New BMI thresholds for ethnic minorities

Researchers from the University of Glasgow have suggested new BMI thresholds for defining overweight and obese individuals in ethnic communities. In an attempt to define new thresholds, researchers from the University of Glasgow analysed data on nearly half a million people who participated in UK Biobank.

They found that the rate of diabetes observed among whites classified as obese with a BMI 30, was matched by South Asians with a BMI 22, Chinese with a BMI 24 and Black people with a BMI 26. This finding supports the use of lower BMIs to define obesity in these differing groups (Figure 1).

“This study confirms that we need to apply different thresholds for obesity interventions for different ethnic groups. If not, we are potentially subjecting non-white groups to discrimination by requiring a higher level of risk before we take action,” said Professor Jill Pell, Director of the Institute of Health and Wellbeing. “Furthermore, a blanket figure for all non-white groups is inappropriate. We need to apply different thresholds for South Asian, black and Chinese individuals.”

Presently, a BMI 30 or above is defined as obese but South Asian, Chinese and black populations have an equivalent risk of diabetes at lower BMIs than white people. The UK’s National Institute of Clinical Excellence has previously issued guidance on the subject to health professionals but recommended that further studies be undertaken to define the thresholds for ethnic minorities.

They used baseline data on the 490,288 participants from the four largest ethnic subgroups: 471,174 (96.1%) white, 9,631 (2.0%) South Asian, 7,949 (1.6%) black, and 1,534 (0.3%) Chinese. Regression models were developed for the association between anthropometric measures (BMI, waist circumference, percentage body fat, and waist-to-hip ratio) and prevalent diabetes, stratified by sex and adjusted for age, physical activity, socioeconomic status, and heart disease.

Among women, a waist circumference of 88cm in the white subgroup equated to the following: South Asians, 70cm; black, 79cm; and Chinese, 74cm. Among men, a waist circumference of 102 m equated to 79, 88, and 88cm for South Asian, black, and Chinese participants, respectively (Figure 1).

The study also showed the differences between South Asian sub-groups were small. The new BMI cut-offs were 21.5 in Pakistani men compared with 22.0 in Indian men, and 21.6 in Pakistani women compared with 22.3 in Indian men. Therefore, it would seem reasonable to apply the same cut-offs across all South Asian communities. The results are published online in the journal Diabetes Care.

“Obesity is the main cause of the worldwide increase in diabetes. Intervening at lower obesity cut-points in people from non-white descent could save many lives,” said Uduakobong Efanga Ntuk, a PhD student who conducted a large part of the research. “Diabetes prevention programs need to be ethnic specific. People from South Asian, Chinese and black descent need to be made aware that they are at a higher risk of diabetes. By adopting a healthy lifestyle including physical activity and a healthy diet, they can significantly reduce their risk.”


This information was originally published by bariatricnews.net

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