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Higher thrombus risk in men who had obesity in adolescence

Updated: Feb 15, 2023

Men who had obesity in their late teens are more at risk of venous thromboembolism (VTE) in the leg or lung in adult life, according to a study from the University of Gothenburg study. The risk rises successively and is highest in those who had severe obesity in adolescence. The outcomes were reported in the paper, 'Obesity in adolescent men increases the risk of venous thromboembolism in adult life', published in the Journal of Internal Medicine.

The study examined data from 1,639,838 men who enlisted for military service in Sweden in the years 1969-2005. Their average age on enlistment was just over 18 years. These individuals were followed up using patient and cause-of-death registers. They reported 29,342 had obesity and 7,236 had severe obesity.

with men with a BMI of 18.5 to <20 kg m−2, men with higher BMI in young adulthood showed an incrementally increasing risk of VTE that was moderately but significantly increased already at normal BMI levels. Adolescent obese men with a BMI of 30 to 35 kg m−2 had an adjusted hazard ratio of 2.93 (95% confidence interval, 2.65 to 3.24) for VTE. Severely obese men with a BMI of ≥35 kg m−2 had a hazard ratio of 4.95 (95% confidence interval, 4.16 to 5.90).

During the follow-up period, with a median duration of 28 years, thrombus in the leg or lung was registered among just over 1 percent (n=18,665) of the study participants: there were 11,395 cases of deep vein thrombosis and 7,270 cases of pulmonary embolism. A successive rise in VTE risk was also observed in the group in the middle and the upper part of the normal BMI range (20-25), compared with the lower part of the normal range (18.5-20).

In the group with obesity, the relative risk was 2.93 compared with the reference group in the study - over twice as high. For those with severe obesity, the corresponding relative risk was 4.95, a nearly fivefold risk for VTE in the leg or lung during the follow-up period.

“Up to now, the association between VTE and obesity has been studied mainly in populations where BMI is measured relatively late in life. By then, the study participants may have developed obesity-related diseases, such as certain forms of cancer, that also affect their thrombus risk,” said Katarina Glise Sandblad, a PhD student at Sahlgrenska Academy, University of Gothenburg, a resident physician specializing in internal medicine at Sahlgrenska University Hospital and the first author of the study. “Consequently, there's a danger of underestimating the risk from obesity. As obesity and severe obesity become more prevalent among children and adolescents, it's increasingly important to study the long-term risks involved.”

“In this study, men who in young adulthood were overweight or obese showed a substantial risk increase for development of VTE later in life compared with lean men. The underlying mechanisms for this association remain to be elucidated,” the authors concluded. “A clinical implication of our findings is that overweight and obesity in young adulthood is an important risk factor for later development of VTE later in life. Given the current global obesity epidemic, this will lead to great suffering and large costs for society. Action should be taken to reduce overweight and obesity early in life.”

Although the current study covers only men, the patterns and associations found are probably similar for women, in the research group's opinion. The researcher team led by Professor Annika Rosengren, Professor of Medicine at the University of Gothenburg. The group has previously conducted studies of obesity and outcomes other than VTE, such as heart attack, stroke, heart failure and cardiomyopathy, where similar patterns in both men and women have been observed.

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