| 1. |
- Baron, Tomasz, et al.
(författare)
-
Test-retest reliability of new and conventional echocardiographic parameters of left ventricular systolic function
- 2019
-
Ingår i: Clinical Research in Cardiology. - : Springer Science and Business Media LLC. - 1861-0684 .- 1861-0692. ; 108:4, s. 355-365
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Reliability of left ventricular function measurements depends on actual biological conditions, repeated registrations and their analyses.Objective: To investigate test–retest reliability of speckle-tracking-derived strain measurements and its determinants compared to the conventional parameters, such as ejection fraction (EF), LV volumes and mitral annular plane systolic excursion (MAPSE).Methods: In 30 patients with a wide range of left ventricular function (mean EF 46.4 ± 16.4%, range 14–73%), standard echo views were acquired independently in a blinded fashion by two different echocardiographers in immediate sequence and analyzed off-line by two independent readers, creating 4 data sets per patient. Test–retest reliability of studied parameters was calculated using the smallest detectable change (SDC) and a total, inter-acquisition and inter-reader intra-class correlation coefficient (ICC).Results: The smallest detectable change normalized to the mean absolute value of the measured parameter (SDCrel) was lowest for MAPSE (10.7%). SDCrel for EF was similar to GLS (14.2 and 14.7%, respectively), while SDCrel for CS was much higher (35.6%). The intra-class correlation coefficient was excellent (> 0.9) for all measures of the left ventricular function. Intra-patient inter-acquisition reliability (ICCacq) was significantly better than inter-reader reliability (ICCread) (0.984 vs. 0.950, p = 0.03) only for EF, while no significant difference was observed for any other LV function parameter. Mean intra-subject standard deviations were significantly correlated to the mean values for CS and LV volumes, but not for the other studied parameters.Conclusions: In a test–retest setting, both with normal and impaired left ventricular function, the smallest relative detectable change of EF, GLS and MAPSE was similar (11–15%), but was much higher for CS (35%). Surprisingly, reliability of GLS was not superior to that of EF. Acquisition and reader to a similar extent influenced the reliability of measurements of all left ventricular function measures except for ejection fraction, where the reliability was more dependent on the reader than on the acquisition.
|
|
| 2. |
- Berglund, Lars, 1955-, et al.
(författare)
-
Early Insulin Response and Insulin Sensitivity are Equally Important as Predictors of Glucose Tolerance after Correction for Measurement Errors
- 2009
-
Ingår i: Diabetes Research and Clinical Practice. - : Elsevier BV. - 0168-8227 .- 1872-8227. ; 86:3, s. 219-224
-
Tidskriftsartikel (refereegranskat)abstract
- Aims: We estimated measurement error (ME) corrected effects of insulin sensitivity (M/I), from euglycaemic insulin clamp, and insulin secretion, measured as early insulin response (EIR) from oral glucose tolerance test (OGTT), on fasting plasma glucose, HbA1c and type 2 diabetes longitudinally and cross-sectional. Methods: : In a population-based study (n = 1128 men) 17 men made replicate measurements to estimate ME at age 71 years. Effect of 1 SD decrease of predictors M/I and EIR on longitudinal response variables fasting plasma glucose (FPG) and HbA1c at follow-ups up to 11 years, were estimated using uncorrected and ME-corrected (with the regression calibration method) regression models. Results: : Uncorrected effect on FPG at age 77 years was larger for M/I than for EIR (effect difference 0.10 mmol/l, 95% CI 0.00;0.21), while ME-corrected effects were similar (0.02 mmol/l, 95% CI -0.13;0.15 mmol/l). EIR had greater ME-corrected impact than M/I on HbA1c at age 82 years (-0.11%, -0.28; -0.01%). Conclusions: : Due to higher ME effect of EIR on glycaemia is underestimated as compared with M/I. By correcting for ME valid estimates of relative contributions of insulin secretion and insulin sensitivity on glycaemia are obtained.
|
|
| 3. |
- Berglund, Lars, 1955-
(författare)
-
Measurement Variability Related to Insulin Secretion and Sensitivity : Assessment and Implications in Epidemiological Studies
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There is a growing interest in random measurement variability of biological variables. In regression models, such variability of the predictors yields biased estimators of coefficients (regression dilution bias). The objectives of this thesis were to develop an efficient method to correct for such bias, to reveal the relative importance of insulin sensitivity and insulin secretion, corrected for regression dilution bias, on glucose tolerance, and to explore the seasonal nature of the variability of insulin sensitivity.A reliability study is often designed to randomly select subjects from the main study. Our idea was to collect replicates for subjects with extreme values on their first measurement. The extreme selection design, in combination with maximum likelihood estimation, resulted in an efficient estimator of a corrected regression coefficient in a simple linear regression model. Results were presented theoretically and with an application: The relation between insulin sensitivity and fasting insulin in Uppsala Longitudinal Study of Adult Men (ULSAM) where the extreme selection design decreased the standard error of the estimated regression coefficient with 28 per cent compared with the random sampling design.We estimated the partial longitudinal effects of the predictors insulin sensitivity and insulin secretion, corrected for regression dilution bias, on glucose tolerance in ULSAM. The effects of the predictors, when corrected, were similar.Insulin sensitivity in ULSAM increased during summer and decreased during winter and insulin secretion exposed opposite variation keeping glucose homeostasis nearly constant. Insulin sensitivity was related to outdoor temperature.In summary, we developed a cost-efficient reliability design for correction for regression dilution bias. Insulin sensitivity and insulin secretion had similar longitudinal effects on glucose tolerance, which implies that interventions aimed at these targets are equally important. Further, we revealed the seasonal nature of variations of insulin sensitivity and insulin secretion. This result has implications on glycaemic control in diabetic patients.
|
|
| 4. |
- Berglund, Lars, 1955-, et al.
(författare)
-
Repeated measures of body mass index and waist circumference in the assessment of mortality risk in patients with myocardial infarction
- 2019
-
Ingår i: Upsala Journal of Medical Sciences. - : TAYLOR & FRANCIS LTD. - 0300-9734 .- 2000-1967. ; 124:1, s. 78-82
-
Tidskriftsartikel (refereegranskat)abstract
- Aims: Weight loss is recommended for myocardial infarction (MI) patients with overweight or obesity. It has, however, been suggested that obese patients have better prognosis than normal-weight patients have, but also that central obesity is harmful. The aim of this study was to examine associations between repeated measures of body mass index (BMI) and waist circumference (WC), and all-cause mortality.Methods and results: A total of 14,224 MI patients aged <75 years in Sweden between the years 2004 and 2013 had measurements of risk factors at hospital discharge. The patients' BMI and WC were recorded in secondary prevention clinics two months and one year after hospital discharge. We collected mortality data up to 8.3 years after the last visit. There were 721 deaths. We used anthropometric measures at the two-month visit and the change from the two-month to the one-year visit. With adjustments for risk factors and the other anthropometric measure the hazard ratio (HR) per standard deviation in a Cox proportional hazard regression model for mortality was 0.64 (95% confidence interval [CI] 0.56-0.74) for BMI and 1.55 (95% CI 1.34-1.79) for WC, and 1.43 (95% CI 1.17-1.74) for a BMI decrease from month two to one year of more than 0.6 kg/m(2). Low BMI and high WC were associated with the highest mortality.Conclusion: High WC is harmful regardless of BMI in MI patients. Reduced BMI during the first year after MI is, however, associated with higher mortality, potentially being an indicator of deteriorated health.
|
|
| 5. |
- Bjorvang, Richelle D., et al.
(författare)
-
Follicular fluid and blood levels of persistent organic pollutants and reproductive outcomes among women undergoing assisted reproductive technologies
- 2022
-
Ingår i: Environmental Research. - : Elsevier. - 0013-9351 .- 1096-0953. ; 208
-
Tidskriftsartikel (refereegranskat)abstract
- Persistent organic pollutants (POPs) are industrial chemicals resistant to degradation and have been shown to have adverse effects on reproductive health in wildlife and humans. Although regulations have reduced their levels, they are still ubiquitously present and pose a global concern. Here, we studied a cohort of 185 women aged 21-43 years with a median of 2 years of infertility who were seeking assisted reproductive technology (ART) treatment at the Carl von Linne Clinic in Uppsala, Sweden. We analyzed the levels of 9 organochlorine pesticides (OCPs), 10 polychlorinated biphenyls (PCBs), 3 polybrominated diphenyl ethers (PBDEs), and 8 perfluoroalkyl substances (PFASs) in the blood and follicular fluid (FF) samples collected during ovum pick-up. Impact of age on chemical transfer from blood to FF was analyzed. Associations of chemicals, both individually and as a mixture, to 10 ART endpoints were investigated using linear, logistic, and weighted quantile sum regression, adjusted for age, body mass index, parity, fatty fish intake and cause of infertility. Out of the 30 chemicals, 20 were detected in more than half of the blood samples and 15 in FF. Chemical transfer from blood to FF increased with age. Chemical groups in blood crossed the blood-follicle barrier at different rates: OCPs > PCBs > PFASs. Hexachlorobenzene, an OCP, was associated with lower anti-Miillerian hormone, clinical pregnancy, and live birth. PCBs and PFASs were associated with higher antral follicle count and ovarian response as measured by ovarian sensitivity index, but also with lower embryo quality. As a mixture, similar findings were seen for the sum of PCBs and PFASs. Our results suggest that age plays a role in the chemical transfer from blood to FF and that exposure to POPs significantly associates with ART outcomes. We strongly encourage further studies to elucidate the underlying mechanisms of reproductive effects of POPs in humans.
|
|
| 6. |
- Byberg, Liisa, et al.
(författare)
-
Total mortality after changes in leisure time physical activity in 50 year old men : 35 year follow-up of population based cohort
- 2009
-
Ingår i: British Journal of Sports Medicine. - : BMJ Publishing Group Ltd. - 0306-3674 .- 1473-0480. ; 338, s. b688-
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To examine how change in level of physical activity after middle age influences mortality and to compare it with the effect of smoking cessation.Design: Population based cohort study with follow-up over 35 years.Setting: Municipality of Uppsala, Sweden.Participants: 2205 men aged 50 in 1970-3 who were reexamined at ages 60, 70, 77, and 82 years.Main Outcome Measure: Total (all cause) mortality.Results: The absolute mortality rate was 27.1, 23.6, and 18.4 per 1000 person years in the groups with low, medium, and high physical activity, respectively. The relative rate reduction attributable to high physical activity was 32% for low and 22% for medium physical activity. Men who increased their physical activity level between the ages of 50 and 60 continued to have a higher mortality rate during the first five years of follow-up (adjusted hazard ratio 2.64, 95% confidence interval 1.32 to 5.27, compared with unchanged high physical activity). After 10 years of follow-up their increased physical activity was associated with reduced mortality to the level of men with unchanged high physical activity (1.10, 0.87 to 1.38). The reduction in mortality associated with increased physical activity (0.51, 0.26 to 0.97, compared with unchanged low physical activity) was similar to that associated with smoking cessation (0.64, 0.53 to 0.78, compared with continued smoking).Conclusions: Increased physical activity in middle age is eventually followed by a reduction in mortality to the same level as seen among men with constantly high physical activity. This reduction is comparable with that associated with smoking cessation
|
|
| 7. |
- Cedervall, Ylva, et al.
(författare)
-
Timed Up-and-Go Dual-Task Testing in the Assessment of Cognitive Function : A Mixed Methods Observational Study for Development of the UDDGait Protocol
- 2020
-
Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 17:5
-
Tidskriftsartikel (refereegranskat)abstract
- New methods to screen for and identify early-stage dementia disorders are highly sought after. The purpose of this pilot study is to develop a study protocol for a dual-task test aimed at aiding the early detection of dementia disorders. We used the Timed Up-and-Go (TUG) test, which is a mobility task involving starting in a sitting position, standing up, walking three meters to cross a line on the floor, turning around, walking back and sitting down again. We combined TUG with the verbal task of naming different animals. Pilot study participants were 43 individuals with and without established dementia diagnoses who attended a clinic for memory assessment. Video-recorded test performances were systematically analysed. Deviant test performances concerning the interplay between test administration and participants' responses to the assessment instructions were revealed and led to refinements being made to the final study protocol. Exploration of the dual-task test outcome measures in a sub-sample of 22 persons, ten with and twelve without dementia, indicated that step-length and number of named animals after the turning point of the dual-task test might constitute appropriate measures for examining this kind of sample. We concluded that the refined study protocol is feasible for testing individuals undergoing initial memory assessments and healthy controls. Follow-up studies with larger samples are being carried out and will bring new knowledge to this area of research. It may also provide an opportunity for further studies exploring possibilities for broad clinical implementation.
|
|
| 8. |
- Emami, Azita, et al.
(författare)
-
Day-to-day variability of stress biomarkers during a music intervention in people living with dementia and their family caregivers
- 2024
-
Ingår i: Science Progress. - 0036-8504 .- 2047-7163. ; 107:3
-
Tidskriftsartikel (refereegranskat)abstract
- Examination of the variability of stress biomarkers among people living with dementia and their family caregivers can provide evidence of stress reactions and corresponding self-regulation capacities, but no such research has been conducted to date. The aim of this study was to examine day-to-day variability patterns of salivary biomarkers in dyads of people living with dementia and their family caregivers and to investigate differences in variability patterns between music intervention and control groups. This study involved secondary analysis of data collected during a two-group, non-randomized open trial examining the effects of an 8-week music intervention on physiological stress markers. A total of 5791 salivary samples from 34 dyads were used to analyze the variability of morning and evening cortisol and of morning dehydroepiandrosterone sulfate (DHEA-S). The variability indices employed were the intra- and inter-individual standard deviation, coefficient of variation, and intra-class correlation coefficient. We found that family caregivers in the music intervention group had significantly greater coefficients of variation for all three biomarker endpoints than those in the control group. Our findings provide evidence that stress biomarkers in family caregivers with functional self-regulation capacities may be more likely to respond to music intervention. However, stress biomarkers in people living with dementia may not be responsive to music intervention, possibly due to their dysfunctional self-regulation capacities. Future stress biomarker studies involving dyads of people living with dementia and family caregivers should consider biomarker variability patterns in determining the effectiveness of behavioral interventions.
|
|
| 9. |
- Emami, Azita, et al.
(författare)
-
Day-to-day variability of stress biomarkers during a music intervention in people living with dementia and their family caregivers
- 2024
-
Ingår i: Science Progress. - : Sage Publications. - 0036-8504 .- 2047-7163. ; 107:3
-
Tidskriftsartikel (refereegranskat)abstract
- Examination of the variability of stress biomarkers among people living with dementia and their family caregivers can provide evidence of stress reactions and corresponding self-regulation capacities, but no such research has been conducted to date. The aim of this study was to examine day-to-day variability patterns of salivary biomarkers in dyads of people living with dementia and their family caregivers and to investigate differences in variability patterns between music intervention and control groups. This study involved secondary analysis of data collected during a two-group, non-randomized open trial examining the effects of an 8-week music intervention on physiological stress markers. A total of 5791 salivary samples from 34 dyads were used to analyze the variability of morning and evening cortisol and of morning dehydroepiandrosterone sulfate (DHEA-S). The variability indices employed were the intra- and inter-individual standard deviation, coefficient of variation, and intra-class correlation coefficient. We found that family caregivers in the music intervention group had significantly greater coefficients of variation for all three biomarker endpoints than those in the control group. Our findings provide evidence that stress biomarkers in family caregivers with functional self-regulation capacities may be more likely to respond to music intervention. However, stress biomarkers in people living with dementia may not be responsive to music intervention, possibly due to their dysfunctional self-regulation capacities. Future stress biomarker studies involving dyads of people living with dementia and family caregivers should consider biomarker variability patterns in determining the effectiveness of behavioral interventions.
|
|
| 10. |
- Hallberg, Ida, et al.
(författare)
-
Associations between lifestyle factors and levels of per- and polyfluoroalkyl substances (PFASs), phthalates and parabens in follicular fluid in women undergoing fertility treatment
- 2023
-
Ingår i: Journal of Exposure Science and Environmental Epidemiology. - : Springer Nature. - 1559-0631 .- 1559-064X. ; 33, s. 699-709
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Concerns have been raised whether exposure to endocrine-disrupting chemicals (EDCs) can alter reproductive functions and play a role in the aetiology of infertility in women. With increasing evidence of adverse effects, information on factors associated with exposure is necessary to form firm recommendations aiming at reducing exposure.Objective: Our aim was to identify associations between lifestyle factors including the home environment, use of personal care products (PCP), and dietary habits and concentrations of EDCs in ovarian follicular fluid.Methods: April-June 2016, 185 women undergoing ovum pick-up for in vitro fertilisation in Sweden were recruited. Correlation analyses were performed between self-reported lifestyle factors and concentration of EDCs analysed in follicular fluid. Habits related to cleaning, PCPs, and diet were assessed together with concentration of six per- and polyfluoroalkyl substances (PFASs) [PFHxS, PFOA, PFOS, PFNA, PFDA and PFUnDA], methyl paraben and eight phthalate metabolites [MECPP, MEHPP, MEOHP, MEHP, cxMinCH, cxMiNP, ohMiNP, MEP, MOHiBP]. Spearman's partial correlations were adjusted for age, parity and BMI.Results: Significant associations were discovered between multiple lifestyle factors and concentrations of EDCs in ovarian follicular fluid. After correcting p values for multiple testing, frequent use of perfume was associated with MEP (correlation rho = 0.41 (confidence interval 0.21-0.47), p < 0.001); hens' egg consumption was positively associated with PFOS (rho = 0.30 (0.15-0.43), p = 0.007) and PFUnDA (rho = 0.27 (0.12-0.40), p = 0.036). White fish consumption was positively associated with PFUnDA (rho = 0.34 (0.20-0.47), p < 0.001) and PFDA (rho = 0.27 (0.13-0.41), p = 0.028). More correlations were discovered when considering the raw uncorrected p values. Altogether, our results suggest that multiple lifestyle variables affect chemical contamination of follicular fluid.Impact statement: This study shows how lifestyle factors correlate with the level of contamination in the ovary by both persistent and semi-persistent chemicals in women of reproductive age. Subsequently, these data can be used to form recommendations regarding lifestyle to mitigate possible negative health outcomes and fertility problems associated with chemical exposure, and to inform chemical policy decision making. Our study can also help form the basis for the design of larger observational and intervention studies to examine possible effects of lifestyle changes on exposure levels, and to unravel the complex interactions between biological factors, lifestyle and chemical exposures in more detail.
|
|
