Evelien Mertens

Muscle mass and muscle function over the adult life span: A cross-sectional study in Flemish adults

BACKGROUND Aging is accompanied with a progressive deterioration of skeletal muscle mass (SMM) and muscle function, also termed sarcopenia. METHODS The aim was to describe SMM (based on bioelectrical impedance) and muscle function of the leg extensors over the adult age span in 819 men and 578 women, aged 18-78 years. The distribution of skeletal muscle index (SMI; SMM/height(2)) groups was described and muscle force-velocity characteristics were examined between SMI-groups over the adult life span. Subjects were divided into age categories and SMI groups to compare their muscle strength characteristics. Isometric and isokinetic strength, ballistic movement speed and muscular endurance of the knee extensors were evaluated on a Biodex dynamometer. RESULTS Age by gender interaction effects were found significant (P<0.01) for all strength tests. In general, the overall drop in slow and faster knee extension strength was larger than the isometric component, with women showing larger losses by the age of 60-70 years compared to men. Regression analysis revealed significant (P<0.01) age-related reductions, with the largest explained variance for the muscular endurance parameter (24%). No age by SMI-group interaction effect was observed for muscle function, but main effects of age and SMI were significant (P<0.01). CONCLUSION The age-related decline in muscle function was stronger in women. Furthermore, a low SMI results in a weaker muscle function compared to a normal SMI in each age-category, pointing out that its relationship with physical disability should therefore be further examined over the adult life-span.

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.

Cross-sectional study on the relationship between the Mediterranean Diet Score and blood lipids

BackgroundBlood lipids are cardiovascular health indicators. High LDL cholesterol values and/or high total cholesterol (TC)/HDL cholesterol ratios are positively related with cardiovascular mortality. Evidence suggests that a Mediterranean diet can reduce the incidence of cardiovascular diseases. Adherence to the Mediterranean diet is often measured by the Mediterranean Diet Score (MDS). However, the association between the Mediterranean diet and blood lipid profiles seems still inconclusive. The aim of this study was to investigate the relationship between the MDS, its different components and blood lipid profiles.MethodsA sample of 506 women and 707 men (aged 18–75 years) was recruited. Three-day diet records were used to calculate the MDS. Blood samples were analyzed for serum TC, LDL and HDL cholesterol. ANOVA was used to analyze blood lipids across the MDS tertiles. A multivariate linear regression analysis was performed to investigate the associations between the MDS, its components and blood lipids, adjusted for several confounders. All analyses were stratified by gender.ResultsFew gender-specific associations were found between the MDS, its components and blood lipids. Only in men, the total MDS was negatively related with LDL cholesterol and the ratio TC/HDL cholesterol while positively with HDL cholesterol. In women, respectively two (MUFA/SFA and cereals) and in men three (fruits & nuts, meat and alcohol) of the nine MDS components were related with blood lipids.ConclusionsAnalyses investigating the relationship between the MDS, its components and blood lipid profiles indicate only limited influence of the Mediterranean diet on blood lipids. More associations were detected in men compared to women.

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.

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.