Power, sample size and sampling costs for clustered data

The data collected in epidemiological or clinical studies are frequently clustered. In such settings, appropriate variance adjustments must be made in order to estimate the sufficient sample size correctly. This paper works through the sample size calculations for clustered data. Importantly, our explicit variance expressions also enable us to optimize the design with respect to the number of clusters and number of subjects; the objective could be either to maximize the power or to minimize the costs with given costs on the clusters and on the individuals. In our approach, units on different levels and treatment groups can have different costs, but the members of the same cluster are assumed to belong to the same treatment group. Design considerations in the health coaching project TERVA are used as motivating examples. R-functions for carrying out the computations presented are provided. (C) 2011 Elsevier B.V. All rights reserved

Cardiorespiratory fitness is associated with sickness absence and work ability

BACKGROUND: Physical activity may sustain the physical aspect of work ability despite health problems such as musculoskeletal disorders and anxiety, which are the most prevalent work-related health problem in Europe. AIMS: To evaluate the association of Finnish municipal workers' accelerometer-measured physical activity, sedentary behaviour, and cardiorespiratory and muscular fitness with their sickness absence levels, perceived work ability and health-related quality of life. METHODS: In connection with a randomized controlled trial recruiting 185 municipal workers, the authors performed baseline data analysis utilizing quantile regression to examine relationships between the outcome variables (all-cause sickness absence for 6 months, perceived work ability and health-related quality of life) and cardiorespiratory fitness, muscular fitness, and physical activity, and sedentary behaviour. All results were adjusted for age, sex and education level. RESULTS: The median duration of all-cause sickness absence over the preceding 6 months was lowest among participants with high cardiorespiratory fitness relative to the lowest tertile (2.0 versus 6.0 days; P < 0.05), and the highest perceived work ability was found among those with high or moderate cardiorespiratory fitness as compared to the lowest tertile (8.0 versus 7.0; P < 0.001). Moderate-to-vigorous physical activity correlated positively with the physical component of health-related quality of life (P < 0.01) and with a high cardiorespiratory-fitness level (P < 0.05). CONCLUSIONS: High cardiorespiratory fitness was associated with decreased all-cause sickness absence days and improved work ability among municipal workers.publishedVersionPeer reviewe

Effects of a Two-Year Home-Based Exercise Training Program on Oxidized LDL and HDL Lipids in Coronary Artery Disease Patients with and without Type-2 Diabetes

We investigated the effect of two-year home-based exercise training program on oxidized low-density lipoprotein LDL (ox-LDL) and high-density lipoprotein HDL (ox-HDL) lipids in patients with coronary artery disease (CAD), both with and without type-2 diabetes (T2D). Analysis of lipoprotein-oxidized lipids was based on the determination of baseline conjugated dienes in lipoprotein lipids. In order to study the effect of an exercise load on ox-LDL and ox-HDL lipids patients in both CAD and CAD + T2D intervention, groups were divided in three based on exercise load (high, medium, and low). During the two-year home-based exercise training program, the study showed that only higher training volume resulted in a decreased concentration of ox-LDL, while the two groups with lower training volumes showed no change. This result indicates that the training load needs to be sufficiently high in order to decrease the concentration of atherogenic ox-LDL lipids in patients with CAD and CAD + T2D. Interestingly, the concentration of ox-HDL did not change in any of the subgroups. This could indicate that the lipid peroxide-transporting capacity of HDL, suggested by results from exercise training studies in healthy adults, may not function similarly in CAD patients with or without T2D. Moreover, the lipid-lowering medication used may have had an influence on these results

Partners of nulliparous women with severe fear of childbirth: a longitudinal 1 study of psychological well being

Background: Little is known about the psychological status of partners of women with severe fear of childbirth (FOC). In this longitudinal study from Helsinki University Central Hospital, we investigated FOC, depression and post- traumatic stress in the partners of women with severe FOC, and possible effects of group psychoeducation and mode of birth. Methods: During pregnancy, 250 partners of nulliparous women with severe FOC participated, 93 in the intervention group and 157 in the control group. At three months postpartum 52 partners in the intervention group and 93 in the control group participated. Both the partners and the childbearing women filled in the Wijma Delivery Expectancy Questionnaire and the Edinburgh Postnatal Depression Scale mid-pregnancy as well as three months postpartum, when they also filled in the Traumatic Event Scale. Results: Partners of women with severe FOC reported less antenatal and postnatal FOC and fewer depressive symptoms than the childbearing women. No partner reached the threshold of severe FOC. No partner reported a possible post-traumatic stress disorder. Group psychoeducation with relaxation was not associated with better or worse psychological well being of the partners. An emergency cesarean section 1 was associated with a more fearful delivery experience in the partners. Conclusion: Partners of nulliparous women with severe FOC neither seem to suffer from severe FOC nor reported post-traumatic stress symptoms after childbirth. They reported better psychological well being than the mothers both during pregnancy and after delivery. An unexpected cesarean may be a negative experience even for 6 partners of childbearing women

Physical activity measured by accelerometry among adolescents participating in sports clubs and non-participating peers

The purpose of this descriptive cross-sectional study is to describe the amount and intensity of physical activity (PA) measured by accelerometry among adolescents participating in organized sports (SCP) and age-matched non-participating peers (NP). SCPs (332) and NPs (139) wore an accelerometer on the hip for seven days. PA was reported using the 1-min exponential moving average. The current moderate-to-vigorous physical activity (MVPA) recommendation of at least an average of 60 min of MVPA daily was reached by 85% of SCPs and 45% of NPs (p PA of Finnish adolescents participating in nine different organized sports and age-matched non-participating peers was measured by accelerometry for one week and the results are reported using the 1-min exponential moving average.Adolescents participating in many organized sports accumulated more PA than non-participants; this was observed in meeting the PA recommendations, total amount of PA at different intensities, and step count.The current PA recommendation of at least an average of 60 min of MVPA per day was reached by 85% of SCPs and 45% of non-participating peers. Vigorous physical activity at least three times per week was incorporated by 96% of SCPs and 81% of NPs. During training days, males participating in soccer, basketball, and cross-country skiing spent more time in MVPA than females participating in the same sports. During non-training days, the time spent in MVPA was similar between males and females participating in sports clubs.</ul

Physical activity measured by accelerometry among adolescents participating in sports clubs and non-participating peers

The purpose of this descriptive cross-sectional study is to describe the amount and intensity of physical activity (PA) measured by accelerometry among adolescents participating in organized sports (SCP) and age-matched non-participating peers (NP). SCPs (332) and NPs (139) wore an accelerometer on the hip for seven days. PA was reported using the 1-min exponential moving average. The current moderate-to-vigorous physical activity (MVPA) recommendation of at least an average of 60 min of MVPA daily was reached by 85% of SCPs and 45% of NPs (p < .001). During training days, the MVPA times among SCPs ranged from 153 ± 39 min in males and 109 ± 35 min in females participating in basketball to 113 ± 33 min in males participating in floorball and 83 ± 32 min in females participating in gymnastics. Sports participation contributes rather strongly to the accumulation of the recommended amount of MVPA. During training days, SCPs, except for females participating in gymnastics, accumulated more MVPA than NPs. During non-training days, only males participating in cross-country skiing and females participating in track and field accumulated more MVPA than NPs. HIGHLIGHTSPA of Finnish adolescents participating in nine different organized sports and age-matched non-participating peers was measured by accelerometry for one week and the results are reported using the 1-min exponential moving average.Adolescents participating in many organized sports accumulated more PA than non-participants; this was observed in meeting the PA recommendations, total amount of PA at different intensities, and step count.The current PA recommendation of at least an average of 60 min of MVPA per day was reached by 85% of SCPs and 45% of non-participating peers. Vigorous physical activity at least three times per week was incorporated by 96% of SCPs and 81% of NPs.During training days, males participating in soccer, basketball, and cross-country skiing spent more time in MVPA than females participating in the same sports. During non-training days, the time spent in MVPA was similar between males and females participating in sports clubs.publishedVersionPeer reviewe

Personalised eHealth intervention to increase physical activity and reduce sedentary behaviour in rehabilitation after cardiac operations: Study protocol for the PACO randomised controlled trial (NCT03470246)

Introduction: Personalized intervention to increase physical Activity and reduce sedentary behaviour in rehabilitation after Cardiac Operations (PACO) is a smartphone-based and accelerometer-based eHealth intervention to increase physical activity (PA) and reduce sedentary behaviour (SB) among patients recovering from cardiac surgery.Design: Prospective randomised controlled trial.Methods and analysis: The present protocol describes a randomised controlled clinical trial to be conducted in the Heart Centres of Kuopio and Turku university hospitals. The trial comprises 540 patients scheduled for elective coronary artery bypass grafting, aortic valve replacement or mitral valve repair. The patients will be randomised into two groups. The control group will receive standard postsurgical rehabilitation guidance. The eHealth intervention group will be given the same guidance together with personalised PA guidance during 90 days after discharge. These patients will receive personalised daily goals to increase PA and reduce SB via the ExSedapplication. Triaxial accelerometers will be exploited to record patients’ daily accumulated PA and SB, and transmit them to the application. Using the accelerometer data, the application will provide online guidance to the patients and feedback of accomplishing their activity goals. The data will also be transmitted to the cloud, where a physiotherapist can monitor individual activity profiles and customise the subsequent PA and SB goals online. The postoperative improvement in patients’ step count, PA, exercise capacity, quality of sleep, laboratory markers, transthoracic echocardiography (TTE) parameters and quality of life, and reduction in SB and incidence of major cardiac events are investigated as outcomes.Conclusions: The PACO intervention aims to build a personalised eHealth tool for the online tutoring of cardiac surgery patients.</p

COMPARISON OF HIGH AND LOW DENSITY AIRBORNE LIDAR DATA FOR FOREST ROAD QUALITY ASSESSMENT

Good quality forest roads are important for forest management. Airborne laser scanning data can help create automatized road quality detection, thus avoiding field visits. Two different pulse density datasets have been used to assess road quality: high-density airborne laser scanning data from Kiihtelysvaara and low-density data from Tuusniemi, Finland. The field inventory mainly focused on the surface wear condition, structural condition, flatness, road side vegetation and drying of the road. Observations were divided into poor, satisfactory and good categories based on the current Finnish quality standards used for forest roads. Digital Elevation Models were derived from the laser point cloud, and indices were calculated to determine road quality. The calculated indices assessed the topographic differences on the road surface and road sides. The topographic position index works well in flat terrain only, while the standardized elevation index described the road surface better if the differences are bigger. Both indices require at least a 1 metre resolution. High-density data is necessary for analysis of the road surface, and the indices relate mostly to the surface wear and flatness. The classification was more precise (31–92%) than on low-density data (25–40%). However, ditch detection and classification can be carried out using the sparse dataset as well (with a success rate of 69%). The use of airborne laser scanning data can provide quality information on forest roads