Alcohol intake linked with aging arteries
Just over a year ago, the UK government reduced the guideline amount of alcohol that’s considered safe from 21 units per week to 14. But the recently published Health Survey for England shows that the average weekly intake for men is about 15 units and for women it’s about 9. In other words a lot of people are drinking a lot more heavily than perhaps they ought to. But is there evidence that this actually does any damage? And can a young person get away with it, as long as they cut down later in life? A lot of the data we have at the moment is from a single snapshot of people’s lives, so may not be giving the whole story. Darragh O’Neil, from UCL, has looked at the drinking habits of a large number of people over several decades, and how this has ultimately affected their blood vessels and he spoke to Chris Smith about the research.
Darragh - Arterial stiffness is an indicator of cardiovascular disease risk and research has, traditionally, relied on cross-sectional research which is just looking at acute alcohol consumption. But by looking at intake longitudinally, we are deepening the understanding of the way in which alcohol intake over time is related to the stiffening of arteries.
Chris - I suppose that following people up over a period of time also captures how people’s drinking behaviour changes because, as people age, they’re likely to drink different amounts and this is likely, in turn, to have a different effect rather than just looking once?
Darragh - Correct, yes. And people’s health changes over time and that can actually influence their drinking behaviours. There’s a concept known as the “sick quitter” hypothesis, which is people stop drinking as a consequence of the onset of poor health and it’s something that, potentially, explains research findings show that former drinkers maybe are at a greater risk of poor health than maybe to people who drink moderately over time.
Chris - People talk about a J shaped curve, don’t they. where along the X axis on the graph is the amount of alcohol that people drink, and then on the Y axis is their risk of having a problem
Darragh - Yes, exactly.
Chris - And people who drink no alcohol, or report drinking no alcohol, appear to have a higher health risk profile than someone who actually drinks quite a lot? So you’re saying that it could be that within those numbers could well be sick quitters who have given up drinking but they have already done damage therefore they appear to be unhealthy and not drinking?
Darragh - Exactly. Yeah that’s correct.
Chris - So how did you do the study and who did you look at?
Darragh - This study is based on a cohort study, which is based on a longitudinal study of UK civil servants. These participants were recruited originally in around 1985; there was just 10,000 of them back then. They took part in repeated assessments of lifestyle behaviours, underwent medical screenings, provided alcohol intake data from the very beginning.
More recently, these individuals also took part in what are known as pulse wave velocity assessment which measure the stiffness of their arteries. We used their longitudinal alcohol intake data to look at its relationship to that stiffening and to how that stiffening subsequently develops over time.
Chris - Before you tell us what happened with the stiff arteries, do you believe these people? The reason for my scepticism is that one of the first things I was always taught at medical school you take anything anyone tells you and double it, whether it’s cigarettes or booze. So this is self-reported alcohol consumption, isn’t it, so actually their intake could have been dramatically different to reality?
Darragh - That’s correct. There’s always that possibility and we do acknowledge that in the study. But previously analysis with this data have shown that there is a consistency between the reporting at the time point that they provided us, so what they provided us in the past with retrospective accounts. So it seems to suggest that there is some validity to what they’re providing us.
Chris - And you’re able to capture with this the history of how much alcohol and when they consumed it what their arteries look like today, effectively?
Darragh - Correct, yeah.
Chris - What does it show?
Darragh - What we found is that those that have consistently drank above 14 units of alcohol a week, those individuals have significantly greater stiffness in their arteries at the beginning of early old age compared to those who consistently drank within the low risk limits, or below that threshold of 14 units a week. And we also found that those that stopped drinking over time showed an increased acceleration in their arteries stiffness during a subsequent interval of four to five years.
Chris - Do you think they are the sick quitters?
Darragh - That is a possibility. We haven’t been able to identify for sure but we have seen that there is some change in their self-reported health over time those that do desist from drinking. But I think there’s further analysis to be performed there to clarify that and to answer that with certainty.
Chris - The ones who were the consistently heavy drinks, this does appear then to have translated into an effectively premature ageing effect in their blood vessels?
Darragh - That’s correct, yes. That’s how we’ve interpreted it.
Chris - Based on what you’ve found then, what are your conclusions? What do you think this tells us about the way in which we use and abuse alcohol?
Darragh - It suggests that by ignoring the health guidelines in terms of low risk drinking behaviors, people are putting themselves, potentially, at an increased risk of cardiovascular ageing over time and that there is a benefit to people to adhere to those safe drinking guidelines and to not consume in excess of 14 units a week.