Sara Knaeps

Ten-year change in sedentary behaviour, moderate-to-vigorous physical activity, cardiorespiratory fitness and cardiometabolic risk: independent associations and mediation analysis

Background We aimed to study the independent associations of 10-year change in sedentary behaviour (SB), moderate-to-vigorous physical activity (MVPA) and objectively measured cardiorespiratory fitness (CRF), with concurrent change in clustered cardiometabolic risk and its individual components (waist circumference, fasting glucose, high-density lipoprotein (HDL) cholesterol, triglycerides and blood pressure). We also determined whether associations were mediated by change in CRF (for SB and MVPA), waist circumference (for SB, MVPA and CRF) and dietary intake (for SB). Methods A population-based sample of 425 adults (age (mean±SD) 55.83±9.40; 65% men) was followed prospectively for 9.62±0.52 years. Participants self-reported SB and MVPA and performed a maximal cycle ergometer test to estimate peak oxygen uptake at baseline (2002–2004) and follow-up (2012–2014). Multiple linear regression and the product of coefficients method were used to examine independent associations and mediation effects, respectively. Results Greater increase in SB was associated with more detrimental change in clustered cardiometabolic risk, waist circumference, HDL cholesterol and triglycerides, independently of change in MVPA. Greater decrease in MVPA was associated with greater decrease in HDL cholesterol and increase in clustered cardiometabolic risk, waist circumference and fasting glucose, independent of change in SB. Greater decrease in CRF was associated with more detrimental change in clustered cardiometabolic risk and all individual components. Change in CRF mediated the associations of change in SB and MVPA with change in clustered cardiometabolic risk, waist circumference and, only for MVPA, HDL cholesterol. Change in waist circumference mediated the associations between change in CRF and change in clustered cardiometabolic risk, fasting glucose, HDL cholesterol and triglycerides. Conclusions A combination of decreasing SB and increasing MVPA, resulting in positive change in CRF, is likely to be most beneficial towards cardiometabolic health.

Independent Associations between Sedentary Time, Moderate-To-Vigorous Physical Activity, Cardiorespiratory Fitness and Cardio-Metabolic Health: A Cross-Sectional Study.

We aimed to study the independent associations of sedentary time (ST), moderate-to-vigorous physical activity (MVPA), and objectively measured cardiorespiratory fitness (CRF) with clustered cardio-metabolic risk and its individual components (waist circumference, fasting glucose, HDL-cholesterol, triglycerides and blood pressure). We also investigated whether any associations between MVPA or ST and clustered cardio-metabolic risk were mediated by CRF. MVPA, ST, CRF and individual cardio-metabolic components were measured in a population-based sample of 341 adults (age 53.8 ± 8.9 years; 61% men) between 2012 and 2014. MVPA and ST were measured with the SenseWear pro 3 Armband and CRF was measured with a maximal exercise test. Multiple linear regression models and the product of coefficients method were used to examine independent associations and mediation effects, respectively. Results showed that low MVPA and low CRF were associated with a higher clustered cardio-metabolic risk (β = -0.26 and β = -0.43, both p<0.001, respectively). CRF explained 73% of the variance in the association between MVPA and clustered cardio-metabolic risk and attenuated this association to non-significance. After mutual adjustment for MVPA and ST, CRF was the most important risk factor for a higher clustered cardio-metabolic risk (β = -0.39, p<0.001). In conclusion, because of the mediating role of CRF, lifestyle-interventions need to be feasible yet challenging enough to lead to increases in CRF to improve someone’s cardio-metabolic health.

Longitudinal study on the association between three dietary indices, anthropometric parameters and blood lipids

BackgroundFrom a health promotion perspective, the use of dietary indices is preferred above single nutrients and foods to evaluate diet quality. Longitudinal research about the association between dietary indices and respectively anthropometric parameters and blood lipids is lacking. The aim of this study was to investigate the longitudinal association between three dietary indices (Healthy Eating Index-2010 (HEI), Mediterranean Diet Score (MDS) and Diet Quality Index (DQI)) and respectively anthropometric parameters and blood lipids.MethodsA three day diet record was completed by 373 men and 197 women in 2002–2004 and 2012–2014. HEI, MDS and DQI were calculated. Waist circumference (WC) and Body Mass Index (BMI) were used as anthropometric parameters. A linear regression analysis was performed to investigate associations between changes in dietary indices and changes in respectively anthropometric parameters and blood lipids, adjusted for potential confounders.ResultsOnly in men an increase in all three dietary indices was associated with a decrease in WC and BMI in the non-adjusted analysis and for HEI and DQI also in the adjusted analysis. No longitudinal associations were found between dietary indices and blood lipids both in men and women.ConclusionsOnly few associations were found between dietary indices and anthropometric parameters, whilst no associations were found with blood lipids. An increase in dietary indices was associated with an improvement in anthropometric parameters only in men. As this is the first study investigating associations between changes in dietary indices and changes in respectively anthropometric parameters and blood lipids, further research is needed to evaluate these possible associations.

Stability of physical activity, fitness components and diet quality indices

Background:Regular physical activity (PA), a high level of fitness and a high diet quality are positively associated with health. However, information about stability of fitness components and diet quality indices is limited. This study aimed to evaluate stability of those parameters.Methods:This study includes 652 adults (men=57.56 (10.28) years; women=55.90 (8.34) years at follow-up) who participated in 2002–2004 and returned for follow-up at the Policy Research Centre Leuven in 2012–2014. Minutes sport per day and Physical activity level (PAL) were calculated from the Flemish Physical Activity Computerized Questionnaire. Cardiorespiratory fitness (CRF), morphological fitness (MORF; body mass index and waist circumference) and metabolic fitness (METF) (blood cholesterol and triglycerides) were used as fitness components. Diet quality indices (Healthy Eating Index-2010 (HEI), Diet Quality Index (DQI), Mediterranean Diet Score (MDS)) were calculated from a diet record. Tracking coefficients were calculated using Pearson/Spearman correlation coefficients (rPearson) and intra-class correlation coefficients (rICC).Results:In both men (rPearson&ICC=0.51) and women (rPearson=0.62 and rICC=0.60) PAL showed good stability, while minutes sport remained stable in women (rPearson&ICC=0.57) but less in men (rPearson&ICC=0.45). Most fitness components remained stable (r⩾0.50) except some METF components in women. In general the diet quality indices and their components were unstable (r<0.50).Conclusions:PAL and the majority of the fitness components remained stable, while diet quality was unstable over 10 years. For unstable parameters such as diet quality measurements are needed at both time points in prospective research.

Associations between physical activity and health-related fitness – volume versus pattern

ABSTRACT Approximately 3.2 million people die of non-communicable diseases (NCD) each year due to insufficient physical activity. Physical activity guidelines are possibly perceived as too demanding and might thus pose a barrier. We addressed the question if a more stable physical activity pattern is associated with higher levels of health-related fitness than one with high and low intensities, regardless of the physical activity level (PAL). Physical activity was objectively measured in 296 men and women (53.7 ± 8.94 years) with the SenseWear Pro Armband®. Using this data, the PAL and a Gini index were calculated to report the physical activity pattern. Health-related fitness was expressed as a fitness index. PAL was weakly correlated to health-related fitness (r = 0.38, P < .0001). The Gini index was also weakly correlated to the fitness index (r = 0.23, P < .0001). Results of the ANCOVA showed that participants in the first quartile of PAL always scored significantly lower for health-related fitness than participants in quartile four, after adjustment for the Gini index. These results suggest that as long as the volume of physical activity is high, health-related fitness will be high as well, independent of the physical activity pattern or variability in intensities throughout the day.

Longitudinal Study on the Association Between Cardiorespiratory Fitness, Anthropometric Parameters and Blood Lipids.

BACKGROUND Longitudinal evidence concerning the association between cardiorespiratory fitness (CRF) and blood lipids and between anthropometric parameters (ANTP) and blood lipids is limited. This study aimed to investigate the association between changes in CRF and ANTP and changes in blood lipids. METHODS In 2002-2004 and 2012-2014, 652 participants were tested. CRF was measured as VO2peak using a maximal ergometer test. Waist circumference (WC) and Body Mass Index (BMI) were used as ANTP. Blood samples were analyzed for total cholesterol (TC), HDL cholesterol, LDL cholesterol and triglycerides. A linear regression analysis was performed to investigate associations between changes in CRF and ANTP and changes in blood lipids. RESULTS After adjustment a decrease in CRF was associated with an increase in triglycerides and a decrease in HDL cholesterol in men. An increase in WC was associated with an increase in TC, LDL cholesterol and ratio total/HDL cholesterol and a decrease in HDL cholesterol, while an increase in BMI was associated with an increase in ratio total/HDL cholesterol and a decrease in HDL cholesterol. CONCLUSIONS WC and BMI were more longitudinally associated with blood lipids compared with CRF. Improving ANTP can enhance the blood lipid profile, while CRF had only limited influence.

Intensity-Specific Differential Leukocyte DNA Methylation in Physical (In)Activity: An Exploratory Approach

The aim of this exploratory study was to investigate how sedentary behavior (SB) and physical activity (PA) influence DNA methylation at a global, gene-specific, and health-related pathway level. SB, light PA (LPA), and moderate-to-vigorous PA (MVPA) were assessed objectively for 41 Flemish men using the SenseWear Pro 3 Armband. CpG site-specific methylation in leukocytes was determined using the Illumina HumanMethylation 450 BeadChip. Correlations were calculated between time spent on the three PA intensity levels and global DNA methylation, using a z-score-based method to determine global DNA methylation levels. To determine whether CpG site-specific methylation can be predicted by these three PA intensity levels, linear regression analyses were performed. Based on the significantly associated CpG sites at α = 0.005, lists were created including all genes with a promoter region overlapping these CpG sites. A biological pathway analysis determined to what extent these genes are overrepresented within several pathways. No significant associations were observed between global DNA methylation and SB (r = 0.084), LPA (r = -0.168), or MVPA (r = -0.125), although the direction of the correlation coefficients is opposite to what is generally reported in literature. SB has a different impact on global and gene-specific methylation than PA, but also LPA and MVPA affect separate genes and pathways. Furthermore, the function of a pathway seems to determine its association with SB, LPA, or MVPA. Multiple PA intensity levels, including SB, should be taken into account in future studies investigating the effect of physical (in)activity on human health through epigenetic mechanisms.

Stability of potential renal acid load: Stability of potential renal acid load

AIM The potential renal acid load (PRAL) has been described in relation to different health outcomes. Outcomes over time and conclusions made are often based on baseline dietary intake values. However, to study reliable long-term associations, parameters calculated based on dietary intake data, such as PRAL, must be stable over time. Therefore, the aim of the present study was to assess the stability of PRAL and its components over a 10-year time period. METHODS PRAL values of three-day dietary intake data from 197 women and 373 men on two assessment moments (2002-2004 and 2012-2014) were calculated. Pearson correlation and intra-class correlation coefficients were used for assessing the stability of PRAL and its components. Level of agreement between the two assessment moments was estimated after splitting up subjects in quintiles of PRAL, calculating kappa values and changes of quintiles over time. RESULTS No significant differences in mean PRAL over time were found. Stability of PRAL and its components was low. Poor agreement between the first and second assessment was shown by low kappa values and change of most of the subjects to an adjacent and non-adjacent quintile after 10 years. CONCLUSIONS Based on nutrition assessments carried out using three-day dietary records, stability of PRAL over a 10-year time period could not be confirmed, even though no significant difference between mean PRAL and its components over time was found. Therefore, interpretation of longitudinal outcomes based on PRAL and its component calculated at baseline should be interpreted with caution.

Relation between sugar-sweetened beverage consumption and micronutrient intake in a prospective study

Micronutrient dilution following sugar-sweetened beverage (SSB) consumption can lead to a qualitative impoverishment of a dietary pattern. The aim of this prospective study was to investigate the relation between SSB consumption and micronutrients. A total 562 adults were tested in 2002 and 2012 for the same anthropometric, lifestyle and nutritional intake activity parameters. Calcium, iron and magnesium intake decreased with increasing baseline SSB intake, and with increasing SSB consumption during the 10 years. A 100 ml increase in SSB consumption was associated with a 22 mg lower intake of calcium, 0.4 mg of iron and 9 mg of magnesium. There was no relation between vitamins and SSB consumption. In conclusion, there was limited evidence in our study, which suggests SSB have minimal dilutional effect on dietary micronutrient consumption. A major limitation of the present study is that of the original 1569 participants in 2002, 36% returned for participation in 2012.

Low 10-year reproducibility of glycaemic index and glycaemic load in a prospective cohort study

When relating glycaemic index (GI) and glycaemic load (GL) to health outcomes, many prospective cohort studies assess the nutritional exposure only once in time, that is, at the start of the study, presuming a stability in nutritional consumption during the course of the study. The aim of this study is to investigate the reproducibility of GI and GL. This is a prospective cohort study in which 562 middle-aged Belgian adults noted all foods and drinks consumed during 3 d in 2002 and 2012. GI and GL were calculated after reference tables. The Pearson correlation coefficients between 2002 and 2012 were 0·27 for GI and 0·41 for GL. For GI, 33 % of the participants remained in the same quintile between 2002 and 2012, whereas 31 % moved to a non-adjacent quintile. For GL, this was 34 and 28 %, respectively. The lowest and the highest quintiles of GI were the most stable, with 40 and 44 % of the participants staying in the same quintile. This was only 22 % for the fourth quintile. The same tendency was present for GL - that is, the most extreme quintiles were the most stable. This study shows 10-year correlation coefficients for GI and GL below 0·50. Multiple nutritional assessments and limiting the analysis to the extreme quintiles of GI and GL will limit a possible misclassification in the prospective cohort studies owing to the low reproducibility.