Is Cohort Representativeness Passé? Poststratified Associations of Lifestyle Risk Factors with Mortality in the UK Biobank

Volume of alcohol intake, heavy episodic drinking, and all-cause mortality in Spain: A longitudinal population-based study

INTRODUCTION

The impact of alcohol consumption on health, particularly in low quantities, remains controversial. Our objective was to assess the association between alcohol volume and heavy episodic drinking (HED) with all-cause mortality, while minimizing many of the known methodological issues.

METHODOLOGY

This longitudinal study used data from the 2011-2012 National Health Survey and the 2014 European Health Survey in Spain. Data from 43,071 participants aged ≥ 15 years were linked to mortality records as of December 2021. Alcohol consumption categories were defined based on intake volume and frequency: never-drinkers, former drinkers, infrequent occasional drinkers (≤once/month), frequent occasional drinkers ( once /month). Regular drinkers (≥once/week) were further classified by volume: >0-10 g/day, >10-20 g/day, >20-40 g/day, and > 40 g/day. Heavy Episodic Drinking (HED) was defined as ≥ 6 and ≥ 5 standard drinks (10 g) within 4-6 h for men and women, respectively. Hazard ratios (HR) were calculated using Cox regression, adjusting for sociodemographic variables, lifestyle factors, health status, and alcohol volume or HED.

RESULTS

Compared to infrequent occasional drinkers, HRs for never-drinkers and former drinkers were 1.30 (95 %CI:1.14-1.47) and 1.32 (95 %CI:1.15-1.50), respectively. No differences in mortality risk were observed for intakes up to 20 g/day, but it increased for consumptions > 20-40 g/day and > 40 g/day (HR = 1.29; 95 %CI:1.05-1.58 and HR = 1.57; 95 %CI:1.14-2.17, respectively). The HR of weekly HED vs. never was 1.31 (95 %CI:0.98-1.75).

CONCLUSIONS

Compared to infrequent occasional drinking, consuming low amounts of alcohol had no impact on mortality risk. However, never-drinkers, former drinkers, individuals with regular consumption > 20 g/day, and those engaging in weekly HED, experienced higher mortality risk.

Joint effects of air pollution and genetic susceptibility on incident primary open-angle glaucoma

BACKGROUND

Air pollutants are important exogenous stimulants to eye diseases, but knowledge of associations between long-term exposure to air pollutants and the risk of primary open-angle glaucoma (POAG) is limited. This study aimed to determine whether long-term exposure to air pollutants, genetic susceptibility, and their joint effects lead to an elevated risk of incident POAG.

METHODS

This is a population-based prospective cohort study from UK Biobank participants with complete measures of air pollution exposure and polygenetic risk scores. Cox proportional hazard models were fitted to assess the individual and joint effects of long-term exposure to air pollutants and genetics on the risk of POAG. In addition, the effect modification of genetic susceptibility was examined on an additive or multiplicative scale.

RESULTS

Among 434,290 participants with a mean (SD) age of 56.5 (8.1) years, 6651 (1.53 %) were diagnosed with POAG during a median follow-up of 13.7 years. Long-term exposure to air pollutants was associated with an increased risk of POAG. The hazard ratios associated with per interquartile range increase in PM2.5, PM2.5 absorbance, PM10, NO2, and NOX individually ranged from 1.027 (95 % CI: 1.001-1.054) to 1.067 (95 % CI: 1.035-1.099). Compared with individuals residing in low-pollution areas and having low polygenic risk scores, the risk of incident POAG increased by 105.5 % (95 % CI: 78.3 %-136.9 %), 79.7 % (95 % CI: 56.5 %-106.5 %), 103.2 % (95 % CI: 76.9 %-133.4 %), 89.4 % (95 % CI: 63.9 %-118.9 %), and 90.2 % (95 % CI: 64.8 %-119.5 %) among those simultaneously exposed to high air pollutants levels and high genetic risk, respectively. Genetic susceptibility interacted with PM2.5 absorbance and NO2 in an additive manner, while no evidence of multiplicative interaction was found in this study. Stratification analyses revealed stronger effects in Black people and the elderly.

CONCLUSION

Long-term air pollutant exposure was associated with an increased risk of POAG incidence, particularly in the population with high genetic predisposition.

Dietary flavonoid intake and risk of hormone-related cancers: A population-based prospective cohort study

BACKGROUND

Dietary flavonoids may have potential effects on hormone-related cancers (HRCs) due to their anti-cancer properties via regulating hormones and suppressing inflammation and oxidative stress. We aimed to examine the association of flavonoid intake with risks of HRCs and whether this association was mediated by blood biomarkers involved in biological mechanisms.

METHODS

This prospective cohort study from UK Biobank included 187,350 participants free of cancer when the last dietary recall was completed. The dietary intakes of flavonoids and subclasses were assessed using 24-hour dietary recalls. Venous blood was collected at baseline and assayed for biomarkers of inflammation, hormones, and oxidative stress. Hazard ratios (HR) and 95 % confidential intervals (CI) for the associations between flavonoid intake and HRCs risk were estimated by the cause-specific Cox proportional hazards model. The role of blood biomarkers in the flavonoids-HRCs association was investigated through mediation analysis.

RESULTS

Over a median follow-up of 9.5 years, 3,392 female breast cancer, 417 ovarian cancer, 516 endometrial cancer, 4,305 prostate cancer, 45 testicular cancer, and 146 thyroid cancer cases were documented. Compared to the lowest quintile, multivariable-adjusted HRs (95 % CIs) in the highest quintile of total flavonoid intake were 0.89 (0.80-0.99) for breast cancer, 0.68 (0.50-0.92) for ovarian cancer, and 0.88 (0.80-0.98) for female-specific cancers. For subclasses, intakes of flavonols and anthocyanidins were inversely associated with the risk of female-specific cancers (Ptrend <0.05). Anthocyanidin intake was positively related to prostate cancer risk, whereas isoflavone intake was inversely linked to thyroid cancer risk (Ptrend <0.05). Additionally, certain biomarkers of inflammation, hormones and oxidative stress jointly mediated the association of flavonoid intake with the risk of female-specific cancers and prostate cancer.

CONCLUSIONS

Our findings highlighted the importance of dietary flavonoids for the prevention of HRCs in the general population, providing epidemiological evidence for dietary guidelines.

EAT-Lancet Diet Pattern, Genetic Predisposition, Inflammatory Biomarkers, and Risk of Lung Cancer Incidence and Mortality

SCOPE

The association between a planetary and sustainable EAT-Lancet diet and lung cancer remains inconclusive, with limited exploration of the role of genetic susceptibility and inflammation.

METHODS AND RESULTS

The study includes 175 214 cancer-free participants in the UK Biobank. Fourteen food components are collected from a 24-h dietary recall questionnaire. A polygenic risk score is constructed through capturing the overall risk variants for lung cancer. Sixteen inflammatory biomarkers are assayed in blood samples. Participants with the highest EAT-Lancet diet scores (≥12) have a lower risk of lung cancer incidence (hazard ratio [HR] = 0.64, 95% confidence interval [CI]: 0.51-0.80) and mortality (HR = 0.65, 95% CI: 0.48-0.88), compared to those with the lowest EAT-Lancet diet scores (≤8). Interestingly, there is a significantly protective trend against both lung adenocarcinoma and lung squamous cell carcinoma with higher EAT-Lancet diet scores. Despite no significant interactions, a risk reduction trend for lung cancer is observed with increasing EAT-Lancet diet scores and decreasing genetic risk. Ten inflammatory biomarkers partially mediate the association between the EAT-Lancet diet and lung cancer risk.

CONCLUSION

The study depicts a lower risk of lung cancer conferred by the EAT-Lancet diet associated with lower inflammation levels among individuals with diverse genetic predispositions.

Accelerometer-derived moderate-to-vigorous physical activity and incident nonalcoholic fatty liver disease

BACKGROUND

The liver effects of concentrated vs. more evenly distributed moderate-to-vigorous physical activity (MVPA) patterns remain unclear. We aimed to examine the association of accelerometer-measured MVPA and different MVPA patterns with liver outcomes.

METHODS

Eighty-eight thousand six hundred fifty-six participants without prior liver diseases from UK Biobank were included. MVPA was measured by a wrist-worn accelerometer. Based on the guideline-based threshold (≥ 150 min/week), MVPA patterns were defined as inactive (< 150 min/week), active weekend warrior (WW; ≥ 150 min/week with ≥ 50% of total MVPA achieved within 1-2 days), and regularly active (≥ 150 min/week but not active WW) patterns. The primary outcome was incident nonalcoholic fatty liver disease (NAFLD).

RESULTS

During a median follow-up of 6.8 years, 562 participants developed NAFLD. Overall, there was a nonlinear inverse association of total MVPA with incident NAFLD (P for nonlinearity = 0.009): the risk of NAFLD rapidly decreased with the increment of MVPA (per 100 min/week increment: HR = 0.68; 95%CI, 0.57-0.81) when MVPA < 208 min/week, while moderately declined (HR = 0.91; 95%CI, 0.84-0.99) when MVPA ≥ 208 min/week. For MVPA patterns, compared with inactive group, both active WW (HR = 0.55, 95%CI, 0.44-0.67) and active regular (HR = 0.49, 95%CI, 0.38-0.63) group were associated with a similar lower risk of NAFLD. Similar results were observed for each secondary outcome, including incident severe liver diseases, incident liver cirrhosis, and liver magnetic resonance imaging-based liver steatosis and fibrosis.

CONCLUSIONS

Regardless of whether MVPA was concentrated within 1 to 2 days or spread over most days of the week, more MVPA was associated with a lower risk of incident liver outcomes, including NAFLD, liver cirrhosis, liver steatosis, and fibrosis, to MVPA more evenly distributed.

Comparing Cadence vs. Machine Learning Based Physical Activity Intensity Classifications: Variations in the Associations of Physical Activity With Mortality

Step cadence-based and machine-learning (ML) methods have been used to classify physical activity (PA) intensity in health-related research. This study examined the association of intensity-specific PA duration with all-cause (ACM) and CVD mortality using the cadence-based and ML methods in 68 561 UK Biobank participants wearing wrist-worn accelerometers. The two-stage-ML method categorized activity type and then intensity. The one-level-cadence-method (1LC) derived intensity-specific duration using all detected steps (including standing utilitarian steps) and cadence thresholds of ≥100 steps/min (moderate intensity) and ≥130 steps/min (vigorous intensity). The two-level-cadence-method (2LC) detected ambulatory steps (i.e., walking and running) and then applied the same cadence thresholds. The 2LC exhibited the most pronounced association at the lower end of duration spectrum. For example, the 2LC showed the smallest minimum moderate-to-vigorous-PA (MVPA) duration (amount associated with 50% of optimal risk reduction) with similar corresponding ACM hazard ratio (HR) to other methods (2LC: 2.8 min/day [95% CI: 2.6, 2.8], HR: 0.83 [95% CI: 0.78, 0.88]; 1LC, 11.1[10.8, 11.4], 0.80 [0.76, 0.85]; ML, 14.9 [14.6, 15.2], 0.82 [0.76, 0.87]). The ML elicited the greatest mortality risk reduction. For example, the medians and corresponding HR in VPA-ACM association: 2LC, 2.0 min/day [95% CI: 2.0, 2.0], HR, 0.69 [95% CI: 0.61, 0.79]; 1LC, 6.9 [6.9, 7.0], 0.68 [0.60, 0.77]; ML, 3.2 [3.2, 3.2], 0.53 [0.44, 0.64]. After standardizing durations, the ML exhibited the most pronounced associations. For example, the standardized minimum durations in MPA-CVD mortality association were: 2LC, -0.77; 1LC, -0.85; ML, -0.94; with corresponding HR of 0.82 [0.72, 0.92], 0.79 [0.69, 0.90], and 0.77 [0.69, 0.85], respectively. The 2LC exhibited the most pronounced association with all-cause and CVD mortality at the lower end of the duration spectrum. The ML method provided the most pronounced association with all-cause and CVD mortality, thus might be appropriate for estimating health benefits of moderate and vigorous intensity PA in observational studies.

Serum Vitamin D and Chronic Musculoskeletal Pain: A Cross-Sectional Study of 349,221 Adults in the UK

Insufficient and deficient vitamin D may be associated with chronic musculoskeletal pain, but study findings are conflicting, and few account for important confounding factors. This cross-sectional study explored the association between serum vitamin D status and chronic musculoskeletal pain in various body sites, adjusting for a wide range and a number of potential confounding factors. Data collected at the baseline assessments of 349,221 UK Biobank participants between 2006 and 2010 were analyzed. Serum 25-hydroxyvitamin D was measured and categorized as <25.0 nmol/L (severe deficiency), 25.0 to 49.9 nmol/L (deficiency), 50.0 to 74.9 nmol/L (insufficiency), and ≥75.0 nmol/L (sufficiency). The outcome was self-reported chronic musculoskeletal pain at any site, neck/shoulder, back, hip, knee, or widespread pain that interfered with usual activities. Potential confounders were identified using directed acyclic graphs and included sociodemographic, lifestyle, psychological factors, and medical comorbidities. Simple models adjusted for age and sex showed significant associations between suboptimal vitamin D status and chronic pain across all sites (odds ratios [ORs] ranged 1.07-2.85). These associations were weakened or became insignificant after accounting for all confounding factors (ORs ≤ 1.01) for chronic regional musculoskeletal pain. Severe vitamin D deficiency remained a significant and positive association with chronic widespread pain after adjusting for all confounding factors (OR [95% confidence interval]: 1.26 [1.07, 1.49]). This study suggests that, while vitamin D status is not a key independent determinant of chronic regional musculoskeletal pain, severe vitamin D deficiency may be associated with chronic widespread pain. PERSPECTIVE: After accounting for various confounders, vitamin D deficiency was not associated with regional musculoskeletal pain. However, the relationship between chronic widespread pain severe vitamin D deficiency remained after confounder adjustment. Use of vitamin D supplements in individuals with chronic widespread pain and severe vitamin D deficiency warrants further exploration.

Air pollutants, genetic susceptibility and the risk of schizophrenia: large prospective study

BACKGROUND

Evidence linking air pollutants and the risk of schizophrenia remains limited and inconsistent, and no studies have investigated the joint effect of air pollutant exposure and genetic factors on schizophrenia risk.

AIMS

To investigate how exposure to air pollution affects schizophrenia risk and the potential effect modification of genetic susceptibility.

METHOD

Our study was conducted using data on 485 288 participants from the UK Biobank. Cox proportional hazards models were used to estimate the schizophrenia risk as a function of long-term air pollution exposure presented as a time-varying variable. We also derived the schizophrenia polygenic risk score (PRS) utilising data provided by the UK Biobank, and investigated the modification effect of genetic susceptibility.

RESULTS

During a median follow-up period of 11.9 years, 417 individuals developed schizophrenia (mean age 55.57 years, s.d. = 8.68; 45.6% female). Significant correlations were observed between long-term exposure to four air pollutants (PM2.5; PM10; nitrogen oxides, NOx; nitrogen dioxide, NO2) and the schizophrenia risk in each genetic risk group. Interactions between genetic factors and the pollutants NO2 and NOx had an effect on schizophrenia events. Compared with those with low PRS and low air pollution, participants with high PRS and high air pollution had the highest risk of incident schizophrenia (PM2.5: hazard ratio = 6.25 (95% CI 5.03-7.76); PM10: hazard ratio = 7.38 (95% CI 5.86-9.29); NO2: hazard ratio = 6.31 (95% CI 5.02-7.93); NOx: hazard ratio = 6.62 (95% CI 5.24-8.37)).

CONCLUSIONS

Long-term exposure to air pollutants was positively related to the schizophrenia risk. Furthermore, high genetic susceptibility could increase the effect of NO2 and NOx on schizophrenia risk.

Post-diagnostic lifestyle and mortality of cancer survivors: Results from a prospective cohort study

OBJECTIVE

Lifestyle factors after cancer diagnosis could influence cancer survival. This study aimed to investigate the joint effects of smoking, physical activity, alcohol consumption, diet and sleep duration on all-cause, cancer and non-cancer mortality of cancer survivors in UK biobank.

METHODS

The follow-up period concluded in December 2021, with post-diagnostic lifestyle factors assessed at baseline. A lifestyle score ranging from 0 to 5 was assigned based on adherence to the selected lifestyle factors. The study employed Cox regression models for hazard ratios (HRs) and Kaplan-Meier for survival rates, with stratified and sensitivity analyses to assess the robustness of our findings under various assumptions.

RESULTS

During a median follow-up of 12.7 years, 5652 deaths were documented from 34,184 cancer survivors. Compared to scoring 0-1, the HRs (95% CIs) for all-cause mortality with lifestyle scores of 2, 3, 4, and 5 were 0.70 (95% CI: 0.64, 0.76), 0.57 (0.52, 0.62), 0.50 (0.45, 0.54) and 0.43 (0.38, 0.48), respectively. Specific cancer types, particularly digestive, breast, female reproductive, non-solid, and skin cancers, showed notable benefits from adherence to healthy lifestyle, with the HRs of 0.55 (0.39, 0.79), 0.54 (0.42, 0.70), 0.32 (0.19, 0.53), 0.58 (0.39, 0.86), and 0.36 (0.28, 0.46) for lifestyle score of 5, respectively. Stratified analyses indicated the association was particularly significant among those with normal/lower BMI and higher Townsend Deprivation Index (Pinteraction = 0.001 and < 0.001, respectively).

CONCLUSIONS

Healthier lifestyles were significantly linked with reduced mortality among cancer survivors. These findings highlight the need for adherence to healthy lifestyle habits to improve survival.

Joint Associations of Diet and Device-Measured Physical Activity with Mortality and Incident CVD and Cancer: A Prospective Analysis of the UK Biobank Study

BACKGROUND

We examined the joint associations of diet and device-measured intensity-specific physical activity (PA) with all-cause mortality (ACM), cardiovascular disease (CVD), and cancer incidence.

METHODS

We used data from 79,988 participants from the UK Biobank, a population-based prospective cohort study. Light PA (LPA), moderate-to-vigorous PA (MVPA), vigorous PA (VPA), and total PA (TPA) were measured using a wrist-worn accelerometer. Diet quality score (DQS) was based on 10 foods and ranged from 0 (unhealthiest) to 100 (healthiest) points. We derived joint PA and diet variables. Outcomes were ACM, CVD, and cancer incidence including PA, diet and adiposity-related (PDAR) cancer.

RESULTS

During a median follow-up of 8 years, 2,863 deaths occurred, 11,053 participants developed CVD, 7,005 developed cancer, and 3,400 developed PDAR cancer. Compared with the least favorable referent group (bottom PA tertile/low DQS), participants with middle and high (total and intensity specific) PA, except for LPA, had lower ACM risk and incident CVD risk, regardless of DQS. For example, among middle and high VPA and high DQS groups, CVD HR were 0.79 (95% CI, 0.74-0.86) and 0.75 (95% CI, 0.69-0.82), respectively. The pattern of cancer results was less pronounced but in agreement with the ACM and CVD incidence findings (e.g., HR, 0.90, 95% CI, 0.81-0.99; 0.88, 0.79-0.98; and 0.82, 0.74-0.92 among high VPA for low, moderate, and high DQS groups, respectively).

CONCLUSIONS

Device-measured PA reveals novel joint associations with diet on health outcomes.

IMPACT

Our results emphasize the crucial role of PA in addition to a healthy diet for reducing chronic diseases and mortality risk.

Association of accelerometer-derived physical activity with all-cause and cause-specific mortality among individuals with cardiovascular diseases: A prospective cohort study

AIMS

To investigate the association of accelerometer-measured intensity-specific physical activity (PA) with all-cause and cause-specific mortality among individuals with cardiovascular disease (CVD).

METHODS

In this prospective cohort study, 8,024 individuals with pre-existing CVD (mean age: 66.6 years, female: 34.1%) from the UK Biobank had their PA measured using wrist-worn accelerometers over a 7-day period in 2013-2015. All-cause, cancer, and CVD mortality was ascertained from death registries. Cox regression modelling and restricted cubic splines were used to assess the associations. Population-attributable fractions (PAFs) were used to estimate the proportion of preventable deaths if more PA were undertaken.

RESULTS

During an average of 6.8 years of follow-up, 691 deaths (273 from cancer and 219 from CVD) were recorded. An inverse non-linear association was found between PA duration and all-cause mortality risk, irrespective of PA intensity. The hazard ratio (HR) of all-cause mortality plateaued at 1800 minutes/week for light-intensity PA (LPA), 320 minutes/week for moderate-intensity PA (MPA) and 15 minutes/week for vigorous-intensity PA (VPA). The highest quartile of PA associated lower risks for all-cause mortality, with HRs of 0.63 (95% confidence interval [CI]: 0.51-0.79), 0.42 (0.33-0.54) and 0.47 (0.37-0.60) for LPA, MPA, and VPA, respectively. Similar associations were observed for cancer and CVD mortality. Additionally, the highest PAF were noted for VPA, followed by MPA.

CONCLUSION

We found an inverse non-linear association between all intensities of PA (LPA, MPA, VPA, and MVPA) and mortality risk in CVD patients using accelerometer-derived data, but with larger magnitude of the associations than that in previous studies based on self-reported PA.

Device-measured sedentary time and intensity-specific physical activity in relation to all-cause and cardiovascular disease mortality: the UK Biobank cohort study

BACKGROUND AND AIMS

Understanding the amounts of intensity-specific movement needed to attenuate the association between sedentary time and mortality may help to inform personalized prescription and behavioral counselling. Herein, we examined the joint associations of sedentary time and intensity-specific physical activity with all-cause and cardiovascular disease (CVD) mortality.

METHODS

Prospective cohort study including 73,729 adults from the UK Biobank who wore an Axivity AX3 accelerometer on their dominant wrist for at least 3 days, being one a weekend day, between June 2013 and December 2015. We considered the median tertile values of sedentary time and physical activity in each intensity band to determine the amount of physical activity needed to attenuate the association between sedentary time and mortality.

RESULTS

During a median of 6.9 years of follow-up (628,807 person-years), we documented 1521 deaths, including 388 from CVD. Physical activity of any intensity attenuated the detrimental association of sedentary time with mortality. Overall, at least a median of 6 min/day of vigorous physical activity, 30 min/day of MVPA, 64 min/day of moderate physical activity, or 163 min/day of light physical activity (mutually-adjusted for other intensities) attenuated the association between sedentary time and mortality. High sedentary time was associated with higher risk of CVD mortality only among participants with low MVPA (HR 1.96; 95% CI 1.23 to 3.14).

CONCLUSIONS

Different amounts of each physical activity intensity may attenuate the association between high sedentary time and mortality.

Wearable device-measured moderate to vigorous physical activity and risk of degenerative aortic valve stenosis

BACKGROUND AND AIMS

Physical activity has proven effective in preventing atherosclerotic cardiovascular disease, but its role in preventing degenerative valvular heart disease (VHD) remains uncertain. This study aimed to explore the dose-response association between moderate to vigorous physical activity (MVPA) volume and the risk of degenerative VHD among middle-aged adults.

METHODS

A full week of accelerometer-derived MVPA data from 87 248 UK Biobank participants (median age 63.3, female: 56.9%) between 2013 and 2015 were used for primary analysis. Questionnaire-derived MVPA data from 361 681 UK Biobank participants (median age 57.7, female: 52.7%) between 2006 and 2010 were used for secondary analysis. The primary outcome was the diagnosis of incident degenerative VHD, including aortic valve stenosis (AS), aortic valve regurgitation (AR), and mitral valve regurgitation (MR). The secondary outcome was VHD-related intervention or mortality.

RESULTS

In the accelerometer-derived MVPA cohort, 555 incident AS, 201 incident AR, and 655 incident MR occurred during a median follow-up of 8.11 years. Increased MVPA volume showed a steady decline in AS risk and subsequent AS-related intervention or mortality risk, levelling off beyond approximately 300 min/week. In contrast, its association with AR or MR incidence was less apparent. The adjusted rates of AS incidence (95% confidence interval) across MVPA quartiles (Q1-Q4) were 11.60 (10.20, 13.20), 7.82 (6.63, 9.23), 5.74 (4.67, 7.08), and 5.91 (4.73, 7.39) per 10 000 person-years. The corresponding adjusted rates of AS-related intervention or mortality were 4.37 (3.52, 5.43), 2.81 (2.13, 3.71), 1.93 (1.36, 2.75), and 2.14 (1.50, 3.06) per 10 000 person-years, respectively. Aortic valve stenosis risk reduction was also observed with questionnaire-based MVPA data [adjusted absolute difference Q4 vs. Q1: AS incidence, -1.41 (-.67, -2.14) per 10 000 person-years; AS-related intervention or mortality, -.38 (-.04, -.88) per 10 000 person-years]. The beneficial association remained consistent in high-risk populations for AS, including patients with hypertension, obesity, dyslipidaemia, and chronic kidney disease.

CONCLUSIONS

Higher MVPA volume was associated with a lower risk of developing AS and subsequent AS-related intervention or mortality. Future research needs to validate these findings in diverse populations with longer durations and repeated periods of activity monitoring.

Diffusion tensor imaging analysis along the perivascular space in the UK biobank

BACKGROUND

The recently discovered glymphatic system may support the removal of neurotoxic proteins, mainly during sleep, that are associated with neurodegenerative diseases such as Alzheimer's and Parkinson's Disease. Diffusion tensor image analysis along the perivascular space (DTI-ALPS) has been suggested as a method to index the health of glymphatic system (with higher values indicating a more intact glymphatic system). Indeed, in small-scale studies the DTI-ALPS index has been shown to correlate with age, cognitive health, and sleep, and is higher in females than males.

OBJECTIVE

To determine whether these relationships are stable we replicated previous findings associating the DTI-ALPS index with demographic, sleep-related, and cognitive markers in a large sample of participants from the UK Biobank.

METHODS

We calculated the DTI-ALPS index in UK Biobank participants (n = 17723). Using Bayesian and Frequentist analysis approaches, we replicate previously reported relationships between the DTI-ALPS index.

RESULTS

We found the predicted associations between the DTI-ALPS index and age, longest uninterrupted sleep window (LUSWT) on a typical night, cognitive performance, and sex. However, these effects were substantially smaller than those found in previous studies. Parameter estimates from this study may be used as priors in subsequent studies using a Bayesian approach. These results suggest that the DTI-ALPS index is consistently, and therefore predictably, associated with demographics, LUWST, and cognition.

CONCLUSION

We propose that the metric, calculated for the first time in a large-scale, population-based cohort, is a stable measure, but one for which stronger links to glymphatic system function are needed before it can be used to understand the relationships between glymphatic system function and health outcomes reported in the UK Biobank.

Occupational physical activity, all-cause, cardiovascular disease, and cancer mortality in 349,248 adults: Prospective and longitudinal analyses of the MJ Cohort

BACKGROUND

Evidence on the health benefits of occupational physical activity (OPA) is inconclusive. We examined the associations of baseline OPA and OPA changes with all-cause, cardiovascular disease (CVD), and cancer mortality and survival times.

METHODS

This study included prospective and longitudinal data from the MJ Cohort, comprising adults over 18 years recruited in 1998-2016, 349,248 adults (177,314 women) with baseline OPA, of whom 105,715 (52,503 women) had 2 OPA measures at 6.3 ± 4.2 years (mean ± SD) apart. Exposures were baseline OPA, OPA changes, and baseline leisure-time physical activity.

RESULTS

Over a mean mortality follow-up of 16.2 ± 5.5 years for men and 16.4 ± 5.4 years for women, 11,696 deaths (2033 of CVD and 4631 of cancer causes) in men and 8980 deaths (1475 of CVD and 3689 of cancer causes) in women occurred. Combined moderately heavy/heavy baseline OPA was beneficially associated with all-cause mortality in men (multivariable-adjusted hazard ratio (HR) = 0.93, 95% confidence interval (95%CI): 0.89-0.98 compared to light OPA) and women (HR = 0.86, 95%CI: 0.79-0.93). Over a mean mortality follow-up of 12.5 ± 4.6 years for men and 12.6 ± 4.6 years for women, OPA decreases in men were detrimentally associated (HR = 1.16, 95%CI: 1.01-1.33) with all-cause mortality, while OPA increases in women were beneficially (HR = 0.83, 95%CI: 0.70-0.97) associated with the same outcome. Baseline or changes in OPA showed no associations with CVD or cancer mortality.

CONCLUSION

Higher baseline OPA was beneficially associated with all-cause mortality risk in both men and women. Our longitudinal OPA analyses partly confirmed the prospective findings, with some discordance between sex groups.

Exposure to Air Pollution, Genetic Susceptibility, and Psoriasis Risk in the UK

Importance

Psoriasis is a common autoinflammatory disease influenced by complex interactions between environmental and genetic factors. The influence of long-term air pollution exposure on psoriasis remains underexplored.

Objective

To examine the association between long-term exposure to air pollution and psoriasis and the interaction between air pollution and genetic susceptibility for incident psoriasis.

Design, Setting, and Participants

This prospective cohort study used data from the UK Biobank. The analysis sample included individuals who were psoriasis free at baseline and had available data on air pollution exposure. Genetic analyses were restricted to White participants. Data were analyzed between November 1 and December 10, 2023.

Exposures

Exposure to nitrogen dioxide (NO2), nitrogen oxides (NOx), fine particulate matter with a diameter less than 2.5 µm (PM2.5), and particulate matter with a diameter less than 10 µm (PM10) and genetic susceptibility for psoriasis.

Main Outcomes and Measures

To ascertain the association of long-term exposure to NO2, NOx, PM2.5, and PM10 with the risk of psoriasis, a Cox proportional hazards model with time-varying air pollution exposure was used. Cox models were also used to explore the potential interplay between air pollutant exposure and genetic susceptibility for the risk of psoriasis incidence.

Results

A total of 474 055 individuals were included, with a mean (SD) age of 56.54 (8.09) years and 257 686 (54.36%) female participants. There were 9186 participants (1.94%) identified as Asian or Asian British, 7542 (1.59%) as Black or Black British, and 446 637 (94.22%) as White European. During a median (IQR) follow-up of 11.91 (11.21-12.59) years, 4031 incident psoriasis events were recorded. There was a positive association between the risk of psoriasis and air pollutant exposure. For every IQR increase in PM2.5, PM10, NO2, and NOx, the hazard ratios (HRs) were 1.41 (95% CI, 1.35-1.46), 1.47 (95% CI, 1.41-1.52), 1.28 (95% CI, 1.23-1.33), and 1.19 (95% CI, 1.14-1.24), respectively. When comparing individuals in the lowest exposure quartile (Q1) with those in the highest exposure quartile (Q4), the multivariate-adjusted HRs were 2.01 (95% CI, 1.83-2.20) for PM2.5, 2.21 (95% CI, 2.02-2.43) for PM10, 1.64 (95% CI, 1.49-1.80) for NO2, and 1.34 (95% CI, 1.22-1.47) for NOx. Moreover, significant interactions between air pollution and genetic predisposition for incident psoriasis were observed. In the subset of 446 637 White individuals, the findings indicated a substantial risk of psoriasis development in participants exposed to the highest quartile of air pollution levels concomitant with high genetic risk compared with those in the lowest quartile of air pollution levels with low genetic risk (PM2.5: HR, 4.11; 95% CI, 3.46-4.90; PM10: HR, 4.29; 95% CI, 3.61-5.08; NO2: HR, 2.95; 95% CI, 2.49-3.50; NOx: HR, 2.44; 95% CI, 2.08-2.87).

Conclusions and Relevance

In this prospective cohort study of the association between air pollution and psoriasis, long-term exposure to air pollution was associated with increased psoriasis risk. There was an interaction between air pollution and genetic susceptibility on psoriasis risk.

Effect of polygenic scores of telomere length alleles on telomere length in newborns and parents

In adults, polygenic scores (PGSs) of telomere length (TL) alleles explain about 4.5% of the variance in TL, as measured by quantitative polymerase chain reaction (qPCR). Yet, these PGSs strongly infer a causal role of telomeres in aging-related diseases. To better understand the determinants of TL through the lifespan, it is essential to examine to what extent these PGSs explain TL in newborns. This study investigates the effect of PGSs on TL in both newborns and their parents, with TL measured by Southern blotting and expressed in base-pairs (bp). Additionally, the study explores the impact of PGSs related to transmitted or non-transmitted alleles on TL in newborns. For parents and newborns, the PGS effects on TL were 172 bp (p =  2.03 × 10-15) and 161 bp (p =  3.06 × 10-8), explaining 6.6% and 5.2% of the TL variance, respectively. The strongest PGS effect was shown for maternally transmitted alleles in newborn girls, amounting to 214 bp (p =  3.77 × 10-6) and explaining 7.8% of the TL variance. The PGS effect of non-transmitted alleles was 56 bp (p = 0.0593) and explained 0.6% of the TL variance. Our findings highlight the importance of TL genetics in understanding early-life determinants of TL. They point to the potential utility of PGSs composed of TL alleles in identifying susceptibility to aging-related diseases from birth and reveal the presence of sexual dimorphism in the effect of TL alleles on TL in newborns. Finally, we attribute the higher TL variance explained by PGSs in our study to TL measurement by Southern blotting.

Polygenic subtype identified in ACCORD trial displays a favorable type 2 diabetes phenotype in the UKBiobank population

INTRODUCTION

We previously identified a genetic subtype (C4) of type 2 diabetes (T2D), benefitting from intensive glycemia treatment in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. Here, we characterized the population of patients that met the C4 criteria in the UKBiobank cohort.

RESEARCH DESIGN AND METHODS

Using our polygenic score (PS), we identified C4 individuals in the UKBiobank and tested C4 status with risk of developing T2D, cardiovascular disease (CVD) outcomes, and differences in T2D medications.

RESULTS

C4 individuals were less likely to develop T2D, were slightly older at T2D diagnosis, had lower HbA1c values, and were less likely to be prescribed T2D medications (P < .05). Genetic variants in MAS1 and IGF2R, major components of the C4 PS, were associated with fewer overall T2D prescriptions.

CONCLUSION

We have confirmed C4 individuals are a lower risk subpopulation of patients with T2D.

Accelerometer-derived physical activity and mortality in individuals with type 2 diabetes

Physical activity (PA) has been shown to reduce diabetes mortality, but largely based on imprecise self-reported data, which may hinder the development of related recommendations. Here, we perform a prospective cohort study of 19,624 individuals with type 2 diabetes (T2D) from the UK Biobank with a median follow-up of 6.9 years. Duration and intensity of PA are measured by wrist-worn accelerometers over a 7-day period. We observe L-shaped associations of longer duration of PA, regardless of PA intensity, with risks of all-cause and cancer mortality, as well as a negatively linear association with cardiovascular disease mortality. 12.7%, 15.8%, and 22.3% of deaths are attributable to the lowest level of light-intensity, moderate-intensity PA, and vigorous-intensity PA, respectively. Collectively, our findings provide insights for clinical guidelines that should highlight the potential value of adherence to greater intensity and duration of PA for patients with T2D.

Impact of weighting on the association between sociodemographic characteristics, health behaviours and cancer, cardiovascular and all-cause mortality in the Australian 45 and Up Study

BACKGROUND

Weighting can improve study estimate representativeness. We examined the impact of weighting on associations between participants' characteristics and cancer, cardiovascular and all-cause mortality in the Australian 45 and Up Study cohort.

METHODS

Raking weighted cohort data to the 2006 Australian population for seven sociodemographic characteristics. Deaths were ascertained via linkage to routinely collected data. Cox's proportional hazards regression quantified associations between 11 sociodemographic and health characteristics and cancer, cardiovascular and all-cause mortality. The ratios of hazard ratios (RHRs) compared unweighted and weighted estimates.

RESULTS

Among 195,052 included participants (median follow-up 11.4 years), there were 7200 cancer, 5912 cardiovascular and 21,840 all-cause deaths. Overall, 102/111 (91.9%) weighted HRs did not differ significantly from unweighted HRs (100%, 86.5% and 89.2% of 37 HRs for cancer, cardiovascular and all-cause mortality, respectively). Significant differences included a somewhat stronger association between single/widowed/divorced (versus married/de-facto) and cardiovascular mortality (unweighted HR=1.25 (95%CI:1.18-1.32), weighted HR=1.33 (95%CI:1.24-1.42), RHR=1.06 (95%CI:1.02-1.11)); and between no school certificate/qualification (versus university degree) and all-cause mortality (unweighted HR=1.21 (95%CI:1.15-1.27), weighted HR=1.28 (95%CI:1.19-1.38), RHR=1.06 (95%CI:1.03-1.10)).

CONCLUSION

Our results support the generalisability of most estimates of associations in the 45 and Up Study, particularly in relation to cancer mortality. Slight distortion of a few associations with cardiovascular or all-cause mortality were observed.

Timing of Moderate to Vigorous Physical Activity, Mortality, Cardiovascular Disease, and Microvascular Disease in Adults With Obesity

OBJECTIVE

To assess the association between timing of aerobic moderate to vigorous physical activity (MVPA) and risk of cardiovascular disease (CVD), microvascular disease (MVD), and all-cause mortality in adults with obesity and a subset with obesity and type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

Participants included adults with obesity (BMI ≥30 kg/m2) and a subset of those with T2D from the UK Biobank accelerometry substudy. Aerobic MVPA was defined as bouts of MVPA lasting ≥3 continuous minutes. Participants were categorized into morning, afternoon, or evening MVPA based on when they undertook the majority of their aerobic MVPA. The reference group included participants with an average of less than one aerobic MVPA bout per day. Analyses were adjusted for established and potential confounders.

RESULTS

The core sample included 29,836 adults with obesity, with a mean age of 62.2 (SD 7.7) years. Over a mean follow-up period of 7.9 (SD 0.8) years, 1,425 deaths, 3,980 CVD events, and 2,162 MVD events occurred. Compared with activity in the reference group, evening MVPA was associated with the lowest risk of mortality (hazard ratio [HR] 0.39; 95% CI 0.27, 0.55), whereas afternoon (HR 0.60; 95% CI 0.51, 0.71) and morning MVPA (HR 0.67; 95% CI 0.56, 0.79) demonstrated significant but weaker associations. Similar patterns were observed for CVD and MVD incidence, with evening MVPA associated with the lowest risk of CVD (HR 0.64; 95% CI 0.54, 0.75) and MVD (HR 0.76; 95% CI 0.63, 0.92). Findings were similar in the T2D subset (n = 2,995).

CONCLUSIONS

Aerobic MVPA bouts undertaken in the evening were associated with the lowest risk of mortality, CVD, and MVD. Timing of physical activity may play a role in the future of obesity and T2D management.

Physical Activity, Mental Activity, and Risk of Incident Stroke: A Prospective Cohort Study

BACKGROUND

Cumulative evidence suggests a correlation between physical or mental activity and the risk of stroke. However, the combined impact of these activities on stroke onset remains unexplored. This study identified physical and mental activity patterns using principal component analysis and investigated their associations with risk of incident stroke in the general population.

METHODS

Our study was sourced from the UK Biobank cohort between 2006 and 2010. Information on physical and mental-related activities were obtained through a touch-screen questionnaire. The incident stroke was diagnosed by physicians and subsequently verified through linkage to Hospital Episode Statistics. Principal component analysis was used to identify potential physical and mental activity patterns. Cox proportional hazard regression models were performed to calculate hazard ratios (HRs) and 95% CIs of incident stroke, adjusting for potential confounders.

RESULTS

The initial UK Biobank cohort originally consisted of 502 411 individuals, of whom a total of 386 902 participants (aged 38-79 years) without any history of stroke at baseline were included in our study. During a median follow-up of 7.7 years, 6983 (1.8%) cases of stroke were documented. The mean age of the included participants was 55.9 years, and the proportion of women was 55.1%. We found that multiple individual items related to physical and mental activity showed significant associations with risk of stroke. We identified 4 patterns of physical activity and 3 patterns of mental activity using principal component analysis. The adherence to activity patterns of vigorous exercise, housework, and walking predominant patterns were associated with a lower risk of stroke by 17% (HR, 0.83 [95% CI, 0.78-0.89]; 20% (HR, 0.80 [95% CI, 0.75-0.85]; and 20% (HR, 0.80 [95% CI, 0.75-0.86), respectively. Additionally, the transportation predominant pattern (HR, 1.36 [95% CI, 1.28-1.45) and watching TV pattern (HR, 1.43 [95% CI, 1.33-1.53) were found to be significantly associated with a higher risk of stroke. These associations remained consistent across all subtypes of stroke.

CONCLUSIONS

Activity patterns mainly related to frequent vigorous exercise, housework, and walking were associated with lower risks of stroke and all its subtypes. Our findings provide new insights for promoting suitable patterns of physical and mental activity for primary prevention of stroke.

Reweighting UK Biobank corrects for pervasive selection bias due to volunteering

BACKGROUND

Biobanks typically rely on volunteer-based sampling. This results in large samples (power) at the cost of representativeness (bias). The problem of volunteer bias is debated. Here, we (i) show that volunteering biases associations in UK Biobank (UKB) and (ii) estimate inverse probability (IP) weights that correct for volunteer bias in UKB.

METHODS

Drawing on UK Census data, we constructed a subsample representative of UKB's target population, which consists of all individuals invited to participate. Based on demographic variables shared between the UK Census and UKB, we estimated IP weights (IPWs) for each UKB participant. We compared 21 weighted and unweighted bivariate associations between these demographic variables to assess volunteer bias.

RESULTS

Volunteer bias in all associations, as naively estimated in UKB, was substantial-in some cases so severe that unweighted estimates had the opposite sign of the association in the target population. For example, older individuals in UKB reported being in better health, in contrast to evidence from the UK Census. Using IPWs in weighted regressions reduced 87% of volunteer bias on average. Volunteer-based sampling reduced the effective sample size of UKB substantially, to 32% of its original size.

CONCLUSIONS

Estimates from large-scale biobanks may be misleading due to volunteer bias. We recommend IP weighting to correct for such bias. To aid in the construction of the next generation of biobanks, we provide suggestions on how to best ensure representativeness in a volunteer-based design. For UKB, IPWs have been made available.

Fetal influence on the human brain through the lifespan

Human fetal development has been associated with brain health at later stages. It is unknown whether growth in utero, as indexed by birth weight (BW), relates consistently to lifespan brain characteristics and changes, and to what extent these influences are of a genetic or environmental nature. Here we show remarkably stable and lifelong positive associations between BW and cortical surface area and volume across and within developmental, aging and lifespan longitudinal samples (N = 5794, 4-82 y of age, w/386 monozygotic twins, followed for up to 8.3 y w/12,088 brain MRIs). In contrast, no consistent effect of BW on brain changes was observed. Partly environmental effects were indicated by analysis of twin BW discordance. In conclusion, the influence of prenatal growth on cortical topography is stable and reliable through the lifespan. This early-life factor appears to influence the brain by association of brain reserve, rather than brain maintenance. Thus, fetal influences appear omnipresent in the spacetime of the human brain throughout the human lifespan. Optimizing fetal growth may increase brain reserve for life, also in aging.

Do the associations of daily steps with mortality and incident cardiovascular disease differ by sedentary time levels? A device-based cohort study

OBJECTIVES

This study aims to examine the associations of daily step count with all-cause mortality and incident cardiovascular disease (CVD) by sedentary time levels and to determine if the minimal and optimal number of daily steps is modified by high sedentary time.

METHODS

Using data from the UK Biobank, this was a prospective dose-response analysis of total daily steps across low (<10.5 hours/day) and high (≥10.5 hours/day) sedentary time (as defined by the inflection point of the adjusted absolute risk of sedentary time with the two outcomes). Mortality and incident CVD was ascertained through 31 October 2021.

RESULTS

Among 72 174 participants (age=61.1±7.8 years), 1633 deaths and 6190 CVD events occurred over 6.9 (±0.8) years of follow-up. Compared with the referent 2200 steps/day (5th percentile), the optimal dose (nadir of the curve) for all-cause mortality ranged between 9000 and 10 500 steps/day for high (HR (95% CI)=0.61 (0.51 to 0.73)) and low (0.69 (0.52 to 0.92)) sedentary time. For incident CVD, there was a subtle gradient of association by sedentary time level with the lowest risk observed at approximately 9700 steps/day for high (0.79 (0.72 to 0.86)) and low (0.71 (0.61 to 0.83)) sedentary time. The minimal dose (steps/day associated with 50% of the optimal dose) of daily steps was between 4000 and 4500 steps/day across sedentary time groups for all-cause mortality and incident CVD.

CONCLUSIONS

Any amount of daily steps above the referent 2200 steps/day was associated with lower mortality and incident CVD risk, for low and high sedentary time. Accruing 9000-10 500 steps/day was associated with the lowest mortality risk independent of sedentary time. For a roughly equivalent number of steps/day, the risk of incident CVD was lower for low sedentary time compared with high sedentary time.

Leisure-time physical activity and all-cause mortality and cardiovascular disease in adults with type 2 diabetes: Cross-country comparison of cohort studies

PURPOSE

This study aimed to quantify the dose-response association and the minimal effective dose of leisure-time physical activity (PA) to prevent mortality and cardiovascular disease in adults with type 2 diabetes.

METHODS

Cross-country comparison of 2 prospective cohort studies including 14,913 and 17,457 population-based adults with type 2 diabetes from the UK and China. Baseline leisure-time PA was self-reported and categorized by metabolic equivalent hours per week (MET-h/week) according to World Health Organization recommendations: none, below recommendation (>0-7.49 MET-h/week); at recommended level (7.5-14.9 MET-h/week); above recommendation (≥15 MET-h/week). Mortality and cardiovascular disease data were obtained from national registries.

RESULTS

During a median follow-up of 12.4 and 9.7 years, in the UK and China cohorts, repectively, higher levels of leisure-time PA were inversely associated with all-cause (1571 and 2351 events) and cardiovascular mortality (392 and 1060 events), mostly consistent with a linear dose-response relationship. PA below, at, and above recommendations, compared with no activity, yielded all-cause mortality hazard ratios of 0.94 (95% confidence interval (95%CI): 0.79-1.12), 0.90 (95%CI: 0.74-1.10), and 0.85 (95%CI: 0.70-1.02) in British adults and 0.87 (95%CI: 0.68-1.10), 0.88 (95%CI: 0.74-1.03), and 0.77 (95%CI: 0.70-0.85) in Chinese adults. Associations with cardiovascular mortality were more pronounced in British adults (0.80 (95%CI: 0.58-1.11), 0.75 (95%CI: 0.52-1.09), and 0.69 (95%CI: 0.48-0.97)) but less pronounced in Chinese adults (1.06 (95%CI: 0.76-1.47), 1.01 (95%CI: 0.80-1.28), and 0.79 (95%CI: 0.69-0.92)). PA at recommended levels was not associated with lower rates of major adverse cardiovascular events (2345 and 4458 events).

CONCLUSION

Leisure-time PA at the recommended levels was not convincingly associated with lower mortality and had no association with risk of major adverse cardiovascular events in British or Chinese adults with type 2 diabetes. Leisure-time PA above current recommendations may be needed to prevent cardiovascular disease and premature mortality in adults with type 2 diabetes.

Device-measured physical activity and cardiometabolic health: the Prospective Physical Activity, Sitting, and Sleep (ProPASS) consortium

BACKGROUND AND AIMS

Physical inactivity, sedentary behaviour (SB), and inadequate sleep are key behavioural risk factors of cardiometabolic diseases. Each behaviour is mainly considered in isolation, despite clear behavioural and biological interdependencies. The aim of this study was to investigate associations of five-part movement compositions with adiposity and cardiometabolic biomarkers.

METHODS

Cross-sectional data from six studies (n = 15 253 participants; five countries) from the Prospective Physical Activity, Sitting and Sleep consortium were analysed. Device-measured time spent in sleep, SB, standing, light-intensity physical activity (LIPA), and moderate-vigorous physical activity (MVPA) made up the composition. Outcomes included body mass index (BMI), waist circumference, HDL cholesterol, total:HDL cholesterol ratio, triglycerides, and glycated haemoglobin (HbA1c). Compositional linear regression examined associations between compositions and outcomes, including modelling time reallocation between behaviours.

RESULTS

The average daily composition of the sample (age: 53.7 ± 9.7 years; 54.7% female) was 7.7 h sleeping, 10.4 h sedentary, 3.1 h standing, 1.5 h LIPA, and 1.3 h MVPA. A greater MVPA proportion and smaller SB proportion were associated with better outcomes. Reallocating time from SB, standing, LIPA, or sleep into MVPA resulted in better scores across all outcomes. For example, replacing 30 min of SB, sleep, standing, or LIPA with MVPA was associated with -0.63 (95% confidence interval -0.48, -0.79), -0.43 (-0.25, -0.59), -0.40 (-0.25, -0.56), and -0.15 (0.05, -0.34) kg/m2 lower BMI, respectively. Greater relative standing time was beneficial, whereas sleep had a detrimental association when replacing LIPA/MVPA and positive association when replacing SB. The minimal displacement of any behaviour into MVPA for improved cardiometabolic health ranged from 3.8 (HbA1c) to 12.7 (triglycerides) min/day.

CONCLUSIONS

Compositional data analyses revealed a distinct hierarchy of behaviours. Moderate-vigorous physical activity demonstrated the strongest, most time-efficient protective associations with cardiometabolic outcomes. Theoretical benefits from reallocating SB into sleep, standing, or LIPA required substantial changes in daily activity.

Assessing the importance of primary care diagnoses in the UK Biobank

The UK Biobank has made general practitioner (GP) data (censoring date 2016-2017) available for approximately 45% of the cohort, whilst hospital inpatient and death registry (referred to as "HES/Death") data are available cohort-wide through 2018-2022 depending on whether the data comes from England, Wales or Scotland. We assessed the importance of case ascertainment via different data sources in UKB for three diseases that are usually first diagnosed in primary care: Parkinson's disease (PD), type 2 diabetes (T2D), and all-cause dementia. Including GP data at least doubled the number of incident cases in the subset of the cohort with primary care data (e.g. from 619 to 1390 for dementia). Among the 786 dementia cases that were only captured in the GP data before the GP censoring date, only 421 (54%) were subsequently recorded in HES. Therefore, estimates of the absolute incidence or risk-stratified incidence are misleadingly low when based only on the HES/Death data. For incident cases present in both HES/Death and GP data during the full follow-up period (i.e. until the HES censoring date), the median time difference between an incident diagnosis of dementia being recorded in GP and HES/Death was 2.25 years (i.e. recorded 2.25 years earlier in the GP records). Similar lag periods were also observed for PD (median 2.31 years earlier) and T2D (median 2.82 years earlier). For participants with an incident GP diagnosis, only 65.6% of dementia cases, 69.0% of PD cases, and 58.5% of T2D cases had their diagnosis recorded in HES/Death within 7 years since GP diagnosis. The effect estimates (hazard ratios, HR) of established risk factors for the three health outcomes mostly remain in the same direction and with a similar strength of association when cases are ascertained either using HES only or further adding GP data. The confidence intervals of the HR became narrower when adding GP data, due to the increased statistical power from the additional cases. In conclusion, it is desirable to extend both the coverage and follow-up period of GP data to allow researchers to maximise case ascertainment of chronic health conditions in the UK.

Prospective study design and data analysis in UK Biobank

Population-based prospective studies, such as UK Biobank, are valuable for generating and testing hypotheses about the potential causes of human disease. We describe how UK Biobank's study design, data access policies, and approaches to statistical analysis can help to minimize error and improve the interpretability of research findings, with implications for other population-based prospective studies being established worldwide.

Brief bouts of device-measured intermittent lifestyle physical activity and its association with major adverse cardiovascular events and mortality in people who do not exercise: a prospective cohort study

BACKGROUND

Guidelines emphasise the health benefits of bouts of physical activity of any duration. However, the associations of intermittent lifestyle physical activity accumulated through non-exercise with mortality and major adverse cardiovascular events (MACE) remain unclear. We aimed to examine the associations of bouts of moderate-to-vigorous intermittent lifestyle physical activity (MV-ILPA) and the proportion of vigorous activity contributing within these bouts with mortality and MACE.

METHODS

In this prospective cohort study, we used data from the UK Biobank on adults who do not exercise (ie, those who did not report leisure-time exercise) who had wrist-worn accelerometry data available. Participants were followed up until Nov 30, 2022, with the outcome of interest of all-cause mortality obtained through linkage with NHS Digital of England and Wales, and the NHS Central Register and National Records of Scotland, and MACE obtained from inpatient hospitalisation data provided by the Hospital Episode Statistics for England, the Patient Episode Database for Wales, and the Scottish Morbidity Record for Scotland. MV-ILPA bouts were derived using a two-level Random Forest classifier and grouped as short (<1 min), medium (1 to <3 min; 3 to <5 min), and long (5 to <10 min). We further examined the dose-response relationship of the proportion of vigorous physical activity contributing to the MV-ILPA bout.

FINDINGS

Between June 1, 2013, and Dec 23, 2015, 103 684 Biobank participants wore an accelerometer on their wrist. 25 241 adults (mean age 61·8 years [SD 7·6]), of whom 14 178 (56·2%) were women, were included in our analysis of all-cause mortality. During a mean follow-up duration of 7·9 years (SD 0·9), 824 MACE and 1111 deaths occurred. Compared with bouts of less than 1 min, mortality risk was lower for bouts of 1 min to less than 3 min (hazard ratio [HR] 0·66 [0·53-0·81]), 3 min to less than 5 min (HR 0·56 [0·46-0·69]), and 5 to less than 10 min (HR 0·48 [0·39-0·59]). Similarly, compared with bouts of less than 1 min, risk of MACE was lower for bouts of 1 min to less than 3 min (HR 0·71 [0·54-0·93]), 3 min to less than 5 min (0·62 [0·48-0·81]), and 5 min to less than 10 min (0·59 [0·46-0·76]). Short bouts (<1 min) were associated with lower MACE risk only when bouts were comprised of at least 15% vigorous activity.

INTERPRETATION

Intermittent non-exercise physical activity was associated with lower mortality and MACE. Our results support the promotion of short intermittent bouts of non-exercise physical activity of moderate-to-vigorous intensity to improve longevity and cardiovascular health among adults who do not habitually exercise in their leisure time.

FUNDING

Australian National Health, Medical Research Council, and Wellcome Trust.

Plant-based dietary patterns, genetic predisposition and risk of colorectal cancer: a prospective study from the UK Biobank

BACKGROUND

Plant-based dietary patterns may affect colorectal cancer (CRC) related outcomes, while risks differ in the quality of plant foods. We aimed to examine the association of plant-based diet quality with risks of CRC incidence and mortality and whether this association was modified by genetic risk.

METHODS

This prospective cohort study included 186,675 participants free of cancer when the last dietary recall was completed. We calculated three plant-based diet indices (PDIs), i.e., the overall plant-based diet index (PDI), the healthful plant-based diet index (hPDI), and the unhealthful plant-based diet index (uPDI) representing adherence to plant-based diets with diverse quality. Genetic risk was characterized using a weighted polygenic risk score (PRS), capturing overall risk variants associated with CRC. Hazard ratios (HR) and 95% confidential intervals (CI) were estimated by the cause-specific Cox proportional hazards model.

RESULTS

Over a follow-up of 9.5 years, 2163 cases and 466 deaths from CRC were documented. The HR of CRC incidence was 0.88 (95% CI, 0.81-0.96) and 0.91 (95% CI, 0.84-0.99) per 10-score increase in PDI and hPDI, respectively. Compared to the lowest quartile, PDI, hPDI, and uPDI in the highest quartile were associated with a 13% decrease, a 15% decrease, and a 14% increase in risk of incident CRC, respectively. We found a joint association of genetic risk and PDIs with incident CRC, with the highest hazard observed in those carrying higher PRS and adhering to lower-quality PDIs. The inverse association of PDI and hPDI with CRC mortality was pronounced in males.

CONCLUSIONS

Our results suggested that better adherence to overall and healthful plant-based diets was associated with a lower risk of CRC, whereas an unhealthful plant-based diet was associated with a higher CRC risk. Consumption of a higher-quality plant-based diet combined with decreased genetic risk conferred less susceptibility to CRC. Our findings highlighted the importance of food quality when adhering to a plant-based dietary pattern for CRC prevention in the general population.

The Impact of Physical Activity Intensity on the Dynamic Progression of Cardiometabolic Multimorbidity: Prospective Cohort Study Using UK Biobank Data

BACKGROUND

Although many studies have reported on the associations between the amount of physical activity (PA) and the transitions of cardiometabolic multimorbidity (CMM), the evidence for PA intensity has not been fully evaluated.

OBJECTIVE

This study aimed to explore the impact of PA intensity on the dynamic progression of CMM.

METHODS

The prospective cohort of this study using data from the UK Biobank included 359,773 participants aged 37-73 years who were recruited from 22 centers between 2006 and 2010. The diagnoses of CMM, which included the copresence of type 2 diabetes (T2D), ischemic heart disease, and stroke, were obtained from first occurrence fields provided by the UK Biobank, which included data from primary care, hospital inpatient record, self-reported medical condition, and death registers. The PA intensity was assessed by the proportion of vigorous PA (VPA) to moderate to vigorous PA (MVPA). Multistate models were used to evaluate the effect of PA intensity on the dynamic progression of CMM. The first model (model A) included 5 transitions, namely free of cardiometabolic disease (CMD) to first occurrence of CMD (FCMD), free of CMD to death, FCMD to CMM, FCMD to mortality, and CMM to mortality. The other model (model B) used specific CMD, namely T2D, ischemic heart disease, and stroke, instead of FCMD and included 11 transitions in this study.

RESULTS

The mean age of the included participants (N=359,773) was 55.82 (SD 8.12) years at baseline, and 54.55% (196,271/359,773) of the participants were female. Compared with the participants with no VPA, participants with intensity levels of >0.75 to <1 for VPA to MVPA had a 13% and 27% lower risk of transition from free of CMD to FCMD (hazard ratio [HR] 0.87, 95% CI 0.83-0.91) and mortality (HR 0.73, 95% CI 0.66-0.79) in model A, respectively. The HR for the participants with no moderate PA was 0.82 (95% CI 0.73-0.92) compared with no VPA. There was a substantially protective effect of higher PA intensity on the transitions from free of CMD to T2D and from T2D to mortality, which reveals the importance of PA intensity for the transitions of T2D. More PA and greater intensity had a synergistic effect on decreasing the risk of the transitions from free of CMD to FCMD and mortality. Male participants, younger adults, adults with a higher BMI, current or previous smokers, and excessive alcohol drinkers could obtain more benefits from higher PA intensity for the lower risk of at least 1 transition from free of CMD, then to CMM, and finally to mortality.

CONCLUSIONS

This study suggests that higher PA intensity is an effective measure for preventing CMM and mortality in the early period of CMM development. Relevant interventions related to higher PA intensity should be conducted.

Long-term exposure to ambient air pollution, genetic susceptibility, and the incidence of bipolar disorder: A prospective cohort study

There is mounting recent evidence showing that air pollution exposure may be related to the risk of mental health, yet the association between long-term exposure to air pollution and the risk of incident bipolar disorder (BD) remains unclear. Thus we aim to identify associations between air pollution and the incidence of BD in a prospective population-based cohort. In total, 482,726 participants who were free of BD from the UK Biobank were included in this prospective study. We applied time-varying Cox proportional hazards models, accounting for relevant confounders, and used annual-year moving averages of air pollution as time-varying exposures. The genetic risk for BD was categorized into three categories (low, intermediate, and high) according to the tertiles of polygenic risk score. During a median of 10.79-year follow-up, 923 incident BD events were recorded. Long-term exposures to PM2.5, PM10, NO2, and NOx were associated with increased BD risk. Estimated HRs (95% CIs) for each interquartile range increase in PM2.5, PM10, NO2, and NOx concentrations were 1.31 (1.18-1.45), 1.19 (1.09-1.31), 1.19 (1.08-1.30), and 1.16 (1.07-1.26), respectively. Associations were still observed and even stronger at pollutant concentrations lower than WHO air quality guideline. In subgroup analysis stratified by genetic risk, we observed consistent associations between all pollutants and BD risk in intermediate and high genetic risk groups, but not in low genetic risk group. For example, the HRs (95% CIs) for PM2.5 were 1.00 (0.94-1.53), 1.30 (1.06-1.59), and 1.34 (1.16-1.54) in low, intermediate, and high genetic groups, respectively. In conclusion, long-term exposure to air pollution was significantly associated with an elevated risk of BD. Associations of air pollution with BD occurred only within intermediate and high genetic risk categories and were even stronger at the pollutants levels below WHO air quality guidelines. These findings could help inform policy makers regarding ambient air quality standards and BD management.

Phenotypic and genetic factors associated with donation of DNA and consent to record linkage for prescription history in the Australian Genetics of Depression Study

Samples can be prone to ascertainment and attrition biases. The Australian Genetics of Depression Study is a large publicly recruited cohort (n = 20,689) established to increase the understanding of depression and antidepressant treatment response. This study investigates differences between participants who donated a saliva sample or agreed to linkage of their records compared to those who did not. We observed that older, male participants with higher education were more likely to donate a saliva sample. Self-reported bipolar disorder, ADHD, panic disorder, PTSD, substance use disorder, and social anxiety disorder were associated with lower odds of donating a saliva sample, whereas anorexia was associated with higher odds of donation. Male and younger participants showed higher odds of agreeing to record linkage. Participants with higher neuroticism scores and those with a history of bipolar disorder were also more likely to agree to record linkage whereas participants with a diagnosis of anorexia were less likely to agree. Increased likelihood of consent was associated with increased genetic susceptibility to anorexia and reduced genetic risk for depression, and schizophrenia. Overall, our results show moderate differences among these subsamples. Most current epidemiological studies do not search for attrition biases at the genetic level. The possibility to do so is a strength of samples such as the AGDS. Our results suggest that analyses can be made more robust by identifying attrition biases both on the phenotypic and genetic level, and either contextualising them as a potential limitation or performing sensitivity analyses adjusting for them.

Identifying healthy individuals with Alzheimer's disease neuroimaging phenotypes in the UK Biobank

BACKGROUND

Identifying prediagnostic neurodegenerative disease is a critical issue in neurodegenerative disease research, and Alzheimer's disease (AD) in particular, to identify populations suitable for preventive and early disease-modifying trials. Evidence from genetic and other studies suggests the neurodegeneration of Alzheimer's disease measured by brain atrophy starts many years before diagnosis, but it is unclear whether these changes can be used to reliably detect prediagnostic sporadic disease.

METHODS

We trained a Bayesian machine learning neural network model to generate a neuroimaging phenotype and AD score representing the probability of AD using structural MRI data in the Alzheimer's Disease Neuroimaging Initiative (ADNI) Cohort (cut-off 0.5, AUC 0.92, PPV 0.90, NPV 0.93). We go on to validate the model in an independent real-world dataset of the National Alzheimer's Coordinating Centre (AUC 0.74, PPV 0.65, NPV 0.80) and demonstrate the correlation of the AD-score with cognitive scores in those with an AD-score above 0.5. We then apply the model to a healthy population in the UK Biobank study to identify a cohort at risk for Alzheimer's disease.

RESULTS

We show that the cohort with a neuroimaging Alzheimer's phenotype has a cognitive profile in keeping with Alzheimer's disease, with strong evidence for poorer fluid intelligence, and some evidence of poorer numeric memory, reaction time, working memory, and prospective memory. We found some evidence in the AD-score positive cohort for modifiable risk factors of hypertension and smoking.

CONCLUSIONS

This approach demonstrates the feasibility of using AI methods to identify a potentially prediagnostic population at high risk for developing sporadic Alzheimer's disease.

Chronotype and mortality - a 37-year follow-up study in Finnish adults

The UK Biobank study on chronotype and mortality suggested small increases of all-cause and cardiovascular mortality in a 6.5-year follow-up. Our aim was to constructively replicate findings from it in a longer follow-up. A questionnaire was administered to the population-based adult Finnish Twin Cohort in 1981 (response rate 84%). The study population included 23 854 participants who replied to the question: "Try to assess to what extent you are a morning person or an evening person," with four response alternatives (anchored from "clearly a morning person" to "clearly an evening person"). Vital status and cause of death data were provided by nationwide registers up to the end of 2018. Hazard ratios for mortality were computed based on 8728 deaths. Adjustments were made for education, alcohol, smoking, BMI, and sleep duration. The covariate adjusted model showed a 9% increase of all-cause mortality for the evening-type group (HR = 1.09, 95% CI 1.01-1.18), with attenuation mainly due to smoking and alcohol. Their importance was highlighted by observing no increased mortality among non-smokers who were at most light drinkers. There was no increase in any cause-specific mortality. Our results suggest that there is little or no independent contribution of chronotype to mortality.

Do associations of physical activity and sedentary behaviour with cardiovascular disease and mortality differ across socioeconomic groups? A prospective analysis of device-measured and self-reported UK Biobank data

OBJECTIVE

To examine if individual-level and area-level socioeconomic status (SES) modifies the association of moderate-to-vigorous physical activity (MVPA), domain-specific physical activity and sedentary behaviour with all-cause mortality (ACM) and incident cardiovascular disease (CVD).

METHODS

We used self-reported (International Physical Activity Questionnaire short form) and accelerometer-measured physical activity and sedentary behaviour data from the UK Biobank. We created an individual-level composite SES index using latent class analysis of household income, education and employment status. The Townsend Index was the measure of area-level SES. Cox proportional hazards regression models stratified across SES were used.

RESULTS

In 328 228 participants (mean age 55.9 (SD 8.1) years, 45% men) with an average follow-up of 12.1 (1.4) years, 18 033 deaths and 98 922 incident CVD events occurred. We found an increased ACM risk of low physical activity and high sedentary behaviour and an increased incident CVD risk of low accelerometer-measured moderate-to-vigorous physical activity (ACCEL_MVPA) and high sitting time. We observed statistically significant interactions for all exposures in ACM analyses by individual-level SES (p<0.05) but only for screen time in area-level SES-ACM analysis (p<0.001). Compared with high self-reported moderate-to-vigorous physical activity (IPAQ_MVPA), adjusted ACM HRs for low IPAQ_MVPA were 1.14 (95% CI 1.05 to .25), 1.15 (95% CI 1.06 to 1.24) and 1.22 (95% CI 1.13 to 1.31) in high, medium and low individual-level SES, respectively. There were higher detrimental associations of low ACCEL_MVPA with decreasing area-level SES for both outcomes and of high screen time with ACM in low area-level SES.

CONCLUSION

We found modest evidence suggesting that the detrimental associations of low MVPA and high screen time with ACM and incident CVD are accentuated in low SES groups.

Participation bias in the UK Biobank distorts genetic associations and downstream analyses

While volunteer-based studies such as the UK Biobank have become the cornerstone of genetic epidemiology, the participating individuals are rarely representative of their target population. To evaluate the impact of selective participation, here we derived UK Biobank participation probabilities on the basis of 14 variables harmonized across the UK Biobank and a representative sample. We then conducted weighted genome-wide association analyses on 19 traits. Comparing the output from weighted genome-wide association analyses (neffective = 94,643 to 102,215) with that from standard genome-wide association analyses (n = 263,464 to 283,749), we found that increasing representativeness led to changes in SNP effect sizes and identified novel SNP associations for 12 traits. While heritability estimates were less impacted by weighting (maximum change in h2, 5%), we found substantial discrepancies for genetic correlations (maximum change in rg, 0.31) and Mendelian randomization estimates (maximum change in βSTD, 0.15) for socio-behavioural traits. We urge the field to increase representativeness in biobank samples, especially when studying genetic correlates of behaviour, lifestyles and social outcomes.

Exploring causality from observational data: An example assessing whether religiosity promotes cooperation

Causal inference from observational data is notoriously difficult, and relies upon many unverifiable assumptions, including no confounding or selection bias. Here, we demonstrate how to apply a range of sensitivity analyses to examine whether a causal interpretation from observational data may be justified. These methods include: testing different confounding structures (as the assumed confounding model may be incorrect), exploring potential residual confounding and assessing the impact of selection bias due to missing data. We aim to answer the causal question 'Does religiosity promote cooperative behaviour?' as a motivating example of how these methods can be applied. We use data from the parental generation of a large-scale (n = approximately 14,000) prospective UK birth cohort (the Avon Longitudinal Study of Parents and Children), which has detailed information on religiosity and potential confounding variables, while cooperation was measured via self-reported history of blood donation. In this study, there was no association between religious belief or affiliation and blood donation. Religious attendance was positively associated with blood donation, but could plausibly be explained by unmeasured confounding. In this population, evidence that religiosity causes blood donation is suggestive, but rather weak. These analyses illustrate how sensitivity analyses can aid causal inference from observational research.

Inpatient care utilisation and expenditure associated with objective physical activity: econometric analysis of the UK Biobank

BACKGROUND

Physical inactivity increases the risk of chronic disease and mortality. The high prevalence of physical inactivity in the UK is likely to increase financial pressure on the National Health Service. The UK Biobank Study offered an opportunity to assess the impact of physical inactivity on healthcare use and spending using individual-level data and objective measures of physical activity. The objective of this study was to assess the associations between objectively measured physical activity levels and future inpatient days and costs in adults in the UK Biobank study.

METHODS

We conducted an econometric analysis of the UK Biobank study, a large prospective cohort study. The participants (n = 86,066) were UK adults aged 43-79 who had provided sufficient valid accelerometer data. Hospital inpatient days and costs were discounted and standardised to mean monthly values per person to adjust for the variation in follow-up times. Econometric models adjusted for BMI, long-standing illness, and other sociodemographic factors.

RESULTS

Mean follow-up time for the sample was 28.11 (SD 7.65) months. Adults in the most active group experienced 0.037 fewer days per month (0.059-0.016) and 14.1% lower inpatient costs ( - £3.81 [ - £6.71 to  - £0.91] monthly inpatient costs) compared to adults in the least active group. The relationship between physical activity and inpatient costs was stronger in women compared to men and amongst those in the lowest income group compared to others. The findings remained significant across various sensitivity analyses.

CONCLUSIONS

Increasing physical activity levels in the UK may reduce inpatient hospitalisations and costs, especially in women and lower-income groups.

Socioeconomic Deprivation, Genetic Risk, and Incident Dementia

INTRODUCTION

Socioeconomic factors and genetic predisposition are established risk factors for dementia. It remains unclear whether associations of socioeconomic deprivation with dementia incidence are modified by genetic risk.

METHODS

Participants in the UK Biobank aged ≥60 years and of European ancestry without dementia at baseline (2006-2010) were eligible for the analysis, with the main exposures area-level deprivation based on the Townsend Deprivation Index and individual-level socioeconomic deprivation based on car and home ownership, housing type and income, and polygenic risk of dementia. Dementia was ascertained in hospital and death records. Analysis was conducted in 2021.

RESULTS

In this cohort study, 196,368 participants (mean [SD] age=64.1 [2.9] years, 52.7% female) were followed up for 1,545,316 person-years (median [IQR] follow-up=8.0 [7.4-8.6] years). In high genetic risk and high area-level deprivation, 1.71% (95% CI=1.44, 2.01) developed dementia compared with 0.56% (95% CI=0.48, 0.65) in low genetic risk and low-to-moderate area-level deprivation (hazard ratio=2.31; 95% CI=1.84, 2.91). In high genetic risk and high individual-level deprivation, 1.78% (95% CI=1.50, 2.09) developed dementia compared with 0.31% (95% CI=0.20, 0.45) in low genetic risk and low individual-level deprivation (hazard ratio=4.06; 95% CI=2.63, 6.26). There was no significant interaction between genetic risk and area-level (p=0.77) or individual-level (p=0.07) deprivation. An imaging substudy including 11,083 participants found a greater burden of white matter hyperintensities associated with higher socioeconomic deprivation.

CONCLUSIONS

Individual-level and area-level socioeconomic deprivation were associated with increased dementia risk. Dementia prevention interventions may be particularly effective if targeted to households and areas with fewer socioeconomic resources, regardless of genetic vulnerability.

Bidirectional associations of sleep and discretionary screen time in adults: Longitudinal analysis of the UK biobank

The direction of the association between discretionary screen time (DST) and sleep in the adult population is largely unknown. We examined the bidirectional associations of DST and sleep patterns in a longitudinal sample of adults in the general population. A total of 31,361 UK Biobank study participants (52% female, 56.1 ± 7.5 years) had two repeated measurements of discretionary screen time (TV viewing and leisure-time computer use) and self-reported sleep patterns (five sleep health characteristics) between 2012 and 2018 (follow-up period of 6.9 ± 2.2 years). We categorised daily DST into three groups (low, <3 h/day; medium, 3-4 h/day; and high, >4 h/day), and calculated a sleep pattern composite score comprising morning chronotype, adequate sleep duration (7-8 h/day), never or rare insomnia, never or rare snoring, and infrequent daytime sleepiness. The overall sleep pattern was categorised into three groups (healthy: ≥ 4; intermediate: 2-3; and poor: ≤ 1 healthy sleep characteristic). Multiple logistic regression analyses were applied to assess associations between DST and sleep with adjustments for potential confounders. Participants with either an intermediate (OR: 1.40; 95% CI: 1.15, 1.71) or a poor (OR: 1.16; 95% CI: 1.10, 1.24) sleep pattern at baseline showed higher odds for high DST at follow-up, compared with those with a healthy baseline sleep pattern. Participants with medium (OR: 1.40; 95% CI: 1.14, 1.71) or high DST (OR: 1.62; 95% CI: 1.30, 2.00) at baseline showed higher odds for poor sleep at follow-up, compared with participants with a low DST. In conclusion, our findings provide consistent evidence that a high DST at baseline is associated with poor sleep over a nearly 7 year follow-up period, and vice versa.

Associations of Physical Activity With Breast Cancer Risk: Findings From the UK Biobank Prospective Cohort Study

PURPOSE

Although physical activity (PA) has been consistently associated with breast cancer, existing evidence is limited to self-reported physical activity, which is prone to dilution bias. Therefore, this aims to examine the associations of device-measured PA domains with breast cancer risk and whether it differs by menopausal status.

METHODS

Prospective cohort study. Data from 48,286 women from the UK Biobank cohort were analyzed. A wrist triaxial accelerometer was used to collect physical activity data for light, moderate, vigorous, moderate to vigorous, and total PA. Cox proportional models were performed to examine the association between PA domains, menopausal status, and breast cancer risk.

RESULTS

Eight hundred thirty-six breast cancer cases were diagnosed during a median of 5.4 years (interquartile range: 4.7-5.9). For total PA, those in the most active quartile had a 26% lower risk of breast cancer (Hazard ratio [HR]: 0.74; 95% confidence interval [CI], 0.61-0.91) compared with those least active. Similar results were observed for light PA (HR: 0.79; 95% CI, 0.64-0.96), and moderate to vigorous PA (HR: 0.78; 95% CI, 0.64-0.96). However, moderate PA (HR: 0.73; 95% CI, 0.44-1.19) and vigorous PA (HR: 0.77; 95% CI, 0.56-1.05) was nonsignificant. No evidence of interaction between PA domains and menopause status was found (P > .10).

CONCLUSION

High levels of PA are associated with a lower risk of breast cancer with similar magnitude of associations observed across different intensity domains.

Association of Circulating Branched-Chain Amino Acids with Cardiovascular Diseases: A Mendelian Randomization Study

BACKGROUND

There have been reports linking branched-chain amino acids (BCAAs) to the hazard of various cardiovascular diseases (CVDs); however, the causal role of this relationship is still unclear. We conducted a study using bi-directional two-sample Mendelian randomization (MR) with the aim of investigating the possible causal correlation between BCAAs and 13 types of cardiovascular diseases.

METHODS

The study analyzed data of the largest genome-wide association studies (GWAS) published for the total BCAAs, encompassing isoleucine, leucine, and valine, which were obtained from the UK Biobank, as well as data for 13 cardiovascular endpoints from the MRC-IEU, the FinnGen consortium, and the EBI database. The approach of the primary dissection used became the inverse-variance-weighted (IVW) approach, with additional analyses using the MR-PRESSO global test as well as MR-Egger regression with a view to determining horizontal pleiotropy. Heterogeneity was evaluated by means of Cochran's Q test. The study also conducted logistic regression dissection for the sake of investigating the correlation between cardiovascular events and serum BCAAs in the UK biobank cohort study.

RESULTS

In this study, it was found that individuals with a genetic predisposition to more elevated levels for circulating total BCAAs had a higher hazard of peripheral arterial disease (OR 1.400, 95% CI 1.063, 1.844; p = 0.017) in addition to stroke (OR 1.266, 95% CI 1.012, 1.585; p = 0.039); circulating valine casually increased the risk of intracerebral hemorrhage (OR 1.760, 95% CI 1.116, 2.776; p = 0.015), along with stroke (OR 1.269, 95% CI 1.079, 1.492; p = 0.004); genetically predicted isoleucine showed a positive association with peripheral arterial disease (OR 1.466, 95% CI 1.044, 2.058; p = 0.027), along with cardioembolic stroke (OR 1.547, 95% CI 1.126, 2.124; p = 0.007); furthermore, leucine causally associated with stroke (OR 1.310, 95% CI 1.031, 1.663, p = 0.027). In the UK Biobank cohort study, we detected that total BCAAs (OR: 1.285; 95% CI: 1.009, 1.636), valine (OR: 1.287; 95% CI: 1.009, 1.642), and isoleucine (OR: 1.352; 95% CI: 1.064, 1.718) were independently linked to stroke, but not leucine (OR: 1.146; 95% CI: 0.901, 1.458). No such association was found for BCAAs with peripheral arterial disease and intracerebral hemorrhage in the cohort study.

CONCLUSIONS

In summary, circulating total BCAAs and valine may be causally associated with stroke. The association of BCAAs with other CVD events needs further study.

Are associations of leisure-time physical activity with mortality attenuated by high levels of chronic ambient fine particulate matter (PM2.5) in older adults? A prospective cohort study

BACKGROUND AND PURPOSE

Although leisure-time physical activity (PA) has established health benefits in older adults, it is equivocal if exercising in environments with high levels of PM_2.5 concentrations is equally beneficial for them. To explore the independent and joint associations of ambient PM_2.5 and PA with all-cause mortality among adults aged 60 or older and to assess the modifying effect of age (60-74 years vs. 75+ years) on the joint associations.

METHODS

A prospective cohort study based on the MJ Cohort repeat examinations (2005-2016) and the Taiwan Air Quality Monitoring Network and death registry linkages (2005-2022). We included MJ Cohort participants aged 60 or more at baseline who attended the health check-ups at least twice (n = 21,760). Metabolic equivalent hours per week (MET-h/week) of leisure-time PA were computed. Multivariable adjusted associations were examined using time-varying Cox proportional hazard models.

RESULTS

There were 3539 all-cause deaths over a mean follow-up of 12.81 (SD = 3.67) years. Ambient PM_2.5 and physical inactivity are both independently associated with all-cause mortality. The joint associations of PA and PM_2.5 concentrations with all-cause mortality differed in the young-old (60-74 years) and the older-old (75+ years) (P for interaction = 0.01); Higher levels of long-term PM_2.5 exposures (≥25 μg/m³) had little influence on the associations between PA and mortality in the young-old (HR = 0.68 (0.56-0.83) and HR = 0.72 (0.59-0.88) for participants with 7.5-<15 and 15+ MET-h/week respectively) but eliminated associations between exposure and outcome in the older-old (HR = 0.91 (0.69-01.21) and HR = 1.02 (0.76-1.38) for participants with 7.5-<15 and 15+ MET-h/week).

CONCLUSION

Long-term exposures to higher PM_2.5 concentrations may eliminate the beneficial associations of PA with all-cause mortality among adults aged 75 and over.

Influence of poor sleep on cardiovascular disease-free life expectancy: a multi-resource-based population cohort study

BACKGROUND

The complexity of sleep hinders the formulation of sleep guidelines. Recent studies suggest that different unhealthy sleep characteristics jointly increase the risks for cardiovascular disease (CVD). This study aimed to estimate the differences in CVD-free life expectancy between people with different sleep profiles.

METHODS

We included 308,683 middle-aged adults from the UK Biobank among whom 140,181 had primary care data linkage. We used an established composite sleep score comprising self-reported chronotype, duration, insomnia complaints, snoring, and daytime sleepiness to derive three sleep categories: poor, intermediate, and healthy. We also identified three clinical sleep disorders captured by primary care and inpatient records within 2 years before enrollment in the cohort: insomnia, sleep-related breathing disorders, and other sleep disorders. We estimated sex-specific CVD-free life expectancy with three-state Markov models conditioning on survival at age 40 across different sleep profiles and clinical disorders.

RESULTS

We observed a gradual loss in CVD-free life expectancy toward poor sleep such as, compared with healthy sleepers, poor sleepers lost 1.80 [95% CI 0.96-2.75] and 2.31 [1.46-3.29] CVD-free years in females and males, respectively, while intermediate sleepers lost 0.48 [0.41-0.55] and 0.55 [0.49-0.61] years. Among men, those with clinical insomnia or sleep-related breathing disorders lost CVD-free life by 3.84 [0.61-8.59] or 6.73 [5.31-8.48] years, respectively. Among women, sleep-related breathing disorders or other sleep disorders were associated with 7.32 [5.33-10.34] or 1.43 [0.20-3.29] years lost, respectively.

CONCLUSIONS

Both self-reported and doctor-diagnosed poor sleep are negatively associated with CVD-free life, especially pronounced in participants with sleep-related breathing disorders.

Associations of changes in physical activity and diet with incident obesity and changes in adiposity: Longitudinal findings from the UK Biobank

We examined the association of changes in physical activity and diet with obesity development and changes in body fat percentage, body mass index, and waist circumference. 31,344 adults without obesity at baseline (age = 56.0 ± 7.5 years; female = 49.1%) from the UK Biobank were included. Physical activity was categorised based on public health guidelines as: inactive; insufficient; and sufficient. Diet category was assigned based on an established composited score that included consumption of fruits, vegetables, fish, red meat (unprocessed), and processed meat. Diet was categorised as: poor; reasonable; and good. Physical activity and diet changes were categorised based on changes in category: worsened; stable; increased (physical activity)/improved (diet). During a mean follow up of 6.8 (SD = ±2.3) years, 1354 (4.3%) participants developed obesity. Compared to stable physical activity-diet, increasing physical activity was associated with the lowest obesity odds, across diet changes (e.g., OR [95%CI]: diet worsened (0.89 [0.69, 1.15]); diet improved (0.65 [0.48, 0.89])). Increasing physical activity with improved diet was associated with the largest difference in body fat percentage (β:-0.62 [-0.82, -0.41]), body mass index (-0.37 [-0.47, -0.28]), and waist circumference (-1.21 [-1.63, -0.79]). Excluding adults with a history of smoking, or major illness, lowered obesity odds among participants with increased physical activity by an additional 11%-21%. In those who decreased physical activity obesity was attenuated when combined with diet improvement. Improvements in physical activity or diet mutually attenuated the deleterious associations of the other behaviour's deterioration. In most analyses, increases in physical activity conferred consistent positive associations against the development of obesity, across dietary change groups.

Association Between Daily Alcohol Intake and Risk of All-Cause Mortality: A Systematic Review and Meta-analyses

Importance

A previous meta-analysis of the association between alcohol use and all-cause mortality found no statistically significant reductions in mortality risk at low levels of consumption compared with lifetime nondrinkers. However, the risk estimates may have been affected by the number and quality of studies then available, especially those for women and younger cohorts.

Objective

To investigate the association between alcohol use and all-cause mortality, and how sources of bias may change results.

Data Sources

A systematic search of PubMed and Web of Science was performed to identify studies published between January 1980 and July 2021.

Study Selection

Cohort studies were identified by systematic review to facilitate comparisons of studies with and without some degree of controls for biases affecting distinctions between abstainers and drinkers. The review identified 107 studies of alcohol use and all-cause mortality published from 1980 to July 2021.

Data Extraction and Synthesis

Mixed linear regression models were used to model relative risks, first pooled for all studies and then stratified by cohort median age (<56 vs ≥56 years) and sex (male vs female). Data were analyzed from September 2021 to August 2022.

Main Outcomes and Measures

Relative risk estimates for the association between mean daily alcohol intake and all-cause mortality.

Results

There were 724 risk estimates of all-cause mortality due to alcohol intake from the 107 cohort studies (4 838 825 participants and 425 564 deaths available) for the analysis. In models adjusting for potential confounding effects of sampling variation, former drinker bias, and other prespecified study-level quality criteria, the meta-analysis of all 107 included studies found no significantly reduced risk of all-cause mortality among occasional (>0 to <1.3 g of ethanol per day; relative risk [RR], 0.96; 95% CI, 0.86-1.06; P = .41) or low-volume drinkers (1.3-24.0 g per day; RR, 0.93; P = .07) compared with lifetime nondrinkers. In the fully adjusted model, there was a nonsignificantly increased risk of all-cause mortality among drinkers who drank 25 to 44 g per day (RR, 1.05; P = .28) and significantly increased risk for drinkers who drank 45 to 64 and 65 or more grams per day (RR, 1.19 and 1.35; P < .001). There were significantly larger risks of mortality among female drinkers compared with female lifetime nondrinkers (RR, 1.22; P = .03).

Conclusions and Relevance

In this updated systematic review and meta-analysis, daily low or moderate alcohol intake was not significantly associated with all-cause mortality risk, while increased risk was evident at higher consumption levels, starting at lower levels for women than men.