A new study of people in Europe found that having a large waist nearly doubled the risk of premature death regardless of whether they were
overweight or not and supports the idea that waist size or waist to hip ratio should be used to assess risk of death.
The study was conducted by researchers from Imperial College London, the German Institute of Human Nutrition, and other research institutions across Europe and was published on 13 November in the New England Journal of Medicine.
The researchers wrote that previous studies relied heavily on BMI (body mass index, a person's weight in kilos divided by the square of their height in metres) to assess the link between body fat (adiposity) and risk of death, but not many had looked into the effect of how the body fat is distributed.
For the study the researchers used data from 359,387 participants from 9 countries that were taking part in the European Prospective Investigation into Cancer and Nutrition (EPIC), one of the largest long-term prospective studies in the world. The average age of the participants when data were first collected was 51.5 years, and 65.4 per cent were women.
Using a statistical tool called Cox regression analysis the investigators looked for links between BMI, waist circumference, and waist-to-hip ratio with risk of death, while taking into account other factors like age, location, education, smoking, alcohol, exercise and height.
The results showed that:
- 14,723 of the participants died over a mean follow up period of 9.7 years.
- Participants with a high BMI, compared with those in the medium range, were more likely to die from cardiovascular diseases and cancer.
- Participants with a low BMI were more likely to die from respiratory diseases.
- BMI of 25.3 for men and 24.3 for women was linked to the lowest risk of death.
- After adjusting for BMI, waist circumference and waist-to-hip ratio were strongly linked to risk of death.
- The 20 per cent of participants with the largest waist circumferences (the top quintile) had waistlines measuring more than 120 cm or 47.2 in for men and more than 100 cm or 39.4 in for women.
- The 20 per cent with the smallest waist circumferences (the bottom quintile) had waists smaller than 80 cm or 31.5 in for men and less than 65 cm or 25.6 in for women.
- For every 5 cm increase in waist circumference the risk of death went up by 17 per cent in men and 13 per cent in women.
- Comparing the top quintile for men had a relative risk of death of 2.05 (95 per cent confidence interval(CI) of 1.80 to 2.33) and for women this figure was 1.78 (95 per cent CI 1.56 to 2.04).
- For waist to hip ratio the top to bottom quintile relative risks were 1.68 (95 per cent CI 1.53 to 1.84) for men and 1.51 (95 per cent CI 1.37 to 1.66) for women.
"BMI remained significantly associated with the risk of death in models that included waist circumference or waist-to-hip ratio (P
They conclude that these findings:
"Suggest that both general adiposity and abdominal adiposity are associated with the risk of death and support the use of waist circumference or waist -to-hip ratio in addition to BMI in assessing the risk of death."
In a separate statement, the team from Imperial College London wrote that the study provides strong evidence that:
"Storing excess fat around the waist poses a significant health risk, even in people not considered to be overweight or obese."
They said doctors should measure waistlines and hips as well as BMI when doing routine health checks.
The researchers found that waist to hip ratios varied widely among different countries in Europe.
They suggested that the reason increased waistlines are linked to higher risk of death could be that fatty tissue in the abdomen secretes cytokines, hormones and chemicals that are known to increase the risk of chronic diseases such as cardiovascular diseases and cancer.
The lead author of the study, Dr Tobias Pischon, a Private Docent at the German Institute of Human Nutrition in Potsdam-Rehbrücke, explained that:
"Abdominal fat is not only a mere energy depot, but it also releases messenger substances that can contribute to the development of chronic diseases. This may be the reason for the link."
The European coordinator of EPIC, professor Elio Riboli, from the Department of Epidemiology and Public Health at Imperial College London, said:
"Although smaller studies have suggested a link between mortality and waist size, we were surprised to see the waist size having such a powerful effect on people's health and premature death."
"Our study shows that accumulating excess fat around your middle can put your health at risk even if your weight is normal based on body mass index scores," he added.
Riboli said that apart from smoking and drinking there are few other individual characteristics that can increase a person's likelihood of early death.
Although the study did not look into why some people have larger waistlines the researchers suggested this was mainly due to genetic factors, physically inactive lifestyles and poor diets.
"The good news is that you don't need to take an expensive test and wait ages for the result to assess this aspect of your health - it costs virtually nothing to measure your waist and hip size."
He said if you have a large waist you should exercise every day, avoid drinking too much alcohol and improve your diet.
"This could make a huge difference in reducing your risk of an early death," he added.
"General and Abdominal Adiposity and Risk of Death in Europe
Pischon, T., Boeing, H., Hoffmann, K., Bergmann, M., Schulze, M.B., Overvad, K., van der Schouw, Y.T., Spencer, E., Moons, K.G.M., Tjonneland, A., Halkjaer, J., Jensen, M.K., Stegger, J., Clavel-Chapelon, F., Boutron-Ruault, M.-C., Chajes, V., Linseisen, J., Kaaks, R., Trichopoulou, A., Trichopoulos, D., Bamia, C., Sieri, S., Palli, D., Tumino, R., Vineis, P., Panico, S., Peeters, P.H.M., May, A.M., Bueno-de-Mesquita, H.B., van Duijnhoven, F.J.B., Hallmans, G., Weinehall, L., Manjer, J., Hedblad, B., Lund, E., Agudo, A., Arriola, L., Barricarte, A., Navarro, C., Martinez, C., Quiros, J.R., Key, T., Bingham, S., Khaw, K.T., Boffetta, P., Jenab, M., Ferrari, P., Riboli, E.
N Engl J Med, Volume 359:2105-2120, November 13, 2008, Number 20.
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Sources: NEJM, Imperial College London.
Written by: Catharine Paddock, PhD