Determine if an Entity is Published Without Loading the Node

A method to quickly determine if a Drupal entity is published without loading the whole node.

/**
 * Determines if an entity is published without loading the whole node.
 *
 * @param $nid
 *  The nid of the entity to check.
 * @return
 *  Returns 1 if the node is published, 0 if not.
 */
protected function isPublished($nid) {
  $sql = "SELECT status FROM {node} WHERE nid = :nid LIMIT 1";
  return (db_query($sql, array(':nid' => $nid))->fetchField()) ? TRUE : FALSE;
}