Genetic and Environmental Factors and Cardiovascular Disease Risk in Adolescents.

Importance: Cardiovascular risk factors in youth have been associated with future cardiovascular disease (CVD), but conventional observational studies are vulnerable to genetic and environmental confounding. Objective: To examine the role of genetic and environmental factors shared by full siblings in the association of adolescent cardiovascular risk factors with future CVD. Design, Setting, and Participants: This is a nationwide cohort study with full sibling comparisons. All men who underwent mandatory military conscription examinations in Sweden between 1972 and 1995 were followed up until December 31, 2016. Data analysis was performed from May 1 to November 10, 2022. Exposures: Body mass index (BMI), cardiorespiratory fitness, blood pressure, handgrip strength, and a combined risk z score in late adolescence. Main Outcomes and Measures: The primary outcome was fatal or nonfatal CVD, as recorded in the National Inpatient Register or the Cause of Death Register before 2017. Results: A total of 1 138 833 men (mean [SD] age, 18.3 [0.8] years), of whom 463 995 were full brothers, were followed up for a median (IQR) of 32.1 (26.7-37.7) years, during which 48 606 experienced a CVD outcome (18 598 among full brothers). All risk factors were associated with CVD, but the effect of controlling for unobserved genetic and environmental factors shared by full siblings varied. In the sibling analysis, hazard ratios for CVD (top vs bottom decile) were 2.10 (95% CI, 1.90-2.32) for BMI, 0.77 (95% CI, 0.68-0.88) for cardiorespiratory fitness, 1.45 (95% CI, 1.32-1.60) for systolic blood pressure, 0.90 (95% CI, 0.82-0.99) for handgrip strength, and 2.19 (95% CI, 1.96-2.46) for the combined z score. The percentage attenuation in these hazard ratios in the sibling vs total cohort analysis ranged from 1.1% for handgrip strength to 40.0% for cardiorespiratory fitness. Consequently, in the sibling analysis, the difference in cumulative CVD incidence at age 60 years (top vs bottom decile) was 7.2% (95% CI, 5.9%-8.6%) for BMI and 1.8% (95% CI, 1.0%-2.5%) for cardiorespiratory fitness. Similarly, in the sibling analysis, hypothetically shifting everyone in the worst deciles of BMI to the middle decile would prevent 14.9% of CVD at age 60 years, whereas the corresponding number for cardiorespiratory fitness was 5.3%. Conclusions and Relevance: In this Swedish national cohort study, cardiovascular risk factors in late adolescence, especially a high BMI, were important targets for CVD prevention, independently of unobserved genetic and environmental factors shared by full siblings. However, the role of adolescent cardiorespiratory fitness in CVD may have been overstated by conventional observational studies.

Safety and effectiveness of monovalent COVID-19 mRNA vaccination and risk factors for hospitalisation caused by the omicron variant in 0.8 million adolescents: A nationwide cohort study in Sweden.

BACKGROUND: Real-world evidence on the safety and effectiveness of Coronavirus Disease 2019 (COVID-19) vaccination against severe disease caused by the omicron variant among adolescents is sparse. In addition, evidence on risk factors for severe COVID-19 disease, and whether vaccination is similarly effective in such risk groups, is unclear. The aim of the present study was therefore to examine the safety and effectiveness of monovalent COVID-19 mRNA vaccination against COVID-19 hospitalisation, and risk factors for COVID-19 hospitalisation in adolescents. METHODS AND FINDINGS: A cohort study was conducted using Swedish nationwide registers. The safety analysis included all individuals in Sweden born between 2003 and 2009 (aged 11.3 to 19.2 years) given at least 1 dose of monovalent mRNA vaccine (N = 645,355), and never vaccinated controls (N = 186,918). The outcomes included all-cause hospitalisation and 30 selected diagnoses until 5 June 2022. The vaccine effectiveness (VE) against COVID-19 hospitalisation, and risk factors for hospitalisation, were evaluated in adolescents given 2 doses of monovalent mRNA vaccine (N = 501,945), as compared to never vaccinated controls (N = 157,979), for up to 5 months follow-up during an omicron predominant period (1 January 2022 to 5 June 2022). Analyses were adjusted for age, sex, baseline date, and whether the individual was born in Sweden. The safety analysis showed that vaccination was associated with 16% lower (95% confidence interval (CI) [12, 19], p < 0.001) risk of all-cause hospitalisation, and with marginal differences between the groups regarding the 30 selected diagnoses. In the VE analysis, there were 21 cases (0.004%) of COVID-19 hospitalisation among 2-dose recipients and 26 cases (0.016%) among controls, resulting in a VE of 76% (95% CI [57, 87], p < 0.001). Predominant risk factors for COVID-19 hospitalisation included previous infections (bacterial infection, tonsillitis, and pneumonia) (odds ratio [OR]: 14.3, 95% CI [7.7, 26.6], p < 0.001), and cerebral palsy/development disorders (OR: 12.7, 95% CI [6.8, 23.8], p < 0.001), with similar estimates of VE in these subgroups as in the total cohort. The number needed to vaccinate with 2 doses to prevent 1 case of COVID-19 hospitalisation was 8,147 in the total cohort and 1,007 in those with previous infections or developmental disorders. None of the individuals hospitalised due to COVID-19 died within 30 days. Limitations of this study include the observational design and the possibility of unmeasured confounding. CONCLUSIONS: In this nationwide study of Swedish adolescents, monovalent COVID-19 mRNA vaccination was not associated with an increased risk of any serious adverse events resulting in hospitalisation. Vaccination with 2 doses was associated with a lower risk of COVID-19 hospitalisation during an omicron predominant period, also among those with certain predisposing conditions who should be prioritised for vaccination. However, COVID-19 hospitalisation in the general population of adolescents was extremely rare, and additional doses in this population may not be warranted at this stage.

Prospective Association of Daily Steps With Cardiovascular Disease: A Harmonized Meta-Analysis.

BACKGROUND: Taking fewer than the widely promoted "10 000 steps per day" has recently been associated with lower risk of all-cause mortality. The relationship of steps and cardiovascular disease (CVD) risk remains poorly described. A meta-analysis examining the dose-response relationship between steps per day and CVD can help inform clinical and public health guidelines. METHODS: Eight prospective studies (20 152 adults [ie, ≥18 years of age]) were included with device-measured steps and participants followed for CVD events. Studies quantified steps per day and CVD events were defined as fatal and nonfatal coronary heart disease, stroke, and heart failure. Cox proportional hazards regression analyses were completed using study-specific quartiles and hazard ratios (HR) and 95% CI were meta-analyzed with inverse-variance-weighted random effects models. RESULTS: The mean age of participants was 63.2±12.4 years and 52% were women. The mean follow-up was 6.2 years (123 209 person-years), with a total of 1523 CVD events (12.4 per 1000 participant-years) reported. There was a significant difference in the association of steps per day and CVD between older (ie, ≥60 years of age) and younger adults (ie, <60 years of age). For older adults, the HR for quartile 2 was 0.80 (95% CI, 0.69 to 0.93), 0.62 for quartile 3 (95% CI, 0.52 to 0.74), and 0.51 for quartile 4 (95% CI, 0.41 to 0.63) compared with the lowest quartile. For younger adults, the HR for quartile 2 was 0.79 (95% CI, 0.46 to 1.35), 0.90 for quartile 3 (95% CI, 0.64 to 1.25), and 0.95 for quartile 4 (95% CI, 0.61 to 1.48) compared with the lowest quartile. Restricted cubic splines demonstrated a nonlinear association whereby more steps were associated with decreased risk of CVD among older adults. CONCLUSIONS: For older adults, taking more daily steps was associated with a progressively decreased risk of CVD. Monitoring and promoting steps per day is a simple metric for clinician-patient communication and population health to reduce the risk of CVD.

Time-varying risk of death after SARS-CoV-2 infection in Swedish long-term care facility residents: a matched cohort study.

OBJECTIVES: To evaluate whether SARS-CoV-2 infection in residents of long-term care (LTC) facilities is associated with higher mortality after the acute phase of infection, and to estimate survival in uninfected residents. DESIGN: Extended follow-up of a previous, propensity score-matched, retrospective cohort study based on the Swedish Senior Alert register. SETTING: LTC facilities in Sweden. PARTICIPANTS: n=3604 LTC residents with documented SARS-CoV-2 until 15 September 2020 matched to 3604 uninfected controls using time-dependent propensity scores on age, sex, health status, comorbidities, prescription medications, geographical region and Senior Alert registration time. In a secondary analysis (n=3731 in each group), geographical region and Senior Alert registration time were not matched for in order to increase the follow-up time in controls and allow for an estimation of median survival. PRIMARY OUTCOME MEASURES: All-cause mortality until 24 October 2020, tracked using the National Cause of Death Register. RESULTS: Median age was 87 years and 65% were women. Excess mortality peaked at 5 days after documented SARS-CoV-2-infection (HR 21.5, 95% CI 15.9 to 29.2), after which excess mortality decreased. From the second month onwards, mortality rate became lower in infected residents than controls. The HR for death during days 61-210 of follow-up was 0.76 (95% CI 0.62 to 0.93). The median survival of uninfected controls was 1.6 years, which was much lower than the national life expectancy in Sweden at age 87 (5.05 years in men, 6.07 years in women). CONCLUSIONS: The risk of death after SARS-CoV-2 infection in LTC residents peaked after 5 days and decreased after 2 months, probably because the frailest residents died during the acute phase, leaving healthier residents remaining. The limited life expectancy in this population suggests that LTC resident status should be accounted for when estimating years of life lost due to COVID-19.

Effectiveness of a fourth dose of mRNA COVID-19 vaccine against all-cause mortality in long-term care facility residents and in the oldest old: A nationwide, retrospective cohort study in Sweden.

Background: The effect of a fourth dose of COVID-19 vaccine on the risk of death in the oldest and frailest individuals is unknown. Methods: Two matched cohorts were formed using Swedish nationwide registers. In the first, residents of long-term care facilities (LTCFs) given a fourth dose of an mRNA vaccine from 1 January 2022 onwards were matched 1:1 on birth year and county of residence to residents given at least a third dose (N = 24,524). In the second, all individuals aged ≥80 years given a fourth dose were matched 1:1 to individuals given at least a third dose (N = 394,104). Cox regression models were used to estimate hazard ratios for all-cause mortality in fourth-dose recipients as compared with in third-dose recipients, with relative vaccine effectiveness (VE) estimated as 1 minus the hazard ratio. Findings: From 7 days after baseline and onwards, there were 1119 deaths in the LTCF cohort during a median follow-up of 77 days and a maximum follow-up of 126 days. During days 7 to 60, the VE of the fourth dose was 39% (95% CI, 29-48), which declined to 27% (95% CI, -2-48) during days 61 to 126. In the cohort of all individuals aged ≥80 years, there were 5753 deaths during a median follow-up of 73 days and a maximum follow-up of 143 days. During days 7 to 60, the VE of the fourth dose was 71% (95% CI, 69-72), which declined to 54% (95% CI, 48-60) during days 61 to 143. The VE of the fourth dose seemed stronger when it was compared to third-dose recipients where at least four months had passed since vaccination (P < 0·001 for interaction). Interpretation: As compared with a third dose, a fourth dose of an mRNA COVID-19 vaccine, administered during the Omicron era, was associated with reduced risk of death from all causes in residents of LTCFs and in the oldest old during the first two months, after which the protection became slightly lower. These findings suggest that a fourth dose may prevent premature mortality in the oldest and frailest even after the emergence of the Omicron variant, although the timing of vaccination seems to be important with respect to the slight waning observed after two months. Funding: There was no funding source for this study.

Risk of SARS-CoV-2 reinfection and COVID-19 hospitalisation in individuals with natural and hybrid immunity: a retrospective, total population cohort study in Sweden.

BACKGROUND: Real-world evidence supporting vaccination against COVID-19 in individuals who have recovered from a previous SARS-CoV-2 infection is sparse. We aimed to investigate the long-term protection from a previous infection (natural immunity) and whether natural immunity plus vaccination (hybrid immunity) was associated with additional protection. METHODS: In this retrospective cohort study, we formed three cohorts using Swedish nationwide registers managed by the Public Health Agency of Sweden, the National Board of Health and Welfare, and Statistics Sweden. Cohort 1 included unvaccinated individuals with natural immunity matched pairwise on birth year and sex to unvaccinated individuals without natural immunity at baseline. Cohort 2 and cohort 3 included individuals vaccinated with one dose (one-dose hybrid immunity) or two doses (two-dose hybrid immunity) of a COVID-19 vaccine, respectively, after a previous infection, matched pairwise on birth year and sex to individuals with natural immunity at baseline. Outcomes of this study were documented SARS-CoV-2 infection from March 20, 2020, until Oct 4, 2021, and inpatient hospitalisation with COVID-19 as main diagnosis from March 30, 2020, until Sept 5, 2021. FINDINGS: Cohort 1 was comprised of 2 039 106 individuals, cohort 2 of 962 318 individuals, and cohort 3 of 567 810 individuals. During a mean follow-up of 164 days (SD 100), 34 090 individuals with natural immunity in cohort 1 were registered as having had a SARS-CoV-2 reinfection compared with 99 168 infections in non-immune individuals; the numbers of hospitalisations were 3195 and 1976, respectively. After the first 3 months, natural immunity was associated with a 95% lower risk of SARS-CoV-2 infection (adjusted hazard ratio [aHR] 0·05 [95% CI 0·05-0·05] p<0·001) and an 87% (0·13 [0·11-0·16]; p<0·001) lower risk of COVID-19 hospitalisation for up to 20 months of follow-up. During a mean follow-up of 52 days (SD 38) in cohort 2, 639 individuals with one-dose hybrid immunity were registered with a SARS-CoV-2 reinfection, compared with 1662 individuals with natural immunity (numbers of hospitalisations were eight and 113, respectively). One-dose hybrid immunity was associated with a 58% lower risk of SARS-CoV-2 reinfection (aHR 0·42 [95% CI 0·38-0·47]; p<0·001) than natural immunity up to the first 2 months, with evidence of attenuation thereafter up to 9 months (p<0·001) of follow-up. During a mean follow-up of 66 days (SD 53) in cohort 3, 438 individuals with two-dose hybrid immunity were registered as having had a SARS-CoV-2 reinfection, compared with 808 individuals with natural immunity (numbers of hospitalisations were six and 40, respectively). Two-dose hybrid immunity was associated with a 66% lower risk of SARS-CoV-2 reinfection (aHR 0·34 [95% CI 0·31-0·39]; p<0·001) than natural immunity, with no significant attenuation up to 9 months (p=0·07). To prevent one reinfection in the natural immunity cohort during follow-up, 767 individuals needed to be vaccinated with two doses. Both one-dose (HR adjusted for age and baseline date 0·06 [95% CI 0·03-0·12]; p<0·001) and two-dose (HR adjusted for age and baseline date 0·10 [0·04-0·22]; p<0·001) hybrid immunity were associated with a lower risk of COVID-19 hospitalisation than natural immunity. INTERPRETATION: The risk of SARS-CoV-2 reinfection and COVID-19 hospitalisation in individuals who have survived and recovered from a previous infection remained low for up to 20 months. Vaccination seemed to further decrease the risk of both outcomes for up to 9 months, although the differences in absolute numbers, especially in hospitalisations, were small. These findings suggest that if passports are used for societal restrictions, they should acknowledge either a previous infection or vaccination as proof of immunity, as opposed to vaccination only. FUNDING: None.

Daily steps and all-cause mortality: a meta-analysis of 15 international cohorts.

BACKGROUND: Although 10 000 steps per day is widely promoted to have health benefits, there is little evidence to support this recommendation. We aimed to determine the association between number of steps per day and stepping rate with all-cause mortality. METHODS: In this meta-analysis, we identified studies investigating the effect of daily step count on all-cause mortality in adults (aged ≥18 years), via a previously published systematic review and expert knowledge of the field. We asked participating study investigators to process their participant-level data following a standardised protocol. The primary outcome was all-cause mortality collected from death certificates and country registries. We analysed the dose-response association of steps per day and stepping rate with all-cause mortality. We did Cox proportional hazards regression analyses using study-specific quartiles of steps per day and calculated hazard ratios (HRs) with inverse-variance weighted random effects models. FINDINGS: We identified 15 studies, of which seven were published and eight were unpublished, with study start dates between 1999 and 2018. The total sample included 47 471 adults, among whom there were 3013 deaths (10·1 per 1000 participant-years) over a median follow-up of 7·1 years ([IQR 4·3-9·9]; total sum of follow-up across studies was 297 837 person-years). Quartile median steps per day were 3553 for quartile 1, 5801 for quartile 2, 7842 for quartile 3, and 10 901 for quartile 4. Compared with the lowest quartile, the adjusted HR for all-cause mortality was 0·60 (95% CI 0·51-0·71) for quartile 2, 0·55 (0·49-0·62) for quartile 3, and 0·47 (0·39-0·57) for quartile 4. Restricted cubic splines showed progressively decreasing risk of mortality among adults aged 60 years and older with increasing number of steps per day until 6000-8000 steps per day and among adults younger than 60 years until 8000-10 000 steps per day. Adjusting for number of steps per day, comparing quartile 1 with quartile 4, the association between higher stepping rates and mortality was attenuated but remained significant for a peak of 30 min (HR 0·67 [95% CI 0·56-0·83]) and a peak of 60 min (0·67 [0·50-0·90]), but not significant for time (min per day) spent walking at 40 steps per min or faster (1·12 [0·96-1·32]) and 100 steps per min or faster (0·86 [0·58-1·28]). INTERPRETATION: Taking more steps per day was associated with a progressively lower risk of all-cause mortality, up to a level that varied by age. The findings from this meta-analysis can be used to inform step guidelines for public health promotion of physical activity. FUNDING: US Centers for Disease Control and Prevention.

Trends in Hip Fracture Incidence, Length of Hospital Stay, and 30-Day Mortality in Sweden from 1998-2017: A Nationwide Cohort Study.

In this nationwide cohort study, we investigated trends in hip fracture incidence, hospital length of stay (LOS), and 30-day mortality after admission in Sweden. The cohort included all individuals in Sweden aged ≥ 50 years with a first hip fracture diagnosis during 1998-2017 (N = 313,761). The outcomes were hip fracture incidence and 30-day mortality. The results showed that the incidence of hip fracture decreased from 79.2 to 46.7/10,000 population in women and from 35.7 to 26.5/10,000 population in men. In contrast, 30-day mortality increased from 4.3% to 6.2% in women (P < 0.001) and from 8.4% to 11.1% in men (P < 0.001). Strong risk factors (P < 1 × 10-25 for all) for 30-day mortality were older age, male sex, and shorter LOS. From 1998 to 2017, LOS decreased by on average 4 days and was shorter in both male and female aged ≥ 90 years compared to those aged 80-89 (P < 0.001 for comparisons). In conclusion, despite population aging, hip fracture incidence in Sweden has decreased over the last 20 years. However, short-term mortality has increased, which to some extent may partly be explained by the fact that LOS has decreased without being adapted to important risk factors.

Risk of infection, hospitalisation, and death up to 9 months after a second dose of COVID-19 vaccine: a retrospective, total population cohort study in Sweden.

BACKGROUND: Vaccine effectiveness against COVID-19 beyond 6 months remains incompletely understood. We aimed to investigate the effectiveness of COVID-19 vaccination against the risk of infection, hospitalisation, and death during the first 9 months after vaccination for the total population of Sweden. METHODS: This retrospective, total population cohort study was done using data from Swedish nationwide registers. The cohort comprised all individuals vaccinated with two doses of ChAdOx1 nCoV-19, mRNA-1273, or BNT162b2, and matched unvaccinated individuals, with data on vaccinations and infections updated until Oct 4, 2021. Two outcomes were evaluated. The first was SARS-CoV-2 infection of any severity from Jan 12 to Oct 4, 2021. The second was severe COVID-19, defined as hospitalisation for COVID-19 or all-cause 30-day mortality after confirmed infection, from March 15 to Sept 28, 2021. FINDINGS: Between Dec 28, 2020, and Oct 4, 2021, 842 974 individuals were fully vaccinated (two doses), and were matched (1:1) to an equal number of unvaccinated individuals (total study cohort n=1 685 948). For the outcome SARS-CoV-2 infection of any severity, the vaccine effectiveness of BNT162b2 waned progressively over time, from 92% (95% CI 92 to 93; p<0·001) at 15-30 days, to 47% (39 to 55; p<0·001) at 121-180 days, and to 23% (-2 to 41; p=0·07) from day 211 onwards. Waning was slightly slower for mRNA-1273, with a vaccine effectiveness of 96% (94 to 97; p<0·001) at 15-30 days and 59% (18 to 79; p=0·012) from day 181 onwards. Waning was also slightly slower for heterologous ChAdOx1 nCoV-19 plus an mRNA vaccine, for which vaccine effectiveness was 89% (79 to 94; p<0·001) at 15-30 days and 66% (41 to 80; p<0·001) from day 121 onwards. By contrast, vaccine effectiveness for homologous ChAdOx1 nCoV-19 vaccine was 68% (52 to 79; p<0·001) at 15-30 days, with no detectable effectiveness from day 121 onwards (-19% [-98 to 28]; p=0·49). For the outcome of severe COVID-19, vaccine effectiveness waned from 89% (82 to 93; p<0·001) at 15-30 days to 64% (44 to 77; p<0·001) from day 121 onwards. Overall, there was some evidence for lower vaccine effectiveness in men than in women and in older individuals than in younger individuals. INTERPRETATION: We found progressively waning vaccine effectiveness against SARS-CoV-2 infection of any severity across all subgroups, but the rate of waning differed according to vaccine type. With respect to severe COVID-19, vaccine effectiveness seemed to be better maintained, although some waning became evident after 4 months. The results strengthen the evidence-based rationale for administration of a third vaccine dose as a booster. FUNDING: None.

Association of dog ownership with accelerometer-measured physical activity and daily steps in 70-year-old individuals: a population-based cross-sectional study.

BACKGROUND: Dog ownership (DO) has been associated with higher levels of self-reported walking and physical activity. However, compared to device-based measures, self-reported measures of physical activity may suffer from bias due to recall and social desirability. They are also incapable of quantifying light-intensity physical activity (LPA) and step volume, both of which may have important health benefits, especially for older adults. In this study, we investigated the association of DO with accelerometer-measured physical activity of different intensities and daily steps in 70-year-old individuals. METHODS: This was a population-based cross-sectional study including 1406 participants aged 70 years [54.1% female] who participated in a health survey in Umeå, Sweden between February 2017-November 2019. All participants self-reported DO [yes/no]. Daily averages of LPA, moderate-to-vigorous-intensity physical activity (MVPA), and steps per day [steps/d] were measured for 1 week using hip-mounted Actigraph GT3X+ accelerometers. Associations were investigated using linear- and logistic regression models, adjusted for sociodemographic and health-related factors, date of examination, and accelerometer wear time. RESULTS: The prevalence of DO was 14.1% [N = 199]. After adjustment for all covariates, DO was associated with 19.2 more minutes/d of LPA [95% CI, 8.8-29.6], 11.4 more minutes/d of MVPA [95% CI, 8.0-14.9] and 1738 more steps/d [95% CI, 1326-2149]. DO was also associated with twice the odds of meeting the physical activity recommendations [OR, 2.07, 95% CI, 1.48-2.90]. Exploratory interaction analyses showed that the association between DO and steps/d was stronger [Pinteraction = 0.030] in female [ß = 2165, 95% CI, 1585-2744] than in male [ß =1255, 95% CI, 664-1845], with a similar trend for MVPA [Pinteraction = 0.082]. CONCLUSIONS: In this study of community-dwelling 70-year-old individuals, DO was associated with higher levels of daily LPA, MVPA, and steps. With the limitation of the observational design of the study, these findings add knowledge regarding the beneficial role that DO may play for promoting physical activity in the older population. In turn, these findings could support the development and evaluation of targeted interventions seeking to promote dog-friendly environments and facilitate dog walking in the community.

Effectiveness of heterologous ChAdOx1 nCoV-19 and mRNA prime-boost vaccination against symptomatic Covid-19 infection in Sweden: A nationwide cohort study.

BACKGROUND: The effectiveness of heterologous prime-boost Coronavirus disease 2019 (Covid-19) vaccination is currently unknown. METHODS: From individuals vaccinated with two doses against Covid-19 in Sweden until July 5, 2021 (N=3,445,061), we formed a study cohort including 94,569 individuals that had received heterologous ChAdOx1 nCoV-19 / BNT162b2 prime-boost vaccination, 16,402 individuals that received heterologous ChAdOx1 nCoV-19 / mRNA-1273 prime-boost vaccination, and 430,100 individuals that received homologous ChAdOx1 nCoV-19 / ChAdOx1 nCoV-19 prime-boost vaccination. In addition, 180,716 individuals were selected who were unvaccinated at the date of vaccination in the corresponding case. Unvaccinated individuals were censored at first dose of any vaccine. Baseline was the date of the second dose of any vaccine, with the same date in the corresponding unvaccinated individual. The outcome included incident symptomatic Covid-19 infection occurring >14 days after baseline. FINDINGS: During a mean follow-up time of 76 (range 1-183) days, symptomatic Covid-19 infection was confirmed in 187 individuals with heterologous vaccine schedules (incidence rate: 2.0/100,000 person-days) and in 306 individuals from the unvaccinated control group (incidence rate: 7.1/100,000 person-days). The adjusted vaccine effectiveness was 67% (95% CI, 59-73, P<0.001) for heterologous ChAdOx1 nCoV-19 / BNT162b2 prime-boost vaccination, and 79% (95% CI, 62-88, P<0.001) for heterologous ChAdOx1 nCoV-19 / mRNA-1273 prime-boost vaccination. When combined and analysed together, the two heterologous vaccine schedules had an effectiveness of 68% (95% CI, 61-74, P<0.001) which was significantly greater (Pinteraction<0.001) than the 50% effectiveness for homologous ChAdOx1 nCoV-19 / ChAdOx1 nCoV-19 (95% CI, 41-58, P<0.001). INTERPRETATION: The findings of this study suggest that the use of heterologous ChAdOx1 nCoV-19 and mRNA prime-boost vaccination is an effective alternative to increase population immunity against Covid-19, including against the Delta variant which dominated the confirmed cases during the study period. These findings could have important implications for vaccination strategies and logistics, and consequently in the battle against the Covid-19 pandemic.

Association Between Risk of COVID-19 Infection in Nonimmune Individuals and COVID-19 Immunity in Their Family Members.

Importance: The association between COVID-19 immunity within families and the risk of infection in nonimmune family members is unknown. Objective: To investigate the association between risk of COVID-19 in nonimmune individuals and the number of their family members with known immunity acquired from a previous COVID-19 infection or full vaccination (2 vaccine doses). Design, Setting, and Participants: In this cohort study of data from nationwide registries in Sweden, all individuals who acquired immunity from either previous COVID-19 infection or full vaccination until May 26, 2021, were considered for inclusion. Each person with immunity was matched 1:1 to an individual without immunity from an identified cohort of individuals with families comprising 2 to 5 members. Exposures: Number of immune family members in each family on April 14, 2021 (index date), who acquired immunity from a previous COVID-19 infection or full vaccination (2 doses of the mRNA-1273, BNT162b2 mRNA, or ChAdOx1 nCoV-19 vaccine). Main Outcomes and Measures: Incident COVID-19 infection in nonimmune family members from April 15 to May 26, 2021. Results: A total of 1 789 728 individuals from 814 806 families were included in the analysis. Each family comprised 2 to 5 family members, with a mean (SD) age at baseline of 51.3 (19.5) years. During a mean (range) follow-up time of 26.3 (1-40) days, 88 797 of 1 549 989 (5.7%) nonimmune family members (mean [SD] age, 51.6 [17.7] years; 790 276 men [51.0%]) were diagnosed with COVID-19. There was an inverse dose-response association between the number of immune members in each family and the risk of incident COVID-19 infection in nonimmune family members. Nonimmune families with 1 immune family member had a 45% to 61% lower risk of contracting COVID-19 (hazard ratio [HR], 0.39-0.55; 95% CI, 0.37-0.61, P < .001). The risk reduction increased to 75% to 86% in families with 2 immune family members (HR, 0.14-0.25; 95% CI, 0.11-0.27; P < .001), 91% to 94% with 3 immune family members (HR, 0.06-0.09; 95% CI, 0.04-0.10; P < .001), and 97% with 4 immune family members (HR, 0.03; 95% CI, 0.02-0.05; P < .001). The results were similar for the outcome of COVID-19 infection that was severe enough to warrant a hospital stay. Conclusions and Relevance: In this cohort study, family members without immunity had a 45% to 97% lower risk of contracting COVID-19 as the number of immune family members increased. Vaccination is a key strategy for decreasing the transmission of the virus within families.

Does exercise prevent major non-communicable diseases and premature mortality? A critical review based on results from randomized controlled trials.

Observational studies show that physical activity is strongly associated with a reduced risk of premature mortality and major non-communicable diseases. We reviewed to which extent these associations have been confirmed in randomized controlled trials (RCTs) for the outcomes of mortality, cardiovascular disease (CVD), type 2 diabetes (T2D), and fracture. The results show that exercise does not reduce all-cause mortality and incident CVD in older adults or in people with chronic conditions, based on RCTs comprising ∼50,000 participants. The results also indicate a lack of effect on cardiovascular mortality in people with chronic conditions, based on RCTs comprising ∼11,000 participants. Furthermore, there is inconsistent evidence regarding the effect of exercise on fractures in older adults, based on RCTs comprising ∼40,000 participants. Finally, based on RCTs comprising ∼17,000 participants, exercise reduces T2D incidence in people with prediabetes when combined with dietary modification, although evidence for the individual effect of exercise is lacking. Identified shortcomings of the current evidence include risks of publication bias, lack of high-quality studies in certain high-risk populations, and inconstant evidence with respect to some outcomes. Thus, additional large trials would be of value, especially with fracture as the primary outcome. In conclusion, according to current RCT evidence, exercise can prevent T2D assuming it is combined with dietary intervention. However, the current evidence shows that exercise does not prevent premature mortality or CVD, with inconsistent evidence for fractures.

Excess Mortality After COVID-19 in Swedish Long-Term Care Facilities.

OBJECTIVE: To compare 30-day mortality in long-term care facility (LTCF) residents with and without COVID-19 and to investigate the impact of 31 potential risk factors for mortality in COVID-19 cases. DESIGN: Retrospective cohort study. SETTING AND PARTICIPANTS: All residents of LTCFs registered in Senior Alert, a Swedish national database of health examinations in older adults, during 2019-2020. METHODS: We selected residents with confirmed COVID-19 until September 15, 2020, along with time-dependent propensity score-matched controls without COVID-19. Exposures were COVID-19, age, sex, comorbidities, medications, and other patient characteristics. The outcome was all-cause 30-day mortality. RESULTS: A total of 3731 residents (median age 87 years, 64.5% female) with COVID-19 were matched to 3731 controls without COVID-19. Thirty-day mortality was 39.9% in COVID-19 cases and 5.7% in controls [relative risk 7.05, 95% confidence interval (CI) 6.10-8.14]. In COVID-19 cases, the odds ratio (OR) for 30-day mortality was 2.44 (95% CI 1.57-3.81) in cases aged 80-84 years, 2.99 (95% CI 1.93-4.65) in cases aged 85-89 years, and 3.28 (95% CI 2.11-5.10) in cases aged ≥90 years, as compared with cases aged <70 years. Other risk factors for mortality among COVID-19 cases included male sex (OR, 2.60, 95% CI 2.22-3.05), neuropsychological conditions (OR, 2.18; 95% CI 1.76-2.71), impaired walking ability (OR, 1.45, 95% CI 1.17-1.78), urinary and bowel incontinence (OR 1.51, 95% CI 1.22-1.85), diabetes (OR 1.36, 95% CI 1.14-1.62), chronic kidney disease (OR 1.37, 95% CI 1.11-1.68) and previous pneumonia (OR 1.57, 95% CI 1.32-1.85). Nutritional factors, cardiovascular diseases, and antihypertensive medications were not significantly associated with mortality. CONCLUSIONS AND IMPLICATIONS: In Swedish LTCFs, COVID-19 was associated with a large excess in mortality after controlling for an extensive number of risk factors. Beyond older age and male sex, several prevalent clinical risk factors independently contributed to higher mortality. These findings suggest that reducing transmission of COVID-19 in LTCFs will likely prevent a considerable number of deaths.

Associations of Visceral Adipose Tissue and Skeletal Muscle Density With Incident Stroke, Myocardial Infarction, and All-Cause Mortality in Community-Dwelling 70-Year-Old Individuals: A Prospective Cohort Study.

Background Aging leads to increased visceral adipose tissue (VAT) and reduced skeletal muscle density. To which extent these are associated with the risk of stroke, myocardial infarction (MI), and all-cause mortality in older adults is unknown. Methods and Results A total of 3294 70-year-old individuals (49.6% women) underwent a health examination in Umeå, Sweden, during 2012 to 2018. VAT and muscle density were measured using dual-energy x-ray absorptiometry and peripheral quantitative computed tomography. Cases of stroke, MI, and all-cause mortality were collected through national registers. Cox regressions were used to calculate hazard ratios (HRs) and 95% CIs per SD greater VAT and per SD lower muscle density. During a mean follow-up of 3.6 years, there were 108 cases of stroke or MI, and 97 deaths. Greater VAT (adjusted HR [aHR], 1.56; 95% CI, 1.09-2.22), but not lower muscle density (aHR, 1.14; 95% CI, 0.97-1.34), was associated with increased risk of stroke or MI. Neither VAT (aHR, 0.95; 95% CI, 0.65-1.41) nor muscle density (aHR, 1.11; 95% CI, 0.92-1.34) was associated with all-cause mortality. The association of VAT with stroke or MI was only significant in men (aHR, 1.86; 95% CI, 1.19-2.91) but not women (aHR, 0.60; 95% CI, 0.25-1.42) (Pinteraction=0.038). Conclusions With the limitation of being an observational study, these findings suggest that VAT is an important obesity-related predictor of cardiovascular risk in 70-year-old men, and by implication, that decreasing VAT may potentially reduce their risk of cardiovascular disease.

Risk factors for COVID-19 diagnosis, hospitalization, and subsequent all-cause mortality in Sweden: a nationwide study.

We conducted a nationwide, registry-based study to investigate the importance of 34 potential risk factors for coronavirus disease 2019 (COVID-19) diagnosis, hospitalization (with or without intensive care unit [ICU] admission), and subsequent all-cause mortality. The study population comprised all COVID-19 cases confirmed in Sweden by mid-September 2020 (68,575 non-hospitalized, 2494 ICU hospitalized, and 13,589 non-ICU hospitalized) and 434,081 randomly sampled general-population controls. Older age was the strongest risk factor for hospitalization, although the odds of ICU hospitalization decreased after 60-69 years and, after controlling for other risk factors, the odds of non-ICU hospitalization showed no trend after 40-49 years. Residence in a long-term care facility was associated with non-ICU hospitalization. Male sex and the presence of at least one investigated comorbidity or prescription medication were associated with both ICU and non-ICU hospitalization. Three comorbidities associated with both ICU and non-ICU hospitalization were asthma, hypertension, and Down syndrome. History of cancer was not associated with COVID-19 hospitalization, but cancer in the past year was associated with non-ICU hospitalization, after controlling for other risk factors. Cardiovascular disease was weakly associated with non-ICU hospitalization for COVID-19, but not with ICU hospitalization, after adjustment for other risk factors. Excess mortality was observed in both hospitalized and non-hospitalized COVID-19 cases. These results confirm that severe COVID-19 is related to age, sex, and comorbidity in general. The study provides new evidence that hypertension, asthma, Down syndrome, and residence in a long-term care facility are associated with severe COVID-19.

Associations of Light, Moderate to Vigorous, and Total Physical Activity With the Prevalence of Metabolic Syndrome in 4,652 Community-Dwelling 70-Year-Olds: A Population-Based Cross-Sectional Study.

In this cross-sectional study, the authors investigated the associations of objectively measured physical activity (PA) with the prevalence of metabolic syndrome (MetS) in older adults. Accelerometer-derived light-intensity PA, moderate to vigorous PA, and steps per day were measured in (N = 4,652) 70-year-olds in Umeå, Sweden, during May 2012-November 2019. The MetS was assessed according to the American Heart Association/ National Heart, Lung and Blood Institute criteria. The prevalence of MetS was 49.3%. Compared with the reference, the odds ratios for MetS in increasing quartiles of light-intensity PA were 0.91 (0.77-1.09), 0.75 (0.62-0.89), and 0.66 (0.54-0.80). For moderate to vigorous PA, the corresponding odds ratios were 0.79 (0.66-0.94), 0.67 (0.56-0.80), and 0.56 (0.46-0.67). For steps per day, the odds ratios were 0.65 (0.55-0.78), 0.55 (0.46-0.65), and 0.45 (0.36-0.55). In summary, this study shows that greater amounts of PA, regardless of intensity, are associated with lower odds of MetS. With the limitation of being an observational study, these findings may have implications for the prevention of MetS in older adults.

Associations of Objectively Measured Physical Activity and Sedentary Time with the Risk of Stroke, Myocardial Infarction or All-Cause Mortality in 70-Year-Old Men and Women: A Prospective Cohort Study.

OBJECTIVE: To study the associations of objectively measured physical activity (PA) and sedentary time (ST) with the combined outcome of incident stroke, myocardial infarction (MI) or all-cause mortality in older adults. METHODS: N = 3343 men and women aged 70 who participated in a health survey between 2012 and 2017 were included. Actigraph GT3X+ accelerometers were used to measure light-intensity PA (LPA), moderate-intensity PA (MPA) and ST for 1 week. Incident cases of cardiovascular disease (CVD) in terms of stroke or MI, and all-cause mortality were identified using national registers. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using multivariable-adjusted Cox regressions. RESULTS: During a mean follow-up of 2.7 years (0.1-5.6), there were 124 events of CVD or all-cause mortality. After adjusting for potential confounders and mediators, every 30-min/day increment in LPA was associated with 11% lower risk of CVD or all-cause mortality (HR 0.89, 95% CI 0.82-0.97), and every 30-min/day increment in MPA was associated with 36% lower risk (HR 0.64, 95% CI 0.48-0.84). Every 1-h/day increment in ST increased the risk of the outcomes by 33% (HR 1.33, 95% CI 1.14-1.56), although there was no significant association among participants who performed ≥ 30 min/day MPA (HR 1.11, 95% CI 0.82-1.50, P = 0.034 for interaction). None of the associations were modified by sex (P > 0.4 for all). CONCLUSION: Objectively measured LPA and MPA are each associated with lower risk of stroke, MI or all-cause mortality in 70-year-old individuals, while ST is associated with increased risk. The greatest risk reduction is observed for MPA, which also appears to attenuate some of the increased risks associated with ST.

Daily step count and incident diabetes in community-dwelling 70-year-olds: a prospective cohort study.

BACKGROUND: Older adults with diabetes take fewer steps per day than those without diabetes. The purpose of the present study was to investigate the association of daily step count with incident diabetes in community-dwelling 70-year-olds. METHODS: This prospective cohort study included N = 3055 community-dwelling 70-year-olds (52% women) who participated in a health examination in Umeå, Sweden during 2012-2017, and who were free from diabetes at baseline. Daily step count was measured for 1 week using Actigraph GT3X+ accelerometers. Cases of diabetes were collected from the Swedish National Patient Register. The dose-response association was evaluated graphically using a flexible parametric model, and hazard ratios (HR) with 95% confidence intervals (CI) were calculated using Cox regressions. RESULTS: During a mean follow-up of 2.6 years, diabetes was diagnosed in 81 participants. There was an inverse nonlinear dose-response association between daily step count and incident diabetes, with a steep decline in risk of diabetes from a higher daily step count until around 6000 steps/day. From there, the risk decreased at a slower rate until it leveled off at around 8000 steps/day. A threshold of 4500 steps/day was found to best distinguish participants with the lowest risk of diabetes, where those taking ≥ 4500 steps/day, had 59% lower risk of diabetes, compared to those taking fewer steps (HR, 0.41, 95% CI, 0.25-0.66). Adjusting for visceral adipose tissue (VAT) attenuated the association (HR, 0.64, 95% CI, 0.38-1.06), which was marginally altered after further adjusting for sedentary time, education and other cardiometabolic risk factors and diseases (HR, 0.58, 95% CI, 0.32-1.05). CONCLUSIONS: A higher daily step count is associated with lower risk of incident diabetes in community-dwelling 70-year-olds. The greatest benefits occur at the lower end of the activity range, and much earlier than 10,000 steps/day. With the limitation of being an observational study, these findings suggest that promoting even a modest increase in daily step count may help to reduce the risk of diabetes in older adults. Because VAT appears to partly mediate the association, lifestyle interventions targeting diabetes should apart from promoting physical activity also aim to prevent and reduce central obesity.

Digital exercise interventions for improving measures of central obesity: a systematic review.

OBJECTIVES: We aimed to systematically review the potential benefits of digital exercise interventions for improving measures of central obesity including visceral adipose tissue (VAT) and anthropometric surrogates for VAT in overweight or centrally obese adults aged 18 or over. METHODS: A systematic literature search was conducted in three databases up until March 2020 (PROSPERO registration nr CRD42019126764). RESULTS: N = 5 studies including 438 participants (age 48-80) with body mass index ≥ 25 kg/m2 met the eligibility criteria and were included. The duration of the interventions ranged from 8 to 24 weeks. No study measured the primary outcome VAT, although in N = 4 studies, waist circumference (WC) decreased by between 1.3 and 5.6 cm in the intervention groups. CONCLUSIONS: This systematic review shows that there is no evidence for the effects of digital exercise on VAT, although digital exercise may decrease WC. These findings highlight the need for additional randomized controlled trials to confirm the findings with respect to WC, and to further investigate the effects of digital exercise on VAT. Together, this may have important implications for reducing the burden of physical inactivity and obesity.