According to the World Health Organization, around one in 20 adults experience depression, a condition that poses a significant public health burden worldwide. The keys that influence the onset of depression are complicated to unravel in each case, but include a combination of biological and lifestyle factors that are considered modifiable targets that can be used to counteract the increasing prevalence of depression.
An international team led by the University of Cambridge and Fudan University (Shanghai) looked at a combination of factors including lifestyle factors, genetics, brain structure, and our immune and metabolic systems to identify underlying mechanisms that could explain this link.
The conclusions of this research, which have been published in Nature Mental Health, point out that a healthy life style That involves moderate alcohol consumption, a healthy diet, regular physical activity, healthy sleep and frequent social connection, while avoiding smoking and excessively sedentary behavior, reduces the risk of depression.
To better understand the relationship between these factors and depression, researchers turned to the UK Biobank, a biomedical database and research resource containing anonymized genetic, lifestyle and health information on its participants. By examining data from 287,282 people, of whom 13,000 had depression, followed over a nine-year period, the team was able to identify Seven healthy lifestyle factors linked to lower risk of depression in a population with varied genetic risk:
- Moderate alcohol consumption
- Eat a healthy diet
- Perform physical activity regularly
- Have a healthy sleep routine
- never smoke
- Low to moderate sedentary behavior
- Maintain frequent social connections
Of all these factors, sleep well (seven to nine hours a night) made the biggest difference, reducing the risk of depression, including single depressive episodes and treatment-resistant depression, by 22%.
The frequent social connectionwhich overall reduced the risk of depression by 18%, was most protective against recurrent depressive disorder.
For its part, moderate alcohol consumption reduced the risk of depression by 11%, eating a healthy diet by 6%, and regular physical activity by 14%. never smoke by 20% and low to moderate sedentary behavior by 13%.
Based on the number of healthy lifestyle factors an individual followed, they were assigned to one of three groups: unfavorable, intermediate and favorable lifestyle. Individuals in the intermediate group were about 41% less likely to develop depression compared to those with an unfavorable lifestyle, while those in the favorable lifestyle group were 57% less likely.
The team then examined the participants’ DNA and assigned each a genetic risk score. This score was based on the number of genetic variants an individual carries that have a known link to depression risk. Those with the lowest genetic risk score were 25% less likely to develop depression compared to those with the highest score, a much smaller impact than lifestyle.
In people with high, medium and low genetic risk of depression, the team also found that a healthy lifestyle can reduce the risk of depression. This research underscores the importance of leading a healthy lifestyle to prevent depression, regardless of a person’s genetic risk.
The teacher Barbara Sahakianfrom the Department of Psychiatry at the University of Cambridge, said: “Although our DNA (the genetic hand we have been dealt) may increase our risk of depression, we have shown that a healthy lifestyle is potentially more important.”
“Some of these lifestyle factors are things we have some control over, so we try to find ways to improve them: making sure we get a good night’s sleep and go out to see friends, for example, which could make a real difference in people’s lives.
They explain why a healthy lifestyle reduces the risk of depression
To understand why a healthy lifestyle might reduce the risk of depression, the team studied other factors. First, they examined brain MRIs of just under 33,000 participants and found a series of brain regions where greater volume (more neurons and connections) was related to a healthy lifestyle. These included the pallidum, thalamus, amygdala, and hippocampus.
Next, the team looked for markers in the blood that indicated problems with the immune system or metabolism (how we process food and produce energy). Among the markers found to be related to lifestyle are C-reactive protein, a molecule produced in the body in response to stress, and triglycerides, one of the main forms of fat that the body uses to store energy for more. forward.
These links are supported by a number of previous studies. For example, the exposure to stress in life can affect our ability to regulate blood sugar, which can lead to impaired immune function and accelerate age-related damage to the body’s cells and molecules. The poor physical activity and lack of sleep They can damage the body’s ability to respond to stress. Loneliness and lack of social support have been found to increase the risk of infection and increase markers of immunodeficiency.
A poorer lifestyle affects our immune system and metabolism, which in turn increases our risk of depression
The team found that the pathway from lifestyle to immune and metabolic functions was the most important. In other words, a poorer lifestyle affects our immune system and metabolism, which in turn increases our risk of depression.
The Dr. Christelle Langley, also from the Department of Psychiatry at the University of Cambridge, said: “We are used to thinking that a healthy lifestyle is important for our physical health, but it is equally important for our mental health. “It is good for brain health and cognition, but also indirectly by promoting a healthier immune system and better metabolism.”
The teacher Jianfeng Fengfrom Fudan University and the University of Warwick, added: “We know that depression can begin as early as adolescence or early adulthood, so educating young people about the importance of a healthy lifestyle and its impact on mental health must begin in schools.
Source: University of Cambridge