Plasma adiponectin was measured among a subset of participants in the NHS and HPFS using the enzyme-linked immunosorbent assay (ALPCO Diagnostics, Salem, NH)31 (link), 33 or competitive radio-imunoassay (Linco Research Inc, St Charles, Mo)32 (link), 34 (link), as previously described. Quality-control samples were randomly interspersed and personnel who were blinded to quality-control status conducted all assays. The coefficients of variation from quality control samples ranged from 3.4–13.0%. To account for potential variation across batches, we corrected plasma adiponectin for measurement batch according to the average batch correction method with adjustment for age and body mass index (BMI)36 (link).