International variationsTheserecommended distinctions along the linear scale may vary from time totime and country to country, making global, longitudinal surveysproblematic. In 1998, the U.S. National Institutes of Health brought U.S. definitions into line with World Health Organizationguidelines, lowering the normal/overweight cut-off from BMI 27.8 to BMI25. This had the effect of redefining approximately 30 millionAmericans, previously "healthy" to "overweight".[citation needed]It also recommends lowering the normal/overweight threshold for SouthEast Asian body types to around BMI 23, and expects further revisionsto emerge from clinical studies of different body types.
InSingapore, the BMI cut-off figures were revised in 2005 with anemphasis on health risks instead of weight. Adults whose BMI is between18.5 and 22.9 have a low risk of developing heart disease and otherhealth problems such as diabetes. Those with a BMI between 23 and 27.4are at moderate risk while those with a BMI of 27.5 and above are athigh risk of heart disease and other health problems.[1 |