical inactivity after full adjustment, OR=1.26 (95% CI: 1.11-1.41). CONCLUSION: Weight gain (during short-, medium- and long-term) is a significant determinant of future physical inactivity independent of baseline weight and activity. Compared with maintaining weight, moderate (0.5-2 kg per year) and large weight gain (>2 kg per year) significantly predict future inactivity; a potentially vicious cycle including further weight gain, obesity and complications associated with a sedentary lifestyle. On the basis of current predictions of obesity trends, we estimate that the prevalence of inactivity in England would exceed 60% in the year 2020.

Evaluation of common genetic variants identified by GWAS for early onset and morbid obesity in population-based samples.

BACKGROUND: Meta-analysis of case-control genome-wide association studies (GWAS) for early onset and morbid obesity identified four variants in/near the PRL, PTER, MAF and NPC1 genes. OBJECTIVE: We aimed to validate association of these variants with obesity-related traits in population-based samples. DESIGN: Genotypes and anthropometric traits were available in up to 31 083 adults from the Fenland, EPIC-Norfolk, Whitehall II, Ely and Hertfordshire studies and in 2042 children and adolescents from the European Youth Heart Study. In each study, we tested associations of rs4712652 (near-PRL), rs10508503 (near-PTER), rs1424233 (near-MAF) and rs1805081 (NPC1), or proxy variants (r (2)>0.8), with the odds of being overweight and obese, as well as with body mass index (BMI), percentage body fat (%BF) and waist circumference (WC). Associations were adjusted for sex, age and age(2) in adults and for sex, age, age group, country and maturity in children and adolescents. Summary statistics were combined using fixed effects meta-analysis methods. RESULTS: We had 80% power to detect odds ratios of 1.046 to 1.092 for overweight and 1.067 to 1.136 for obesity. Variants near PRL, PTER and MAF were not associated with the odds of being overweight or obese, or with BMI, %BF or WC after meta-analysis (P>0.15). The NPC1 variant rs1805081 showed some evidence of association with %BF (ß=0.013 s.d./allele, P=0.040), but not with any of the remaining obesity-related traits (P>0.3). CONCLUSION: Overall, these variants, which were identified in a GWAS for early onset and morbid obesity, do not seem to influence obesity-related traits in the general population.

Physical activity intensity and subclinical atherosclerosis in Danish adolescents: the European Youth Heart Study.

The aim was to investigate the associations between physical activity (PA), cardiorespiratory fitness (CRF) and intima media thickness (IMT) or stiffness. This was a population-based cross-sectional study (n = 336) of Danish adolescents [mean age (standard deviation, SD): 15.6 (0.4) years]. PA intensity was assessed objectively (ActiGraph model GT3X) and CRF using a progressive maximal bicycle test. Carotid IMT and arterial stiffness were assessed using B-mode ultrasound. In a multivariate analysis (adjusted for pubertal development and smoking status), CRF was inversely associated with measures of carotid stiffness (standard beta: -0.20 to -0.15, P < 0.05) in boys, but not in girls. No associations were observed between any of PA and IMT. Boys in the least fit quartile had significantly stiffer carotid arteries compared to the most fit quartile (difference between lowest and highest quartile ranging between 0.4 and 0.5 SD, P < 0.05). This difference in arterial stiffness between low and high quartiles was similar for moderate-to-vigorous PA (MVPA). Further adjustment for sedentary time attenuated the difference observed between quartiles MVPA slightly. Adiposity did not attenuate these differences. Our observations suggest that increasing CRF or MVPA in the least active group of the population may be beneficial for vascular health.

Physical activity reduces the risk of incident type 2 diabetes in general and in abdominally lean and obese men and women: the EPIC-InterAct Study.

AIMS/HYPOTHESIS: We examined the independent and combined associations of physical activity and obesity with incident type 2 diabetes in men and women. METHODS: The InterAct case-cohort study consists of 12,403 incident type 2 diabetes cases and a randomly selected subcohort of 16,154 individuals, drawn from a total cohort of 340,234 participants with 3.99 million person-years of follow-up. Physical activity was assessed by a four-category index. Obesity was measured by BMI and waist circumference (WC). Associations between physical activity, obesity and case-ascertained incident type 2 diabetes were analysed by Cox regression after adjusting for educational level, smoking status, alcohol consumption and energy intake. In combined analyses, individuals were stratified according to physical activity level, BMI and WC. RESULTS: A one-category difference in physical activity (equivalent to approximately 460 and 365 kJ/day in men and women, respectively) was independently associated with a 13% (HR 0.87, 95% CI 0.80, 0.94) and 7% (HR 0.93, 95% CI 0.89, 0.98) relative reduction in the risk of type 2 diabetes in men and women, respectively. Lower levels of physical activity were associated with an increased risk of diabetes across all strata of BMI. Comparing inactive with active individuals, the HRs were 1.44 (95% CI 1.11, 1.87) and 1.38 (95% CI 1.17, 1.62) in abdominally lean and obese inactive men, respectively, and 1.57 (95% CI 1.19, 2.07) and 1.19 (95% CI 1.01, 1.39) in abdominally lean and obese inactive women, respectively. CONCLUSIONS/INTERPRETATION: Physical activity is associated with a reduction in the risk of developing type 2 diabetes across BMI categories in men and women, as well as in abdominally lean and obese men and women.