BackgroundCycling is a recreational activity and mode of commuting with substantial potential to improve public health in many countries around the world. The aim of this study was to examine prospective associations between recreational and commuter cycling, changes in cycling habits, and risk of type 2 diabetes (T2D) in Danish adults from the Diet, Cancer and Health cohort study.Methods and FindingsAt baseline from 1993 to 1997, 24,623 men and 27,890 women from Denmark, 50–65 y of age and free of T2D and other chronic diseases, underwent a number of assessments, including completing a lifestyle questionnaire also addressing cycling habits. Approximately 5 y later, at a second examination, participants completed a new, updated lifestyle questionnaire. Cox regression was used to estimate hazard ratios (HRs) of incident T2D registered in the Danish National Diabetes Registry, according to recreational and commuter cycling and changes in cycling habits, with adjustment for a priori known T2D risk factors. During 743,245.4 person-years of follow-up (mean follow-up 14.2 y), 6,779 incident cases of T2D were documented. Multivariable adjusted HRs (95% confidence interval [CI]) were 1, 0.87 (0.82, 0.93), 0.83 (0.77, 0.89), 0.80 (0.74, 0.86) and 0.80 (0.74, 0.87) (p for trend = <0.001) for 0, 1–60, 61–150, 151–300, and >300 min/wk of total cycling (recreational and commuter cycling), respectively. In analysis of seasonal cycling, multivariable adjusted HRs (95% CI) were 1, 0.88 (0.83, 0.94), and 0.80 (0.76, 0.85) for non-cyclists, seasonal cyclists (those cycling only in summer or winter), and those cycling during both summer and winter, respectively. How changes in total cycling from baseline to the second examination affected risk was also investigated, and multivariable adjusted HRs (95% CI) were 1, 0.88 (0.78, 1.01), 0.80 (0.69, 0.91), and 0.71 (0.65, 0.77) for non-cyclists and for those who ceased, initiated, or continued cycling between baseline and the second examination, respectively. Lastly, in the analysis of commuter cycling, multivariable HRs (95% CI) were 1, 0.72 (0.60, 0.87), 0.83 (0.69, 1.00), and 0.70 (0.57, 0.85) (p for trend = <0.001) for cycling 0, 1–60, 61–150, and >150 min/wk to work, respectively. The main limitation of the current study is the use of self-reported physical activity.ConclusionsCommuter and recreational cycling was consistently associated with lower risk of T2D in Danish adults. Our results also provide evidence that late-in-life initiation of or continued engagement in cycling lowers risk of T2D.

Background: During the recent decade presence of digital media, especially handheld devices, in everyday life, has been increasing. Survey data suggests that children and adults spend much of their leisure on screen media, including use of social media and video services. Despite much public debate on possible harmful effects of such behavioral shifts, evidence from rigorously conducted randomized controlled trials in free-living settings, investigating the efficacy of reducing screen media use on physical activity, sleep, and physiological stress, is still lacking. Therefore, a family and home-based randomized controlled trialthe SCREENS trialis being conducted. Here we describe in detail the rationale and protocol of this study. Methods: The SCREENS pilot trial was conducted during the fall of 2018 and spring of 2019. Based on experiences from the pilot study, we developed a protocol for a parallel group randomized controlled trial. The trial is being conducted from May 2019 to ultimo 2020 in 95 families with children 4-14 years recruited from a population-based survey. As part of the intervention family members must handover most portable devices for a 2-week time frame, in exchange for classic mobile phones (not smartphones). Also, entertainment-based screen media use during leisure must be limited to no more than 3 hours/week/person. At baseline and follow-up, 7-day 24-h physical activity will be assessed using two triaxial accelerometers; one at the right hip and one the middle of the right thigh. Sleep duration will be assessed using a single channel EEG-based sleep monitor system. Also, to assess physiological stress (only assessed in adults), parameters of 24-h heart rate variability, the cortisol awakening response and diurnal cortisol slope will be quantified using data sampled over three consecutive days. During the study we will objectively monitor the families' screen media use via different software and hardware monitoring systems.

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Background: The screen-media landscape has changed drastically during the last decade with wide-scale ownership and use of new portable touchscreen-based devices plausibly causing changes in the volume of screen media use and the way children and young people entertain themselves and communicate with friends and family members. This rapid development is not sufficiently mirrored in available tools for measuring children's screen media use. The aim of this study was to develop and evaluate a parent-reported standardized questionnaire to assess 6-10-year old children's multiple screen media use and habits, their screen media environment, and its plausible proximal correlates based on a suggested socio-ecological model. Methods: An iterative process was conducted developing the SCREENS questionnaire. Informed by the literature, media experts and end-users, a conceptual framework was made to guide the development of the questionnaire. Parents and media experts evaluated face and content validity. Pilot and field testing in the target group was conducted to assess test-retest reliability using Kappa statistics and intraclass correlation coefficients (ICC). Construct validity of relevant items was assessed using pairwise non-parametric correlations (Spearman's). The SCREENS questionnaire is based on a multidimensional and formative model. Results: The SCREENS questionnaire covers six domains validated to be important factors of screen media use in children and comprises 19 questions and 92 items. Test-retest reliability (n = 37 parents) for continuous variables was moderate to substantial with ICC's ranging from 0.67 to 0.90. For relevant nominal and ordinal data, kappa values were all above 0.50 with more than 80% of the values above 0.61 indicating good test-retest reliability. Internal consistency between two different time use variables (from n = 243) showed good correlations with rho ranging from 0.59 to 0.66. Response-time was within 15 min for all participants.

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