Vigorous Intermittent Lifestyle Physical Activity and Cancer Incidence Among Nonexercising Adults: The UK Biobank Accelerometry Study.

Importance: Vigorous physical activity (VPA) is a time-efficient way to achieve recommended physical activity (PA) for cancer prevention, although structured longer bouts of VPA (via traditional exercise) are unappealing or inaccessible to many individuals. Objectives: To evaluate the dose-response association of device-measured daily vigorous intermittent lifestyle physical activity (VILPA) with incident cancer, and to estimate the minimal dose required for a risk reduction of 50% of the maximum reduction. Design, Setting, and Participants: This was a prospective cohort analysis of 22 398 self-reported nonexercising adults from the UK Biobank accelerometry subsample. Participants were followed up through October 30, 2021 (mortality and hospitalizations), or June 30, 2021 (cancer registrations). Exposures: Daily VILPA of up to 1 and up to 2 minutes, assessed by accelerometers worn on participants' dominant wrist. Main Outcomes and Measures: Incidence of total cancer and PA-related cancer (a composite outcome of 13 cancer sites associated with low PA levels). Hazard ratios and 95% CIs were estimated using cubic splines adjusted for age, sex, education level, smoking status, alcohol consumption, sleep duration, fruit and vegetable consumption, parental cancer history, light- and moderate-intensity PA, and VPA from bouts of more than 1 or 2 minute(s), as appropriate. Results: The study sample comprised 22 398 participants (mean [SD] age, 62.0 [7.6] years; 10 122 [45.2%] men and 12 276 [54.8%] women; 21 509 [96.0%] White individuals). During a mean (SD) follow-up of 6.7 (1.2) years (149 650 person-years), 2356 total incident cancer events occurred, 1084 owing to PA-related cancer. Almost all (92.3%) of VILPA was accrued in bouts of up to 1 minute. Daily VILPA duration was associated with outcomes in a near-linear manner, with steeper dose-response curves for PA-related cancer than total cancer incidence. Compared with no VILPA, the median daily VILPA duration of bouts up to 1 minute (4.5 minutes per day) was associated with an HR of 0.80 (95% CI, 0.69-0.92) for total cancer and 0.69 (95% CI, 0.55-0.86) for PA-related cancer. The minimal dose was 3.4 minutes per day for total (HR, 0.83; 95% CI, 0.73-0.93) and 3.7 minutes for PA-related (HR, 0.72; 95% CI, 0.59-0.88) cancer incidence. Findings were similar for VILPA bout of up to 2 minutes. Conclusions and Relevance: The findings of this prospective cohort study indicate that small amounts of VILPA were associated with lower incident cancer risk. Daily VILPA may be a promising intervention for cancer prevention in populations not able or motivated to exercise in leisure time.

Associations Between Adolescent Sport and Exercise Participation and Device-Assessed Physical Activity in Adulthood: Evidence From the 1970 British Cohort Study.

BACKGROUND: Adolescence is a critical period filled with life changes. Early implementation of effective health promotion strategies could help alleviate the morbidity and mortality associated with inactivity. This study investigated whether adolescent participation in exercise and sport is associated with device-assessed physical activity (PA) levels in midlife. METHODS: A total of 2984 participants (41.2% male) from the 1970 British Cohort Study were included. Participants were surveyed at age 16 years on 5 indicators of exercise and sport participation. Total daily PA and moderate to vigorous PA (MVPA) at age 46 years were measured using a thigh-worn accelerometer, worn for 7 days. Associations between each adolescent exercise or sport indicator and adulthood total daily PA and MVPA were examined using linear regressions, adjusting for sex, wear time, body mass index, smoking, disability, malaise, alcohol consumption, social class, education, and self-rated health. RESULTS: In fully adjusted models, adolescents who reported exercising "much more" than others (8.6 min/d; 95% confidence interval, -0.1 to 17.1), who played sports at the park/playground more than once a week (8.5 [3.0-14.0] min/d), and who exercised on the most recent Saturday (3.8 [0.7-6.9] min/d) had higher adult total PA levels than those who reported the lowest activity levels. There was no evidence of an association between greater sport and exercise participation at age 16 y and MVPA at age 46 y. There was no association between sports at school and either measure of adult PA. CONCLUSION: Active adolescents, particularly those who engaged in out-of-school exercise, had higher total daily PA levels, but not MVPA levels, in midlife. This highlights the potential of early PA interventions to improve PA levels in adulthood.

Does moderate to vigorous physical activity mediate the association between depression and physical function in midlife: Evidence from two British birth cohort studies.

BACKGROUND: Mental health and physical health are intrinsically linked, yet the mechanisms are not well understood. We investigated whether moderate-vigorous physical activity (MVPA) mediated the association between depression and physical function (PF) in midlife. METHODS: Individuals from two UK birth cohorts born within one week in 1958 (n = 7278) and 1970 (n = 6097) with data on depression (ages 33/34; Malaise Inventory), MVPA (age 42; self-reported) and PF (ages 50/56; Short Form-36 subscale). Covariates included sex, childhood and adulthood social class, maternal mental health, childhood mood, alcohol consumption, smoking habits, sleep, marital status, BMI and long-standing illness/disability. Linear or multinomial logistic regression models examined associations between depression, MVPA and PF. We used a parametric g-computation mediation analysis approach to estimate percent differences in PF. RESULTS: Depression was associated with less frequent MVPA and poorer PF. Lower MVPA was associated with worse PF. The direct effect - randomised analogue not operating via MVPA - of depression on PF was -18.8 % (95%CI:--25.8,-11.8) and -15.8 % (20.6,-11.0) in the 1958 and 1970 cohorts, respectively. The indirect effect - operating via MVPA - was -0.5 % (-1.0,-0.03) and -0.2 % (-0.6, 0.3), resulting in a total proportion mediated of 3.1 % (0.1, 6.0) and 0.9 % (-1.6, 3.4). LIMITATIONS: MVPA was self-reported. Intermediate confounders and mediators were measured at the same age, however associations did not change in sensitivity analysis considering age 46 MVPA (1958 cohort). CONCLUSIONS: Although higher MVPA was protective against poor PF, there was only minor evidence that it mediated the association between depression and PF. Further investigation into other potential mediators of pathways from mental to physical health is needed.

Associations Between Factors Across Life and One-Legged Balance Performance in Mid and Later Life: Evidence From a British Birth Cohort Study.

INTRODUCTION: Despite its associations with falls, disability, and mortality, balance is an under-recognized and frequently overlooked aspect of aging. Studies investigating associations between factors across life and balance are limited. Understanding the factors related to balance performance could help identify protective factors and appropriate interventions across the life course. This study aimed to: (i) identify socioeconomic, anthropometric, behavioral, health, and cognitive factors that are associated with one-legged balance performance; and (ii) explore how these associations change with age. METHODS: Data came from 3,111 members of the MRC National Survey of Health and Development, a British birth cohort study. Multilevel models examined how one-legged standing balance times (assessed at ages 53, 60-64, and 69) were associated with 15 factors across life: sex, maternal education (4 years), paternal occupation (4 years), own education (26 years), own occupation (53 years), and contemporaneous measures (53, 60-64, 69 years) of height, BMI, physical activity, smoking, diabetes, respiratory symptoms, cardiovascular events, knee pain, depression and verbal memory. Age and sex interactions with each variable were assessed. RESULTS: Men had 18.8% (95%CI: 13.6, 23.9) longer balance times than women at age 53, although this difference decreased with age (11.8% at age 60-64 and 7.6% at age 69). Disadvantaged socioeconomic position in childhood and adulthood, low educational attainment, less healthy behaviors, poor health status, lower cognition, higher body mass index (BMI), and shorter height were associated with poorer balance at all three ages. For example, at age 53, those from the lowest paternal occupational classes had 29.6% (22.2, 38.8) worse balance than those from the highest classes. Associations of balance with socioeconomic indicators, cognition and physical activity became smaller with age, while associations with knee pain and depression became larger. There were no sex differences in these associations. In a combined model, the majority of factors remained associated with balance. DISCUSSION: This study identified numerous risk factors across life that are associated with one-legged balance performance and highlighted diverse patterns of association with age, suggesting that there are opportunities to intervene in early, mid and later life. A multifactorial approach to intervention, at both societal and individual levels, may have more benefit than focusing on a single risk factor.

Replacing Sedentary Time with Light or Moderate-Vigorous Physical Activity Across Levels of Frailty.

We sought to examine how much sedentary times needs to be replaced by light or moderate-vigorous physical activity in order to reduce frailty and protect against mortality. We built isotemporal substitution models to assess the theoretical effect of replacing sedentary behavior with and equal amount of light or moderate-vigorous activity on frailty and mortality in community-based adults aged 50 years and older. Controlling for age, sex, body mass index, marital status, race, education, employment status, and National Health and Nutrition Examination Study cycle, replacing one hour of sedentary time with moderate-vigorous or light physical activity daily was associated with a lower Frailty Index. For mortality, results varied based on frailty level. Replacing sedentary behavior with moderate-vigorous exercise was associated with lower mortality risk in vulnerable individuals, however, replacing sedentary behavior with light activity was associated with lower mortality risk in frailer individuals.