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Journal: Preventive medicine


Active travel (cycling, walking) is beneficial for the health due to increased physical activity (PA). However, active travel may increase the intake of air pollution, leading to negative health consequences. We examined the risk-benefit balance between active travel related PA and exposure to air pollution across a range of air pollution and PA scenarios. The health effects of active travel and air pollution were estimated through changes in all-cause mortality for different levels of active travel and air pollution. Air pollution exposure was estimated through changes in background concentrations of fine particulate matter (PM2.5), ranging from 5 to 200μg/m3. For active travel exposure, we estimated cycling and walking from 0 up to 16h per day, respectively. These refer to long-term average levels of active travel and PM2.5 exposure. For the global average urban background PM2.5 concentration (22μg/m3) benefits of PA by far outweigh risks from air pollution even under the most extreme levels of active travel. In areas with PM2.5 concentrations of 100μg/m3, harms would exceed benefits after 1h 30min of cycling per day or more than 10h of walking per day. If the counterfactual was driving, rather than staying at home, the benefits of PA would exceed harms from air pollution up to 3h 30min of cycling per day. The results were sensitive to dose-response function (DRF) assumptions for PM2.5 and PA. PA benefits of active travel outweighed the harm caused by air pollution in all but the most extreme air pollution concentrations.

Concepts: Pollution, United States Environmental Protection Agency, Particulate, Visibility, Smog, Air pollution, Dust, Scrubber


To examine associations of time spent sitting in cars with markers of cardio-metabolic risk in Australian adults.

Concepts: Automobile, Happy Feet


Fetal alcohol spectrum disorders (FASDs) are lifelong disabilities caused by prenatal alcohol exposure. Prenatal alcohol use is common in the UK, but FASD prevalence was unknown. Prevalence estimates are essential for informing FASD prevention, identification and support. We applied novel screening algorithms to existing data to estimate the screening prevalence of FASD. Data were from a population-based cohort study (ALSPAC), which recruited pregnant women with expected delivery dates between 1991 and 1992 from the Bristol area of the UK. We evaluated different missing data strategies by comparing results from complete case, single imputation (which assumed that missing data indicated no exposure and no impairment), and multiple imputation methods. 6.0% of children screened positive for FASD in the analysis that used the single imputation method (total N = 13,495), 7.2% in complete case analysis (total N = 223) and 17.0% in the analysis with multiply imputed data (total N = 13,495). A positive FASD screen was more common among children of lower socioeconomic status and children from unplanned pregnancies. Our analyses showed that the complete case and single imputation methods that are commonly used in FASD prevalence studies are likely to underestimate FASD prevalence. Although not equivalent to a formal diagnosis, these screening prevalence estimates suggest that FASD is likely to be a significant public health concern in the UK. Given current patterns of alcohol consumption and recent changes in prenatal guidance, active case ascertainment studies are urgently needed to further clarify the current epidemiology of FASD in the general population of the UK.


Many factors contribute to sleep disturbance among young adults. Social media (SM) use is increasing rapidly, and little is known regarding its association with sleep disturbance.

Concepts: Sleep, The Association, Sunshine pop


The principal objective was to determine the extent to which physical activity (PA) accounts for differences in leukocyte telomere length (LTL) in a large random sample of U.S. adults. Another purpose was to assess the extent to which multiple demographic and lifestyle covariates affect the relationship between PA and LTL. A total of 5823 adults from the National Health and Nutrition Examination Survey (NHANES 1999-2002) were studied cross-sectionally. Employing the quantitative polymerase chain reaction method, LTL was compared to standard reference DNA. PA was indexed using MET-minutes using self-reported frequency, intensity, and duration of participation in 62 physical activities. Covariates were controlled statistically. Telomeres were 15.6 base pairs shorter for each year of chronological age (F=723.2, P<0.0001). PA was inversely related to LTL after adjusting for all the covariates (F=8.3, P=0.0004). Telomere base pair differences between adults with High activity and those in the Sedentary, Low, and Moderate groups were 140, 137, and 111, respectively. Adults with High activity were estimated to have a biologic aging advantage of 9years (140 base pairs÷15.6) over Sedentary adults. The difference in cell aging between those with High and Low activity was also significant, 8.8years, as was the difference between those with High and Moderate PA (7.1years). Overall, PA was significantly and meaningfully associated with telomere length in U.S. men and women. Evidently, adults who participate in high levels of PA tend to have longer telomeres, accounting for years of reduced cellular aging compared to their more sedentary counterparts.

Concepts: DNA, Genetics, Polymerase chain reaction, Senescence, Base pair, DNA replication, Reverse transcriptase, Telomere


The vegetarian diet is thought to have health benefits including reductions in type 2 diabetes, hypertension, and obesity. Evidence to date suggests that vegetarians tend to have lower mortality rates when compared with non-vegetarians, but most studies are not population-based and other healthy lifestyle factors may have confounded apparent protective effects. The aim of this study was to evaluate the association between categories of vegetarian diet (including complete, semi and pesco-vegetarian) and all-cause mortality in a large population-based Australian cohort. The 45 and Up Study is a cohort study of 267,180 men and women aged ≥45years in New South Wales (NSW), Australia. Vegetarian diet status was assessed by baseline questionnaire and participants were categorized into complete vegetarians, semi-vegetarians (eat meat≤once/week), pesco-vegetarians and regular meat eaters. All-cause mortality was determined by linked registry data to mid-2014. Cox proportional hazards models quantified the association between vegetarian diet and all-cause mortality adjusting for a range of potential confounding factors. Among 243,096 participants (mean age: 62.3years, 46.7% men) there were 16,836 deaths over a mean 6.1years of follow-up. Following extensive adjustment for potential confounding factors there was no significant difference in all-cause mortality for vegetarians versus non-vegetarians [HR=1.16 (95% CI 0.93-1.45)]. There was also no significant difference in mortality risk between pesco-vegetarians [HR=0.79 (95% CI 0.59-1.06)] or semi-vegetarians [HR=1.12 (95% CI 0.96-1.31)] versus regular meat eaters. We found no evidence that following a vegetarian diet, semi-vegetarian diet or a pesco-vegetarian diet has an independent protective effect on all-cause mortality.

Concepts: Nutrition, Obesity, Meat, Diets, New South Wales, Vegetarianism, Veganism, Pescetarianism


The relationship between strength training (ST) behavior and mortality remains understudied in large, national samples, although smaller studies have observed that greater amounts of muscle strength are associated with lower risks of death. We aimed to understand the association between meeting ST guidelines and future mortality in an older US adult population.

Concepts: Death, Demography, Actuarial science, Muscle contraction


Advancements in accelerometer analytic and visualization techniques allow researchers to more precisely identify and compare critical periods of physical activity (PA) decline by age across the lifespan, and describe how daily PA patterns may vary across age groups. We used accelerometer data from the 2003-2006 cohorts of the National Health and Nutrition Examination Survey (NHANES) (n=12,529) to quantify total PA as well as PA by intensity across the lifespan using sex-stratified, age specific percentile curves constructed using generalized additive models. We additionally estimated minute-to-minute diurnal PA using smoothed bivariate surfaces. We found that from childhood to adolescence (ages 6-19) across sex, PA is sharply lower by age partially due to a later initiation of morning PA. Total PA levels, at age 19 are comparable to levels at age 60. Contrary to prior evidence, during young adulthood (ages 20-30) total and light intensity PA increases by age and then stabilizes during midlife (ages 31-59) partially due to an earlier initiation of morning PA. We additionally found that males compared to females have an earlier lowering in PA by age at midlife and lower total PA, higher sedentary behavior, and lower light intensity PA in older adulthood; these trends seem to be driven by lower PA in the afternoon compared to females. Our results suggest a re-evaluation of how emerging adulthood may affect PA levels and the importance of considering time of day and sex differences when developing PA interventions.

Concepts: Male, Female, Obesity, Gender, Sex, Developmental psychology, Human development, Young adult


Wearable devices to self-monitor physical activity have become popular with individuals and healthcare practitioners as a route to the prevention of chronic disease. It is not currently possible to reconcile feedback from these devices with activity recommendations because the guidelines refer to the amount of activity required on top of normal lifestyle activities (e.g., 150min of moderate-to-vigorous intensity activity per week over-and-above normal moderate-to-vigorous lifestyle activities). The aim of this study was to recalibrate the feedback from self-monitoring. We pooled data from four studies conducted between 2006 and 2014 in patients and volunteers from the community that included both sophisticated measures of physical activity and 10-year risk for cardiovascular disease and type 2 diabetes (n=305). We determined the amount of moderate-to-vigorous intensity activity that corresponded to FAO/WHO/UNU guidance for a required PAL of 1.75 (Total Energy Expenditure/Basal Metabolic Rate). Our results show that, at the UK median PAL, total moderate-to-vigorous intensity physical activity will be around 735min per week (~11% of waking time). We estimate that a 4% increase in moderate-to-vigorous intensity activity will achieve standardised guidance from FAO/WHO/UNU and will require ~1000min of moderate-to-vigorous intensity activity per week. This study demonstrates that feedback from sophisticated wearable devices is incompatible with current physical activity recommendations. Without adjustment, people will erroneously form the view that they are exceeding recommendations by several fold. A more appropriate target from self-monitoring that accounts for normal moderate-to-vigorous lifestyle activities is ~1000min per week, which represents ~15% of waking time.

Concepts: Medicine, Metabolism, Energy, Light, Obesity, Cardiovascular disease, Radiation, Energeia


Uncertainty remains about whether personal financial incentives could achieve sustained changes in health-related behaviors that would reduce the fast-growing global non-communicable disease burden. This review aims to estimate whether: i. financial incentives achieve sustained changes in smoking, eating, alcohol consumption and physical activity; ii. effectiveness is modified by (a) the target behavior, (b) incentive value and attainment certainty, © recipients' deprivation level.

Concepts: Psychology, Alcohol, The Target, Behavior, Motivation, Incentive, Behavioural sciences, Microeconomics