Tell me how you live and I will tell you what risks you incur as you grow older

Sleep quality, diet, socialisation, smoking and alcohol consumption are habits known to influence our health, but what happens when these variables combine among themselves? How do they affect the chances of developing pathologies as we age? A study published in Frontiers in Public Health analyses for the first time how 9 lifestyle habits tend to combine and remain grouped together over time in healthy middle-aged people, predisposing them to develop certain pathologies in the future depending on this combination. Among other things, the study has identified that high alcohol consumption is often associated with poor sleep quality and predisposes over time to the development of psychiatric illnesses. These results show that interventions aimed at improving health should focus on the combination of lifestyle habits, not just one in particular, and should also focus on the prevention of the potential disease to develop.

The Barcelona Brain Health Initiative is a research project of the Institut Guttmann, in collaboration with the University of Barcelona and Harvard Medical School (Boston, USA), which aims to learn and understand how we can preserve brain health over time. For this study, the researchers analysed 9 life habits in a cohort of more than 3,000 people: cognitive reserve, socialisation, nutrition, alcohol, body mass index, physical activity, sleep quality, vital plan and tobacco. ‘Existing studies have so far focused on variables individually, but not on how they tend to cluster and how they influence health when they coexist. Nor had they taken into account psychological factors such as vital plan, which has been shown to have a strong impact on brain health,’ says David Bartrés-Faz, Principal Investigator of the BBHI and Professor of Medical Psychology at the Faculty of Medicine and Health Sciences of the University of Barcelona.

Based on how lifestyle habits tend to cluster in people, the results of the analysis identified 5 profiles of individuals, based on their lifestyle and associated potential risks:

(a) Healthy: with good indices of cognitive activity, nutrition, physical activity, sleep quality, socialisation and vital plan, a body mass index (BMI) within normality, and low tobacco and alcohol consumption.

b) Low cognitive reserve: people with low cognitive activity (few cognitively stimulating activities) and lower socialisation and vital plan scores, but with better values for alcohol, tobacco and BMI consumption, compared to other groups.

c) Obesogenic: characterised by high BMI, poor nutrition and low physical activity.

d) Severe smokers: they also have lower vital plan scores and high levels of cholesterol and hypertension.

e) Alcohol-sleep: they consume alcohol at harmful levels and have poor sleep quality. In addition, they tend to smoke and have low indices of well-being, quality of life, life meaning, socialisation and perception of mental and general health.

To establish these categories, the researchers used an unsupervised classification machine learning technique, which allows them to "identify associations between apparently unrelated variables and discover hidden patterns in the data," explains Javier Solana Sánchez, PhD in Biomedical Engineering and Research Director at the Institut Guttmann. ‘In this way, we can segment a large dataset into more manageable and specific subgroups, which gives us additional information and allows us to perform deeper analyses to make better data-driven decisions,’ he adds.

By analysing the health evolution of the members of each trajectory, the team established associations between each profile and the risk of developing different pathologies. First, they showed that the ‘healthy’ trajectory has a lower risk of developing chronic diseases and better general and mental health. In the high BMI profile, the most pronounced risk is that of multimorbidity, which implies having more than one diagnosed chronic pathology, such as cancer, diabetes or kidney disease. Alcohol consumers have a moderate risk of multimorbidity and a high risk of psychiatric pathologies (mainly anxiety and depression), while heavy smokers are more likely to develop cardiovascular diseases, followed by neurological pathologies and multimorbidity.

First study on the impact of cognition, socialisation, vital plan and sleep

The low cognitive activity profile deserves special mention, as no previous study had ever explored the joint impact of cognition, socialisation, vital plan and sleep. The results indicate that the main risk for this profile is the development of neurological diseases.

‘This study is especially relevant because it has established people profiles taking into account the coexistence of healthy and unhealthy habits, transcending the classic binary categorisation: people generally have some good and some bad habits, so our approach is much more realistic and, therefore, allows us to propose solutions adapted to real life’, says Alba Roca, neuropsychologist and pre-doctoral researcher of the study.

Based on these results, the research team highlights that it is important to design interventions that take into account life habits as a whole. ‘It is not enough to do cognitively stimulating activities, but they must also be combined with better socialisation and the development of a life plan,’ says Roca. And it is especially important that they are personalised, because evidence shows that uniform interventions are not effective in promoting long-term change, as lifestyle habits are persistent by nature, and focusing on possible pathologies can improve adherence to change,’ he adds. This is important at any age, as lifestyles have a protective effect even in young people, but it is ‘crucial during middle age, when health problems related to the cumulative effect of an unhealthy lifestyle start to emerge,’ concludes Bartrés-Faz.