A Novel, Open Access Method to Assess Sleep Duration Using a Wrist-Worn Accelerometer

Wrist-worn accelerometers are increasingly being used for the assessment of physical activity in population studies, but little is known about their value for sleep assessment. We developed a novel method of assessing sleep duration using data from 4,094 Whitehall II Study (United Kingdom, 2012-2013) participants aged 60-83 who wore the accelerometer for 9 consecutive days, filled in a sleep log and reported sleep duration via questionnaire. Our sleep detection algorithm defined (nocturnal) sleep as a period of sustained inactivity, itself detected as the absence of change in arm angle greater than 5 degrees for 5 minutes or more, during a period recorded as sleep by the participant in their sleep log. The resulting estimate of sleep duration had a moderate (but similar to previous findings) agreement with questionnaire based measures for time in bed, defined as the difference between sleep onset and waking time (kappa = 0.32, 95%CI:0.29,0.34) and total sleep duration (kappa = 0.39, 0.36,0.42). This estimate was lower for time in bed for women, depressed participants, those reporting more insomnia symptoms, and on weekend days. No such group differences were found for total sleep duration. Our algorithm was validated against data from a polysomnography study on 28 persons which found a longer time window and lower angle threshold to have better sensitivity to wakefulness, while the reverse was true for sensitivity to sleep. The novelty of our method is the use of a generic algorithm that will allow comparison between studies rather than a "count" based, device specific method.

The triglyceride to high-density lipoprotein ratio identifies children who may be at risk of developing cardiometabolic disease

AIM

It is important to develop simple, reliable methods to identify high-risk individuals who may benefit from intervention. This study investigated the association between the triglyceride to high-density lipoprotein cholesterol (TG/HDL) ratio and cardiometabolic risk, cardiorespiratory fitness and physical activity in children.

METHODS

Anthropometric, biochemical parameters, cardiorespiratory fitness and accelerometry determined physical activity were assessed in 155 children (80 girls) from 10 to 14 years of age from Bedfordshire, UK. Participants were grouped into high and low TG/HDL ratio groups, according to published thresholds. MANCOVA and logistic regression were used in the analysis.

RESULTS

Cardiometabolic risk factor levels were significantly higher in participants with a high TG/HDL ratio (p < 0.05). The odds of having high waist circumference (OR = 13.99; 95% CI 2.93, 69.25), elevated systolic blood pressure (5.27; 1.39, 20.01), high non-HDL cholesterol (19.47; 4.42, 85.81) and ≥2 cardiometabolic risk factors (15.32; 3.10, 75.79) were higher in participants with a high TG/HDL ratio. The TG/HDL ratio values were significantly lower in those with high cardiorespiratory fitness (p = 0.01), but there was no association with physical activity.

CONCLUSION

These findings support the use of the TG/HDL ratio to identify children with cardiometabolic risk factors who may be at risk of developing cardiometabolic disease.

Movement as Medicine for Type 2 Diabetes: protocol for an open pilot study and external pilot clustered randomised controlled trial to assess acceptability, feasibility and fidelity of a multifaceted behavioural intervention targeting physical activity in primary care

BACKGROUND

Physical activity (PA) and nutrition are the cornerstones of diabetes management. Several reviews and meta-analyses report that PA independently produces clinically important improvements in glucose control in people with Type 2 diabetes. However, it remains unclear what the optimal strategies are to increase PA behaviour in people with Type 2 diabetes in routine primary care.

METHODS

This study will determine whether an evidence-informed multifaceted behaviour change intervention (Movement as Medicine for Type 2 Diabetes) targeting both consultation behaviour of primary healthcare professionals and PA behaviour in adults with Type 2 diabetes is both acceptable and feasible in the primary care setting. An open pilot study conducted in two primary care practices (phase one) will assess acceptability, feasibility and fidelity. Ongoing feedback from participating primary healthcare professionals and patients will provide opportunities for systematic adaptation and refinement of the intervention and study procedures. A two-arm parallel group clustered pilot randomised controlled trial with patients from participating primary care practices in North East England will assess acceptability, feasibility, and fidelity of the intervention (versus usual clinical care) and trial processes over a 12-month period. Consultation behaviour involving fidelity of intervention delivery, diabetes and PA related knowledge, attitudes/beliefs, intentions and self-efficacy for delivering a behaviour change intervention targeting PA behaviour will be assessed in primary healthcare professionals. We will rehearse the collection of outcome data (with the focus on data yield and quality) for a future definitive trial, through outcome assessment at baseline, one, six and twelve months. An embedded qualitative process evaluation and treatment fidelity assessment will explore issues around intervention implementation and assess whether intervention components can be reliably and faithfully delivered in routine primary care.

DISCUSSION

Movement as Medicine for Type 2 Diabetes will address an important gap in the evidence-base, that is, the need for interventions to increase free-living PA behaviour in adults with Type 2 diabetes. The multifaceted intervention incorporates an online accredited training programme for primary healthcare professionals and represents, to the best of our knowledge, the first of its kind in the United Kingdom. This study will establish whether the multifaceted behavioural intervention is acceptable and feasible in routine primary care.

TRIAL REGISTRATION

Movement as Medicine for Type 2 Diabetes (MaMT2D) was registered with Current Controlled Trials on the 14th January 2012: ISRCTN67997502. The first primary care practice was randomised on the 5th October 2012.

The hypertriglyceridemic waist, waist-to-height ratio, and cardiometabolic risk

OBJECTIVE

To investigate whether the hypertriglyceridemic waist (HW) phenotype and waist-to-height ratio (WHTR) are associated with cardiometabolic disorders in children and adolescents.

STUDY DESIGN

This was a cross-sectional design study. Anthropometry, biochemical variables, and cardiorespiratory fitness were assessed in 234 participants (122 girls) aged 10-19 years from Bedfordshire, United Kingdom. The HW phenotype was defined as a waist circumference ≥90(th) percentile for age and sex, and triglyceride concentrations ≥1.24 mmol/L, and a high WHTR defined as >0.5. ANCOVA and logistic regression were used in the analysis.

RESULT

In participants with the HW phenotype, the odds of having high cardiorespiratory fitness (mL/kg/min) were lower (0.045; 95% CI 0.01, 0.42), and the odds of having low high-density lipoprotein cholesterol (4.41; 1.50, 12.91), impaired fasting glucose (3.37; 1.06, 10.72), and ≥1 (4.78; 1.32, 17.29) and ≥2 risk factors (7.16; 2.38, 21.54) were higher than those without the phenotype. Those with a high WHTR had higher odds of having low high-density lipoprotein cholesterol (2.57; 1.11, 5.95), high diastolic blood pressure (3.21; 1.25, 8.25), and ≥2 risk factors (5.57; 2.05, 15.17) than those with normal WHTR.

CONCLUSION

The HW phenotype may be a better simple marker than WHTR for identifying children and adolescents at risk for cardiometabolic disorders.

Choice of activity-intensity classification thresholds impacts upon accelerometer-assessed physical activity-health relationships in children

Background

It is unknown whether using different published thresholds (PTs) for classifying physical activity (PA) impacts upon activity-health relationships. This study explored whether relationships between PA (sedentary [SED], light PA [LPA], moderate PA [MPA], moderate-to-vigorous PA, vigorous PA [VPA]) and health markers differed in children when classified using three different PTs.

Methods

104 children (63 girls) aged 10–14 years wore an RT3 triaxial accelerometer for seven days and measures of adiposity and cardiometabolic risk markers were taken.

Results

Significant associations (p< .05) in boys were found between LPA and body mass index z-score and waist circumference z-score for the Rowlands et al PT only (β =  .459 and.401, respectively) and body fat% (BF%) for the Chu et al PT only (β = .322) and in girls with BF% for the Rowlands et al PT only (β =  .303) and systolic BP and blood glucose for the Vanhelst et al PT only (β = −.298 and −.283, respectively). MPA was significantly (p<.05) associated with BF%, diastolic BP, and cardiorespiratory fitness (CRF) for the Chu et al PT only in girls (β = −.436, −.529, and .446, respectively). SED was significantly (p<.05) associated with triglycerides (β = .492) for the Rowlands et al PT only in boys and VPA with CRF (p<.05) for the Rowlands et al and Vanhelst et al PTs only in girls (β = .416 and .352, respectively).

Conclusions

The choice of PT impacted upon activity-health relationships. A consensus on appropriate accelerometer thresholds for quantifying PA intensity and sedentary behaviour is needed in order to make accurate evidence-based recommendations for health promotion.

Accelerometry-assessed sedentary behaviour and physical activity levels during the segmented school day in 10-14-year-old children: the HAPPY study

The school day offers several different time periods that provide varying opportunities for sedentary time (SED) and engagement in physical activity (PA), yet little is known about the PA and sedentary behaviour patterns of boys and girls during these times. The volume, intensity and temporal distributions of SED and PA undertaken by 135 schoolchildren aged 10-14 years, during different segments of the school day: (a) school transport, (b) morning recess, (c) lunch break, (d) class time and (e) after school, were explored using triaxial accelerometry. PA was categorised into SED, light PA (LPA), moderate PA (MPA) and vigorous PA (VPA). Girls engaged in significantly more SED and LPA than boys during recess and lunch break (p < 0.05), while boys engaged in significantly higher levels of VPA during recess (p < 0.001) and MPA and VPA during lunch break (p < 0.001). PA engagement was similar between sexes during other segments of the day.

CONCLUSION

PA patterns appear more beneficial for health in boys during less structured school-based time periods and interventions may therefore target opportunities for girls to be physically active during these times to overcome this observed sex deficit.