OBJECTIVE:Historically, many children and adolescents with sickle cell disease (SCD) were underweight. Treatment advances like hydroxyurea have been associated with improved growth. We hypothesized that increased hemoglobin (Hb) levels would be associated with increased weight status of children with SCD. METHODS:Investigators at 6 institutions conducted a retrospective chart review of all patients aged 2 to 19 years of age for the calendar years 2007-2009. Height, weight, baseline Hb levels, demographic information, and select comorbidities were recorded from the most recent clinic visit. Overweight and obesity were defined as >/=85th and >/=95th BMI percentiles for age and gender, respectively, and underweight was defined as sample, 22.4% were overweight or obese, whereas only 6.7% were underweight. Overweight or obese status was associated with sickle genotypes other than Hb SS or Hb Sbeta0 disease, and were associated with higher baseline Hb levels. Underweight individuals were more likely to be male, older, and have had at least 1 SCD-related complication. After adjusting for demographic factors, any SCD-related complication, SCD-directed treatments, and obesity-related conditions, there was a 36% increased odds of overweight/obesity for each 1 g/dL increase in baseline Hb levels. CONCLUSIONS:Nearly one-quarter of children and adolescents with SCD in New England are overweight or obese. Longitudinal studies are needed to determine the impact of elevated BMI on the morbidity and mortality of both children and adults with SCD.