Vigorous activity reduces all-cause mortality
A STUDY of more than 200 000 middle-aged and older adults in Australia has found those who engage in vigorous activity have 9%‒13% risk reductions for all-cause mortality, even after adjusting for the total amount of activity. The research, published in JAMA Internal Medicine, was based on data from the Sax Institute’s 45 and Up study, a large prospective cohort study of men and women from the general population of NSW, using activity data linked to all-cause mortality data from 2006 to 2014. The researchers found that during more than 1.4 million person-years of follow-up (mean 6.52 years), 7435 deaths were registered. Compared with those who reported no moderate to vigorous physical activity (MVPA), the adjusted hazard ratios for all-cause mortality were 0.66, 0.53 and 0.46 for those who reported 10‒149, 150‒299 and 300 or more minutes per week of activity, respectively. “Among those who reported any MVPA, the proportion of vigorous activity revealed an inverse dose-response relationship with all-cause mortality: compared with those reporting no vigorous activity (crude death rate, 3.84%) the fully adjusted hazard ratio was 0.91 (95% CI, 0.84-0.98; crude death rate, 2.35%) in those who reported some vigorous activity (but <30% of total activity) and 0.87 (95% CI, 0.81-0.93; crude death rate, 2.08%) among those who reported 30% or more of activity as vigorous”, the researchers wrote. “The association between the proportion of MVPA as vigorous activity and all-cause mortality was consistent across age groups, sexes, activity levels, obese and nonobese participants, and participants with and without existing cardiometabolic disease (there were no statistically significant interactions at P < .05).” They said their findings were in line with other studies that had reported significant benefits of vigorous activity in reducing mortality. “In this middle to older adult population, these findings suggest that even small amounts of vigorous activity may supplement the benefits of moderate activity alone”, they wrote.

Worth referring obese patients to some weight loss programs
CLINICIANS should consider referring overweight or obese patients to Weight Watchers or Jenny Craig, according to a systematic review of the long-term efficacy of weight loss programs. The research, published in Annals of Internal Medicine, was based on the results of 45 studies, including 39 randomised controlled trials of at least 12 weeks duration. The review compared the efficacy of commercial or proprietary weight loss programs with control/education interventions and behavioural counselling among overweight and obese adults. Control/education interventions involved patients receiving no intervention, printed materials, a health curriculum, or fewer than three sessions with a provider. The authors found that only 11 weight loss regimens had been rigorously studied, including market leading programs Weight Watchers (low calorie conventional foods and points tracking), Jenny Craig (low calorie meal replacements) and Nutrisystem (low calorie meal replacements). At 12 months, Weight Watchers participants achieved at least 2.6% greater weight loss than those receiving control/education interventions, and Jenny Craig resulted in at least 4.9% greater weight loss. Nutrisystem resulted in at least 3.8% greater weight loss at 3 months than control/education and counselling. Very-low-calorie programs, including Medifast and OPTIFAST, resulted in at least 4.0% greater short-term weight loss than counselling, but some attenuation of effect occurred after 6 months. Results for the low calorie meal replacement program SlimFast were mixed, the authors wrote. They said additional research was needed to confirm the long-term efficacy of programs such as Nutrisystem and SlimFast, and internet-based commercial weight loss regimens, which were becoming increasingly popular. “Clinicians might consider prioritizing referral only for those commercial programs that have a substantial body of evidence showing a consistent, long-term effect”, the authors wrote. An accompanying editorial said that while the review confirmed the efficacy of Weight Watchers and Jenny Craig, most commercial programs had not been rigorously evaluated. “Future research should evaluate whether partnering physician counselling with these programs improves effectiveness”, they said.

Low BMI linked to dementia in ageing population
A LARGE retrospective cohort study of almost two million UK general practice patients has found being underweight in middle and old age carries an increased risk of dementia. The research, published in The Lancet Diabetes & Endocrinology, found that compared with people of a healthy weight, underweight people (BMI <20 kg/m²) had a 34% higher risk of dementia, with the incidence of dementia falling for every increasing BMI category — obese people with a BMI of more than 40 kg/m² had a 29% lower dementia risk than people with a healthy weight. “Further adjustment for six potential confounders … made little difference to this monotonic inverse association between BMI and dementia risk, and if anything seemed to slightly accentuate the trend”, the researchers wrote. They had excluded general practice patients who had less than 12 months of historical data, patients who did not have a BMI recorded (48% of the eligible cohort), those judged to be outliers and those with a previous history of dementia from the cohort, leaving a total of 1 958 191 people (representing 18 786 640 person-years of follow-up). Median BMI of participants was 26.4 kg/m², median age at baseline was 55 years and 1 072 485 (55%) of participants were women. During a median of 9.1 years of follow-up, 45 507 people had a first diagnosis of dementia, at an overall rate of 2.4 cases per 1000 person-years. Dementia was strongly associated with increasing age and more common in women than men in those older than 70 years. “Our findings contradict previous suggestions that obese people in mid-life have a higher subsequent risk of dementia”, the researchers wrote. “The reasons for and public health consequences of these findings need further investigation.” An accompanying commentary said the study had several limitations that meant the findings should be interpreted with care. “Many considerations are needed in the assessment of the epidemiology of the association between BMI and late-onset dementia, as is the case for many recorded associations involving late-life disorders.”

Statin use changes with different guidelines
A US study has found that applying paediatric guidelines for statin therapy in adolescents and young adults, rather than adult guidelines, could result in more than 400 000 additional adolescents and young adults taking statins. The cross-sectional research, published in JAMA Pediatrics, of 6338 people aged 17‒21 years, found that 2.5% would qualify for statin treatment under the paediatric guidelines compared with 0.4% under the adult guidelines. The researchers said paediatric guidelines considered additional cardiovascular risk factors beyond age and low-density lipoprotein cholesterol (LDL-C) concentration. They wrote that adolescents and young adults who met the paediatric criteria had lower mean LDL-C levels (167.3 [3.8] v 210.0 [7.1] mg/dL) but higher proportions of other cardiovascular risk factors, including hypertension (10.8% v 8.4%), smoking (55.0% v 23.9%) and obesity (67.7% v 18.2%) compared with those who met the adult guidelines. “Extrapolating to the US population of 20.4 million young people aged 17 to 21 years, 483 500 (95% CI, 482 100-484 800) individuals would be eligible for statin treatment under the pediatric guidelines compared with 78 200 (95% CI, 77 600-78 700) under the adult guidelines”, they wrote. “Given the current uncertain state of knowledge and conflicting guidelines for treatment of lipid levels among youth aged 17 to 21 years, physicians and patients should engage in shared decision making around the potential benefits, harms, and patient preferences for treatment.”

Focus on patient autonomy not always best
RESEARCH into how institutional cultures and policies surrounding patient autonomy shape physicians’ approaches to do-not-resuscitate (DNR) decision making at the end of life, has found a singular focus on autonomy might inadvertently undermine patient care. The research, published in JAMA Internal Medicine, was based on semistructured, indepth, qualitative interviews of 58 internal medicine physicians from three US and one UK academic medical centres by years of experience, ranging from 1 to 45 years, and medical subspecialty. “A hospital’s culture and policies’ prioritization of autonomy vs best interest appears to influence the way in which physician trainees conceptualize patient autonomy”, the authors wrote. “This finding may subsequently influence the degree of choice and recommendations physician trainees are willing to offer regarding DNR decision making.” The researchers found that less experienced physicians at autonomy-focused hospitals expressed their responsibility for decision making up to a certain point but then appeared more hesitant to take on that responsibility. Trainees at hospitals that encouraged a best-interest decision-making approach were “more comfortable” at expressing clinical judgement against resuscitation when appropriate. “It is ironic that the very policies that seek to empower patients might inadvertently deprive them of their autonomy through an overemphasis on a reductionist checklist approach to autonomy”, the authors wrote, saying policies more oriented to best-interest decision making might encourage physicians to shift their focus “from a discourse of choice to one of care and compassion”.

Storage time of red cells does not affect patient outcomes
RED-cell unit storage time is not associated with significant differences in the change in multiple organ dysfunction scores (MODS) in patients undergoing cardiac surgery, a study published in the New England Journal of Medicine has shown. The randomised trial conducted at multiple sites in the US from 2010 to 2014 included 1098 patients aged 12 years or older undergoing complex cardiac surgery who received a transfusion of red cells. Patients were assigned to receive leucocyte-reduced red cells stored for 10 days or less (shorter term storage group) or for 21 days or more (longer term storage group) for all intraoperative and postoperative transfusions. The authors measured the change in the MODS from the preoperative score to the highest composite score through Day 7 or the time of death or discharge. The median storage time of red-cell units was 7 days in the shorter term storage group and 28 days in the longer term storage group. The mean change in MODS was an increase of 8.5 and 8.7, respectively. The 7-day mortality was 2.8% in the shorter term storage group and 2.0% in the longer term storage group, and 28-day mortality was 4.4% and 5.3%, respectively. Adverse events did not differ significantly between groups, except for hyperbilirubinemia which was more common in the longer term storage group. The authors said their results “do not support the preferential transfusion of red cells with shorter storage periods in patients 12 years of age or older who are undergoing complex cardiac surgery”. However, further research was needed to determine whether red cell storage duration had a clinical effect in other patient populations, they wrote.

AMD may be linked to calcium supplements
A US population-based study of adults aged 40 years and older has found those who self-reported taking more than 800 mg a day of supplementary calcium had higher odds of being diagnosed with age-related macular degeneration (AMD). The research, published in JAMA Ophthalmology, found the association, after adjustment for a variety of confounders, was specific to those who were older than the mean age of participants with an AMD diagnosis. The study was based on 3191 participants evaluated for the presence or absence of AMD by fundus photography and interviewed on their use of dietary supplements and antacids. It found 248 participants (7.8%) with a mean age of 67.2 years were diagnosed with AMD. The mean age of those without AMD was 55.8 years. The researchers wrote that it was “noteworthy that the 800-mg cut-off point for the highest quintile of self-reported calcium intake is below the recommended total daily intake of calcium for men and women in the United States”. They hypothesised that there was possibly a threshold above which the consumption of calcium might be a risk factor for the development for AMD, with that threshold below the recommended total daily intake. However, the authors said that, as with any cross-sectional study, they could not make any claims regarding causation, which would require longitudinal analysis.

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