BackgroundThe association between weight change during early adulthood and cardiometabolic diseases remains uncertain in Chinese population. Whether the association varies with comprehensive cardiovascular health (CVH) in midlife assessed by "Life's Essential 8" has not been characterized. We aim to examine the associations of early adulthood weight change and midlife "Life's Essential 8" CVH status with cardiometabolic outcomes in a Chinese cohort.MethodsThe study participants were from the China Cardiometabolic Disease and Cancer Cohort (4 C) Study. This analysis included 72,610 middle-aged and older participants followed for a median of 3.6 years. At baseline, the participants recalled body weight at age 20 and 40 years, and we calculated change in weight and BMI between 20 and 40 years of age. Health behaviors information in "Life's Essential 8" was collected by questionnaire, and health factors were measured in the study center. During follow-up, we ascertained incident cardiovascular events based on medical records, and diagnosed incident diabetes according to the American Diabetes Association 2010 criteria.Results72,610 study participants were included with a mean age of 56.0 +/- 8.8 years and 29% of them were males. Weight gain of more than 10 kg between 20 and 40 years of age was associated with 22% increased risk of incident cardiovascular events (HR: 1.22; 95%CI: 1.04-1.43) and 38% increased risk of diabetes (HR: 1.38; 95%CI: 1.25-1.53) compared to stable weight. Besides, the association of weight gain more than 10 kg in early adulthood with cardiometabolic risk was even stronger in those with low CVH score in midlife (HR: 2.44; 95%CI: 2.01-2.97 for incident cardiovascular events; HR: 2.20; 95%CI: 1.90-2.55 for incident diabetes) or with few ideal cardiovascular health metrics in midlife.ConclusionsOur study indicated that weight gain in early adulthood was associated with significantly increased risk of cardiometabolic diseases. And the association could be stronger in those with poor CVH profiles in midlife. These findings confirmed the significance of weight management during early adulthood and suggested that individuals who experienced substantial weight gain in early life should be encouraged to maintain good CVH status in Chinese population.