News Round-up

 

 

Healthy Lifestyle Linked to Slower Memory Decline in Older Adults

A healthy lifestyle, in particular a healthy diet, is associated with slower memory decline, finds a decade-long study of older adults in China, published in The BMJ.

Even for carriers of the apolipoprotein E (APOE) gene – the strongest known risk factor for Alzheimer’s disease and related dementias – a healthy lifestyle was found to slow memory loss.

Memory continuously declines as people age, but evidence from existing studies is insufficient to assess the effect of a healthy lifestyle on memory in later life. And given the many possible causes of memory decline, a combination of healthy behaviours might be needed for an optimal effect.

To explore this further, researchers analysed data from 29,000 adults aged at least 60 years (average age 72; 49% women) with normal cognitive function who were part of the China Cognition and Aging Study.

At the start of the study in 2009, memory function was measured using the Auditory Verbal Learning test (AVLT) and participants were tested for the APOE gene (20% were found to be carriers). Follow-up assessments were then conducted over the next 10 years in 2012, 2014, 2016, and 2019.

A healthy lifestyle score combining six factors was then calculated: healthy diet, regular exercise, active social contact (e.g. seeing friends and family), cognitive activity (e.g. writing, reading, playing mahjong), non-smoking, and never drinking alcohol.

Based on their score, ranging from 0 to 6, participants were put into favourable (4 to 6 healthy factors), average (2 to 3 healthy factors), or unfavourable (0 to 1 healthy factors) lifestyle groups and into APOE carrier and non-carrier groups. After accounting for a range of other health, economic and social factors, the researchers found that each individual healthy behaviour was associated with a slower than average decline in memory over 10 years.

A healthy diet had the strongest effect on slowing memory decline, followed by cognitive activity and then physical exercise.

Compared with the group that had unfavourable lifestyles, memory decline in the favourable lifestyle group was 0.28 points slower over 10 years based on a standardised score (z score) of the AVLT, and memory decline in the average lifestyle group was 0.16 points slower.

Participants with the APOE gene with favourable and average lifestyles also experienced a slower rate of memory decline than those with an unfavourable lifestyle (0.027 and 0.014 points per year slower, respectively).

What’s more, those with favourable or average lifestyles were almost 90% and almost 30% less likely to develop dementia or mild cognitive impairment relative to those with an unfavourable lifestyle, and the APOE group had similar results. This is an observational study so can’t establish cause and the researchers acknowledge some limitations, such as the potential for measurement errors due to self-reporting of lifestyle factors, and the possibility of selection bias, as some participants did not return for follow-up evaluations.

But this was a large study with a long follow-up period, allowing for evaluation of individual lifestyle factors on memory function over time. And findings remained significant after further analyses, suggesting that they are robust.

As such, the researchers say their results provide strong evidence that adherence to a healthy lifestyle with a combination of positive behaviours is associated with a slower rate of memory decline, even for people who are genetically susceptible to memory decline.

They suggest further research could focus on the effects of a healthy lifestyle on memory decline across the lifespan, acknowledging that memory problems can also affect younger people, not included in this study. “These results might offer important information for public health initiatives to protect older adults against memory decline,” they conclude.

“Prevention is important, given the absence of effective treatments for Alzheimer’s disease and related dementias,” say researchers in a linked editorial.

However, they point out that these results do not help to determine which among the six health behaviours included in the score (or specific combination) is the best target for dementia prevention, or when in the life course to focus prevention efforts. Further insight is also needed to determine whether the differences in memory decline observed in this study are clinically meaningful, they add.

They suggest a similar approach that led to a substantial reduction in cardiovascular disease should be taken with dementia prevention, “identifying not only the factors that matter most but also the threshold at which they matter, and the age when intervention is likely to be most effective.”

^{Research: Jia J, et al. (2023). Association between healthy lifestyle and memory decline in older adults: 10 year, population based, prospective cohort study. BMJ; doi: https://doi.org/10.1136/bmj-2022-072691}

 

 

Heightened Risk of Cardiovascular Disease in People with Coeliac Disease

People with coeliac disease might have fewer known risk factors for cardiovascular disease, but still have a heightened risk of developing it, finds a study led by researchers from Oxford Population Health, published online in the journal BMJ Medicine.

It’s not clear what the reasons for this might be, and further research is needed to unearth the drivers behind these associations. This includes the role of a gluten-free diet, which those affected are required to follow to ease symptoms, say the study authors.

Around 1% of the UK population has coeliac disease. The condition is more common in women and is typically diagnosed in childhood and adolescence or between the ages of 40 and 60, say the researchers.

The published evidence on whether coeliac disease is associated with a heightened risk of cardiovascular disease is mixed, and previous studies have tended to not investigate the potential role of traditional cardiovascular risk factors, such as blood pressure or cholesterol. To find out whether traditional cardiovascular risk factors might contribute to the link between coeliac disease and a heightened risk of cardiovascular disease (ischaemic heart disease, heart attack, and stroke), the researchers drew on medical data supplied by UK Biobank participants.

The UK Biobank is a population-based study that recruited around half a million 40-69 year olds from England, Scotland, and Wales between 2006 and 2010. Of these, 2083 had coeliac disease but no cardiovascular disease, when recruited. Their cardiovascular health was monitored, using linked hospital records and death certificates, for an average of just over 12 years.

Those with coeliac disease were more likely to be women – 56% vs 71.5% – and of white ethnicity – 95% vs 99% – than those who didn’t have the condition. During the monitoring period, 40,687 diagnoses of cardiovascular disease were recorded among all the surviving UK Biobank participants. Some 218 of these incidents were in people with coeliac disease – equivalent to an annual rate of 9 in every 1000 people – compared with an annual rate of 7.4/1000 in those without the condition.

This translates into a 27% heightened risk of cardiovascular disease for people with coeliac disease compared with those who didn’t have it, after accounting for a wide range of potentially influential lifestyle, medical, and cardiovascular disease factors. Risk seemed to increase the longer a person had been living with their condition – to a 30% increased risk among those who had had coeliac disease for less than 10 years, rising to an increased risk of 34% among those who had had it for 10 or more years.

Yet people with coeliac disease had fewer of the known risk factors for cardiovascular disease (including overweight or obesity; high systolic blood pressure; a history of smoking; and high cholesterol) being more likely to have a lower BMI and a lower systolic blood pressure. And they were more likely to have a so-called ideal cardiovascular risk score (23% vs 14%), and less likely to have a poor risk score (5% vs 9%) than people with coeliac disease.

When the researchers explored the potential joint effects of coeliac disease and cardiovascular risk score on incident cardiovascular disease, the risk increased by more than 60% in people with coeliac disease plus an ideal cardiovascular disease risk score compared with those with an ideal risk score but no coeliac disease. This is an observational study, and as such can’t establish cause and effect. And the researchers acknowledge various limitations to their findings, including that cardiovascular disease risk factors were measured at one point in time only. But a number of autoimmune conditions are associated with a heightened risk of cardiovascular disease as a result of systemic inflammation, they point out. The researchers didn’t look into dietary factors, but some previously published research suggests that a gluten free diet might reduce inflammation and therefore cardiovascular disease risk, while other studies indicate that this diet might actually boost the risk.

“This study highlights the importance of cardiovascular disease as a potential complication of coeliac disease. Further research into the drivers and mechanistic pathways of this association is warranted.

“In addition, an investigation is warranted into the extent to which any risk reduction is reported by adherence to a gluten-free diet in people with coeliac disease, or whether a gluten-free diet itself contributes to the increased risk identified,” they write.

And they conclude: “Given the increased rates of cardiovascular disease reported in people with coeliac disease who have an ideal and moderate cardiovascular disease risk score, clinicians should make patients with coeliac disease aware of their elevated risk, and work with their patients to optimise their cardiovascular health.”

^{Research: Conroy M, et al. (2023). Association between coeliac disease and cardiovascular disease: prospective analysis of UK Biobank data. BMJ Medicine.; https://bmjmedicine.bmj.com/content/bmjmed/2/1/e000371.full.pdf}

 

 

Midlife Obesity Linked to Heightened Frailty Risk in Older Age

Carrying far too much weight, including a midriff bulge, from mid-life onwards, is linked to a heightened risk of physical frailty in older age, finds research published in the open access journal BMJ Open.

Frailty is often wrongly perceived as a purely wasting disorder, say the researchers, who emphasise the importance of keeping trim throughout adulthood to help minimise the risk.

Frailty is characterised by at least 3 and pre-frailty by 1-2 of the following 5 criteria: unintentional weight loss; exhaustion; weak grip strength; slow walking speed; and low physical activity levels. It’s associated with vulnerability to falls, disability, hospital admission, reduced quality of life and death.

Mounting evidence suggests that obese older adults may be at increased risk because obesity aggravates the age-related decline in muscle strength, aerobic capacity, and physical function. But few studies have tracked weight changes and frailty risk over the long-term.

The researchers therefore drew on participants in the population based Tromsø Study to find out whether general (BMI) and abdominal (waist circumference) obesity separately and jointly, might affect the risk of pre-frailty/frailty.

The Tromsø Study consists of seven survey waves of 45,000 residents from Tromsø, Norway, aged 25 to 99, carried out between 1974 and 2015-16. The current study drew on data from waves 4 (1994-5) to 7 (2015-16).

The final analysis included 4509 people aged 45 or older. The average age at baseline was 51, with the average monitoring period lasting 21 years. A BMI of less than 18.5 was categorised as underweight, normal as 18.5-24.9, overweight as 25–29.9, and obesity as 30 and above.

Waist circumference was categorised as normal (94 cm or less for men and 80 cm or less for women); moderately high (95–102 cm for men and 81–88 cm for women); and high (above 102 cm for men and above 88 cm for women).

By 2015-16, 28% of participants were pre-frail, 1% were frail, and 70.5% were strong. In all, nearly 51% of those who were strong and 55% of those categorised as pre-frail were women.

While participants in both the strong and pre-frail/frail groups put on weight and expanded their waistlines during the monitoring period, there were higher proportions of participants with normal BMIs and waistlines at the start of the monitoring period in the strong group.

With the exception of co-existing conditions, such as diabetes, potentially influential factors, including alcohol intake and smoking, educational attainment, marital status, social support, and physical activity levels differed significantly between the strong and pre-frail/frail groups and were accounted for in the analysis.

Those who were obese in 1994, assessed by BMI alone, were nearly 2.5 times more likely to be pre-frail/frail at the end of the monitoring period than those with a normal BMI.

Similarly, those with a moderately high or high waist circumference, to start off with, were, respectively, 57% and twice as likely, to be pre-frail/frail than those with a normal waistline.

Those who started off with a normal BMI but moderately high waist circumference, or who were overweight but had a normal waistline, weren’t significantly more likely to be pre-frail/frail at the end of the monitoring period. But those who were both obese and who had a moderately-high waist circumference at the start of the monitoring period were.

Higher odds of pre-frailty/frailty were also observed among those who put on weight and among those whose waistlines expanded than in those whose weight and waistlines remained the same throughout.

While the findings echo those of previous long-term studies, this is an observational study, which didn’t track potentially influential changes in lifestyle, diet, and friendship networks that might have occurred during the monitoring period. And the researchers point out that the findings were still significant for participants with baseline obesity and higher waist circumference when the over 60s were excluded from the analysis. Few underweight people were included in the study. But there are some plausible biological explanations for their findings, the researchers suggest.

These include the increased inflammatory capacity of fat cells and their infiltration into muscle cells, both of which likely boost naturally occurring age related decline in muscle mass and strength, so heightening the risk of frailty, they explain.

Nevertheless, they conclude: “In the context where the population is rapidly ageing and the obesity epidemic is rising, growing evidence recognises the subgroup of ‘fat and frail’ older individuals in contrast to viewing frailty only as a wasting disorder.” Their study “highlights the importance of routinely assessing and maintaining optimal BMI and [waist circumference] throughout adulthood to lower the risk of frailty in older age,” they add.

^{Paper: Uchai S, et al. (2023) Body mass index, waist circumference and pre-frailty/frailty: the Tromsø study 1994−2016. BMJ Open; https://bmjopen.bmj.com/content/13/2/e065707}

 

 

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