The Prevalence of Metabolically Unhealthy Normal Weight and Its Influence on the Risk of Diabetes

Diabetes is a major health problem and metabolically unhealthy is an important risk factor.To conduct the first nationally representative study on epidemiological data of metabolically unhealthy normal weight (MUNW) focused only on nondiabetic subjects and determine the predictive effect on diabetes in China.A longitudinal study was conducted using data from the Rich Healthcare Group in China. Metabolic status was determined by the revised National Cholesterol Education Program Adult Treatment Panel III criteria, and individuals with 2 or more criteria were categorized as MUNW and diagnosed with metabolic syndrome (MetS) if they met 3 or more.Of a total of 63 830 nondiabetic normal-weight individuals, 8935 (14.0%) were classified as MUNW and 1916 (3.00%) were diagnosed with MetS. After adjusting for potential confounders, individuals with MUNW had a greater diabetes risk (4.234, 95% CI 3.089-5.803) than those without MUNW during an average of 3.10 years of follow-up. Also, the multivariable-adjusted hazard ratios for developing diabetes were 3.069 (95% CI 1.790-5.263), 7.990 (95% CI 4.668-13.677), and 11.950 (95% CI 6.618-21.579) for participants with 1, 2, and 3 or more components, respectively, compared with those without any components. Further analyses suggested that the number of MetS components present is associated with the risk of diabetes, especially in metabolically unhealthy normal-weight young male adults. Multivariable-adjusted hazard ratios (95% CI) for incident diabetes among individuals with 1, 2, and at least 3 components were 4.45 (1.45-13.72), 9.82 (3.05-31.64), and 15.13 (3.70-61.84) for participants aged ≤44 years, and 3.55 (1.81-6.97), 8.52 (4.34-16.73), and 13.69 (6.51-28.77) for male participants, respectively.The prevalence of MUNW is 14% in Chinese normal-weight nondiabetic individuals, and active intervention is necessary for this category of people. The presence of MUNW significantly increases the risk of diabetes, and the risk of diabetes is associated with the number of MetS components present in the patient.