Do rapid BMI growth in childhood and early-onset obesity offer cardiometabolic protection to obese adults in mid-life? Analysis of a longitudinal cohort study of Danish men

OBJECTIVE Some obese individuals have no cardiometabolic abnormalities; they are 'metabolically healthy, but obese' (MHO). Similarly, some non-obese individuals have cardiometabolic abnormalities, that is, 'metabolically at risk, normal weight' (MANW). Previous studies have suggested that early-onset obesity may be associated with MHO. We aimed to assess whether body mass index (BMI) in childhood and early-onset obesity are associated with MHO. SETTING General population longitudinal cohort study, Denmark. PARTICIPANTS From 362 200 young men (mean age 20) examined for Danish national service between 1943 and 1977, all obese men (BMI ≥31 kg/m(2), N=1930) were identified along with a random 1% sample of the others (N=3601). Our analysis includes 2392 of these men attending a research clinic in mid-life (mean age 42). For 613 of these men, data on childhood BMI are available. We summarised childhood BMI growth (7-13 years) using a multilevel model. Early-onset obesity was defined as obesity at examination for national service. OUTCOME MEASUREMENT We defined metabolic health at the mid-life clinic as non-fasting serum cholesterol <6.6 mmol/L, non-fasting glucose <8.39 mmol/L and pulse pressure <48 mm Hg. Participants were categorised into four groups according to their obesity (BMI ≥30 kg/m(2)) and metabolic health in mid-life. RESULTS 297 of 1097 (27.1%) of obese men were metabolically healthy; 826 of 1295 (63.8%) non-obese men had at least one metabolic abnormality. There was no evidence that rapid BMI growth in childhood or early-onset obesity was associated with either MHO or the MANW phenotype, for example, among obese men in mid-life, the OR for MHO comparing early-onset obesity with non-early-onset obesity was 0.97 (95% CI 0.85 to 1.10). CONCLUSIONS We found no robust evidence that early-onset obesity or rapid BMI growth in childhood is protective for cardiometabolic health.