A study has found that men with a high BMI in their upper teens had an elevated risk of severe COVID-19, requiring hospitalisation later in life.
Body mass index (BMI) is a measure that uses height and weight to work out if your weight is healthy. A high BMI can mean you are overweight, obese, or severely obese. Regarding COVID-19, being overweight or obese is a recognised risk factor for severe COVID-19, however, there have been no conclusive studies that monitor large groups of individuals whose obesity was identified at an early age, and to understand the effect of COVID-19 infection.
The study analysed the relationship between upper teenage men with a high BMI with the risk of severe COVID-19 infection and was carried out by the University of Gothenburg.
The research is published in the journal Obesity.
Studying the association between high BMI and Covid
The research includes data from the Swedish Military Service Conscription Register on 1,551,670 men in Sweden, born between 1950 and 1987, who were recruited for military service in the period 1969-2005. At the outset, their height and weight were measured.
The researchers merged the conscription data with three Swedish medical registers – the National Patient Register, the Intensive Care Register, and the Cause of Death Register – revealed a clear connection between high BMI in adolescence and the risk of getting COVID-19, many years later, severely enough to require hospitalisation. A clear link was found between high BMI in upper teens and needing intensive care for the disease.
For the study, scientists divided the men into six groups, from underweight (BMI 15–18.5) to three levels of normal weight (18.5–20, 20–22.5 and 22.5–25), followed by overweight (25–30) and obesity (BMI of 30 or more). Of the whole group during the study year (2020), 4,315 men with COVID-19 required hospitalisation; 729 of them received intensive care, and 224 died from COVID-19.
Astoundingly, the study found that even men who had been in the 22.5-25 BMI range in adolescence had an elevated risk of needing hospital care for COVID-19. The need increased continuously with high BMI results from the time of conscription 15 to 50 years earlier.
“At population level, we can see that being overweight in the late teens raises the risk of hospitalisation and intensive care for COVID-19. For those with teenage obesity, the risk of admission to an intensive care unit is more than twice as high as for those with a BMI of 18.5–20,” said Josefina Robertson. A researcher at Sahlgrenska Academy, University of Gothenburg, a doctor specialising in infectious diseases at the Sahlgrenska University Hospital and the first author of the study.
Her colleague Maria Åberg is an associate professor at the School of Public Health and Community Medicine at Sahlgrenska Academy; a physician specialising in general medicine in the regional health, part of Region Västra Götaland, and the last author of the study.
“Several studies have identified overweight as a risk factor for becoming severely ill with COVID-19, and we’re now showing that overweight and obesity even in early life plays a part,” Åberg said.
Adverse impact on the immune system
It is well known that being obese with a high BMI can be linked to an elevated risk of becoming severely ill from various infectious diseases, such as influenza. Obesity has an adverse impact on the immune system and worsens a person’s propensity for inflammation, which can contribute to more serious infections.
In the present study, the early BMI values were found to accompany the men up to middle age. This is evident from the data from health tests known as health-profile assessments, devised by the Health Profile Institute (HPI), for 151,693 of the participants.
Josefina Robertson comments: “It’s interesting to see that the men’s BMI in adolescence is a risk factor for severe COVID-19 many years later. A high BMI in the men’s teens also persisted into middle age, which is a trend that other studies have shown as well. That’s why it’s important to take preventive measures against obesity even at a young age, especially ahead of future viral pandemics.”