Introduction Modern day lifestyles are characterized by large amounts of prolonged sedentary activities, which may pose a risk to health in its own right although little is known about the effects on mental health. We examined the association between several types of common sedentary behaviors (TV viewing, internet use, reading), and different aspects of mental health. Methods We conducted a two year follow-up of 6359 (aged 64.9 ± 9.1 yrs) men and women from the English Longitudinal Study of Ageing, a cohort of community dwelling older adults. Self-reported TV viewing time, reading, and use of the internet was assessed at baseline. Mental health was assessed using the 8-item Centre of Epidemiological Studies Depression (CES-D) scale to measure depressive symptoms, and neuropsychological tests of memory and verbal fluency to assess cognitive function. Results At baseline TV viewing time (≥6hrs/d versus <2 hrs/d) was associated with higher depressive symptoms (coefficient = 0.49, 95% CI, 0.63 – 0.35) and poorer global cognitive function (−1.16, −1.00 – −1.31). Conversely, participants using the internet reported lower depressive symptoms (−0.58, −0.50 – −0.66) and higher global cognitive function (1.27, 1.37 – 1.18). There was no association between any sedentary behaviors at baseline and change in mental health measures over follow-up, suggesting that the difference in scores persisted but did not increase over time. Conclusions Some, but not all sedentary behaviors are linked to adverse mental health. It is likely that these associations are being driven by the contrasting environmental and social contexts in which they occur.

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The association between psychological distress and CVD risk is largely explained by behavioral processes. Therefore, treatment of psychological distress that aims to reduce CVD risk should primarily focus on health behavior change.

IMPORTANCERecommendations for the number of steps per day may be easier to enact for some people than the current time-and intensity-based physical activity guidelines, but the evidence to support steps-based goals is limited.OBJECTIVE To describe the associations of step count and intensity with all-cause mortality and cancer and cardiovascular disease (CVD) incidence and mortality. DESIGN, SETTING, AND PARTICIPANTSThis population-based prospective cohort study used data from the UK Biobank for 2013 to 2015 (median follow-up, 7 years) and included adults 40 to 79 years old in England, Scotland, and Wales. Participants were invited by email to partake in an accelerometer study. Registry-based morbidity and mortality were ascertained through October 2021. Data analyses were performed during March 2022.EXPOSURES Baseline wrist accelerometer-measured daily step count and established cadence-based step intensity measures (steps/min): incidental steps, (<40 steps/min), purposeful steps (Ն40 steps/min); and peak-30 cadence (average steps/min for the 30 highest, but not necessarily consecutive, min/d).MAIN OUTCOMES AND MEASURES All-cause mortality and primary and secondary CVD or cancer mortality and incidence diagnosis. For cancer, analyses were restricted to a composite cancer outcome of 13 sites that have a known association with reduced physical activity. Cox restricted cubic spline regression models were used to assess the dose-response associations. The linear mean rate of change (MRC) in the log-relative hazard ratio for each outcome per 2000 daily step increments were also estimated. RESULTSThe study population of 78 500 individuals (mean [SD] age, 61 [8] years; 43 418 [55%] females; 75 874 [97%] White individuals) was followed for a median of 7 years during which 1325 participants died of cancer and 664 of CVD (total deaths 2179). There were 10 245 incident CVD events and 2813 cancer incident events during the observation period. More daily steps were associated with a lower risk of all-cause (MRC, −0.08; 95% CI, −0.11 to −0.06), CVD (MRC, −0.10; 95% CI, −0.15 to −0.06), and cancer mortality (MRC, 95% CI, −0.11; −0.15 to −0.06) for up to approximately 10 000 steps. Similarly, accruing more daily steps was associated with lower incident disease. Peak-30 cadence was consistently associated with lower risks across all outcomes, beyond the benefit of total daily steps. CONCLUSIONS AND RELEVANCEThe findings of this population-based prospective cohort study of 78 500 individuals suggest that up to 10 000 steps per day may be associated with a lower risk of mortality and cancer and CVD incidence. Steps performed at a higher cadence may be associated with additional risk reduction, particularly for incident disease.

ImportanceStep-based recommendations may be appropriate for dementia-prevention guidelines. However, the association of step count and intensity with dementia incidence is unknown.ObjectiveTo examine the dose-response association between daily step count and intensity and incidence of all-cause dementia among adults in the UK.Design, Setting, and ParticipantsUK Biobank prospective population-based cohort study (February 2013 to December 2015) with 6.9 years of follow-up (data analysis conducted May 2022). A total of 78 430 of 103 684 eligible adults aged 40 to 79 years with valid wrist accelerometer data were included. Registry-based dementia was ascertained through October 2021.ExposuresAccelerometer-derived daily step count, incidental steps (less than 40 steps per minute), purposeful steps (40 steps per minute or more), and peak 30-minute cadence (ie, mean steps per minute recorded for the 30 highest, not necessarily consecutive, minutes in a day).Main Outcomes and MeasuresIncident dementia (fatal and nonfatal), obtained through linkage with inpatient hospitalization or primary care records or recorded as the underlying or contributory cause of death in death registers. Spline Cox regressions were used to assess dose-response associations.ResultsThe study monitored 78 430 adults (mean [SD] age, 61.1 [7.9] years; 35 040 [44.7%] male and 43 390 [55.3%] female; 881 [1.1%] were Asian, 641 [0.8%] were Black, 427 [0.5%] were of mixed race, 75 852 [96.7%] were White, and 629 [0.8%] were of another, unspecified race) over a median (IQR) follow-up of 6.9 (6.4-7.5) years, 866 of whom developed dementia (mean [SD] age, 68.3 [5.6] years; 480 [55.4%] male and 386 [54.6%] female; 5 [0.6%] Asian, 6 [0.7%] Black, 4 [0.4%] mixed race, 821 [97.6%] White, and 6 [0.7%] other). Analyses revealed nonlinear associations between daily steps. The optimal dose (ie, exposure value at which the maximum risk reduction was observed) was 9826 steps (hazard ratio [HR], 0.49; 95% CI, 0.39-0.62) and the minimal dose (ie, exposure value at which the risk reduction was 50% of the observed maximum risk reduction) was 3826 steps (HR, 0.75; 95% CI, 0.67-0.83). The incidental cadence optimal dose was 3677 steps (HR, 0.58; 95% CI, 0.44-0.72); purposeful cadence optimal dose was 6315 steps (HR, 0.43; 95% CI, 0.32-0.58); and peak 30-minute cadence optimal dose was 112 steps per minute (HR, 0.38; 95% CI, 0.24-0.60).Conclusions and RelevanceIn this cohort study, a higher number of steps was associated with lower risk of all-cause dementia. The findings suggest that a dose of just under 10 000 steps per day may be optimally associated with a lower risk of dementia. Steps performed at higher intensity resulted in stronger associations.