<prompt> The changes occuring in the disease frequency over many years is calledCyclic trendSeasonal trendSecular trendNone of the above  <response>: . long term or secular trends implies changes in the occurrence of disease over a long period of time.generally several years or decades.a secular trend implies a consistent tendency to change in a paicular direction or a definitive movement in one direction. ref:park;s textbook,ed 22,pg no 63 