Nicola Lasikiewicz

Exploration of basal diurnal salivary cortisol profiles in middle-aged adults: Associations with sleep quality and metabolic parameters

The use of saliva samples is a practical and feasible method to explore basal diurnal cortisol profiles in free-living research. This study explores a number of psychological and physiological characteristics in relation to the observed pattern of salivary cortisol activity over a 12-h period with particular emphasis on sleep. Basal diurnal cortisol profiles were examined in a sample of 147 volunteers (mean age 46.21+/-7.18 years). Profiles were constructed for each volunteer and explored in terms of the area under the curve (AUC) of the cortisol-awakening response with samples obtained immediately upon waking (0, 15, 30 and 45 min post waking) and at 3, 6, 9 and 12h post waking to assess diurnal decline. Diurnal mean of cortisol was based on the mean of cortisol at time points 3, 6, 9 and 12h post waking. Psychological measures of perceived stress and sleep were collected with concurrent biological assessment of fasting plasma glucose, insulin, blood lipids and inflammatory markers. Blunted cortisol profiles, characterised by a reduced AUC, were observed in the majority (78%) of a middle-aged sample and were associated with significantly poorer sleep quality and significantly greater waist-hip ratio (WHR). Blunted cortisol profiles were further associated with a tendency to exhibit a less favourable metabolic profile. These findings suggest that reduced cortisol secretion post waking may serve as an additional marker of psychological and biological vulnerability to adverse health outcomes in middle-aged adults.

Psychological benefits of weight loss following behavioural and/or dietary weight loss interventions. A systematic research review

It is generally accepted that weight loss has significant physiological benefits, such as reduced risk of diabetes, lowered blood pressure and blood lipid levels. However, few behavioural and dietary interventions have investigated psychological benefit as the primary outcome. Hence, systematic review methodology was adopted to evaluate the psychological outcomes of weight loss following participation in a behavioural and/or dietary weight loss intervention in overweight/obese populations. 36 Studies were selected for inclusion and were reviewed. Changes in self-esteem, depressive symptoms, body image and health related quality of life (HRQoL) were evaluated and discussed. Where possible, effect sizes to indicate the magnitude of change pre- to post- intervention were calculated using Hedges g standardised mean difference. The results demonstrated consistent improvements in psychological outcomes concurrent with and sometimes without weight loss. Improvements in body image and HRQoL (especially vitality) were closely related to changes in weight. Calculated effect sizes varied considerably and reflected the heterogeneous nature of the studies included in the review. Although the quality of the studies reviewed was generally acceptable, only 9 out of 36 studies included a suitable control/comparison group and the content, duration of intervention and measures used to assess psychological outcomes varied considerably. Further research is required to improve the quality of studies assessing the benefits of weight loss to fully elucidate the relationship between weight loss and psychological outcomes.

Manipulation of glycemic response with isomaltulose in a milk-based drink does not affect cognitive performance in healthy adults

Previous research suggests that glucoregulation and nutrient interventions, which alter circulating glucose, impact cognitive function. To examine the effect of modulating glycemic response using isomaltulose on cognitive function 24 healthy male adult participants consumed energy and macronutrient-matched milk-based drinks containing 50 g isomaltulose, 50 g sucrose or a water control in a counterbalanced within-subject design. Interstitial glucose was measured continuously in 12 subjects and all provided 9 capillary measures on each test day. A 30-min cognitive test battery was administered before and twice (+35 and +115 min) after drink ingestion. Immediate, delayed, recognition, verbal and working memory, and psychomotor performance were assessed. Glycemic profiles induced by the drinks differed significantly during the first but not the second post-drink test battery. Neither administration of the sucrose nor isomaltulose drinks produced consistent effects on verbal or working memory, or psychomotor performance. This study used isomaltulose as an investigative tool to lower glycemic response. Importantly, it demonstrates a lack of effect of modulating glucose on cognitive performance based on reliable, continuously measured glycemia. It refutes the hypothesis that glycemia is associated with cognitive performance and questions the suggestion that isomaltulose has an effect on cognitive performance.

Correspondence of continuous interstitial glucose measurement against arterialised and capillary glucose following an oral glucose tolerance test in healthy volunteers.

The aim of the present study was to validate the Glucoday continuous interstitial ambulatory glucose-monitoring device (AGD) against plasma glucose measured from arterialised venous (AV) and glucose from capillary whole blood (finger prick, FP) in non-diabetic subjects in response to an oral glucose tolerance test. Fifteen healthy overweight men (age 30-49 years, BMI 26-31 kg/m2) participated. Glucose levels were measured before, during and after consumption of an oral 75 g glucose load using twelve FP samples and forty-four 1 ml AV blood samples during 180 min. Interstitial glucose was measured via the AGD. Three venous samples for fasting insulin were taken to estimate insulin resistance. Profiles of AGD, AV and FP glucose were generated for each participant. Glucose values for each minute of the measurement period were interpolated using a locally weighted scatterplot smoother. Data were compared using Bland-Altman plots that showed good correspondence between all pairs of measurements. Concordance between the three methods was 0.8771 (Kendalls W, n 15, P < 0.001). Concordance was greater between AV and FP (W = 0.9696) than AGD and AV (W = 0.8770) or AGD and FP (W = 0.8764). Analysis of time to peak glucose indicated that AGD measures lagged approximately 15 min behind FP and AV measures. Percent body fat was significantly correlated with time to peak glucose levels for each measure, while BMI and estimated insulin resistance (homeostatic model assessment, HOMA) were not. In conclusion, AGD shows good correspondence with FP and AV glucose measures in response to a glucose load with a 15 min time lag. Taking this into account, AGD has potential application in nutrition and behaviour studies.

Exploring stress-induced cognitive impairment in middle aged, centrally obese adults

Extensive research has shown that psychosocial stress can induce cognitive impairment. However, few studies have explored impairment following acute stress exposure in individuals with central obesity. Central obesity co-occurs with glucocorticoid excess and can lead to elevated cortisol responses to stress. It is not clear whether centrally obese individuals exhibit greater cognitive impairment following acute stress. Cortisol responses to stress versus no-stress control were compared in 66 high- and low waist to hip ratio (WHR) middle-aged adults (mean age of 46 ± 7.17 years). Cognitive performance post exposure was assessed using Cambridge Automated Neuropsychological Test Battery. It was hypothesised that high WHR would exhibit greater cortisol in response to stress exposure and would show poorer cognitive performance. Males, particularly of high WHR, tended to secrete greater cortisol during stress exposure. Exposure to stress and increasing WHR were specifically associated with poorer performance on declarative memory tasks (spatial recognition memory and paired associates learning). These data tentatively suggest a reduction in cognitive performance in those with central obesity following exposure to acute stress. Further research is needed to elucidate the effects of stress on cognition in this population.

Stress, cortisol and central obesity in middle aged adults

Design and Methods: Correlation and outcome analyses of an ABPM database. BP variability (BPV), was defined as the weighted average of awake and sleep SD of BP. The following were defined using systolic (SDs) and diastolic (SDd) BPV: BP Variability Ratio (BPVR), defined as SDs/SDd, estimates the slope of the systolic-vs-diastolic pressure relationship using symmetric regression (the corresponding symmetric Ambulatory Arterial Stiffness Index is 1–1/BPVR); dV = SDs2-SDd2; U = (SDs-SDd)SDs; and dS/PP = (SDs-SDd)/PP, where PP is the pulse pressure.Introduction: Obesity is associated with various psychological and physiological disturbances. Of interest is the relationship between central obesity and psychological stress. Central obesity is characterised by increased adipose tissue, often associated with glucocorticoid excess,specifically, the stress hormone cortisol. Consequently, a disturbed cortisol basal diurnal rhythm and impaired responses to psychological stress in middle aged adults with central obesity may be observed. n nMethod: In study one, basal diurnal cortisol profiles were examined (n=147; mean = 46.21 ± 7.18 years) in a sample of high and low waist hip ratio (WHR) males and females. Profiles were explored in terms of the area under the curve (AUC) of the cortisol-awakening response and diurnal decline. In study two, cortisol responses to a psychological stressor versus no-stress control (n=66; mean = 46 ± 7.17 years) in a sample of high and low WHR individuals were explored. n nResults: Blunted cortisol profiles, characterised by a reduced AUC,were observed in the majority (78%) of a middle-aged sample and were associated with significantly greater WHR. Further, blunted cortisol profiles were associated with a less favourable metabolic profile. When exposed to a psychological stressor, high WHR individuals, specifically males, tended to secrete greater cortisol. n nConclusion: The findings suggest that central obesity is associated with altered cortisol responsivity. This highlights the vulnerability of high WHR individuals to stress related illness and disease. Further research, however, is required to elucidate whether stress exposure increases the propensity for central obesity or whether central obesity elevates stress responsivity.

Perceived Stress, Thinking Style, and Paranormal Belief

Paranormal beliefs often become stronger in times of stress. Such beliefs have also been found to vary in accordance with thinking style, whereby stronger beliefs are often observed in experiential thinkers. Little research, however, has explored the interaction between perceived stress and thinking style. Eighty-two males and females aged 18 to 62 years (Mu2009=u200929.96u2009±u200912.53 years) completed measures of perceived stress, thinking style (rational and experiential), and paranormal belief. The results revealed stronger beliefs in experiential thinkers, compared with those with a rational thinking style. Perceived stress alone was not a prominent predictor of belief, but the combination of stress and thinking style, specifically high-perceived stress with a rational thinking style, significantly predicted greater global paranormal belief, belief in superstition, traditional religious belief, and belief in psi. High-perceived stress appeared to facilitate belief in rational thinkers as conversely belief was lowest in rational thinkers under conditions of low-perceived stress. These findings suggest that stress may lower the propensity for rational thinking and consequently encourage belief in scientifically unsubstantiated phenomena. This interaction may have implications for coping during stressful situations.

Exploring stress, central obesity and cognitive performance in Chinese Singaporeans.

Being centrally obese or possessing a high waist-hip ratio (WHR) is often associated with elevated cortisol, which may increase vulnerability to stress (Epel et al., 2000). A high WHR combined with stress exposure can also lead to cognitive impairment (Lasikiewicz et al., 2013). These observations are predominantly derived from Western populations. It is unclear whether the same holds true for Southeast Asians based on noted differences in body shape. The current study explored differences in WHR, salivary cortisol and cognitive performance in 49 Chinese Singaporeans (mean age 51 ± 6.43 years). Cognitive performance was assessed before and after exposure to the Trier Social Stress Test (TSST; Kirschbaum et al., 1993) versus no-stress control. The TSST was effective in inducing a psychological and physiological stress response. Further, high WHR females exposed to stress secreted more cortisol across the experimental session compared to no-stress or low WHR females. When considered in terms of responders versus nonresponders based on cortisol change, high WHR female responders exhibited poorer performance on the Auditory Verbal Learning (delayed recall) and Spatial Recognition Memory tasks. However, the same was not true for males. The findings offer some continued support for the suggestion that subtle interactions exist between stress and central obesity, which may influence stress responsivity and cognition but only in females. More research is needed to elucidate the mechanisms which give rise to these effects, particularly in Asian samples, with due consideration of the adequacy of markers of central obesity in this population.

Smartphone Use and Work Related Wellbeing

While the smartphone allows employees to connect with work “anytime and anywhere”, the demands to carry out work related tasks outside work hours may translate into extra demands on employees and incur negative outcomes such as work related fatigue. Alternatively, smartphone use may help to distract the employee from work issues or recover from the demands of work, though activities such as music and games. With Singapore having the highest smartphone penetration rate per capita (90 % of the population) in the world, this study aimed to explore associations between both work related and personal smartphone use in non-work time and work related rumination, fatigue, and job stress in full-time employed Singaporean adults. Sixty-seven male and female working adults (mean age 36.5years, SD = 9.35) from a diverse range of occupations completed online measures of work related and personal smartphone use during non-work hours and work related rumination, detachment, fatigue and recovery. The results indicated that smartphone use significantly decreased with increasing age. Further, work related smartphone use was significantly, positively correlated with personal use, problem-solving pondering but also work demand. Personal smartphone use also significantly, positively correlated with problem-solving pondering. Psychological detachment was the best predictor of personal smartphone use. The findings suggest that work related smartphone use in non-work time may facilitate work performance through problem solving, whilst personal use may promote psychological detachment from work. However, the link between work related smartphone use and job demand may signal risk. More research is required in a smartphone dense population such as Singapore to clarify these relationships.

Psychological benefits of weight loss: a systematic research review

Introduction: It is generally accepted that weight loss has significant physiological benefits, such as reduced risk of diabetes, lowered blood pressure and blood lipid levels. However, few behavioural and dietary interventions have investigated psychological benefit as the primary outcome. n nMethod: Systematic review methodology was adopted to evaluate the psychological outcomes of weight loss following participation in a behavioural and/or dietary weight loss intervention in overweight/obese populations. 35 studies were selected for inclusion and were reviewed. n nResults: Changes in self-esteem, depressive symptoms, body image and health related quality of life (HRQoL) were evaluated and discussed.The results demonstrated consistent improvements in psychological outcomes concurrent with and sometimes without weight loss. Improvements in body image and HRQoL (especially vitality) were closely related to changes in weight. n nConclusion: Although the quality of the studies reviewed was generally acceptable, only 8 out of 35 studies included a suitable control/comparison group and the content, duration of intervention and measures used to assess psychological outcomes varied considerably. Further research is required to improve the quality of studies assessing the benefits of weight loss to fully elucidate the relationship between weight loss and psychological outcomes.Introduction: The role of the workplace as an opportunity for improving health has been highlighted in recent reports. The East Midlands Platform for Health and Wellbeing is a network of private, public and voluntary sector organisations working to improve health and reduce obesity. Member organisations commit to undertake actions to improve health and wellbeing of employees, individuals and/or communities. As part of Slimming World’s commitment, this pilot assessed the merits of providing weight management support via the workplace at two large regional employers. nMethods: 278 British Gas and Nottingham University Hospitals NHS Trust employees were offered 12 weeks’ support at either a bespoke workplace group or established community-based Slimming World group. Weight change was recorded weekly. Dietary and physical activity behaviours, along with aspects of psychological health were assessed by questionnaire pre and post-programme. nResults: 121 employees (meeting inclusion criteria) joined a workplace-based group and 114 a community-based group. nWeight and attendance: Mean joining BMI was 32.4kg/m2. 138 (59%) participants completed the programme (attended within final 4 weeks).Behaviour changes: Participants who completed both questionnaires (n=87), reported positive changes in dietary and physical activity behaviours (all p<.001) (figure 1), and psychological health (mental wellbeing, self-worth and self-esteem, all p<0.05). There were no significant differences between worksite and community intervention groups for any outcomes. nConclusion: Providing weight management support via the workplace significantly reduced weight of participants (-3.9%). Completer analysis also revealed positive changes in healthy eating habits and activity levels, and also importantly psychological health, which may impact on working life. The Slimming World programme works effectively within both the work setting and via community-based provision when employees are recruited via the workplace.