This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'Changes in occurrence of disease over very long period of time is \nSelect and explain. \nA. Modern epidemic, B. Seasonel trend, C. Secular trend, D. Propagatedepidemics', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Long-term or secular trends The term "secular trend" implies changes in the occurrence of disease (i.e., a progressive increase or decrease) over a long period of time, generally several years or decades. Although it may have sho-term fluctuations imposed on it, a secular trend implies a consistent tendency to change in a paicular direction or a definite movement in one direction. Examples include coronary hea disease, lung cancer and diabetes which have shown a consistent upward trend in the developed countries during the past 50 years or so, followed by a decline of such diseases as tuberculosis, typhoid fever, diphtheria and polio. Ref : Park 23rd edition Pgno : 66', 'role': 'assistant'}]