Which of the following is true about Secular trend -: (A) Road side accident is a good example, (B) Due to environmental factors, (C) Is due to normally occuring variation in herd immunity, (D) Consistent change in a paicular direction over a period of time
Answer is D. Ans. is 'd' i.e., Consistent change in a paicular direction over a period of time The term 'Secular trend' implies changes in the occurrence of disease i.e. a progressive increase or decrease in incidence over a long period of time, such as several years or decades.