The risk of a patient developing venous thromboembolism (VTE) increases with their height, with taller people more likely to experience it, according to Swedish researchers.
They said their findings showed that height was an “independent predictor” for VTE in both men and women and that, as a result, it should be included in thrombosis risk assessments.
“We hope that height will come to be included in risk assessments for VTE”
The study included cohort of 1.6 million male army conscripts without previous VTE, and another cohort of 1.1 million first-time pregnant women.
By analysing the correlation between height and risk of VTE in sibling pairs as well, the researchers said they could adjust their results for other genetic similarities and familial environmental factors.
The correlation was found to be equally strong among sibling pairs, indicating that the height itself and not another factor caused the link, said the study authors.
“Compared with the tallest women (>185cm) and men (>190cm), there was a graded decreased risk by lower height for both men and women. The risk was lowest in women and men with the shortest stature (<155 and <160cm, respectively),” they said in the journal Circulation: Cardiovascular Genetics.
For example, in women aged around 60 with a height of around 155cm – just over five feet – the risk of VTE was 3%, whereas it increased to 6% for women of the same age who were over 185cm tall – slightly over six feet.
For men aged around 60 and under 160cm tall – around five feet and two inches – the risk was found to be 2%, whereas for men of the same age over 190cm – about six feet and two inches – the risk rose to 7%.
“We are… sure that our findings are of high statistical significance”
The study authors, from Lund University, noted that tall people had a higher hydrostatic pressure in the body, compared to shorter people, which could explain the findings.
They noted that the longer a person’s legs were, the longer their blood vessels needed to be, making it more difficult for blood to flow back to the heart. The slow blood flow was probably what increases the risk of thrombosis, suggested the researchers.
Lead study author Dr Bengt Zöller, associate professor at Lund, said: “We used several Swedish registers in the largest and hitherto only countrywide study. We are therefore sure that our findings are of high statistical significance.
“We hope that height will come to be included in risk assessments for VTE,” he said.
He added: “Another question which needs to be answered is whether compression hose is effective in tall individuals to counteract the increased hydrostatic pressure. The new findings give rise to more in depth research.”