This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'Secular trend means - \nSelect and explain. \nA. Seasonal changes, B. Periodical changes, C. Religion changes, D. Long term changes', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Long term or secular trends \n\nThe term secular trend implies changes in the occurrence of disease over a long period of time, generally several years or decades.\nThere may be progressive increase or decrease in the occurrence of disease.\n\nExamples -\n\nCHD, lung cancer, and DM have shown a consistent upward trend in developed countries.\nTB, typhoid fever, diphtheria and polio have shown a declined trend in developed countries.', 'role': 'assistant'}]