Associations of cereal grains intake with cardiovascular disease and mortality across 21 countries in Prospective Urban and Rural Epidemiology study

Objective To evaluate the association between intakes of refined grains, whole grains, and white rice with cardiovascular disease, total mortality, blood lipids, and blood pressure in the Prospective Urban and Rural Epidemiology (PURE) study.

Design Prospective cohort study.

Setting PURE study in 21 countries.

Participants 148 858 participants with median follow-up of 9.5 years.

Exposures Country specific validated food frequency questionnaires were used to assess intakes of refined grains, whole grains, and white rice.

Main outcome measure Composite of mortality or major cardiovascular events (defined as death from cardiovascular causes, non-fatal myocardial infarction, stroke, or heart failure). Hazard ratios were estimated for associations of grain intakes with mortality, major cardiovascular events, and their composite by using multivariable Cox frailty models with random intercepts to account for clustering by centre.

Results Analyses were based on 137 130 participants after exclusion of those with baseline cardiovascular disease. During follow-up, 9.2% (n=12 668) of these participants had a composite outcome event. The highest category of intake of refined grains (≥350 g/day or about 7 servings/day) was associated with higher risk of total mortality (hazard ratio 1.27, 95% confidence interval 1.11 to 1.46; P for trend=0.004), major cardiovascular disease events (1.33, 1.16 to 1.52; P for trend<0.001), and their composite (1.28, 1.15 to 1.42; P for trend<0.001) compared with the lowest category of intake (<50 g/day). Higher intakes of refined grains were associated with higher systolic blood pressure. No significant associations were found between intakes of whole grains or white rice and health outcomes.

Conclusion High intake of refined grains was associated with higher risk of mortality and major cardiovascular disease events. Globally, lower consumption of refined grains should be considered.

Reference: BMJ 2021;372:m4948

Association between low density lipoprotein and all cause and cause specific mortality in Denmark: prospective cohort study

Objective To determine the association between levels of low density lipoprotein cholesterol (LDL-C) and all cause mortality, and the concentration of LDL-C associated with the lowest risk of all cause mortality in the general population.

Design Prospective cohort study.

Setting Denmark; the Copenhagen General Population Study recruited in 2003-15 with a median follow-up of 9.4 years.

Participants Individuals randomly selected from the national Danish Civil Registration System.

Main outcome measures Baseline levels of LDL-C associated with risk of mortality were evaluated on a continuous scale (restricted cubic splines) and by a priori defined centile categories with Cox proportional hazards regression models. Main outcome was all cause mortality. Secondary outcomes were cause specific mortality (cardiovascular, cancer, and other mortality).

Results Among 108 243 individuals aged 20-100, 11 376 (10.5%) died during the study, at a median age of 81. The association between levels of LDL-C and the risk of all cause mortality was U shaped, with low and high levels associated with an increased risk of all cause mortality. Compared with individuals with concentrations of LDL-C of 3.4-3.9 mmol/L (132-154 mg/dL; 61st-80th centiles), the multivariable adjusted hazard ratio for all cause mortality was 1.25 (95% confidence interval 1.15 to 1.36) for individuals with LDL-C concentrations of less than 1.8 mmol/L (<70 mg/dL; 1st-5th centiles) and 1.15 (1.05 to 1.27) for LDL-C concentrations of more than 4.8 mmol/L (>189 mg/dL; 96th-100th centiles). The concentration of LDL-C associated with the lowest risk of all cause mortality was 3.6 mmol/L (140 mg/dL) in the overall population and in individuals not receiving lipid lowering treatment, compared with 2.3 mmol/L (89 mg/dL) in individuals receiving lipid lowering treatment. Similar results were seen in men and women, across age groups, and for cancer and other mortality, but not for cardiovascular mortality. Any increase in LDL-C levels was associated with an increased risk of myocardial infarction.

Conclusions In the general population, low and high levels of LDL-C were associated with an increased risk of all cause mortality, and the lowest risk of all cause mortality was found at an LDL-C concentration of 3.6 mmol/L (140 mg/dL).

Reference: BMJ 2020;371:m4266

Living risk prediction algorithm (QCOVID) for risk of hospital admission and mortality from coronavirus 19 in adults: national derivation and validation cohort study

Objective To derive and validate a risk prediction algorithm to estimate hospital admission and mortality outcomes from coronavirus disease 2019 (covid-19) in adults.

Design Population based cohort study.

Setting and participants QResearch database, comprising 1205 general practices in England with linkage to covid-19 test results, Hospital Episode Statistics, and death registry data. 6.08 million adults aged 19-100 years were included in the derivation dataset and 2.17 million in the validation dataset. The derivation and first validation cohort period was 24 January 2020 to 30 April 2020. The second temporal validation cohort covered the period 1 May 2020 to 30 June 2020.

Main outcome measures The primary outcome was time to death from covid-19, defined as death due to confirmed or suspected covid-19 as per the death certification or death occurring in a person with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the period 24 January to 30 April 2020. The secondary outcome was time to hospital admission with confirmed SARS-CoV-2 infection. Models were fitted in the derivation cohort to derive risk equations using a range of predictor variables. Performance, including measures of discrimination and calibration, was evaluated in each validation time period.

Results 4384 deaths from covid-19 occurred in the derivation cohort during follow-up and 1722 in the first validation cohort period and 621 in the second validation cohort period. The final risk algorithms included age, ethnicity, deprivation, body mass index, and a range of comorbidities. The algorithm had good calibration in the first validation cohort. For deaths from covid-19 in men, it explained 73.1% (95% confidence interval 71.9% to 74.3%) of the variation in time to death (R²); the D statistic was 3.37 (95% confidence interval 3.27 to 3.47), and Harrell’s C was 0.928 (0.919 to 0.938). Similar results were obtained for women, for both outcomes, and in both time periods. In the top 5% of patients with the highest predicted risks of death, the sensitivity for identifying deaths within 97 days was 75.7%. People in the top 20% of predicted risk of death accounted for 94% of all deaths from covid-19.

Conclusion The QCOVID population based risk algorithm performed well, showing very high levels of discrimination for deaths and hospital admissions due to covid-19. The absolute risks presented, however, will change over time in line with the prevailing SARS-C0V-2 infection rate and the extent of social distancing measures in place, so they should be interpreted with caution. The model can be recalibrated for different time periods, however, and has the potential to be dynamically updated as the pandemic evolves.

Reference: BMJ 2020;371:m3731

Life Expectancy after Bariatric Surgery in the Swedish Obese Subjects Study

Obesity shortens life expectancy. Bariatric surgery is known to reduce the long-term relative risk of death, but its effect on life expectancy is unclear.

METHODS

We used the Gompertz proportional hazards regression model to compare mortality and life expectancy among patients treated with either bariatric surgery (surgery group) or usual obesity care (control group) in the prospective, controlled Swedish Obese Subjects (SOS) study and participants in the SOS reference study (reference cohort), a random sample from the general population.

RESULTS

In total, 2007 and 2040 patients were included in the surgery group and the control group, respectively, and 1135 participants were included in the reference cohort. At the time of the analysis (December 31, 2018), the median duration of follow-up for mortality was 24 years (interquartile range, 22 to 27) in the surgery group and 22 years (interquartile range, 21 to 27) in the control group; data on mortality were available for 99.9% of patients in the study. In the SOS reference cohort, the median duration of follow-up was 20 years (interquartile range, 19 to 21), and data on mortality were available for 100% of participants. In total, 457 patients (22.8%) in the surgery group and 539 patients (26.4%) in the control group died (hazard ratio, 0.77; 95% confidence interval [CI], 0.68 to 0.87; P<0.001). The corresponding hazard ratio was 0.70 (95% CI, 0.57 to 0.85) for death from cardiovascular disease and 0.77 (95% CI, 0.61 to 0.96) for death from cancer. The adjusted median life expectancy in the surgery group was 3.0 years (95% CI, 1.8 to 4.2) longer than in the control group but 5.5 years shorter than in the general population. The 90-day postoperative mortality was 0.2%, and 2.9% of the patients in the surgery group underwent repeat surgery.

CONCLUSIONS

Among patients with obesity, bariatric surgery was associated with longer life expectancy than usual obesity care. Mortality remained higher in both groups than in the general population. (Funded by the Swedish Research Council and others; SOS ClinicalTrials.gov number, NCT01479452. opens in new tab.)

Reference: N Engl J Med 2020; 383:1535-1543

Effect of exercise training for five years on all cause mortality in older adults—the Generation 100 study: randomised controlled trial

Objective To evaluate the effect of five years of supervised exercise training compared with recommendations for physical activity on mortality in older adults (70-77 years).

Design Randomised controlled trial.

Setting General population of older adults in Trondheim, Norway.

Participants 1567 of 6966 individuals born between 1936 and 1942.

Intervention Participants were randomised to two sessions weekly of high intensity interval training at about 90% of peak heart rate (HIIT, n=400), moderate intensity continuous training at about 70% of peak heart rate (MICT, n=387), or to follow the national guidelines for physical activity (n=780; control group); all for five years.

Main outcome measure All cause mortality. An exploratory hypothesis was that HIIT lowers mortality more than MICT.

Results Mean age of the 1567 participants (790 women) was 72.8 (SD 2.1) years. Overall, 87.5% of participants reported to have overall good health, with 80% reporting medium or high physical activity levels at baseline. All cause mortality did not differ between the control group and combined MICT and HIIT group. When MICT and HIIT were analysed separately, with the control group as reference (observed mortality of 4.7%), an absolute risk reduction of 1.7 percentage points was observed after HIIT (hazard ratio 0.63, 95% confidence interval 0.33 to 1.20) and an absolute increased risk of 1.2 percentage points after MICT (1.24, 0.73 to 2.10). When HIIT was compared with MICT as reference group an absolute risk reduction of 2.9 percentage points was observed (0.51, 0.25 to 1.02) for all cause mortality. Control participants chose to perform more of their physical activity as HIIT than the physical activity undertaken by participants in the MICT group. This meant that the controls achieved an exercise dose at an intensity between the MICT and HIIT groups.

Conclusion This study suggests that combined MICT and HIIT has no effect on all cause mortality compared with recommended physical activity levels. However, we observed a lower all cause mortality trend after HIIT compared with controls and MICT.

Trial registration ClinicalTrials.gov NCT01666340.

Reference: BMJ 2020;371:m3485

Menstrual cycle regularity and length across the reproductive lifespan and risk of premature mortality: prospective cohort study

Objective To evaluate whether irregular or long menstrual cycles throughout the life course are associated with all cause and cause specific premature mortality (age <70 years).

Design Prospective cohort study.

Setting Nurses’ Health Study II (1993-2017).

Participants 79 505 premenopausal women without a history of cardiovascular disease, cancer, or diabetes and who reported the usual length and regularity of their menstrual cycles at ages 14-17 years, 18-22 years, and 29-46 years.

Main outcome measures Hazard ratios and 95% confidence intervals for all cause and cause specific premature mortality (death before age 70 years) were estimated from multivariable Cox proportional hazards models.

Results During 24 years of follow-up, 1975 premature deaths were documented, including 894 from cancer and 172 from cardiovascular disease. Women who reported always having irregular menstrual cycles experienced higher mortality rates during follow-up than women who reported very regular cycles in the same age ranges. The crude mortality rate per 1000 person years of follow-up for women reporting very regular cycles and women reporting always irregular cycles were 1.05 and 1.23 for cycle characteristics at ages 14-17 years, 1.00 and 1.37 for cycle characteristics at ages 18-22 years, and 1.00 and 1.68 for cycle characteristics at ages 29-46 years. The corresponding multivariable adjusted hazard ratios for premature death during follow-up were 1.18 (95% confidence interval 1.02 to 1.37), 1.37 (1.09 to 1.73), and 1.39 (1.14 to 1.70), respectively. Similarly, women who reported that their usual cycle length was 40 days or more at ages 18-22 years and 29-46 years were more likely to die prematurely than women who reported a usual cycle length of 26-31 days in the same age ranges (1.34, 1.06 to 1.69; and 1.40, 1.17 to 1.68, respectively). These relations were strongest for deaths related to cardiovascular disease. The higher mortality associated with long and irregular menstrual cycles was slightly stronger among current smokers.

Conclusions Irregular and long menstrual cycles in adolescence and adulthood are associated with a greater risk of premature mortality (age <70 years). This relation is slightly stronger among women who smoke.

Reference: BMJ 2020;371:m3464

Histopathology and ultrastructural findings of fatal COVID-19 infections in Washington State: a case series

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of an ongoing pandemic, with increasing deaths worldwide. To date, documentation of the histopathological features in fatal cases of the disease caused by SARS-CoV-2 (COVID-19) has been scarce due to sparse autopsy performance and incomplete organ sampling. We aimed to provide a clinicopathological report of severe COVID-19 cases by documenting histopathological changes and evidence of SARS-CoV-2 tissue tropism.

Methods

In this case series, patients with a positive antemortem or post-mortem SARS-CoV-2 result were considered eligible for enrolment. Post-mortem examinations were done on 14 people who died with COVID-19 at the King County Medical Examiner’s Office (Seattle, WA, USA) and Snohomish County Medical Examiner’s Office (Everett, WA, USA) in negative-pressure isolation suites during February and March, 2020. Clinical and laboratory data were reviewed. Tissue examination was done by light microscopy, immunohistochemistry, electron microscopy, and quantitative RT-PCR.

Findings

The median age of our cohort was 73·5 years (range 42–84; IQR 67·5–77·25). All patients had clinically significant comorbidities, the most common being hypertension, chronic kidney disease, obstructive sleep apnoea, and metabolic disease including diabetes and obesity. The major pulmonary finding was diffuse alveolar damage in the acute or organising phases, with five patients showing focal pulmonary microthrombi. Coronavirus-like particles were detected in the respiratory system, kidney, and gastrointestinal tract. Lymphocytic myocarditis was observed in one patient with viral RNA detected in the tissue.

Interpretation

The primary pathology observed in our cohort was diffuse alveolar damage, with virus located in the pneumocytes and tracheal epithelium. Microthrombi, where observed, were scarce and endotheliitis was not identified. Although other non-pulmonary organs showed susceptibility to infection, their contribution to the pathogenesis of SARS-CoV-2 infection requires further examination.

Funding

None.

Reference: The Lancet, VOLUME 396, ISSUE 10247, P320-332, AUGUST 01, 2020

Central fatness and risk of all cause mortality: systematic review and dose-response meta-analysis of 72 prospective cohort studies

Objective To quantify the association of indices of central obesity, including waist circumference, hip circumference, thigh circumference, waist-to-hip ratio, waist-to-height ratio, waist-to-thigh ratio, body adiposity index, and A body shape index, with the risk of all cause mortality in the general population, and to clarify the shape of the dose-response relations.

Design Systematic review and meta-analysis.

Data sources PubMed and Scopus from inception to July 2019, and the reference lists of all related articles and reviews.

Eligibility criteria for selecting studies Prospective cohort studies reporting the risk estimates of all cause mortality across at least three categories of indices of central fatness. Studies that reported continuous estimation of the associations were also included.

Data synthesis A random effects dose-response meta-analysis was conducted to assess linear trend estimations. A one stage linear mixed effects meta-analysis was used for estimating dose-response curves.

Results Of 98 745 studies screened, 1950 full texts were fully reviewed for eligibility. The final analyses consisted of 72 prospective cohort studies with 2 528 297 participants. The summary hazard ratios were as follows: waist circumference (10 cm, 3.94 inch increase): 1.11 (95% confidence interval 1.08 to 1.13, I²=88%, n=50); hip circumference (10 cm, 3.94 inch increase): 0.90 (0.81 to 0.99, I²=95%, n=9); thigh circumference (5 cm, 1.97 inch increase): 0.82 (0.75 to 0.89, I²=54%, n=3); waist-to-hip ratio (0.1 unit increase): 1.20 (1.15 to 1.25, I²=90%, n=31); waist-to-height ratio (0.1 unit increase): 1.24 (1.12 to 1.36, I²=94%, n=11); waist-to-thigh ratio (0.1 unit increase): 1.21 (1.03 to 1.39, I²=97%, n=2); body adiposity index (10% increase): 1.17 (1.00 to 1.33, I²=75%, n=4); and A body shape index (0.005 unit increase): 1.15 (1.10 to 1.20, I²=87%, n=9). Positive associations persisted after accounting for body mass index. A nearly J shaped association was found between waist circumference and waist-to-height ratio and the risk of all cause mortality in men and women. A positive monotonic association was observed for waist-to-hip ratio and A body shape index. The association was U shaped for body adiposity index.

Conclusions Indices of central fatness including waist circumference, waist-to-hip ratio, waist-to-height ratio, waist-to-thigh ratio, body adiposity index, and A body shape index, independent of overall adiposity, were positively and significantly associated with a higher all cause mortality risk. Larger hip circumference and thigh circumference were associated with a lower risk. The results suggest that measures of central adiposity could be used with body mass index as a supplementary approach to determine the risk of premature death.

Reference: BMJ 2020;370:m3324

Trends in excess mortality associated with atrial fibrillation over 45 years (Framingham Heart Study): community based cohort study

Objective To assess temporal trends in the association between newly diagnosed atrial fibrillation and death.

Design Community based cohort study.

Setting Framingham Heart Study cohort, in 1972-85, 1986-2000, and 2001-15 (periods 1-3, respectively), in Framingham, MA, USA.

Participants Participants with no atrial fibrillation, aged 45-95 in each time period, and identified with newly diagnosed atrial fibrillation (or atrial flutter) during each time period.

Main outcome measures The main outcome was all cause mortality. Hazard ratios for the association between time varying atrial fibrillation and all cause mortality were calculated with adjustment for time varying confounding factors. The difference in restricted mean survival times, adjusted for confounders, between participants with atrial fibrillation and matched referents at 10 years after a diagnosis of atrial fibrillation was estimated. Meta-regression was used to test for linear trends in hazard ratios and restricted mean survival times over the different time periods.

Results 5671 participants were selected in time period 1, 6177 in period 2, and 6174 in period 3. Adjusted hazard ratios for all cause mortality between participants with and without atrial fibrillation were 1.9 (95% confidence interval 1.7 to 2.2) in time period 1, 1.4 (1.3 to 1.6) in period 2, and 1.7 (1.5 to 2.0) in period 3 (P_trend=0.70). Ten years after diagnosis of atrial fibrillation, the adjusted difference in restricted mean survival times between participants with atrial fibrillation and matched referents decreased by 31%, from −2.9 years (95% confidence interval −3.2 to −2.5) in period 1, to −2.1 years (−2.4 to −1.8) in period 2, to −2.0 years (−2.3 to −1.7) in period 3 (P_trend=0.03).

Conclusions No evidence of a temporal trend in hazard ratios for the association between atrial fibrillation and all cause mortality was found. The mean number of life years lost to atrial fibrillation at 10 years had improved significantly, but a two year gap compared with individuals without atrial fibrillation still remained.

Reference: BMJ 2020;370:m2724

Association between prediabetes and risk of all cause mortality and cardiovascular disease: updated meta-analysis

Objective To evaluate the associations between prediabetes and the risk of all cause mortality and incident cardiovascular disease in the general population and in patients with a history of atherosclerotic cardiovascular disease.

Design Updated meta-analysis.

Data sources Electronic databases (PubMed, Embase, and Google Scholar) up to 25 April 2020.

Review methods Prospective cohort studies or post hoc analysis of clinical trials were included for analysis if they reported adjusted relative risks, odds ratios, or hazard ratios of all cause mortality or cardiovascular disease for prediabetes compared with normoglycaemia. Data were extracted independently by two investigators. Random effects models were used to calculate the relative risks and 95% confidence intervals. The primary outcomes were all cause mortality and composite cardiovascular disease. The secondary outcomes were the risk of coronary heart disease and stroke.

Results A total of 129 studies were included, involving 10 069 955 individuals for analysis. In the general population, prediabetes was associated with an increased risk of all cause mortality (relative risk 1.13, 95% confidence interval 1.10 to 1.17), composite cardiovascular disease (1.15, 1.11 to 1.18), coronary heart disease (1.16, 1.11 to 1.21), and stroke (1.14, 1.08 to 1.20) in a median follow-up time of 9.8 years. Compared with normoglycaemia, the absolute risk difference in prediabetes for all cause mortality, composite cardiovascular disease, coronary heart disease, and stroke was 7.36 (95% confidence interval 9.59 to 12.51), 8.75 (6.41 to 10.49), 6.59 (4.53 to 8.65), and 3.68 (2.10 to 5.26) per 10 000 person years, respectively. Impaired glucose tolerance carried a higher risk of all cause mortality, coronary heart disease, and stroke than impaired fasting glucose. In patients with atherosclerotic cardiovascular disease, prediabetes was associated with an increased risk of all cause mortality (relative risk 1.36, 95% confidence interval 1.21 to 1.54), composite cardiovascular disease (1.37, 1.23 to 1.53), and coronary heart disease (1.15, 1.02 to 1.29) in a median follow-up time of 3.2 years, but no difference was seen for the risk of stroke (1.05, 0.81 to 1.36). Compared with normoglycaemia, in patients with atherosclerotic cardiovascular disease, the absolute risk difference in prediabetes for all cause mortality, composite cardiovascular disease, coronary heart disease, and stroke was 66.19 (95% confidence interval 38.60 to 99.25), 189.77 (117.97 to 271.84), 40.62 (5.42 to 78.53), and 8.54 (32.43 to 61.45) per 10 000 person years, respectively. No significant heterogeneity was found for the risk of all outcomes seen for the different definitions of prediabetes in patients with atherosclerotic cardiovascular disease (all P>0.10).

Conclusions Results indicated that prediabetes was associated with an increased risk of all cause mortality and cardiovascular disease in the general population and in patients with atherosclerotic cardiovascular disease. Screening and appropriate management of prediabetes might contribute to primary and secondary prevention of cardiovascular disease.

Reference: BMJ 2020;370:m2297