<prompt> Secular trend is shown by -Epidemics of measlesCoronary heart diseaseDengue feverAll of the above  <response>: Ans. is b i.e., Coronary heart disease The term secular trend implies changes in the occurrence of disease over a long period of time, generally several years or decades. There may be progressive increase or decrease in the occurrence of disease. Examples -i CHD, lung cancer, and DM have shown a consistent upward trend in developed countries.ii TB, typhoid fever, diphtheria and polio have shown a declined trend in developed countries. 