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- Bexelius, Christin, et al.
(author)
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Estimation of Physical Activity Levels Using Cell Phone Questionnaires: A Comparison With Accelerometry for Evaluation of Between-Subject and Within-Subject Variations
- 2011
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In: Journal of Medical Internet Research. - : Journal of Medical Internet Research / Gunther Eysenbach. - 1438-8871. ; 13:3
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Journal article (peer-reviewed)abstract
- Background: Physical activity promotes health and longevity. Further elaboration of the role of physical activity for human health in epidemiological studies on large samples requires accurate methods that are easy to use, cheap, and possible to repeat. The use of telecommunication technologies such as cell phones is highly interesting in this respect. In an earlier report, we showed that physical activity level (PAL) assessed using a cell phone procedure agreed well with corresponding estimates obtained using the doubly labeled water method. However, our earlier study indicated high within-subject variation in relation to between-subject variations in PAL using cell phones, but we could not assess if this was a true variation of PAL or an artifact of the cell phone technique. less thanbrgreater than less thanbrgreater thanObjective: Our objective was to compare within-and between-subject variations in PAL by means of cell phones with corresponding estimates using an accelerometer. In addition, we compared the agreement of daily PAL values obtained using the cell phone questionnaire with corresponding data obtained using an accelerometer. less thanbrgreater than less thanbrgreater thanMethods: PAL was measured both with the cell phone questionnaire and with a triaxial accelerometer daily during a 2-week study period in 21 healthy Swedish women (20 to 45 years of age and BMI from 17.7 kg/m(2) to 33.6 kg/m(2)). The results were evaluated by fitting linear mixed effect models and descriptive statistics and graphs. less thanbrgreater than less thanbrgreater thanResults: With the accelerometer, 57% (95% confidence interval [CI] 40%-66%) of the variation was within subjects, while with the cell phone, within-subject variation was 76% (95% CI 59%-83%). The day-to-day variations in PAL observed using the cell phone questions agreed well with the corresponding accelerometer results. less thanbrgreater than less thanbrgreater thanConclusions: Both the cell phone questionnaire and the accelerometer showed high within-subject variations. Furthermore, day-to-day variations in PAL within subjects assessed using the cell phone agreed well with corresponding accelerometer values. Consequently, our cell phone questionnaire is a promising tool for assessing levels of physical activity. The tool may be useful for large-scale prospective studies.
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| 2. |
- Bexelius, Christin, et al.
(author)
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Measures of Physical Activity Using Cell Phones: Validation Using Criterion Methods
- 2010
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In: JOURNAL OF MEDICAL INTERNET RESEARCH. - : JMIR Publications Inc.. - 1438-8871. ; 12:1
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Journal article (peer-reviewed)abstract
- Background: Physical activity is associated with reduced risks of many chronic diseases. Data collected on physical activity in large epidemiological studies is often based on paper questionnaires. The validity of these questionnaires is debated, and more effective methods are needed. Objective: This study evaluates repeated measures of physical activity level (PAL) and the feasibility of using a Java-based questionnaire downloaded onto cell phones for collection of such data. The data obtained were compared with reference estimates based on the doubly labeled water method and indirect calorimetry (PAL(ref)). Method: Using a Java-based cell phone application, 22 women reported their physical activity based on two short questions answered daily over a 14-day period (PAL(cell)). Results were compared with reference data obtained from the doubly labeled water method and indirect calorimetry (PAL(ref)). Results were also compared against physical activity levels assessed by two regular paper questionnaires completed by women at the end of the 14-day period (PAL(quest1) and PAL(quest2)). PAL(cell), PAL(quest1), and PAL(quest2) were compared with PAL(ref) using the Bland and Altman procedure. Results: The mean difference between PAL(cell), and PAL(ref) was small (0.014) with narrow limits of agreement (2SD = 0.30) Compared with PAL(ref) the mean difference was also small for PAL(quest1) and PAL(quest2) (0.004 and 0.07, respectively); however, the limits of agreement were wider (PAL(quest), 2SD = 0.50 and PAL(quest2), 2SD = 0.90). The test for trend was statistically significant for PAL(quest1) (slope of regression line = 0.79, P = .04) as well as for PAL(quest2) (slope of regression line = 1.58, P andlt; .001) when compared with PAL(ref). Conclusion: A Java-based physical activity questionnaire administered daily using cell phones produced PAL estimates that agreed well with PAL reference values. Furthermore, the limits of agreement between PAL obtained using cell phones, and reference values were narrower than for corresponding estimates obtained using paper questionnaires. Java-based questionnaires downloaded onto cell phones may be a feasible and cost-effective method of data collection for large-scale prospective studies of physical activity.
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| 3. |
- Wetterholm, Madeleine, et al.
(author)
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Validation of Two Automatic Blood Pressure Monitors With theAbility to Transfer Data via Bluetooth
- 2019
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In: Journal of Medical Internet Research. - : JMIR Publications Inc.. - 1438-8871. ; 21:4
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Journal article (peer-reviewed)abstract
- Background: Patients with chronic diseases are in need of regular health controls. Diabetes mellitus type 2 is currently the mostprevalent chronic metabolic disease. A majority of diabetic patients have at least one comorbid chronic disease, where hypertensionis the most common. The standard for blood pressure (BP) measurement is manual BP monitoring at health care clinics.Nevertheless, several advantages of self-measured BP have been documented. With BP data transfer from an automatic BPmonitor via Bluetooth to software, for example, a smartphone app, home measurement could effectively be integrated into regularcare.Objective: The aim of this study was to validate two commercially available automatic BP monitors with the ability to transferBP data via Bluetooth (Beurer BM 85 and Andersson Lifesense BDR 2.0), against manual BP monitoring in patients with type2 diabetes.Methods: A total of 181 participants with type 2 diabetes were recruited from 6 primary care centers in Stockholm, Sweden.BP was first measured using a manual BP monitor and then measured using the two automatic BP monitors. The mean differencesbetween the automatic and manual measurements were calculated by subtracting the manual BP monitor measurement from theautomatic monitor measurement. Validity of the two automatic BP monitors was further assessed using Spearman rank correlationcoefficients and the Bland-Altman method.Results: In total, 180 participants, 119 men and 61 women, were included. The mean age was 60.1 (SD 11.4) years and themean body mass index was 30.4 (SD 5.4) kg/m2. The mean difference between the Beurer BM 85 and the manual BP monitorwas 11.1 (SD 11.2) mmHg for systolic blood pressure (SBP) and 8.0 (SD 8.1) mmHg for diastolic blood pressure (DBP). Themean difference between the Andersson Lifesense BDR 2.0 and the manual BP monitor was 3.2 (SD 10.8) mmHg for SBP and4.2 (SD 7.2) mmHg for DBP. The automatic BP measurements were significantly correlated (P<.001) with the manual BPmeasurement values (Andersson Lifesense BDR 2.0: r=0.78 for SBP and r=0.71 for DBP; Beurer BM 85: r=0.78 for SBP andr=0.69 for DBP).Conclusions: The two automatic BP monitors validated measure sufficiently accurate on a group level, with the AnderssonLifesense BDR 2.0 more often falling within the ranges for what is acceptable in clinical practice compared with the Beurer BM85.
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