Research news in brief

Low socio-economic status reduces life expectancy

Swiss research, published in The Lancet, has found that low socio-economic status is linked to significant reductions in life expectancy and should be considered a major risk factor for ill health and early death in national and global health policies. Cancer Council Victoria contributed to the study, which analysed data from 1.7 million people worldwide. The World Health Organization (WHO) in its Global Action Plan for the Prevention and Control of Non-Communicable Diseases aims to reduce non-communicable diseases by 25% by 2025, but omits socio-economic status as a risk factor for these diseases. The authors wrote that their study was the first to compare the impact of low socio-economic status with other major risk factors as defined by the WHO, such as physical inactivity, smoking, diabetes, high blood pressure, obesity and high alcohol intake. The review included data from 48 studies. It used a person’s job title to estimate their socio-economic status and looked at whether they died early. When compared with their wealthier counterparts, people with low socio-economic status were almost 1.5 times (46%) more likely to die before they were 85 years old. Among people with low socio-economic status, 55 600 (15.2% of men and 9.4% of women) died before the age of 85 years, compared with 25 452 (11.5% of men and 6.8% of women) of people with high socio-economic status. The study also estimated that 41% of the men and 27% of the women analysed had low socio-economic status and that this was associated with a reduction in life expectancy of 2.1 years, similar to being inactive (2.4 years). The greatest reductions were for smoking and diabetes (4.8 and 3.9 years, respectively). Comparatively, high blood pressure, obesity and high alcohol consumption were associated with smaller reductions in life expectancy (1.6, 0.7 and 0.5 years, respectively) than low socio-economic status.

E-cigs associated with heart disease

Research from the University of California has found that habitual e-cigarette users were more likely than the non-smoking control participants to have increased cardiac sympathetic activity (increased adrenaline levels in the heart) and increased oxidative stress, which are known mechanisms by which tobacco cigarettes increase cardiovascular risk. The study, published in JAMA Cardiology, included 23 habitual e-cigarette users (who all used e-cigarettes most days for a minimum of 1 year) and 19 non-e-cigarette user control participants between the ages of 21 and 45 years. The inclusion criteria included no current tobacco cigarette smoking and no known health problems. The authors wrote that the findings had critical implications for the long term cardiac risks associated with habitual e-cigarette use and mandated a re-examination of aerosolised nicotine and its metabolites. “Nicotine, which is the major bioactive ingredient in e-cigarette aerosol, with its metabolites, may harbour unrecognised, sustained adverse physiologic effects that lead to an increased cardiovascular risk profile in habitual e-cigarette users.” The researchers noted that they could not confirm causality on the basis of a single, small study, and that further research into the potential adverse cardiovascular health effects of e-cigarettes was warranted.

Height gene variations isolated

Australian researchers, in a study published in Nature, have identified over 80 rare or low-frequency genetic variants associated with human height. The authors from the University of Melbourne, the University of Western Australia, the University of Tasmania, Griffith University and the University of Sydney wrote that while the newly found gene variations are rarer than the 700 previously discovered to be linked to height, they can have a big impact, increasing height by up to 2 cm. This is more than 10 times the average effect of the more common genetic variants. Previously-discovered genes may explain about 20% of the inheritance of height, and the discovery of these new gene variants adds an extra 1.7% to this figure. This finding may also have implications for understanding the genes underlying other complex human traits, and may provide new tools for predicting disease risks and developing treatments, the authors wrote.

Seeing the same GP reduces hospitalisations

Older patients who see the same GP over time experience fewer avoidable admissions to hospital for certain conditions, according to a study published by The BMJ. Researchers from the UK think tank, the Health Foundation, analysed patient level data from English primary and secondary care records for over 230 000 patients, aged between the ages of 62 and 82 years, between April 2011 and March 2013. They focused on older patients because they accounted for a high proportion of both GP consultations and potentially avoidable hospital admissions. The authors found that continuity of care varied considerably across general practices in England, and tended to be lower in larger practices. Patients who saw the same GP a greater proportion of the time experienced fewer admissions to hospital for ambulatory care sensitive conditions than other patients. Compared with patients with low continuity of care, patients with medium continuity of care experienced almost 9% fewer admissions, and those with high continuity of care experienced just over 12% fewer admissions. This association was particularly true among patients who were heavy users of primary care (more than 18 visits over the study period). In a linked editorial, authors from the University of Bristol suggested that seeing the same doctor “builds trust and a sense of mutual responsibility between patients and GPs,” while a primary care system that is increasingly fragmented “provides the setting for patients to choose to attend an emergency department instead”.

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