Life-long body mass index trajectories and cardiometabolic biomarkers-the Danish diet, cancer, and health-next generations cohort.

Background/objectives: Higher body mass index (BMI) is strongly associated with cardiovascular metabolic diseases, however, BMI changes across the lifespan may be complex and non-linear. Furthermore, heterogeneous BMI trajectories may exhibit different cardiometabolic traits. We aimed to identify BMI trajectories over up to 50 years and examine their associations with cardiometabolic biomarkers.

Subjects/methods: In total, 30,581 participants from the Danish Diet, Cancer and Health - Next Generations cohort were included in the study. Participants recalled their weight history for each decade through questionnaires. Weight and height were measured, and blood samples were collected during a clinic visit. Cardiometabolic biomarkers (Hemoglobin A1c, total cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, C-reactive Protein, and creatinine) were determined. Latent class growth models were applied to model BMI trajectories from age 20 until the current age. The optimal number of groups was selected according to Bayesian Information Criteria, the integrated completed likelihood, and the mean posterior probability of each group. Linear and logistic regression models were used to examine the association between distinct BMI trajectories and cardiovascular biomarkers, with adjustment for age, sex, and smoking status.

Results: Four distinct BMI trajectories were identified: "Stable low BMI" group (32%, n = 9753), "Gradual BMI increase" (45%, n = 13,780), "Early high BMI" group (3%, n = 771), and "Steeper BMI increase" group (21%, n = 6277). Compared to the "Stable low BMI" group, all other trajectory groups showed significant associations with adverse cardiometabolic biomarkers. For instance, the "Steeper BMI increase" group was associated with elevated triglycerides (β = 0.36 mmol/L, 95% CI: 0.34, 0.38), followed by the "Early high BMI" group (β = 0.30 mmol/L, 95% CI: 0.26, 0.34) and the "Gradual BMI increase" group (β = 0.12 mmol/L, 95% CI: 0.11, 0.13).

Conclusion: Both those with constant high BMI and steeply increased BMI trajectories from age 20 had more unfavorable cardiometabolic profiles compared to those maintaining lower BMI throughout adulthood.