Schleicher RL, Sternberg MR, Potischman N, et al. - As indicated by data from the 2007–2010 NHANES, there is a contribution of vitamin D supplements to elevated serum levels of 25-hydroxyvitamin D [25(OH)D] in the US population, researchers herein investigated if 25(OH)D keep on increasing during NHANES 2011–2014 and if links of 25(OH)D with preselected covariates varied across time periods. They recorded 25(OH)D among adults (≥20 y) using LC-MS/MS. Employing a multiple linear regression model, evaluation of 25(OH)D alterations between two 4-y survey periods, namely 2007–2010 and 2011–2014, was conducted. According to findings, the overall adjusted increment in 25(OH)D was no more statistically significant following adjustment for vitamin D supplement dose. This implies that alterations in 25(OH)D levels of US adults between NHANES periods 2007–2010 and 2011–2014 may primarily be related to alterations in vitamin D supplementation.