Katrien Wijndaele

Objectively Measured Sedentary Time, Physical Activity, and Metabolic Risk: The Australian Diabetes, Obesity and Lifestyle Study (AusDiab)

OBJECTIVE—We examined the associations of objectively measured sedentary time and physical activity with continuous indexes of metabolic risk in Australian adults without known diabetes. RESEARCH DESIGN AND METHODS—An accelerometer was used to derive the percentage of monitoring time spent sedentary and in light-intensity and moderate-to-vigorous–intensity activity, as well as mean activity intensity, in 169 Australian Diabetes, Obesity and Lifestyle Study (AusDiab) participants (mean age 53.4 years). Associations with waist circumference, triglycerides, HDL cholesterol, resting blood pressure, fasting plasma glucose, and a clustered metabolic risk score were examined. RESULTS—Independent of time spent in moderate-to-vigorous–intensity activity, there were significant associations of sedentary time, light-intensity time, and mean activity intensity with waist circumference and clustered metabolic risk. Independent of waist circumference, moderate-to-vigorous–intensity activity time was significantly beneficially associated with triglycerides. CONCLUSIONS—These findings highlight the importance of decreasing sedentary time, as well as increasing time spent in physical activity, for metabolic health.

Television viewing time independently predicts all-cause and cardiovascular mortality: the EPIC Norfolk Study

BACKGROUND Television viewing (TV), a highly prevalent behaviour, is associated with higher cardiovascular risk independently of physical activity. The relationship with mortality, however, is relatively unknown. METHODS We examined the prospective relationship between TV time and all-cause, cardiovascular and cancer mortality in a population-based cohort [The European Prospective Investigation into Cancer and Nutrition (EPIC), Norfolk] of 13 197 men and women {age [SD (standard deviation)]: 61.5 ± 9.0 years}. Participants were free from stroke, myocardial infarction and cancer at baseline in 1998-2000 and were followed up for death ascertainment until 2009 (9.5 ± 1.6 years). TV time, total physical activity energy expenditure (PAEE), education level, smoking status, alcohol consumption, anti-hypertensive and lipid-lowering medication use, participant and family history of disease and total energy intake were self-reported; height and weight were measured by standardized procedures. Hazard ratios (HRs) [95% confidence interval (CI)] for mortality were estimated per 1-h/day increase in TV. RESULTS Each 1-h/day increase in TV time was associated with increased hazard of all-cause (HR = 1.04, 95% CI = 1.01-1.09; 1270 deaths) and cardiovascular (HR = 1.07, 95% CI = 1.01-1.15; 373 deaths), but not cancer mortality (HR = 1.04, 95% CI = 0.98-1.10; 570 deaths). This was independent of gender, age, education, smoking, alcohol, medication, diabetes history, family history of cardiovascular disease and cancer, body mass index (BMI) and PAEE. They were similar when stratified by gender, age, education, BMI and PAEE. The population-attributable fraction for all-cause mortality comparing the highest TV tertile (>3.6 h/day) with the lowest (<2.5 h/day) was 5.4%. CONCLUSIONS These findings suggest that public health recommendations should consider advising a reduction in TV time, a predominant leisure activity in modern society, in addition to advocating physical activity.

Objectively Measured Sedentary Time, Physical Activity, and Metabolic Risk

OBJECTIVE—We examined the associations of objectively measured sedentary time and physical activity with continuous indexes of metabolic risk in Australian adults without known diabetes. RESEARCH DESIGN AND METHODS—An accelerometer was used to derive the percentage of monitoring time spent sedentary and in light-intensity and moderate-to-vigorous–intensity activity, as well as mean activity intensity, in 169 Australian Diabetes, Obesity and Lifestyle Study (AusDiab) participants (mean age 53.4 years). Associations with waist circumference, triglycerides, HDL cholesterol, resting blood pressure, fasting plasma glucose, and a clustered metabolic risk score were examined. RESULTS—Independent of time spent in moderate-to-vigorous–intensity activity, there were significant associations of sedentary time, light-intensity time, and mean activity intensity with waist circumference and clustered metabolic risk. Independent of waist circumference, moderate-to-vigorous–intensity activity time was significantly beneficially associated with triglycerides. CONCLUSIONS—These findings highlight the importance of decreasing sedentary time, as well as increasing time spent in physical activity, for metabolic health.

Increased cardiometabolic risk is associated with increased TV viewing time.

PURPOSE Television viewing time, independent of leisure time physical activity, has cross-sectional relationships with the metabolic syndrome and its individual components. We examined whether baseline and 5-yr changes in self-reported television viewing time are associated with changes in continuous biomarkers of cardiometabolic risk (waist circumference, triglycerides, HDL-cholesterol, systolic and diastolic blood pressure, fasting plasma glucose, and a clustered cardiometabolic risk score) in Australian adults. METHODS The Australian Diabetes, Obesity and Lifestyle Study (AusDiab) is a prospective, population-based cohort study with biological, behavioral, and demographic measures collected in 1999-2000 and 2004-2005. Noninstitutionalized adults aged > or =25 yr were measured at baseline (11,247; 55% of those completing an initial household interview); 6400 took part in the 5-yr follow-up biomedical examination, and 3846 met the inclusion criteria for this analysis. Multiple linear regression analysis was used, and unstandardized B coefficients (95% confidence intervals (CI)) are provided. RESULTS Baseline television viewing time (10 h.wk-1 unit) was not significantly associated with change in any of the biomarkers of cardiometabolic risk. Increases in television viewing time over 5 yr (10 h.wk-1 unit) were associated with increases in waist circumference (men: 0.43 cm, 95% CI = 0.08-0.78 cm, P = 0.02; women: 0.68 cm, 95% CI = 0.30-1.05, P < 0.001), diastolic blood pressure (women: 0.47 mm Hg, 95% CI = 0.02-0.92 mm Hg, P = 0.04), and the clustered cardiometabolic risk score (women: 0.03, 95% CI = 0.01-0.05, P = 0.007). These associations were independent of baseline television viewing time and baseline and change in physical activity and other potential confounders. CONCLUSIONS These findings indicate that an increase in television viewing time is associated with adverse cardiometabolic biomarker changes. Further prospective studies using objective measures of several sedentary behaviors are required to confirm causality of the associations found.

A Continuous Metabolic Syndrome Risk Score Utility for epidemiological analyses

This study was designed to validate a continuous metabolic syndrome risk score (cMSy) using the International Diabetes Federation risk factors (1). Increasing evidence supports using a cMSy instead of a binary definition for epidemiological analyses: 1 ) dichotomizing continuous outcome variables reduces statistical power (2); 2 ) cardiovascular risk is a progressive function of several metabolic syndrome (MSy) risk factors, eliminating the need to dichotomize these factors (3); and 3 ) cardiovascular and diabetes risk increase progressively with increasing numbers of MSy risk factors, eliminating the need to dichotomize …

Sedentary behaviour, physical activity and a continuous metabolic syndrome risk score in adults.

Objective:The association of sedentary behaviour and leisure time physical activity with a validated continuous metabolic syndrome risk score was investigated in adults.Subjects/Methods:A number of 992 adults (559 men) without cardiovascular disease or diabetes. Subjects reported time spent in leisure time physical activity and television watching/computer activities. A validated metabolic syndrome risk score, based on waist circumference, triglycerides, blood pressure, fasting plasma glucose and high-density lipoprotein cholesterol, was used. The metabolic syndrome risk score and time spent in sedentary behaviour and physical activity were analysed as continuous variables using multiple linear regression.Results:Metabolic syndrome risk was positively associated with time spent watching television/computer activities, irrespective of physical activity level, and after adjustment for age, education level, smoking status and dietary intake in women aged ⩾45 years (β=0.184, P<0.05). Independent of the time being sedentary, moderate to vigorous leisure time physical activity was inversely associated with metabolic syndrome risk in men (<45 years: β=−0.183, P<0.01; ⩾45 years: β=−0.192, P<0.01) and women aged ⩾45 years (β=−0.203, P<0.01).Conclusions:Although cross-sectional, the present results support inclusion of efforts to decrease sedentary behaviour in metabolic syndrome prevention strategies for women aged ⩾45 years, besides promotion of moderate to vigorous physical activity, since both behavioural changes might show additional effects.

Reliability and Validity of the Flemish Physical Activity Computerized Questionnaire in Adults

The purpose of this study was to investigate the test-retest reliability and concurrent validity of the Flemish Physical Activity Computerized Questionnaire (FPACQ) in employed/unemployed and retired people. The FPACQ was developed to assess detailed information on several dimensions of physical activity and sedentary behavior over a usual week. A triaxial accelerometer, the RT3 Triaxial Research Tracker (RT3), in combination with a written 7-day activity record, was used as the objective criterion measure. In employed/unemployed people, 2-week test-retest reliability for several activity variables calculated from the FPACQ was good to excellent with intraclass correlations (ICCs) ranging from .67 to .99. In retired people ICCs were lower but, except for time spent eating, still fair to excellent, ranging from .57 to .96. Except for time spent in leisure time activities for men and the average energy expenditure related to sports participation in women, correlations between the RT3 and the FPACQ generally supported the relative validity of the FPACQ for employed/unemployed people (r ranging from .37 to .88). Values for retired people were somewhat lower (r ranging from .15 to .85), but most variables still reached at least moderate correlations. Concerning absolute validity, the FPACQ generally overestimated physical activity and underestimated sedentary behavior compared to the RT3. From this study, it can be concluded that the FPACQ is a reliable and reasonably valid questionnaire for assessing different dimensions of physical activity and sedentary behavior.

Determinants of Early Weaning and Use of Unmodified Cow's Milk in Infants: A Systematic Review

Introduction of complementary foods (weaning) before 4 to 6 months of age and unmodified cows milk before age 12 months are associated with several health risks. To develop effective interventions to discourage these practices, evidence of their determinants is needed. This systematic review identified documents from seven electronic databases (database inception 2008) and reference lists, and by contacting authors. Seventy-eight studies in developed countries, published between 1976 and 2008, quantifying the association between either feeding practice and its potential determinants were included. Study quality was systematically assessed in terms of representativeness, sample size, method of outcome ascertainment, and approach to statistical analysis. The distribution of evidence for each determinant was visualized in a harvest plot showing the strength and direction of associations found and the quality of relevant studies. The strength of evidence for each determinant was summarized as strong, moderate, limited, or inconclusive, using an algorithm based on the consistency of the results of studies of the highest available quality. Strong evidence denoted that the determinant was examined in three or more high-quality studies and >/=75% of results were consistent. Strong evidence was found for six determinants of early weaning (ie, young maternal age, low maternal education, low socioeconomic status, absence or short duration of breastfeeding, maternal smoking, and lack of information or advice from health care providers) and for two determinants of early introduction of unmodified cows milk (ie, low maternal education and low socioeconomic status). Of these determinants, improving advice given by health care providers appears the most tractable area for intervention in the short term.

Television Viewing and Incident Cardiovascular Disease: Prospective Associations and Mediation Analysis in the EPIC Norfolk Study

Background Although television viewing time is detrimentally associated with intermediate cardiovascular risk factors, the relationship with incident total (i.e. combined fatal and non-fatal) cardiovascular disease (CVD), non-fatal CVD and coronary heart disease is largely unknown. This study examined whether television viewing time is associated with these three outcomes, independently of physical activity energy expenditure and other confounding variables. Methodology/Principal Findings A population-based cohort of 12,608 men and women (aged 61.4±9.0), free from stroke, myocardial infarction and cancer at baseline in 1998–2000 were followed up until 2007 (6.9±1.9 years). Participants self-reported education, smoking, alcohol use, antihypertensive, lipid lowering and antidepressant medication, disease history, total energy intake, sleep duration, physical activity and television viewing. BMI, waist circumference, blood pressure, triglycerides, HDL cholesterol and glycated haemoglobin (HbA1c) were measured by standardized procedures; a clustered metabolic risk score was constructed. Every one hour/day increase in television viewing was associated with an increased hazard for total (HR = 1.06, 95%CI = 1.03–1.08; 2,620 cases), non-fatal CVD (HR = 1.06, 95%CI = 1.03–1.09; 2,134 cases), and coronary heart disease (HR = 1.08, 95%CI = 1.03–1.13; 940 cases), independent of gender, age, education, smoking, alcohol, medication, diabetes status, CVD family history, sleep duration and physical activity energy expenditure. Energy intake, BMI, waist circumference, blood pressure, triglycerides, HDL cholesterol, HbA1c and the clustered metabolic risk score only partially mediated these associations. Conclusions These results indicate that the most prevalent leisure time (sedentary) behaviour, television viewing, independently contributes to increased CVD risk. Recommendations on reducing television viewing time should be considered.

Specific associations between types of physical activity and components of mental health.

Findings of previous studies suggest that the relationship between physical activity and mental health may change across different domains of physical activity, different dimensions of mental health, and different population subgroups. The present study examined associations between five types of physical activity with different contents: housework, leisure active transportation, biking to/from work, walking to/from work, and sports participation, and two dimensions of mental health: perceived stress and psychological distress, in 1919 participants aged 20-65 years, using the data from the Flemish Policy Research Centre Sport, Physical Activity and Health. Multiple logistic regression analyses were performed with the total sample, and with the sample stratified by gender, age, and occupational category. Further, separate models were used in the gender and age subgroups of each occupational category. Sports participation was the only type of physical activity inversely associated with both stress (OR=0.375; CI: 0.200-0.704) and distress (OR=0.480; CI: 0.253-0.910). Sports participation related to less distress in unemployed mid-aged adults, and to less stress in unemployed women, unemployed young adults, and young adults with blue-collar jobs. Housework was associated with more stress and more distress in women with blue-collar jobs. In young adults with white-collar jobs, however, an inverse association between housework and distress was found. Biking to and from work was associated with more stress in men with blue-collar jobs. Results invite consideration for the utility, and perhaps the necessity, of differentiated health recommendations for physical health and for mental health in different population subgroups.