Obesity has been related to subclinical inflammation and decreased levels of adiponectin. We examined the relationship between inflammatory markers and adiponectin and the change in body mass index (BMI) between childhood and adulthood. Our study included 368 subjects (176 men and 192 women) from a population-based cohort whose weight and height had been recorded at the age of seven years. They participated in this study as adults (with a mean age of 46 years); levels of adiponectin, interleukin-1 receptor antagonist (IL-1 Ra) and high-sensitivity C-reactive protein (hs-CRP) were measured. The relative change of BMI from childhood to adulthood was significantly associated with levels of IL-1 Ra (men: r=0.27 [95% CI: 0.12 to 0.40] and women: 0.64 [0.55 to 0.72]), hs-CRP (r=0.15 and 0.52, respectively) and adiponectin (r=-0.13 and -0.29, respectively) in both genders. Decreased levels of adiponectin and elevated levels of IL-1 Ra and hs-CRP at adulthood appear to be related to the change in BMI between childhood and adulthood.