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.

The results also supported earlier findings that BMI is strongly linked to risk of death in that, as the authors explained:

“BMI remained significantly associated with the risk of death in models that included waist circumference or waist-to-hip ratio (P

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Sources: NEJM, Imperial College London.

Written by: Catharine Paddock, PhD