A recent study made in China/USA published by Zhang and colleagues revealed that increase of body mass index (BMI) during adolescence has a high correlation with adult type 2 diabetes (insulin-dependent). The importance of this study is due to the relevance of the disease, which in the USA has reached epidemic proportions: one in three Americans will have diabetes by the year 2050.
Body mass index is a parameter to measure the tissue composition of the organism, divided in muscle, fat and bone. It derives from the mass (weight) and height of an individual. The BMI is defined as the body mass divided by the square of the body height, and is expressed in kg/m2. The commonly accepted ranges of BMI are the following: underweight if BMI<18.5 kg/m2, normal weight if BMI is between 18.5 and 25, overweight if BMI is between 25 and 30, obese if BMI>30.
It was already known a correlation between high BMI levels in childhood and diabetes in adult age, but Zhang and colleagues surprisingly reveal that the correlation between BMI and diabetes doesn’t depend on the level of BMI, but on its way of growing (although higher BMI in childhood makes the person more prone to develop diabetes). The study shows that that if the BMI at the age between 10–19 years grows linearly, there is a higher risk to have hyperglycaemia (high levels of glucose in blood) in adult age, which is the step before type II diabetes.
Why BMI increase during teenage correlates to diabetes?
Because this is the time when sexual maturation occurs. A complex interplay between various gonadal and adrenal steroid hormones arises, and it has been shown that they affect glucose and insulin levels during adolescence, independently of adiposity.
Therefore, adolescence is a critical temporal window for BMI control to reduce the risk of adult hyperglycaemia.
The main article:
Zhang, T., Xu, J., Li, S. et al. Trajectories of childhood BMI and adult diabetes: the Bogalusa Heart Study. Diabetologia (2019) 62: 70. https://doi.org/10.1007/s00125-018-4753-5
Zhang T, Zhang H, Li Y et al (2017) Long-term impact of temporal sequence from childhood obesity to hyperinsulinemia on adult metabolic syndrome and diabetes: the Bogalusa Heart Study. Sci Rep 7(1):43422.
Jiang X, Srinivasan SR, Dalferes ER, Berenson GS (1997) Plasma insulin-like growth factor 1 distribution and its relation to blood pressure in adolescents: the Bogalusa Heart Study. Am J Hypertens 10(7):714–719.
Srinivasan SR, Freedman DS, Sundaram GS et al (1986) Racial (black-white) comparisons of the relationship of levels of endogenous sex hormones to serum lipoproteins during male adolescence: the Bogalusa Heart Study. Circulation 74(6):1226–1234.