Non-linear relationship between birthweight and cardiometabolic risk factors in Chinese adolescents and adults

To investigate the relationship between birthweight and cardiometabolic traits in two cohorts: one of Chinese adolescents and one of Chinese adults.

Birthweight and clinical data, including anthropometric traits, fasting plasma glucose and fasting plasma insulin levels, blood pressure and lipid profiles were collected from 2035 adolescents and 456 adults. A subset of 735 subjects underwent an oral glucose tolerance test to measure the glucose and insulin concentrations at 0, 15, 30, 60 and 120 min.

Among adolescents, birthweight showed U-shaped relationships with larger body size, obesity, abdominal obesity in girls, insulin resistance and worse lipid profiles (0.0013 < P(quadratic) < 0.0499), as well as an inverse association with fasting plasma glucose (P(linear) = 0.0368). After further adjustment for adiposity, decreasing birthweight was associated with elevated fasting plasma glucose levels, greater insulin resistance and worse lipid profiles (3.1 × 10⁻⁵ < P(linear) < 0.0058). Among adults, high birthweight was associated with larger body size and abdominal obesity in men, while low birthweight was associated with elevated glucose levels at 15, 30, 60 and 120 min and a greater area under the curve at 0-120 min, as well as with β-cell dysfunction (6.5 × 10⁻⁵ < P(linear) < 0.0437). Adjustment for adult adiposity did not substantially change the relationships. There was significant interaction between birthweight and abdominal obesity in elevating fasting plasma insulin and homeostasis model assessment of insulin resistance (P > 0.05), with abdominally obese adolescents in the lowest birthweight category (≤ 2.5 kg) having the highest risk of insulin resistance.

Both high and low birthweights are associated with an increased risk of cardiometabolic abnormalities including obesity, abdominal obesity, hyperglycaemia, dyslipidaemia and insulin resistance, as well as with β-cell dysfunction.