Validity of self-reported measures of workplace sitting time and breaks in sitting time

CLARK, B. K., A. A. THORP, E. A. H. WINKLER, P. A. GARDINER, G. N. HEALY, N. OWEN, and D. W. DUNSTAN. Validity of Self-Reported Measures of Workplace Sitting Time and Breaks in Sitting Time. Med. Sci. Sports Exerc., Vol. 43, No. 10, pp. 1907-1912, 2011. Purpose: To understand the prevalence and potential health effect of prolonged workplace sedentary (sitting) time, valid measures are required. Here, we examined the criterion validity of a brief self-reported measure of workplace sitting time and breaks in sitting time. Methods: An interviewer-administered questionnaire was used to assess workplace sitting time (h.d(-1)) and breaks from sitting per hour at work in a convenience sample of 121 full-time workers (36% men, mean age = 37 yr, 53% office based). These self-reported measures were compared with accelerometer-derived sedentary time (hours per day, = 100 counts per minute) during work hours. Results: Self-reported sitting time was significantly correlated with accelerometer-derived sedentary time (Pearson r = 0.39, 95% confidence interval = 0.22-0.53), with an average sitting time 0.45 h.d(-1) higher than average sedentary time. Bland-Altman plots and regression analysis showed positive associations between the difference in sitting and sedentary time and the average of sitting and sedentary time (mean difference = -2.75 h + 0.47 x average sitting and sedentary time; limits of agreement = +/- 2.25 h.d(-1)). The correlation of self-reported breaks per sitting hour with accelerometer-derived breaks per sedentary hour was also statistically significant (Spearman r(s) = 0.26, 95% confidence interval = 0.11-0.44). Conclusions: This study is the first to examine the criterion validity of an interviewer-administered questionnaire measure of workplace sitting time and breaks in sitting time using objective criterion measures. The workplace sitting measure has acceptable properties for use in observational studies concerned with sedentary behavior in groups of workers; however, the wide limits of agreement suggest caution in estimating individuals' sitting time with high precision. Using self-reported measures to capture patterns of workplace sitting (such as breaks in sitting time) requires further development

Safety, immunogenicity, and reactogenicity of BNT162b2 and mRNA-1273 COVID-19 vaccines given as fourth-dose boosters following two doses of ChAdOx1 nCoV-19 or BNT162b2 and a third dose of BNT162b2 (COV-BOOST): a multicentre, blinded, phase 2, randomised trial

Background Some high-income countries have deployed fourth doses of COVID-19 vaccines, but the clinical need, effectiveness, timing, and dose of a fourth dose remain uncertain. We aimed to investigate the safety, reactogenicity, and immunogenicity of fourth-dose boosters against COVID-19.Methods The COV-BOOST trial is a multicentre, blinded, phase 2, randomised controlled trial of seven COVID-19 vaccines given as third-dose boosters at 18 sites in the UK. This sub-study enrolled participants who had received BNT162b2 (Pfizer-BioNTech) as their third dose in COV-BOOST and randomly assigned them (1:1) to receive a fourth dose of either BNT162b2 (30 µg in 0·30 mL; full dose) or mRNA-1273 (Moderna; 50 µg in 0·25 mL; half dose) via intramuscular injection into the upper arm. The computer-generated randomisation list was created by the study statisticians with random block sizes of two or four. Participants and all study staff not delivering the vaccines were masked to treatment allocation. The coprimary outcomes were safety and reactogenicity, and immunogenicity (antispike protein IgG titres by ELISA and cellular immune response by ELISpot). We compared immunogenicity at 28 days after the third dose versus 14 days after the fourth dose and at day 0 versus day 14 relative to the fourth dose. Safety and reactogenicity were assessed in the per-protocol population, which comprised all participants who received a fourth-dose booster regardless of their SARS-CoV-2 serostatus. Immunogenicity was primarily analysed in a modified intention-to-treat population comprising seronegative participants who had received a fourth-dose booster and had available endpoint data. This trial is registered with ISRCTN, 73765130, and is ongoing.Findings Between Jan 11 and Jan 25, 2022, 166 participants were screened, randomly assigned, and received either full-dose BNT162b2 (n=83) or half-dose mRNA-1273 (n=83) as a fourth dose. The median age of these participants was 70·1 years (IQR 51·6–77·5) and 86 (52%) of 166 participants were female and 80 (48%) were male. The median interval between the third and fourth doses was 208·5 days (IQR 203·3–214·8). Pain was the most common local solicited adverse event and fatigue was the most common systemic solicited adverse event after BNT162b2 or mRNA-1273 booster doses. None of three serious adverse events reported after a fourth dose with BNT162b2 were related to the study vaccine. In the BNT162b2 group, geometric mean anti-spike protein IgG concentration at day 28 after the third dose was 23 325 ELISA laboratory units (ELU)/mL (95% CI 20 030–27 162), which increased to 37 460 ELU/mL (31 996–43 857) at day 14 after the fourth dose, representing a significant fold change (geometric mean 1·59, 95% CI 1·41–1·78). There was a significant increase in geometric mean anti-spike protein IgG concentration from 28 days after the third dose (25 317 ELU/mL, 95% CI 20 996–30 528) to 14 days after a fourth dose of mRNA-1273 (54 936 ELU/mL, 46 826–64 452), with a geometric mean fold change of 2·19 (1·90–2·52). The fold changes in anti-spike protein IgG titres from before (day 0) to after (day 14) the fourth dose were 12·19 (95% CI 10·37–14·32) and 15·90 (12·92–19·58) in the BNT162b2 and mRNA-1273 groups, respectively. T-cell responses were also boosted after the fourth dose (eg, the fold changes for the wild-type variant from before to after the fourth dose were 7·32 [95% CI 3·24–16·54] in the BNT162b2 group and 6·22 [3·90–9·92] in the mRNA-1273 group).Interpretation Fourth-dose COVID-19 mRNA booster vaccines are well tolerated and boost cellular and humoral immunity. Peak responses after the fourth dose were similar to, and possibly better than, peak responses after the third dose

Cardiovascular and mental health benefits of soy consumption: role of soy isoflavones.

Regular soy consumption has been shown to reduce cardiovascular (CV) risk through plasma cholesterol reduction. According to the current health claim, this benefit is attributed to soy protein (SP). Dietary intervention trials indicate that isoflavones (ISO), weak phytoestrogens in soy, may also contribute by offering additional vascular and metabolic protection. Equol, a metabolite of the ISO daidzein (DAZ) with greater estrogenic potency, may be an important mediator of such effects. This thesis examines effects of soy, in particular, ISO consumption on CV risk factors and the potential for ISOs to enhance cognition, possibly through improvements of circulatory function. Two crossover design intervention trials were undertaken: a food-based intervention, investigating differential effects of SP and ISO on plasma lipids and other risk factors for CVD, and an ISO supplementation trial, examining effects on cognition and vascular function. Both addressed whether benefits were dependent on equol production. In the first trial, 91 subjects with untreated mild hypercholesterolemia were randomised to consume each of the following three diets in random order for sequential 6 week periods: (S) soy foods containing 24 g of SP and 75-90 mg ISO per day, (SD) soy/dairy foods containing 12 g SP, 12 g dairy protein (DP) and 75-90 mg ISO per day or (D) dairy foods containing 24 g DP only per day. At the end of each diet period, blood lipids, flow-mediated dilatation (FMD) of the brachial artery, blood pressure, arterial compliance and anthropometric measures were assessed. Compared with the control diet (D), there was a small but significant reduction in total cholesterol on the S diet only (2.8 + 1.1%, P<0.05), which could be accounted for by a decrease in saturated fat intake. FMD was found to be significantly improved when SD and S diet data were nested (P=0.03). Plasma triglycerides (TG) improved on both the SD and S diets compared with D (P<0.01). Other lipid, metabolic and vascular parameters did not differ between diets. There were no differences in outcomes between equol (n=30) and non equol producers (n=61). In a subsequent 12 week double-blind supplementation trial, 34 healthy males were randomised to take 4 capsules providing 120mg ISO per day or a matching placebo for 6 weeks, after which they crossed over to the alternate supplement. FMD and cognitive assessments relating to measures of memory and executive function were performed at the beginning and end of each treatment phase. Spatial working memory, a test in which females consistently perform better than males, was significantly improved by ISO supplementation (P<0.02). However, other measures of cognition and FMD were unaffected and there were no differences between equol (n=8) and non-equol producers (n=26). These interventions indicate that ISOs offer specific health benefits, independent of equol production. ISO supplementation can enhance specific cognitive processes which appear dependent on estrogen activation. Additionally, soy foods containing ISOs improved FMD and TG but were unable to improve LDL cholesterol, even in equol producers. Thus dietary ISOs may reduce CV risk but the validity of the current health claim for SP is questioned.Thesis (Ph.D.) - University of Adelaide, School of Molecular and Biomedical Science, 200

Relevance of Sympathetic Nervous System Activation in Obesity and Metabolic Syndrome

Sympathetic tone is well recognised as being implicit in cardiovascular control. It is less readily acknowledged that activation of the sympathetic nervous system is integral in energy homeostasis and can exert profound metabolic effects. Accumulating data from animal and human studies suggest that central sympathetic overactivity plays a pivotal role in the aetiology and complications of several metabolic conditions that can cluster to form the Metabolic Syndrome (MetS). Given the known augmented risk for type 2 diabetes, cardiovascular disease, and premature mortality associated with the MetS understanding the complex pathways underlying the metabolic derangements involved has become a priority. Many factors have been proposed to contribute to increased sympathetic nerve activity in metabolic abnormalities including obesity, impaired baroreflex sensitivity, hyperinsulinemia, and elevated adipokine levels. Furthermore there is mounting evidence to suggest that chronic sympathetic overactivity can potentiate two of the key metabolic alterations of the MetS, central obesity and insulin resistance. This review will discuss the regulatory role of the sympathetic nervous system in metabolic control and the proposed pathophysiology linking sympathetic overactivity to metabolic abnormalities. Pharmacological and device-based approaches that target central sympathetic drive will also be discussed as possible therapeutic options to improve metabolic control in at-risk patient cohorts

Prolonged sitting: Is it a distinct coronary heart disease risk factor?

Purpose of revie

Sedentary behaviors and subsequent health outcomes in adults: A systematic review of longitudinal studies, 1996-2011

Context: To systematically review and provide an informative synthesis of findings from longitudinal studies published since 1996 reporting on relationships between self-reported sedentary behavior and device-based measures of sedentary time with health-related outcomes in adults

Alternating bouts of sitting and standing attenuates postprandial glucose responses

This study aimed to examine whether reductions in sitting time through alternating 30-min bouts of sitting and standing can reduce postprandial glucose, insulin, and triglyceride responses.Twenty-three overweight/obese sedentary office workers (17 males and six females; mean ± SD: age, 48.2 ± 7.9 yr; body mass index, 29.6 ± 4.0 kg · m(-2)) undertook two short-term (5 d) experimental conditions in an equal, randomized (1:1) order. In a simulated office environment, participants performed typical occupational tasks for 8 h · d(-1) while in a 1) seated work posture (control condition) or 2) interchanging between a seated and standing work posture every 30 min using an electric, height-adjustable workstation (intervention condition). Fasting and postprandial blood samples after a mixed test drink were collected hourly for 4 h on days 1 and 5 of each condition to assess serum insulin, plasma glucose, and triglycerides. Dietary intake (kJ · d(-1)) and physical activity were standardized during each condition. The trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12611000632998).After adjustment for time (days 1 and 5), incremental area under the analyte time curve differed significantly between conditions for plasma glucose (P = 0.007) but not for serum insulin or plasma triglycerides. Adjusted mean glucose incremental area under the analyte time curve was lowered by 11.1% after the intervention condition (6.38 mM · h(-1) (confidence interval, 5.04-7.71)) relative to the control condition (7.18 mM · h(-1) (confidence interval, 5.85-8.52)). No temporal changes (days 1 vs 5) between conditions were observed.Alternating standing and sitting in 30-min bouts results in modest beneficial effects on postprandial glucose responses in overweight/obese office workers